So I took FMC #850 out for a family cruise last weekend over to the in-laws house for a bbq, maybe an 8 mile round trip is all, 75-80 degree Spring day. It was my girlfriend and my daughters first time riding in it (I've been working on 850 in the driveway for the last two years!) They both loved sitting in the front seat looking out at the world. It's a completely different experience driving and riding in an FMC coach then a standard class A motorhome. We stopped at the gas station and I put 25.00 of non-ethanol fuel in it for kicks. Everything was working great, the only issue I was feeling was a mild flat/dead spot on acceleration from a stop, and at times it would not build rpms real fast with the throttle hammered. Like the 440 was a little loaded up?, OR was it running too lean?? (These were thoughts that were running through my head at the time). It could be caused by multiple things, I will dive into that after I fix my vapor lock issue. Anyway, upon leaving the In-laws bbq, after showing off the rig, and getting ohh's and ahh's. We loaded back up. As I was getting in and about to start 850 up, I happily said to Kt, "I'm really feeling good and confident about the old FMC", (After all, I just got done with ALL the mechanical maintenance you can almost do to a motorhome's running gear!!!) So we headed out, got about two miles down the road, then bam! 850 starts obviously starving for fuel, luckily I was able to nurse the throttle through a few lonnngggg stale green stop lights that we got lucky on, and didn't have to stop before turning onto the old back streets of neighborhood that we live in. So as I still nurse the throttle, I see my house is in sight! Going to make it to the driveway! Nope! Died flat on her a$$ one block from the house. I put on the four ways, ran to the back and opened her up (rear engine Chrysler 440), first thing I did was unscrew the fuel filter canister and found only a table spoon on the bottom (should of been full of fuel), and the filter looked like new still. I put the filter back together quickly, took the air filter housing loose on top of the carb (Thermoquad) and pumped the throttle by hand to listen for fuel. I didn't hear any fuel spraying, so I pumped it maybe ten times then I heard fuel spraying!! yay! Closed the rear doors, run to the front and she fired right up! Kt looked at me and said, "Damn, you are good?" I laughed hahaha.
In my history with a manual fuel pump motor vapor locking, I've never been able to get them started back up and running "on there own" until they cool off, like 30 minutes. 850 was only shut down/out of service/capput for 1-2 minutes in the middle of the road. So by me opening the fuel filter before the manual pump release pressure? Or? Why would the carb start pumping fuel again? Where did the fuel come from? Kinda weird.
What I did different with the fuel system before this "Sunday Drive", was I installed a 3-port fuel filter "after" the manual pump, 5/16" in and out, 1/4" vapor port to return to tank (I read that this style of system prevents vapor lock) I didn't have my new vented fuel cap arrive in the mail yet, so I left the old factory gas cap loose so the tank would vent. Even with the original straight fuel line from the pump to the carb, I think it would have still vapor locked, but who knows, this was the warmest temp day I've driven it so far.
The fuel pump that is on the 440 is old, I don't know what pressure it's pushing either, I need to go pick up an inline gauge and check. But in my history trying to stop vapor lock situations, replacing the manual pump never solved it. So I need to just go electric. I want to run the best pump available, should I buy the Red Holley and regulator? Or?? We have a Red Holley on our 1986 P30 rig, it's been working well, but kinda loud, the P30 also has a built in fuel return system in the manual pump. The 440 does not, that pump will have to go, and put a fuel pump block off plate on.
Which electric fuel pumps and regulators do you run? And at what pressure is your Thermoquad happy at?
Thank you
You have a rear engine, where is the gas tank? I would question the fuel pump before condemning the entire fuel system. An old pump is bound to be weak so it could very well be lack of fuel from a bad pump. The fact that you had no vapor pressure when you opened up the system makes me believe that you did not have vapor lock.Vapor lock is caused by gas boiling in the lines and with the rear engine I don't see the lines getting much preheat from the engine heat and exhaust going back towards the tank like a front engine system where the tank and lines are all downstream of the heat source.
