KOER test problem... HELP ASAP

[rcfast]

Ok, i'm having a problem. On my 94 explorer at idle it just pours out black smoke (rich) and idles really rough. I have researched it and the FPR seems to be a common problem, however I disconected the FPR vacuum line and there is no sign of fuel in there. Also with the vacuum line un plugged it still has the at idle problem. It did get a SES light well it was missing at idle and I was able to pull the codes with KOEO and got 111, then 157, and 158. Both of those indicated a maf problem, so I disconnected the maf and tried it out and it still had the same problem (pouring black smoke out at idle). So I did some more reading and decided to try and conduct a KOER test, well when I start the engine the SES light just keeps flashing 9 times over and over no matter what I do. So why is it just flashing 9 times and not letting me conduct the test?

 

[410Fortune]

how are you performing the KOER test? with a code reader or with a jumper wire?

Just checking the vacuum line for gas is not enough evidence to rule out the FPR, you need to do a fuel rail pressure test IMO

Also what is the SES you speak of?

 

[rcfast]

I meant CEL instead of SES. I tried doin the KOER with a jumper wire. As for just checking for fuel in the line I couldn't see the pressure being high enough for it to run as rich as it's running, I would think it would have to have a ruptured diaphram to cause it to run as rich as it is. I could be wrong though.

 

[410Fortune]

engine is running, then you install the wire, or jumper wire in place, then start then engine?

Fuel pressure test is the first thing to do when you have a overly rich condition and no codes...it will either rule it out, or find your problem instantly

 

[rcfast]

engine is running, then you install the wire, or jumper wire in place, then start then engine?

Fuel pressure test is the first thing to do when you have a overly rich condition and no codes...it will either rule it out, or find your problem instantly

Jumper wire in place then start the engine. Are you supposed to start the engine and then install the jumper wire?

When I get home I will check the fuel pressure as long as I have the right adapter.

 

[410Fortune]

its a shrader valve on the fuel rail, you can actually use a cheapo tire gage (dial type) in a pinch, dont expect the gage to work long after this.

Yes start engine then jumper wire I believe

 

[rcfast]

its a shrader valve on the fuel rail, you can actually use a cheapo tire gage (dial type) in a pinch, dont expect the gage to work long after this.

Yes start engine then jumper wire I believe

I'm still having problems with the KOER.. I'm wondering if maybe it's the TPS and if thats what is causing the KOER test problem and the idle problem. If you where to press the throttle right when you started teh KOER test would it just keep flashing 9 times like it is for me?

 

[410Fortune]

No

the TPS should not have anything to do with the KOER test.

it is QUITE possible your PCM itself has been fried.
I have personally seen 3ea 1st gen PCMs fail

The KOEO test works fine?

 

[rcfast]

No

the TPS should not have anything to do with the KOER test.

it is QUITE possible your PCM itself has been fried.
I have personally seen 3ea 1st gen PCMs fail

The KOEO test works fine?

Ya KOEO works fine.

 

[410Fortune]

do you have the ability to find a friend with the exact same truck? same transmission, same year, can you swap PCM's with theirs for testing?

What is the calibration code on your computer? (I may have one you can try COW1 I beleive is the code on mine)

 

[rcfast]

do you have the ability to find a friend with the exact same truck? same transmission, same year, can you swap PCM's with theirs for testing?

What is the calibration code on your computer? (I may have one you can try COW1 I beleive is the code on mine)

What where the symptoms on the ones that where fried?

Just now I cleared the codes and then started it. Right away I got a check engine light and I read it, the code was 157 but there was no 158. 157 (R,M) Mass Air Flow signal is/was low or grounded - MAF. Now if the MAF is fine what else could cause this code?

 

[410Fortune]

all 3 were different, one had no codes, ran like crap.
One had like 8 codes, ran like crap, barely ran at times, no power over 3000 RPM
the other had 02 sensor codes that would not go away even after tripple checking the sensors and wires, ran like crap

what makes you think the MAS is fine?
The wiring to the MAS?

jsut because its clean on the sensor wires does not mean the MAS is working properly.

A bad MAS will cause all sorts of issues.




http://www.therangerstation.com/tech_library/OBD_I.html

 

[savagefan]

Your truck will start and run with the pcm disconnected. Try it see if she still smokes. If so excess fuel pressure or bum injectors are likely to blame. Remember, when you disconnect the vac. line to regulator it goes into full pressure mode. So check fuel pressure at idle with line on and off.

 

[410Fortune]

he means MAS disconnected, not PCM

 

[rcfast]

he means MAS disconnected, not PCM

Ya I figured that being that without the pcm you won't have fuel or spark. I have already disconnected the mas after getting the code and it still runs the same. That is what lead me to belive the mas isn't the problem in this case, so that is why i'm trying to figure if there is anything else that shares power with the maf that could be causing problems. I actually have a lot of experience with diagnosing and repairing chevy's (probably a curse word here) and I have all the diagnostic tools and equipment for OBDII chevy vehicles. Being that this is OBDI and a ford I don't have much in terms of diagnostics, so i'm trying to make due with what I have. The vehicle is actually my brothers but I need to get it fixed because i'm having to give him rides everywhere. From the problems that i'm having im inclined that there is some sort of sensor or electrical problem somewhere for the fact that I can't get the KOER to work and the instant MAS code.

 

[410Fortune]

check the wiring to the MAS
check the fuel pressure

 

[rcfast]

I just checked the fuel pressure. It was 40psi with the engine off and 32 with the engine running.

For the MAF wiring I used my multimeter and tested the ground and power wire. I noticed that with the ground if I put one lead on the ground and then grounded the other lead i would get .100 volts. Then when i put the one lead on the positive terminal I would get 12.6. I thought that was a little odd and the same thing happened when testing for the ground. It seems like there might be some feedback, i'm really starting to think it's the PCM. Whats the best way to test the wiring to be sure?

 

[rcfast]

Also I forgot to say.. When I tested the fuel pressure it held 40 psi for 10 minutes and was still holding it until I released the pressure. So the diaphram in the FPR isn't ruptured and the injectors aren't leaking.

 

[410Fortune]

Check the torque on your upper and lower intake manifold bolts, these intakes are notorious for developing leaks with age.

However with your immediate MAS code I expect the issue lies somewhere in the MAS wiring or signal.
I do not know how to test the votage of the MAS signals, I never had to but yo ucertainly can test the continuity from the MAS to the PCM, you will need a wiring pin out for your PCM.
Keep in mind the grey/red wire is whats called the signal sensor return and it runs to many sensors on the engine.

 

[CDW6212R]

BTW, the fuel pressure regulator doesn't leak fuel when it's bad. The diaphram is for lowering the fuel pressure. At idle the vacuum pulls the diaphram, and thus it should be that 32psi range. The pressure should go up with the line off.

Only WOT should provide that high 40psi of pressure. Go back and check the FPR again, good luck.