my eec is acting up... ran codes... | Ford Explorer Forums - Serious Explorations

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my eec is acting up... ran codes...

91ROKKRAWLER

Well-Known Member
Joined
December 6, 2007
Messages
510
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City, State
Bend, OR
Year, Model & Trim Level
'91 Xploder
i replaced my upper intake manifold gasket and my valve cover gaskets. i had several plugs undone and i'm pretty sure i plugged them all back in right. a few days after, i went and got some engine cleaner from o' reilys. i sprayed 2 cans onto the engine while it was warm, pressure washed it at the car wash, and then started it up and drove away.

here lately whenever i drive over a certain distance (4-5 miles?) my CEL comes on. well i was idling at the 7/11 and my a/c compressor kept kickin on and off so i unplugged it. i got home and decided to run codes. i came up with the following...

FIRST TEST
------------
KOEO
79
79
------------
CM
41
54
41
54

------------
KOER
42
42
------------

I then cleared the stored codes by disconnectin my jump wire while it was runnin codes a second time.

I RE-tested two more times and came up with this both times

KOEO
79
-------
CM
111
111
-------
KOER
42
-------

when i looked it up my KOEO (79) was a/c on during test... how can it be on when its unplugged?!?!?
then my KOER (42) is 0xygen sensor running rich, right side. is this because i sprayed the engine cleaner on and possibly got it into my air filter since i took my front duct down to the bumper off?

HELP!!!!!!!!!!
 



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Remember that the PCM can't see past the end of its proverbial nose. It only knows what it can see at the connector -- It doesn't have good enough eyes to go all the way out to the compressor to see that you've unplugged it. My code list points out that a KOEO 79 means that the PCM is seeing power at pin 10 during the KOEO test, which it will see if the AC switch is on, whether or not the compressor is plugged in or not. If you know the switch is off, then look for a short to power in the wire that goes to pin 10 (might also explain why your compressor was cycling unexpectedly).

I could possibly see an air filter/air intake saturated with a cleaner triggering a rich code. I could also see this being caused by a short to power in the O2 sensor wiring, possibly from a connector that got contaminated when you cleaned the engine or something that didn't get back together right when you changed the gaskets. Or maybe something got hooked up wrong fuel wise and the fuel system is dumping too much gas in.

A couple of things I would probably do: check fuel pressure to make sure it's right. backprobe the O2 sensor circuit and see if there are any obvious errors in the O2 sensor signal. Pull spark plugs and check exhaust to see if other indicators suggest that the engine really is running rich, or if the engine is really running lean (to see if the O2 sensor is simply reporting what it sees, or if it isn't really seeing what's in the exhaust).
 






i think the only things we disconnected were the vacuum lines, tps, iac, throttle linkage, heater hose to intake, and the two big connectors on the passenger side. i'll look it over again but as far as my filter goes, its pretty much exposed to the elements. no inner fenders, no duct work, and a slot cut in the side of the box to act as a cold air intake, it takes its air in from the passenger side fender and bumper area...

i know the a/c switch is off in the cab, and unplugged so maybe its a fuse or wiring. where would i look? at the switch itself or... also is there suppose to be gaps between the upper intake and the lower intake? i fit the intake right and the gasket right but there is like 4 slots on the passenger side of the intake... i will take pics later.

thanks shorty
 






i know the a/c switch is off in the cab, and unplugged so maybe its a fuse or wiring. where would i look? at the switch itself or...
Maybe the switch itself isn't opening, or elsewhere in the circuit. I don't know physically where that wire runs through the harness -- you may just have to trace it as best you can.

also is there suppose to be gaps between the upper intake and the lower intake? i fit the intake right and the gasket right but there is like 4 slots on the passenger side of the intake...
I'm not sure where those 4 slots would be, but I look at mine and I don't see any gas between the upper intake and the lower intake. There are a few spots where you can't see the gasket from the outside, and it kind of looks like there's a gap there, but that's just because the gasket isn't visible.
 






ok so its gotten worse!!!

i got a new air filter, pulled the o2 sensor and cleaned the tip off, and i've ran codes over and over...

i'm now getting

KOEO
11
-------
CM
111
111
-------
KOER
42
-------

so its still pointing me to the o2 sensor. earlier today, while stopped at my mailboxes, my truck stalled. i have gas in it, 1/4 tank, and it was in gear not moving. i went to let off the brake and it stalled on me. i restarted it, and it kinda stumbled to acceleration.

also, i went to look at it earlier and i started it. i listened to the fuel pump, it had a high pitch whine (assuming the normal whine) for about 5 seconds. then it fell into a lower warbling sound and the truck started running weird.

so do i fix it by buying a for sale sign, buying dynamite and blasting caps or is there an easy solution?
 