The gas tank is in front of the engine on the other side of the firewall. I am picking up a new in line fuel pressure gauge and seeing what I have for fuel pressure first before spending any money on parts etc...It could very well be that old pump. Im sure the pump was new when the engine was rebuilt in the early 90's, but it sat for 17 years before I purchased it!! W% I will know more info in a couple days.
I'm with Rick on this one.
Fixed! For starters, don't believe everything you read on the internet! I read that putting this 3-port filter on after the fuel pump would keep fuel moving enough to help with vapor lock issues....well it killed my fuel pressure. I put a gauge on it, and I was getting 0-to barely 3pounds, when I crimped the 1/4" vapor line coming out of the filter, I have a solid 7 pounds going to the carb. W% So I was starving the engine of fuel, resorting in my sluggish acceleration and slow rpm build under load. AND it mildly vapor locked due to not enough pressure and volume. So yes Rick and MJ, it was definitely a pump issue caused by my own dumb doing. I am going to leave the mechanical pump on, and go back to the stock single 5/16" line straight to the carb, and I will carry a spare pump in the rig. Not going to redesign the fuel system anytime soon. Thanks
As you had not been driving the rig steadily, This is not really applicable, But when any problem arises , Go to the last thing you did to that system , And that is usually where you will find your problem D:oH! Frank
I know that Frank. Don't make me feel any dumber for my mistakes. N:( Hey! If it weren't for trial and error, we wouldn't have this great panel of "experts" here at CWVRV!! :D
Did anyone mention to go back to the last thing you did? :)rotflmao :)rotflmao :)rotflmao
Even if the panel of experts did write that Rick, It wouldn't of mattered? Who listens to advise anymore? :) hahaahahaha
Or Advice :)rotflmao :)rotflmao :)rotflmao Frank
So here's a bump/update on this thread....
Rick, I tested my fuel pump for volume today, I get a 1/2 pint at 30 seconds of engine run time at idle. That's half of what I should be getting? Correct? All my fuel system before the pump is in great condition. Now for my reasoning for checking fuel pump volume. So today was a great cruise day, with my fresh tires and a bunch of other stuff done, I wanted to get her out for some shake down runs. She runs great all over town, stop light to stop light, outside temp was in the 80's. BUT, when you hammer down on the throttle to get up to say 55mph like on a highway on ramp, the engine would just fall flat about 3/4's of the way up to highway speed, I could back off the throttle and it would hold a 40 mph line, then smooth up and be fine, until I wanted to try and get back up to 55. I know it was running out of fuel, but I also had NO vapor lock issues in town. So I think I need another pump. This pump puts out just shy of 7 pounds (good),but weak volume.
Well, here is your answer, short and sweet, you need a new pump.
Now the long explanation of why. Pressure is a product of volume against resistance. Your pump puts out a measured volume and it is produced with a diaphragm being pushed by a spring. The camshaft in the engine forces the diaphragm up which draws gas from the tank and the spring forces the diaphragm down which forces the gas to the carburetor. It is that spring that determines your fuel pressure. In order for that pressure to be met there has to be resistance in the line. An open fuel line from the pump to a can for instance will have no measurable resistance therefor no pressure. In actual use you have the needle and seat in the carburetor and the inlet is sized to be a restriction. Now you have the restriction you need to hold back the full flow of gas so now it is the pressure of the spring that is the determining force for the pressure. In your case it is 7 lbs. when you are not using more gas than the carburetor can use. Here is where the volume equation comes in. In order to maintain the pressure you have to be able to supply more gas than the engine is using, if not pressure drops. And as you said, basically you are running out of gas.
Now, the reason why.
There can be several reasons why, this really needs more testing to be sure but you said you tested the pump and got very little volume out of it. I would do one more test to cover all the bases and to make sure you are not replacing another pump for nothing. You already have the pump pressure tester so I am guessing it is a pressure/vacuum gauge? Hook it into the gas line before the fuel pump between the pump and the tank and see if it is drawing any significant vacuum. A very little is normal. If it is then you have a restriction in the line somewhere that needs to be addressed and it may not be the pumps fault. This would be indicated by 7-10 inches of vacuum on the inlet line. A engine driven fuel pump can draw a lot of vacuum, I just recently sucked a boat gas tank I was using to move a motor home around in on itself because I forgot to open the vent!
