thanks supercab. guess it's time to go school!
let you know how it goes.

 

Sooooooo, have you fixed it???

 

>Sooooooo, have you fixed it???

nope. but thanks for asking. i have been really busy with life stuff. truck running o.k. except for the check engine light, rough idle and the bad mileage, so i have been making do. i need a block of time to check for vacuum leaks and diagnose parts etc. and am waiting for better weather cause my garage is just the driveway.
i'll be in touch soon though. thanks again.

 

[updated:LAST EDITED ON 23-Apr-02 AT 10:30 PM (EST)]well i am sorry to say i am back again. still code 31. i just put on a new EVR (EGR regulator) and it made no difference. I thought for sure that was it cause there was lots of vacuum going to it but none coming out at WOT. the new one is the same. this leads me to believe that maybe the EVR is not getting the proper signal to open up in order to switch vacuum onto the EGR. how do i figure that out? I also put a vacuum pump on the EGR and the engine died so that means it is good right? I cleared the codes as well.
Supercab75: i have not tried the out the window test yet - my new pump doesn't have that much line yet.

any other suggestions on how to kill code 31?

 

[updated:LAST EDITED ON 01-May-02 AT 08:57 AM (EST)]I am new to FTE. Arrived here in search of answers to 'Check Engine'. I have a 89 5 liter with the same problems but the light is only on now when hot and at idle. Have changed EGR and EVR(only $40 Cdn at Ford dealer), and checked green vacuum line and EGR position sensor. (I must pass emission testing where I live.)
What did you finally conclude was the problem?

 

>I am new to FTE. Arrived here in search of answers to
>'Check Engine'. I have a 89 5 liter with the same problems
>but the light is only on now when hot and at idle. Have
>changed EGR and EVR(only $40 Cdn at Ford dealer), and
>checked green vacuum line and EGR position sensor. (I
>must pass emission testing where I live.)
>What did you finally conclude was the problem?

i have not concluded anything yet. i just got back from a trip to Kamloops BC from Richmond hauling horses to a horse show. Truck ran OK but "Check engine" light was on the whole way. it is idling really rough now and i now have an exhaust leak at the manifold. the power through those mountain passess was not so good. top speed up the hills was 70 KMH (43 MPH). Anyway, i cannot figure the problem put. i still have code 31 and have replaced the EGR postion sensor on top of the EGR, the green vacuum line and have replaced the EGR regulator. absolutely no difference. i am completely stumped. i am ready to drive it in to a mechanic if someone here doesn't come to my rescue.

anyone?

 

Rusty, My local tech guy said 31 was an EGR fault but the Ford dealer tells me it is for "canister or EGR valve control system".
What is the nature of your exhaust manifold leak? Any leak upstream of the O2 sensor will effect air/fuel ratios, hence drive problems. The O2 sensor is not operational until warm. Does it idle OK on cold start?
I have discoverd that the EGR position sensor is VERY sensitive. I'm taking a wild guess here; you may have a plugged CAT. Additional back pressure could effect the EGR, and could cause an exhaust leak under load. It may be time to visit the garage, but before you take it to someone read the info on www.smogsite.com
Good luck and keep us posted!

 

I am sorry to say but I have the exact same problem (Code 31).

I have a ’92 460 and am pretty sure I have the EEGR. At least that’s what the book says.
I was getting the "Chuck Engine" (lol) light just above idle. When I'd drive at highway speed with the rpm's up, the light would go off. Slow down and sit in traffic and it'd come back on.

I disconnected the "green hose" and have been driving it that way for some time now because I too have not been able to find any info and planned to bring it to a Ford specialist. Funny thing is, now with the hose disconnected, the light is opposite. On at highway speed and off around idle. I pulled the code on this light (don't remember what I got), it was the opposite EVR sensor / EGR error. My MPG is for crap now too.

I hate EFI/Emissions with all the damn sensors, I never replace the right thing. I had an '86 EFI 302 Bronco and spent about as much on sensors as a good used engine.

It’s been a while since I have looked around on this problem but the last thing I was looking at was the cat. So I’ll have to agree with ****** for now. I have a rich rotten egg smell to my exhaust while the truck warms up. The truck was running rich since I brought it from Arizona to Colorado. I replaced the plugs, cleaned the K&N and even the replaced the O2 sensor. Smell went away for a while but it’s back. I planned to install a high flow cat so I’ll see if this does the trick.

Who the heck knows until somebody figures this one out.