KOER 42: O2 sensor indicates system is rich. So the first question I would naturally ask would be: based on other symptoms (exhaust condition, spark plug condition, etc.) does the engine really seem to be running rich or is the engine running lean?

By the book, the first test with most O2 sensor codes is to check fuel pressure.
 






i decided to try to clean my maf. i did clean it and i plan on disconnecting the battery for 10 min< to reset the ecu. i'll let you if that does it.
 






replacing the o2 sensor, and cleanin the maf didn't do it. i'll replace the plugs tomorrow. right now the KOER codes are 21 42 and 96. thats accurate as of today. CM and KOEO are both pass right now.
 






KOER 21 is for the ECT: usually means the engine wasn't fully warmed up for the KOER test. check engine temp and repeat test.

My code list and Brooklyn Bays code list (both "generic" lists) indicate that a KOER 96 is for an AIR system, which your Explorer doesn't have. Maybe in this application it really points to a fuel pump circuit fault, but I'm not sure.

Outside of that, it looks like you are still working on a KOER 42. In addition to replacing parts, have you tried any of the tests that have been suggested?
 






i haven't been able to yet. i don't have the tool to do it and autozone charges 145 just to RENT the tool to check fuel pressure. in the upcoming days (since i've been moving and stuff) i am gonna try to change my plugs so i can see if they show burning rich... i'll keep you updated.
 












i was definetly told wrong then... lol
 






so it was 35 psi running idle and 40 when goosed. i changed the plugs and it seemed to run better but it still throws the KOER 42. i tested it twice because the first time it still had the 96 and 42. everything else KOEO - CM is Passing. just the KOER is killin me. i'm guessin it is runnin rich cuz i'm using quite a bit of fuel. and it has a gassy smell from the exhaust, which is heavily sooted.
 






Sounds like it might be running rich. When you changed the spark plugs, what did they old ones look like? sooty and carboned up?

Any sign of gas in the vacuum line to the FPR?
 






the plugs had a white powdery look to them. high speed glazing? how would i check the fpr?
 






You check the FPR by testing fuel pressure, which you've already done, and the FPr is controlling fuel pressure beautifully. The suggestion to check the vacuum line is meant to check that the diaphragm has or hasn't ruptured. When that diaphragm ruptures, it dumps unmetered fuel into the intake through that vacuum line, which causes the engine to run rich. It should be as simple as running the engine, then pulling the vacuum line off of the FPR and seeing if there's any gas in that vacuum line.

Which spark plug did yours look most like http://www.ngksparkplugs.com/techinfo/spark_plugs/faq/faqread2.asp
 






between normal and deposits
 






checked my fpr vacuum line, dry... i also installed a cold air intake for more air. is there a possibility my throttle body, iac, tps or somthin is bad? would that throw a seperate code?
 






Spark plugs suggest to me that it is running rich, and maybe getting some oil/coolant into the combustion chamber.

Any of those other things could be bad, and they may or may not set their own codes. You have to remember that the computer (especially these older ones) aren't always that smart. All the computer knows right now is that it is reading a rich signal on the O2 sensor and nothing it does to the fuel injector pulse width "fixes" the problem.

When you tested fuel pressure, how long did you leave the gauge on? I know many people have reported that they would put the gauge on, the pressure would look normal for a time, then the FPR would shut closed and the pressure would spike, causing the rich condition. It might be useful to rig it up so you can monitor the pressure while driving, drive it until the CEL comes on, then see if the pressure stays normal.

It might also be useful to put a voltmeter on the O2 sensor signal and see what it is doing.
 



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80-82 psi... dips to 72ish when i rev it. i didn't use pipe tape last time so i had fuel everywhere. now i used pipe tape and its showin about 80-82 at idle... REALLY RICH...

so that points to my fpr right?
 






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