If the gauge shows vacuum/pressure, vacuum/pressure as you are idling then you have a bad valve in the pump and the pump is bad.
The most common cause of inlet line restriction is a clogged filter sock on the tank inlet, assuming you have changed any filters in the line.
Thanks for the advice/knowledge Rick! I just have a stand alone gauge for checking pressure. My vacuum gauge has an 1/8" line, might be a pain to adapt. I could probably buy a tee to do the job. When I pull the fuel lines, I'll do a restriction test with my mouth ??? and see how well fuel pulls from the tank, if any dought to too much restriction, I'll dig deeper
You will never be able to tell anything that way! It will feel like there is a lot of restriction just trying to suck gas and then you get a mouth full of toxic gasoline! This stuff is not the same as the gas we used to ste...... er... borrow from tanks at night with the garden hose. That stuff just tasted bad, this stuff will kill you!
Too late Rick, I got a small taste of it yesterday, the fuel pulls right out with very little effort I found out :'( ....haha. I'm no stranger to gas/diesel syphoning. My Grandpa once told me that he was happy to have lived a full life, even after having his hands in gasoline his entire life! He was surprised....
An old time mechanic I studied under always had a bucket of gas outside and that was the parts washer bucket. It was also where you washed off cuts and scrapes. Just think of the chemicals you are introducing into the body nowadays if you do that! ??? ??? And back then if you got gas on your hands the smell went away in an hour or so, not today, you are stuck with it for days.
Of coarse back then it was lead you were introducing. that does pretty much destroy brain cells. Of coarse back then it was lead...................... uh, wait a minute.
haha! yes lead, I was thinking the same thing. And yes on the parts wash bucket, grandpa used to clean all his tools in the gas bucket too (like after an engine build).
It's a $15 part! Just replace it already W%
Went through the fuel pump debate myself last year. Found out the ethanol in recent years is terribly bad for old fuel pumps, not being nice to the diaphragm. So, even if not leaking fuel into crankcase of my 440, it was not producing enough flow.
Then I found out there are a lot of various pumps out there for the 440! Many are too high pressure for my Edelbrock carb, while others are too low volume for the thirsty demands of the 440. I wanted to stay mechanical, for constant duty and remote area serviceability. I ended up installing an Edelbrock manual pump, and it has worked perfectly! I also replaced the hard lines with new 3/8", larger line.
I posted the results of my research on pumps here: http://www.classicwinnebagos.com/forum/index.php/topic,10687.msg64475.html#msg64475
-Walt
Quote from: PwrWgnWalt on August 09, 2016, 01:49 AM
Went through the fuel pump debate myself last year. Found out the ethanol in recent years is terribly bad for old fuel pumps, not being nice to the diaphragm. So, even if not leaking fuel into crankcase of my 440, it was not producing enough flow.
Then I found out there are a lot of various pumps out there for the 440! Many are too high pressure for my Edelbrock carb, while others are too low volume for the thirsty demands of the 440. I wanted to stay mechanical, for constant duty and remote area serviceability. I ended up installing an Edelbrock manual pump, and it has worked perfectly! I also replaced the hard lines with new 3/8", larger line.
I posted the results of my research on pumps here: http://www.classicwinnebagos.com/forum/index.php/topic,10687.msg64475.html#msg64475 (http://www.classicwinnebagos.com/forum/index.php/topic,10687.msg64475.html#msg64475)
-Walt
I found that most factory 440 pumps were all 30 gallons an hour. You can buy a "high performance" pump that was for dual four barrel set ups and there pressure was between 7.5-9 pounds, or the stock replacement is between 5.5-7 (which is what I ordered). They were both/all 30 gallon flow.
