Rough idle and check engine light

[proffessor1979]

How do I know if I have a 4.0 pushrod or SOHC. I'm hoping I don't have to take the intake manifold off and what not.

 

[aldive]

How do I know if I have a 4.0 pushrod or SOHC. I'm hoping I don't have to take the intake manifold off and what not.

What does it say on the top of the intake cover?

 

[aldive]

I didn't see that you haver a '94 before. You have the OHV motor, the SOHC was not available that year.

 

[proffessor1979]

OK i didn't think so. I'm looking through the Haynes manual and its got me wondering.

So the fuel pressure regulator and/or EGR valve should be pretty straight forward to replace? At least it looks like it.

So I'm looking at Napa online, and i have my truck spec'd out and it lists the following two....would they both fit? I'm wondering why the big price difference.


Fuel Pressure Regulator
MPF
319504 $79.99



Fuel Pressure Regulator
CRB
219504 $132.00

 

[ma96782]

Sometimes the price difference is just cause it's mfn by different folks.........you know, brand x vs. brand y............some folks like to buy only brand x and will pay the extra. As for, "reliability of the part or quality," well that is something you get to know, when you buy and have a good or bad experiance with it............then you'll say, "I'll never buy brand Z again."

I looked on the Rock Auto site and the fuel pressure regulators looked almost the same (from diff mfns).........prices were more closer,then your NAPA example.

http://www.rockauto.com/


Aloha, Mark

 

[proffessor1979]

Hopefully my last question

so for this

KOER Code 327
EGR Sensor
Below minimum voltage

is it talking about the egr pressure feedback sensor, or egr valve position sensor?

 

[proffessor1979]

bump

 

[MrShorty]

As I understand the '94's EGR system, it uses a pressure feedback sensor rather than an EGR valve position sensor. Both types of EGR sensor perform the same basic function -- telling the computer about the operation of the EGR system so the computer can control the EGR valve. An EGR position sensor is usually mechanically coupled the valve and reports how far open the valve is (picture something like a TPS). Pressure feedback sensor is measuring the exhaust backpressure at the EGR valve, and the computer uses that (via a feedback loop) to control how far the EGR valve is open.

KOER 327 is in reference to the signal from the PFE/DPFE sensor.

Did you ever get results for the KOEO test? I was waiting for those results before making any recommendations.

 

[Glacier991]

First off, I highly doubt your problem is the FPR. Stay with what the computer is telling you for now. Secondly, in a majority of cases, when there is an EGR problem, the problem is in the PFE or DPFE (system depending) and not the EGR valve itself.

But Shorty is the resident guru on these things and reading computer codes, I'd follow his advice. I agree 100% with him so far.

 

[proffessor1979]

As I understand the '94's EGR system, it uses a pressure feedback sensor rather than an EGR valve position sensor. Both types of EGR sensor perform the same basic function -- telling the computer about the operation of the EGR system so the computer can control the EGR valve. An EGR position sensor is usually mechanically coupled the valve and reports how far open the valve is (picture something like a TPS). Pressure feedback sensor is measuring the exhaust backpressure at the EGR valve, and the computer uses that (via a feedback loop) to control how far the EGR valve is open.

KOER 327 is in reference to the signal from the PFE/DPFE sensor.

Did you ever get results for the KOEO test? I was waiting for those results before making any recommendations.

Thanks! I am trying to find another place that tests for free by me. Considering i already got the KOER test i'd hate to pay just for the KOEO test

I don't want to go back to the place i got it done simply b/c it obviously didn't seem he knew what he was doing.

 

[proffessor1979]

some new issues this morning, not sure if they could be related.

I go to back out of my drive way, put it in reverse, and it studders pretty hard twice, then doesn't move. Mind you it is still in reverse. I put it back in drive and went forward a little and the car studdered again in drive.

Put it back in reverse, it bucked a little and then i was able to drive. I got to the wawa and the same thing happened.

Could this be related to the other issues? I mean i wasn't having any transmission problems up until this morning. I would think with something like the car not even moving when it's in reverse there would have been some signs that the transmission needed to be looked at.

