EGR Issue and Rough Running

[LStoudenmire]

My Ex' has been recently running very rough on low end and the gas mileage has plummeted. I ran the codes and received a 332(KOEO) this week, and this morning prior to beginning to work on it recieved a 538(KOER) and a 33(KOEO). The 332 and the 33 point to a EGR problem, and the 538 appears to be some type of user error according to Haynes.

According to the Haynes, when testing, you should turn the sterring wheel 1/2 turn and depress the brake pedal after receiving the ID Codes, and I have done this as well during the test. ( At first thought maybe I had not done it at the right time. But have tested 7 to 20 times with same results.)

I have replaced both the EGR Valve and the PFE Sensor 3 yrs ago and it corretced an issue I had then. This AM I went and purchased a new PFE SEnsor and EGR Valve and replaced them both to no avail. I checked the IAC, as described in the Haynes Manual and did not receive an Ohm reading when I tested the terminals and the outside of the case, indicating an internal short. However, neither of the codes refer to a problem with the IAC.

Any additional suggestions and help would be appreciated as I'm at the end of ideas. Thanks.

 

[LStoudenmire]

bump

 

[MrShorty]

I would guess that KOEO code was a 33x, which still pionts to an EGR issue ('94 shoudl output three digit codes.). KOEO codes almost have to be electrical faults, so I would suspect we are back to checking that 3 yr old PFE sensor. Make sure the wiring between the sensor and the computer is intact, too.

 

[LStoudenmire]

I double checked the Codes again and it really is a 33. According to Haynes the 33 is " EGR Valve Not opening; Insufficient flow Detected"

Also, I swapped out the PFE Sensor and the EGR Valve yesterday and neither corrected the problem. All wiring appears to be OK and intact.

Thanks for your help.

 

[MrShorty]

Are you sure it isn't a 111 then? I would really expect to see a three digit code there?

I forgot to mention, the 538 is indeed operator error. Perhaps Haynes forgot to mention the dynamic response portion (aka "goose test") of the KOER test.

IS the PFE seeing Vref? What is the PFE outputting?

 

[LStoudenmire]

It is displaying a 1-1-1 prior to the remainder of the codes, but I interpretted that from Haynes as just a normal code that is always displayed.

After doing some additional reading last night, it does appear that Haynes has left out the depressing of the gas pedal during the test. I will try that tonight.

Not sure about the PFE Seeing vref or the PFE Output.

 

[410Fortune]

Now did you reset the battery after replacing the EGR?

the 111 could be all clear for present codes, and then it gives you the memory codes.

How are you testing for codes? scanner?

 

[LStoudenmire]

No, I didnt reset the computer after installing the PFE Sensor or the EGR Valve. I did reset the computer SAt monring prior to installing the parts just to verify the codes.

And I'm using a scanner first and then the CEL Method as a 2nd opinion for verification.

Also, the CEL is not displaying now while running. It was displaying about 3 weeks ago, when everything was acting fine, but while traveling on a recent 3 hr trip, it went out and never displayed again leaving me to think everything was fine and maybe I had gotten some bad gas or trash or something). Then on the return trip, it started running rough and the loss of power was evident.

I may try and replace the IAC this evening to see if that corrects the problem.

 

[410Fortune]

replacing the IAC wont do a damn thing for a driveability issue. Idle air control valve, not driving air control valve.

Throwing $$$ at it does nothing.

So you are saying the power loss is still there, and now you get no CEL?
computer may be suspect, if its giving you EGR codes and the EGR all checks out...

 

[LStoudenmire]

That's correct. No CEL but rough running. When Idling, I'm not seeing a change in RPM's, but it barely sounds like it is not running evenly. At a constant speed, it seems to be fine.

It is most noticeable when:

1. Idling, the gear shift is vibrating more than usual (it's manual)
2. While increasing speed at low RPM's rough running
3. At highway speeds, when climbing a hill, I may lose 5 to 10 MPH with no pickup at all.

I did try goosing during a test last night, and didnt receive the 538 error, but must have had the A/C on because I got a 67, so I'm closer to getting a KOER Code. I'll try again tonight.

Thanks guys for your help. I have been able to diagnose and correct most all problems before, but this ine has me stumped.