Ok, wow, I just read your thread Walt on the different pump ratings, I had no idea there where so many.... I only talked with parts nerds over the phone and asked them specs on the pumps they could get here locally....When I order parts, or talk to a parts person over the phone, I always use 1976 Chrysler New Yorker for my vehicle. I'm not sure how to break down that math for an idle run test, I just googled mechanical fuel pump volume test, and read 1 pint at 30 seconds idle is sufficient for a v8, I never knew this #, nor have I tested for this in the past, I would have just thrown on a new pump and crossed my fingers..... When I tested output, I had half that volume. I learned something new that day. Today I get the new pump. I would like to do a vacuum test pre pump like Rick mentioned, but I don't think I will unless I have output volume issues with the new pump. Then I will dig deeper.
Quote from: EldoradoBill on August 08, 2016, 09:19 PM
It's a $15 part! Just replace it already W%
25 dollars here...I had to save up.
I picked the new pump up, and the first obvious good sign was the inlet size on the new pump is 3/8. My old pump is 5/16. I installed the pump, but had to go buy a new fitting for the outbound side of the fuel filter and a few feet of 3/8 hose to finish the plumbing. I will now have a complete 3/8 fuel line from the tank to the pump. This will help with volume for sure.
New pump has 7-8 pounds pressure, and 1 pint of fuel at 30 seconds idle. Still need to drive.
That pressure may or may not give you problems. Have to try it and see. If the pressure gets too high it can push the needle off of the seat and flood the carb or it can force too much gas in too quickly when the float drop and the needle opens and also flood it that way. The second scenario is a tough one because it is almost impossible to catch it happening, all you notice is really bad gas mileage so if your gas mileage drops drastically then that is something to think about.
I don't know anything about the Dodge engines, but the Chevy motors have the return line on the mech pump that should limit the fuel pressure to some degree.
You could always add a Holley fuel pressure regulator between your pump and the engine.
The regulator might work but not likely, they need more pressure differential to work off of. Example, it would want to see like 20lbs. in so it could regulate to 5lbs. out.
After all the excellent advice given here on this topic, this may sound a little simple-minded, but please indulge me. I was having similar problems, bogging on hills and stalling after stops. My Warrior has a clear plastic fuel filter halfway between the tank and the pump. The filter is fresh, but the short lengths of rubber hose connecting it were old, and soft. I suspected they were collapsing under a strong vacuum, so I changed them. The new hose was a lot stiffer. It's been just a little while, but I haven't experienced the stalling and bogging since. Also the motor starts a lot quicker. Odd, really.
Just my 2 cents :-[
That is entirely possible but if you are getting that much suction from the tank you may also have a clogged pick up sock. A filter before the pump is really not needed on a mechanical pump since anything that makes it up the line will generally pass through the pump and be caught in a filter upstream. This lessons the suction load on the pump but I can tell you that a mechanical pump in good condition will pull quite a vacuum.
have you changed the tiny-and-easily-plugged filter that sits in the carburetor inlet fitting?
Bill
I have a Thermoquad, their is no filter in the carb. I have been out of town, haven't had a chance to run it yet....
Quote from: EldoradoBill on August 12, 2016, 08:33 PM
have you changed the tiny-and-easily-plugged filter that sits in the carburetor inlet fitting?
Bill
Yes, last year, but when I went to change it again, the fitting was stuck and the tubing started to twist, so I tightened it back up. Replacing that tube is going to be a headache, but it's not leaking, so it can wait. Since I have an inline filter ahead of it, the filter is probably not going to clog anytime soon.
Quote from: Rickf1985 on August 12, 2016, 04:14 PM
That is entirely possible but if you are getting that much suction from the tank you may also have a clogged pick up sock. A filter before the pump is really not needed on a mechanical pump since anything that makes it up the line will generally pass through the pump and be caught in a filter upstream. This lessons the suction load on the pump but I can tell you that a mechanical pump in good condition will pull quite a vacuum.
How much trouble is it to check/clean that sock? It's very likely to be dirty, at least, after all these years :-[
To do it right means dropping the tank and pulling out the sending unit to get to it to clean it. The down and dirty way of doing it, and this is ONLY if you do not have an in tank pump, is to blow a little air back through the line. I do not mean put your air nozzle on there and blast away!!! That method will remove the dirt, and the sock! You just want to gently blow some air into the line to push the fuel in the line back out and some air with it to dislodge some of the crap some the filter sock. Keep in mind that this stuff is still in the tank and will eventually end up back on the sock so you are just buying yourself some time this way.
