Classic Winnebagos & Vintage RVs

Topic Boards => Ford, John Deere, Oshkosh, Freightliner, & all others => Topic started by: edog1973 on October 09, 2016, 09:13 PM

Title: Fuel Cutoff Oil Pressure Switch
Post by: edog1973 on October 09, 2016, 09:13 PM
So, while trying to figure out why the tank switch did not work on the HR I discovered that the wiring for the entire system had been cut up, chopped out and spliced into who knows what.  Obviously someone who did not understand the system had worked on it in the past.  I've got most of it straightened out now, but want to reconnect the oil pressure switch that cuts the fuel pumps when the engine is not running.  It was was not connected at all any more and it's output was simply wired hot.  The sensor is still there with the cut off wire stubs.  I put a meter on it and it show open with the engine off (as expected) and 350 to 450 ohms when the engine is running.  This resistance seemed a little high to me.  Does anyone know what proper readings should be?
Title: Re: Fuel Cutoff Oil Pressure Switch
Post by: CapnDirk on October 10, 2016, 09:39 AM
It's on or off, not a matter of resistance ("like in feeding a gauge), like the red idiot light when you no oil pressure on an old rig as apposed to the gauge.  There are two switches there,  one each doing as described above.  is your oil pressure gauge working correctly?  Just checking to see if you have the right one.


This thread has a nice picture to help sort it out.


http://www.classicwinnebagos.com/forum/index.php/topic,10080.msg62355.html#msg62355 (http://www.classicwinnebagos.com/forum/index.php/topic,10080.msg62355.html#msg62355)
Title: Re: Fuel Cutoff Oil Pressure Switch
Post by: edog1973 on October 11, 2016, 10:42 PM
I picked up a new oil pressure switch today and installed it.  The new switch read .2 ohms with the engine running. This is more like what I expected. So to answer my own question high resistance across a switch probably means it's bad or going bad.
Title: Re: Fuel Cutoff Oil Pressure Switch
Post by: tmsnyder on October 12, 2016, 09:43 AM

YEs 350 ohms seems high for a switch.

Quote from: edog1973 on October 11, 2016, 10:42 PM
I picked up a new oil pressure switch today and installed it.  The new switch read .2 ohms with the engine running. This is more like what I expected. So to answer my own question high resistance across a switch probably means it's bad or going bad.
Title: Re: Fuel Cutoff Oil Pressure Switch
Post by: easymoney on December 20, 2016, 03:30 PM
This is easymoney. i want to know if you have the fuel pressure specs on a 460cid ford. I am new to the forum and i have found that everyone is glad to help us ignorant rv owners .
Title: Re: Fuel Cutoff Oil Pressure Switch
Post by: Rickf1985 on December 20, 2016, 05:27 PM
It would help if we knew what you were working on, year, make, model.
Title: Re: Fuel Cutoff Oil Pressure Switch
Post by: easymoney on December 21, 2016, 02:22 PM
I knew to do that but was in a hurry i guess---


1987 coachmen classic class a= john deere chassis=460cid=i have ordered the service man
Title: Re: Fuel Cutoff Oil Pressure Switch
Post by: DaveVA78Chieftain on December 21, 2016, 08:54 PM
The manual you ordered says 4.3 PSI for a 460CI engine with a Holley 4180 carburetor.
Title: Re: Fuel Cutoff Oil Pressure Switch
Post by: easymoney on December 21, 2016, 09:14 PM
Thanks Dave : This forum is super with people like you that wants to help others. Thanks