I just bought a 94 F150 today for a steal of a price. Or at least I think so. It's an automatic, 302, 4x4 XLT.



However it has an idle issue. I swung by the closest auto parts dealer so that they could scan for codes. It came up with;
3-37
3-34 ( EVP - EGR did not respond properly during test - EVP )
3-32

They're all codes that deal with the EGR valve and pressure sensor. I've heard that these trucks usually have an idle problem because the rubber hoses drying out and crack allowing extra oxygen in. Are there any diagrams explaining where the pressure sensor hose is?
Has anyone had this problem of a surging idle? Any help would be appreciated.

 

I can also smell fuel when the hood is open. Any suggestions on where to start??

 

i dont know anything about that but im sure some who does will chime in soon. but thats a nice truck man, looks good. wheres the front bumper tho?

 

I bought it without one, and I'd like to do a tubi front bumper. Thanks for the compliments.

 

Were the codes pulled during KOEO or KOER test?

 

My question is, is it a SD, or a MAF truck...Also, is it a OB-I, or OB-II truck...?

Because not a lot of trucks were MAF in 1994.....Much less OB-II....


Bout time you started posting up on here Josh....Need to fill out the rest of ya info, in your User Control Panel....

 

nice looking truck. it should be obd1. i dont thing they did the obd2 til 96

 

I'm not sure. This is my first OBD-1 vehicle so I took it to autozone. There's an older ford mechanic in there, that actually is worth a damn. He jumped the pins and I got the codes from the "morse code" in the dash.
3-37
3-34
3-32
They're all EGR and pressure hose codes. Does anyone have a diagram or picture reference for these hoses? I just deleted the EGR in my camaro, but I'm unfamiliar with this 5.0.

Correct OBD-1

 

Here ya go...


From my private stockpile of diagrams....

 

I was underneath the truck, spraying the EGR and random hoses with WD-40 looking for a vacuum leak when I noticed that my exhaust was cut off right after the cat. Would this affect my EGR's performance?

 

If you got an O'reillys in your town stop by there they should have a code reader that reads obd1. We do at our store. I would like to see what the ecm says during koer to make a better diagnosis. From what you are describing it sounds like a vacuum leak, these trucks have hard vacuum line (the bane of my existence) they tend to crumble and break. Clean your throttle body out with crc throttle body cleaner. You would be amazed what a difference that will make in idle quality. You mentioned a smell of fuel coming from under the hood, do you care to elaborate on that? It could be linked to your rough idle problem.

 

Codes are listed, see post #1 and 8. (I don't know what the dash in them "-" is for though?)

No cutting off exhaust after cat would not effect EGR system.

334 suggest the valve is or might be stuck part way open/can't close (might explain rough idle)

332 suggests it didn't fully open (might not be able to if stuck part way open rather then limited "down" travel?)

337 might simply mirror/enforce 334 in this case "voltage above max" too "high" simply put but when be the question.

Fuel smell under the hood, look at the injectors top and bottom real close one or more of the O rings on em may be leaking a little bit. Gotta look real close though it might be very hard to detect.

Have you done a complete tune up on it yet?

Checked/set base timing?

Checked fuel pressure?

 

Guys, if an injector is STICKING, and shooting more fuel than needed....Would that make a fuel smell?


I'm thinking in the mindset of a carb overflowing the bowl...

 

Take the EGR off, and check it for proper operation, and see if there is carbon caking the pintel/seat. Another thing to check is the hard vacuum line from the solinoid to the EGR. Hook a vacuum pump to it at the solinoid, and apply vaccum. THe EGR should open, and should hold vacuum for 30+ seconds.

 

I found a leak on the front of my fuel tank. (Single tank shortbed)
I'll post updates when I found the vacuum leak.