Careful guys. Your mixing Dodge and GM products together which have 2 different fuel system designs. This will confuse people.
N:(
Yeah! Stay on topic!! Patiently wait for my lazy butt to drive mine and see if I fixed it!! :P
I added the pump disclaimer so that anyone reading this from another forum would know not to blow back through a pump.
Quote from: Rickf1985 on August 15, 2016, 11:30 AM
To do it right means dropping the tank and pulling out the sending unit to get to it to clean it. The down and dirty way of doing it, and this is ONLY if you do not have an in tank pump, is to blow a little air back through the line. I do not mean put your air nozzle on there and blast away!!! That method will remove the dirt, and the sock! You just want to gently blow some air into the line to push the fuel in the line back out and some air with it to dislodge some of the crap some the filter sock. Keep in mind that this stuff is still in the tank and will eventually end up back on the sock so you are just buying yourself some time this way.
Thanks, Rick. Very helpful. I didn't want to start a new topic just for this question!
Yesterday was the perfect 100 degree day to take it for a drive..... :-[ . Ran great from stop light to stop light, Ran great on the 40 mph four lane hwy hammering the throttle down, then it ran great on the 50 mph four lane hwy hammering the throttle down from time to time picking up speed. I'm now about 7-8 miles away from home where I decided to take Interstate I-5 back to the house. It ran like $hit as soon as I merged into traffic on the Interstate!!! Same scenario as described earlier in this thread (pulls hard until about 50 mph). It seems as though when the ambient or "under hood" temps get to a certain temp, It starts vapor locking...So I took it easy and drove it home, runs great at slow speeds! These rear engine FMC's pack some serious heat in the engine compartment. I couldn't even touch the rear bumper it was so hot! I opened the rear access hatch to the engine, and touched the fuel supply line before the pump, and it was smoking hot, even with the fuel tank in front of the engine behind the fire wall, the fuel supply line was hotter than hell, that doesn't help with vapor lock issues....So I'm going to check the supply line for any resistance (like the fuel tank pick up assembly, which was mentioned earlier in this thread), and if all is good there, I will order a Carter 4070 electric pump and install and then get rid of the mechanical pump....
I was never aware this was a rear engine, not that it would have made a difference in my diagnosis. What does the fuel line runs past that is hot? Exhaust? I would think something is wrong since they made more of these than just yours and they all apparently ran just fine as did yours up to this point. Is the fuel line and exhaust all in their original configuration? Does the engine mounted pump run a bypass back to the tank? Older Dodge Power wagons and WC's used a bypass fuel filter as did the V8 AMC Jeeps. It is mounted close to the carburetor with the bypass line on top so gases can go back to the tank and also keeps fluid circulating.
The fuel line is no closer to anything then any other 440 out there i suppose It used to have an electric pump in it, but was removed long ago I guess? Some of the wiring is still intact and a Carter style fuel pump mount still in the rig. The fuel supply line blows through clean, I checked that tonight. I just need to install an electric pump and more then likely put this to bed. I may still pull the Thermoquad and inspect (I rebuilt it close to 3 years ago). I put low style exhaust manifolds on it that came in some of the late 70's class c dodges. so it's not stock configuration. No fuel return to the tank. I already tried that, and it killed my fuel pressure!! I think the crap fuel we have now is the main culprit.
How close to the fuel line are the manifolds? A simple metal shield between the manifold and the line will deflect a LOT of heat. And you did the return line with a bad fuel pump. Got to remember that. The fuel return line has to have a restriction that is why I was thinking that filter I mentioned.
Remember when I did the return line, My pressure went from 7 to 1 pound with the old pump, so it wasn't the old pumps problem. The flow volume with the old pump was bad.
My supply line runs about 6" away from the exhaust manifold
Here's the old Carter elec pump mount still in the rig....Both the fuel filter and new pump will be located on the firewall instead of the side of the radiator.