 

[410Fortune]

clogged cat converter possibly

 

[LStoudenmire]

You know, I just had my muffler replaced last week. The installer stated that he thought I needed to replace it, but they wanted $160.00 for the converter and a additional pipe to bypass the second converter.

That may be it. I'll check further.

 

[410Fortune]

$160 is actually not bad at all.

 

[porshapower]

$160 is actually not bad at all.

This is weird. The same thing is going on with my 96 explorer 4.0 5spd. I had a check engine light got the codes replaced the pfe sensor and the egr valve and thats fixed now..no more cel. Now my shifter shakes a little and the idling has a slight slight stumble as you have described. I replaced the IAC and it did nothing. Replaced the spark plugs and no change. Cleaned out the MAF with no luck. Cleaned out the throttle body with the "teflon coating safe" cleaner with no luck. Have run techron and seafoam through the gas with no luck. All vacuums and connections are fine. Hate to throw any more $ at this. Was thinking wires but it drives like new when you accelerate its only at idle that it acts up. Wonder about my catalytic converter. I am going to do the seafoam cleaner through the vacuum line tomorrow and see where this takes me. Good Luck and Ill keep you posted if I come across anything as it seems we have the same problem.....

 

[410Fortune]

Most OHV 4.0L's I have had dont run exatcly perfectly smooth at idle once they get some miles on them
The motor mounts and trans mount wear out, they are just rubber, this contributes to a slight "stumble" as well as just age.... Ford fought this drivetrain vibration early on with a stupid shock that went from frame to motor mount, and also with those stupid steel donuts on the T case and rear axle (band aids)

A full tune up (my version of full tune up is ALOT) really helps keep them running strong, but I wouldnt consider a slight shifter vibration or stumble out of the ordinary for a OHV 4.0L with more then 100K on the OD.

 

[LStoudenmire]

The only thing is that it has been running smooth and the issue just happened all of a sudden, instead of gradual, leading me to believe that something is broken. Esp. since experiencing the sudden loss of power (esp. the loss of 5 to 10 MPH on the highway) and the idle issue. I'll try the catalytic converter and see what happens.

I am also going to change out the spark plugs and wires after I get this solved. I know it will help the gas mileage out anyway. Where's the best place to get new wires? Don't need anything high performance.

And how is it change out the motor mounts and trans mounts? Is that something the experienced DIY'er can do?

 

[410Fortune]

the engine mounts and trans mounts are not a huge job to replace, but for the engine mounts you do have to hoist the engine up an inch or two, the engine mounts last far longer then the trans.
replacing the trans mount is a easy job and good idea to do if you have higher miles.

Your cat converter can be tested, well the tailpipe for flow, before you just throw $$$ at it.

A stumble can also be from gasoline quality, here in CO we get ethenol gas part of the year and I can tell you that stuff does not run as smooth

Wires: I like Taylor wires, they are not expensive: truckperformance.com

 

[LStoudenmire]

Just for an update. After continually reading about the symptoms I am having being attributed to a clogged catalytic converter and the fact that I viisited the muffler shop last week, and they told me I needed a catalytic converter, I thought I would have a test pipe installed today to see if it cured my problem. (Whew! How's that for a run on sentence.)

Well, guess what? It didn't solve it. However, it does seem better. I can climb hills now onthe Interstate without losing 10-15 mph, but its still not right. I will be visiting my local mechanic and will let him figure it out. I give up this time. I'll keep you posted.

 

[LStoudenmire]

New Update......
I had a test pipe installed to replace the Cat Converters, to see if they were causing the problem. The problem did seem to be slightly better, but not cured. I took the Ex' to a shop to have a professional take a look at it, and they attributed it to a bad coil, spark plugs and plug wires. I went and bought all the necessary parts, and removed the existing coil and tested it and it seemed to be ok. I reinstalled the old coil and installed the plugs and wires and all is well again. Funny thing is that I was in the process of gathering all the parts necessary for a tuneup last week to start this weekend.

Thanks for all help.

 

[410Fortune]

Full tune up then, plugs play a major role in the engine running properly The hardest problems to diagnose are when there are multiple things contributing to it running poorly.