Up until today it was fine, no hard shifting..no slipping etc.

thoughts?

 

[MrShorty]

Thanks! I am trying to find another place that tests for free by me. Considering i already got the KOER test i'd hate to pay just for the KOEO test

I don't want to go back to the place i got it done simply b/c it obviously didn't seem he knew what he was doing.

Does this mean you've decided not to try to do it yourself?
Finding someone who will pull codes for free is kind of hit and miss. As you found, parts counter guys may be able to hook up the test, but much of the time don't really know enough specifics about Ford's system to get the most information from it. If you keep looking you might by chance come across someone who knows what they are doing and is willing to do it for nothing. IMO, if you want to be your own diagnostic technician, you will be far ahead in the game if you learn to do it yourself. Review my "notes on pulling EEC-IV codes" and any of the many sets of instructions that are available on the net and in good repair manuals.
On the other hand, paying someone to diagnose it for you isn't necessarily a bad thing, if the diagnostic fee includes pulling codes and running the necessary pinpoint tests to determine the exact cause of the trouble code.
As for the other, new symptoms, I believe they could be related. In any case, I like to fix what's known to be bad (in this case, something's known to be wrong with the EGR system), then see which symptoms are resolved and which remain and go from there.

 

[proffessor1979]

I'm definitely going to try and fix the problem myself, but I don't know how i could test it myself. I suppose I could get a volt meter and try it that way. It seems like doing it that way me be over my head at this point.

 

[MrShorty]

I'm definitely going to try and fix the problem myself, but I don't know how i could test it myself. I suppose I could get a volt meter and try it that way. It seems like doing it that way me be over my head at this point.

You'll never know until you try. If it helps, the first time I went over the test instructions, I thought I might be in over my head. After trying it, though, it all came together and made sense.

 

[StillKicken]

Professor,
I got my code reader from Advance for a little over $30. I think I could have done it with my multimeter, but didn't want to worry about wires coming undone and driving me crazy. And it comes with excellent instructions.

http://www.partsamerica.com/ProductDetail.aspx?categorycode=3389&mfrcode=ACN&mfrpartnumber=CP9015

Good Luck!

 

[proffessor1979]

wow thanks...I'm going to pick up that tester.

ON a side note, I got my transmission services last night ..drain/fill..filter..gasket etc because of the above mentioned problems.

It seemed fine, but as the truck gets warmer it seems is when the problems happen. When I am driving it's fine, but once i slow down to <10 mph, and from a stop accelerate up past 10 mph its noisy and i can feel it shaking. It's only in that mph range from 0 -10mph

And in Reverse as well. I hope it's related to my EGR system issues some how.

 

[baby3848]

same problem but the engine light has yet to come up with a newer motor installed have a code checker and all that came up was egr sensor voltage out of range changed and checked some now after driving it around for a week checked codes again and have a buch of circut failers ( but still no engine light coming on!) so we are in the process of changing the pcm then we can try again( just a note we changed the maf sensor and dpf sensor and it didn't help)all other sensors tested okay

 

[proffessor1979]

I changed the sensor, and no more check engine light.

Now though it feels like there's a loss of power or something. If I'm driving and I step on the gas it will go up to like 3K RPM, then fall back down to like 2K. Meanwhile I'll have it floored the whole time. Then if it doesn't do that it will jump up all the way to almost redlining and I'll have to take my foot off the gas.

I know I put the sensor on correctly so I'm confused as to whether this is a new problem or not. I ordered the fuel pressure regulator, but I think it's either the wrong one or I just haven't found it on my truck yet. It looks too big.

Any ideas on the loss of power and RPM issue?

 

[BrooklynBay]

If you corrected the problem, and now don't have a check engine light, then you have to clear the code for the PCM to relearn. It could do it on its own, but will take longer.

 

[proffessor1979]

How bad of an idea is it to clear the code by disconnecting the battery for a little while?

IT's wierd this problem never happened before. On the way to work it was almost as if as soon as i hit 3K RPM it just wouldn't do anything anymore. If i let up on th pedal then pushed it back down it started to move.

The Check engine light is actually back on.

Thanks for everyone's help