And to finish drawing the picture Rick, here is the supply line running out of the firewall to the filter to the pump. The 3/8" rubber line comes out of the firewall, down to steel and runs along the outside frame rail, then does a 180* next to the genny oil filter and over to the filter etc...
I also took the thermoquad off last night and found no restrictions or anything weird with it other than I was able to snug up the bowl cover screws a little...I was able to blow freely through the needle and seat.
Ok, the pictures help a lot. The radiated heat on the pump may cause issues mainly because you do not have airflow over it like you would in a front mounted setup. The other thing I see is I follow the fuel line past the generator and down and don't I see the exhaust and muffler right there? Or is that the fuel line to the right of that red thing on the fire wall?
And by the way, Yes, your old pump had a volume problem, remember how you get pressure? Volume has to have a restriction, if you have low volume then even a small restriction will not give any pressure where as high volume through a small hole will be a lot of restriction, hence more pressure. And you can get vapor lock even with an electric pump if the gas boils faster than it can flow through the line. That is the idea behind return line plumbing, keep the gas flowing so it does not have time to boil.
The red thing you see up on the firewall is the genny in-line fuel shut off valve I put on it. The line to the right is the 440 fuel supply. Both mufflers are mounted directly under the genny, so yes the duel exhaust pipes are under the fuel line as it runs along the frame.
That could be a source of heat related fuel problems too. All you need is a flat metal shield with an inch of space between the shield and the lines between the heat source and the fuel line, The metal deflects the radiated heat and the air gap takes care of what the shield absorbs. And if the shield is painted silver or chrome even better.
Well.....I installed the electric pump and relocated the fuel supply lines further away from the exhaust. The pump puts out 6.5 pounds pressure. The spark plugs i looked at are showing lean burn vs rich. Took it for a drive and as soon as I hit the highway!!!! BAM still have the same issues! It actually runs worse with the new pump. I had to nurse her home around 25 mph's. I pulled the coil and it checks out good on the specs (I even compared it to three other coils at the part store), I also checked the resistance specs for the pick-up coil in the dizzy = good. So I am going to tear into the Thermoquad I guess...
I was looking through a Jegs catalog I got and I saw insulated fuel line covering. I usually deal with Summit but I am sure it is available across the board. Are you checking the pressure at the carb with it running or are you checking the deadhead pressure? Deadhead means nothing, that just tells you what the pump is capable of with 0 flow. If anything on the carb be sure the float drop is set right, a lot of people concentrate so much on the height setting they do not set the drop and the float does not drop enough to let fuel in at a fast enough rate.
Today I just did a "deadhead" test like you mentioned. I'll maybe hook the gauge back up and run it, I was thinking about taking the air filter assembly off also. It's a bit of a pain working/trouble shooting an engine thats 29' behind ya! I buy from Summit also Rick, and I do have some heat wrap and part of the fuel lines. I did notice that the fuel lines were cooler today after a quick stop to get out and look at the engine, they and everything else gets hot fairly quick at idle in the 90 plus degree day we had today though.
What you can do is disconnect the fuel line before all of the pumps and run it out of gas so the carb is empty. Then hook the line back up to the pump and while you are watching the gauge have someone turn it on and watch the pressure as it fills the carb up. In your case that is about as real world as you can get short of running a gauge wire all the way to the front. You will not have long to see what the pressure is since it should fill the carb in seconds. If it takes longer than that then you have flow issues. If that is the case considering all you have done I would check the carb for float drop, inlet needle size and any restriction in the needle and seat area. Could be a piece of rubber from an old line stuck in the entrance to the needle.