 

 

>I am sorry to say but I have the exact same problem (Code
>31).
>
>I have a ’92 460 and am pretty sure I have the EEGR. At
>least that’s what the book says.
>I was getting the "Chuck Engine" (lol) light just above
>idle. When I'd drive at highway speed with the rpm's up, the
>light would go off. Slow down and sit in traffic and it'd
>come back on.
>
>I disconnected the "green hose" and have been driving it
>that way for some time now because I too have not been able
>to find any info and planned to bring it to a Ford
>specialist. Funny thing is, now with the hose disconnected,
>the light is opposite. On at highway speed and off around
>idle. I pulled the code on this light (don't remember what I
>got), it was the opposite EVR sensor / EGR error. My MPG is
>for crap now too.
>
>I hate EFI/Emissions with all the damn sensors, I never
>replace the right thing. I had an '86 EFI 302 Bronco and
>spent about as much on sensors as a good used engine.
>
>It’s been a while since I have looked around on this problem
>but the last thing I was looking at was the cat. So I’ll
>have to agree with ****** for now. I have a rich rotten egg

>smell to my exhaust while the truck warms up. The truck was
>running rich since I brought it from Arizona to Colorado. I
>replaced the plugs, cleaned the K&N and even the replaced
>the O2 sensor. Smell went away for a while but it’s back. I
>planned to install a high flow cat so I’ll see if this does
>the trick.
>
>Who the heck knows until somebody figures this one out.


well thanks for your input ****** and F350ccdrw. first for F350ccdrw, i'll bet that your light goes out because at cruise you have more vacuum- so i bet you have a vacuum leak somewhere. my truck runs lean - i got a code 41 last time i checked.
******..... the code 31 and rough idle were going on months before the exhaust leak. i sprung the leak pulling a horse trailer through the BC mountains just last weekend. very steep hill. sprung a leak doing the same thing 2 years ago as well. as far as the cat goes, i have a new (1 yr old) 3" stainless exhaust put on with a new high flow 3" RV cat. i doubt it is plugged. i had a plugged cat when i bought the truck so i remember the symptoms. doesn't seem like that is a problem now. i can say that the idle is roughr now since the trip last weekend and maybe the exhaust leak is making it worse. it really wants to stall more now then it did before. the O2 sensor is pretty new too.
i have not checked the "cannister" really. but i did check for vacuum to the EVR and it seemed pretty healthy under Part open throttle. i am wondering if the EGR did get some crap in it somehow but because it is the EEGR it cannot be taken apart and cleaned as far as i can tell. still stumped and i haven't much time so i'll have one mroe crack at it and then it's off to the shop. maybe i can do us all a favour by paying someone a few hundered to fix it and tell us what the problem is eh?

 

First off, i dont expect a response, and I really hate to pull this thread from the deepest of dead. After all, I was just a kid back in 2002.🤣 However, in 2023, I'm fighting the exact issues as you. Almost no explanation is required because after a few days of diagnosis, I've come across the same issues with a broken green vacuum line brand new egr and position sensor with no change a constant check engine light. I've also swapped the vacuum solenoids and position sensor with others I had on a parts engine. What I do know is that if I hook the egr directly to the manifold, the engine bogs down and runs bad. However, the light goes out in the dash. Alternatively, i can also push the egr position sensor by hand, and the light will also go out. However, I don't think that's my issue, but rather, I'm just tricking the puter box into thinking the egr is functional. Like you, I'm uncertain if the EVR is getting the proper signal to open up in order to switch vacuum onto the EGR. I've been searching for vacuum leaks to no avail. Basically, what I'm asking is, after 21 years, did you ever find the source of the problem?

 

I’ve got a 1988 F150 5.0L with this exact issue, I can’t figure it out. Any info is appreciated!

 

I caved in and bought a new evp sensor without properly diagnosing it. I hate to do that but after a bunch of screwing around I was at a dead end. Code 31 and check engine light went out and so far haven't come back in about 1000km. To my surprise both spare evp sensors I had kicking around on the shelf for YEARS now were both bad. Go figure.....🙃

However all of that said I now seem to be having some drivability issues now in that the truck occasionally has a relatively harsh jerking at part throttle or very light acceleration. I've unplugged the connector for the evp and the truck will not jerk but obviously the check engine light will turn on. On the other hand I think I might get slightly better gas mileage than I was getting before changing the sensor however I don't know for sure. I'm not going to worry too much about the jerking the light is gone and it makes me feel better about myself. It very likely could be a problem with the new Chinese sensor im not sure. For now I bought the walker 2 to 1 cat delete (my truck is a 4.9i6) I was going to do that anyways and if I have a plugged cat It will hopefully make some sort of a difference. I doubt it though. I'll have to toy around with it, I just too much on the go right now as far as project vehicles are concerned.

 

I had a bad evp sensor, it tested bad with a multimeter, so I bought a new one and replaced it. The code 31o remains.

 

all I can say is there's a good right up on fsb fourm by a guy named Seattle fsb regarding testing the egr system. Go through that and the Haynes manual and understand the system. The only other thing I can add is that I would invest in a vacuum gauge and a hand vacuum pump and test all of the vacuum lines and soup can for leaks (although insignificant I did find a few leaks). Also I set myself back with diagnosing because when I went to put the vac lines back on the soup can after testing it for leaks I put the lines on backwards. Don't do that the plastic top for the soup can is a 1 way valve.