I've got the carb on the bench, going to work on it today hopefully
Simple solution.......................... 5.9 Cummins. W% :D
Here's what I found with the TQ:
Everything looks great! Except for my float bowl adjustment from a couple years ago....I bent the "tang" that touches/closes the needle in order to set the correct 1" float height. Doing some homework today, a Thermoquads floats are adjusted by bending the float arm itself. I didn't know that. SO....now I need to figure out the correct position of the needle shut off metal tang, then adjust the float height. Reading info online hasn't quite answered this question completely...some say the float should almost touch the air horn body (in the closed position),then adjust the float? But when the float assembly is down to where it almost touches the body, it puts the needle/float tang at a crazy angle? It still shuts off fuel flow, but looks like its pushing the needle to the side vs straight in on it? Is this making any sense to anyone? Lol. I'm not seeing much info on "needle drop" specs with the TQ
It has been a LONG time since I worked on a TQ but if I remember correctly when the float is sitting on the table the tang will be at about a 30 degree angle. you do want it pushing pretty much straight at the needle. Worse comes to worse you can probably still buy just a new float.
Yes Rick, a friend recommended I replace my plastic floats with brass also. On the web they are about 25 bucks. I'm going to double and triple check my float height/position and current needle drop/full open measurements before I order. I love just throwing money at the beast. I have two fuel systems now? Which do I run if new floats fixes? So many decisions.....and wasted time. $@!#@! I have a FMC club camping trip I'm trying to make by the end of the month....There's going to be 9 other FMC's, Id sure like to see other ones besides mine. Who knows... i??
Quote from: Rickf1985 on September 12, 2016, 12:36 PM
It has been a LONG time since I worked on a TQ but if I remember correctly when the float is sitting on the table the tang will be at about a 30 degree angle. you do want it pushing pretty much straight at the needle. Worse comes to worse you can probably still buy just a new float.
When I adjusted the tang to meet the needle straight on, it puts my float extremely low into the bowl when in the closed position, to where I would have to bend the float
upwards to get my 1" height. All the information I've read/learned about Thermoquads float system, show adjustments being made bending the float downward to get the correct height, not upward? Like the floats should be up almost touching the air horn/gasket when closed? I'm probably going to modify my floats first before buying others and give it a shot. I miss Holley external float adjustments....lol
It is possible these floats were adjusted before plus the adjustments you made will change everything so you are starting from scratch. But starting with the needle being pushed straight is a good place to start. Do a google search for "Carter Thermoquad float" and look at the pictures that come up and you will get a good idea of where they should be. Get as close as you can.
I've never owned a Dodge (and never will), but does this guide help you any? http://www.autozone.com/repairinfo/repairguide/repairGuideContent.jsp?pageId=0900c1528007fc3f (http://www.autozone.com/repairinfo/repairguide/repairGuideContent.jsp?pageId=0900c1528007fc3f)
Quote from: Rickf1985 on September 12, 2016, 07:30 PM
It is possible these floats were adjusted before plus the adjustments you made will change everything so you are starting from scratch. But starting with the needle being pushed straight is a good place to start. Do a google search for "Carter Thermoquad float" and look at the pictures that come up and you will get a good idea of where they should be. Get as close as you can.
That's exactly what Im going to do.....
That's a good link for diagrams and measurements for the TQ too Brian.
I found a needle that was sticking in the closed position way to easily, was grooved, after cleaning the needle tip off best i could, it still wants to be sticky....So I just ordered brass floats and a new needle/seat.
I think you may have found your problem. That would suck after spending so much time and money on the rest of the fuel system! At least you have a good supply of fuel pumps on hand. W%
Quote from: Rickf1985 on September 14, 2016, 10:37 AM
I think you may have found your problem. That would suck after spending so much time and money on the rest of the fuel system! At least you have a good supply of fuel pumps on hand. W%
YES!! Your reading my mind Rick! NOW I will have to choose which system to run???? Electric or Manual.... Hm? $@!#@! I'm pretty sure I will leave the electric pump mounted in place, and have it for back up if ever needed, but by-pass it and just go back to the mechanical system. I never pulled the mechanical pump off, just by-passed it to run the electric pump, so easy peesy. All the FMC owners I've talked with say they never have vapor lock issues with the short length fuel system and design etc...You even thought that too Rick. I hope my fix works....just waiting on shipping now.
| [/size]I put the new brass floats in and have smooth working needles.....BUT same issues. Pulls hard until 40 mph or so, then starts falling on its face. Brought her home and pulled the tank pick-up out, I thought maybe I'd see a pin hole or something up high, but no, looks to be in excellent condition. I think I need a new carburetor. I'm out of trouble shooting options as far as I'm concerned....[/size][/font] |
I am beginning to wonder if there is not something mechanical in the engine? Cam timing or cam worn? Have you checked fuel pressure while this is actually happening? That is the only way to determine the fuel system condition.
FIXED!!!! I tapped in a fuel pressure gauge with clear tubing, taped the gauge to outside rear window, as I drove the rig my helper watched the gauge. Under hard acceleration, the pressure would drop to zero followed by air bubbles! We then started by passing the supply line. WAM!! It was the fuel filter assembly introducing AIR into the system before the fuel pump. It ran great down the highway maintaining 6 psi with no bubbles. Talk about throwing me for a loop ??? I was ready to give up for awhile on this one. Thank you Rick for sticking this one out with me. And everyone else too...Seriously. I will post a couple pics tomorrow of the gauge set up
Heres the clear tubing and fuel pressure gauge tapped into the system post pump.
This issue really through me for a loop, I knew it was fuel related, but I kept focusing on the wrong end of fuel pump (as described in lengthy detail in this thread). I've only had this issue one other time, years ago, and it was on a 1986 Ford diesel truck, and we found the air using clear tubing also. Something to keep in mind folks....AND if you do have an air leak pre pump, doesn't mean you will EVER see a leak when the engine is not running.... W% I thought I should have seen some fuel seepage somewhere....NOT
I thought I said something about pulling air several pages ago. The main thing is that it is fixed and you have LOTS of leftover parts now. You should NEVER have a fuel issue again.
I actually only lost about a 125 bucks and 14 days off the end of my life on this one....2 fuel pumps, a couple misc carb parts, fuel line. Could of been worse... ???
In case you might need some reference info in the future: Daves Thermoquad Page (http://dave78chieftain.com/Thermoquad.html)
DAMN! ??? I will never try to give advice on a Thermoquad again! Just pass that link on.
LOL Rick. Born from fighting the same problem he had. I still have the problem. Will be trying out his suggestion when I get my Winne back on the road. I am currently tied up rebuilding the Isuzu 3.2L V6 in my Rodeo that spun number 1 rod bearing. I simply cannot believe Isuzu said 1 quart in 1000 miles is acceptable when the problem was not enough drain holes in the piston oil rings. I just did not know about that little bit of info. OK, back to carburation and fuel delivery. Dave
Yes Dave, I've gone through your info many times, such a wealth of info for everyone, very much appreciated.
I tell you what people...If you think you are having issues with running out of fuel under a hard load, tap in a piece of clear tubing with a fuel pressure gauge at your carb and take it for a drive and see what's going on. You can then by pass fuel lines and filters pre pump and find your problem. Hell of a lot easier with a front engine rig, one person can trouble shoot it driving down the road.
I was ready to park the FMC and take a break from it...I figured it was just going to need a new carburetor, even though I couldn't find any other problems with the TQ after I just had it out and apart??.....Imagine how pissed you would be after spending 400 dollars on a carb, just to have the same issue!!!!!!!!! $@!#@! $@!#@! $@!#@! An issue that's FREE!!!!!!
I too have the same Rodeo with the 3.2. Uses a quart of oil between oil changes. When I first met my girlfriend six years ago, the car was using 2-3 quarts between oil changes!! I did my homework, and like you said Dave, Isuzu has bad oil relief holes in the pistons, and they got around it without any recalls past 36k miles. I changed to 10w-30 standard dino, and I also cleaned out the EGR intake tube that runs inside the intake manifold, They clog up with suit/carbon. You can email/message me if you need some more details on cleaning that tube Dave. We have 180k on the clock, and it's actually going up for sale this week, we bought a newer car. Ok back on track OZ
QuoteI also cleaned out the EGR intake tube that runs inside the intake manifold, They clog up with suit/carbon.
I have the engine out of the car and tore down in my garage. Top & bottom halves of Combined Chamber (inside and Outside) are all clean and shiny now.