So what's the update or did the hurricane put a damper on things?

 

hehehe if the hurricane is reaching me then the world is in trouble. i live in fairbanks, ak. i am in the process of switching the sensors and cleaning the maf sensor right now just checking up on how to clean it. then i will go for a test drive, pull the plugs and let you know how it goes.

 

Cool. I guess you can work on your car all night long this time of the year and never need a drop light. hey - clean you plugs to, the left side that was rich.

 

cleaned plugs, maf sensor and switched o2 sensors. runs worse and the left side is still rich and the right still spot on. havent done anything to the fuel pressure regulator yet though. oh and the check engine light still comes on. took it quite awhile but she came back. ran worse even before the check engine light came on though.

 

Did you clear the KAM - disconnect the battery. If not it would still be correcting left by adding more fuel and then the right side might have started to do this too if the O2 sensor is bad. I assume you checked the plugs then to see left still rich and right still normal. This is a good physical check. Get the new codes - well they'd onle be new if you disconnected the battery. Make sure you do this and get new codes. If after swapping the O2 sensors, you still get the same codes, then we have eliminted the O2 sensors as culprit. I wonder then too if you still have any lean bank codes. Cleaning the MAF should have fixed that. If not, the MAF could be bad - I've been recently informed that cleaning does not always work.

Curious, did the MAF look dirty? Good to clean it anyway. But I wonder if it was dirty, and KAM was not cleared, then it, from all past reports, would run everything lean. A bad O2 could then over ride that and make one side go lean.

Now since you are in Alaska, I assume this is not a California emmision car. If this is correct, you actually have a MFI systm - Multiport Fuel Injection - where all 3 injectors on a bank open up at the same time. A CA car is SFI - sequential fuel injection - and each injector opens up one at a time. You would think MFI dumps a bunch of fuel on top of the 2 intake valves that are not open at the time but no. There is a constant change of flow inside the intake manifold. It always goes to the one open intake valve. So dumping fuel in anywhere it will always go to the open intake valve/cylinder.

So this background is important to know because you are getting an entire bank going lean. As I mentioned before, there is only 1 control device that can affect just a right or left bank. That is the O2 sensors. This is the absolute truth. But then we must know why the O2 sensor is calling the left lean.

If it is truely lean, then we need to look at what affects only one side of the motor. Anything above the intake valves affects both sides since the intake manifold connects all cylinders. Below them is a bunch of cast iron and a couple critcal gaskets. Namely the head gasket. It is possible to have a leaking head gasket, or a cracket head, or a cracked block all which could leak coolant into a cylinder. Now there is a new source or O2 - H2O right? This could be sensed as a lean side and then the MFI juices up all the injectors.

I'm not sur what you did to the motor before. If it was totally rebuilt or not.

I guess at this point. Make sure you have new fresh codes, let me know, amd we can go from there.

Hey look! A susnet. Bet you haven't seen one of those in a while.

 

nope sure havent seen one for awhile.i disconnected the battery so the old codes should have been erased. next available time i have i will try to get the codes read again. is it the icm that controls how long the injectors stay open or the main pcm? when i had the engine out i never opened anything up. as soon as i got it out i realized that it was the aluminum spacer at the back of the crank that was my problem so i just replaced that along with the coresponding bolts and put it back in the same way that it was when i bought it.

 

OK then. Let's see what codes you have now. There is something because you have a CEL.

ICM does not touch the injectors. It only controls the coil. So if you have the Fed car, 3 injectors fire at once. Yes it is possible then, that one or more injectors on the left bank are bad. Too bad you don't have SFI as that's is much easier to pin point specific cylinders.

 

There is also a dynamic cylinder balance test you can run. I forgot about this. It might not work on your's. Maybe only on SFI cars.

When you run the KOER test, keep the car running and within 2 minutes of KOER finishing, goose the gas pedal - just like 1/2 throttle for an instant. This is where I'm not sure if it shuts down each injector or the spark, one at a time. If it's injectors, it wont work on your MFI. But it does drop each cylinder one at a time and looks for RPM drop. PCM will throw a specific cylinder code if it's off more than something like 10%.

Maybe your parts guy can help you try this.

 

This computer operated cylinder balance test does indeed work only for SFI engines. The computer disable each injector one at a time.

 

That's what I was afraid of. This guy has a serious A/F mix problem and we can't figure it out. I hope he won't have to start pulling heads off and magnufluxing for cracks...

So on this cylinder balance test - I tried it once on mine (it is California SFI). I could tell it was going through it's cycle as the R's were dropping. But when it was done, at least I think it was done, I got no new codes. Not even balance test pass. Shouldn't this be a 90 code? I'm wondring if the test never completed even though I let it go for 5 minutes.

By the way, do you know if it's possible to get 2 and 3 digit codes out of the same PCM? I've never gotten any 2 digit codes. Maybe this is why Ididn't get a 90?

 

I've been kind of following his AF problem, but haven't had anything additional to contribute. O2 sensor codes can be among the hardest to diagnose. I'll try to review this thread and see if I have anything additional to contribute as far as the O2 sensor code goes.

I'm not familiar with the cylinder balance test, other than knowing that it exists for SFI models. Both of mine are MFI, and so I haven't ever been able to run the test.

As for the 2/3 digit KOEO/KOER/CM code issue: A computer should output either 2 digit or 3 digit, but not both. As it relates to the Explorers (4.0 was the only engine in the EEC-IV years): '91 outputs 2 digit codes, '92-'95 output 3 digit codes. From the manuals I've seen, that's the way it should be. There may be exceptions, but I wouldn't expect many. Note that the 2/3 digit issue applies to KOEO/KOER/CM DTC's, not to the cylinder balance test output.

 

So waht do you mean on the cylinder output test codes? The only codes I have referrenced for this test are 2 digit. 10 is bad cylider 1, 20 is bad cylinder 2...I never saw any 3 digit codes referencing specific cylinders for this test. So My California sequntial fuel injected car, 1993, has only shown me 3 digit codes for the problems I have had. Yet it does run the cylinder balance test as I have been able to initiate it. If I can't get 2 digit codes, and the test only throws out 2 digit codes - well then really what good is the test if it can't tell me the outcome? What am I missing here?

 

I mean that the cylinder balance test codes should be as listed in the manuals (10, 20, ...., 90, 77). I've often wondered how you get a "0" digit when you are counting voltage pulses; I expect it's something like the way some scanners will output a "10" for the separator pulse in the KOEO test. In that case, since I would be doing it by counting voltage pulses, I'd probably call them one digit codes (2 with a long pause). Like I said, I have no experience with the EEC-IV cylinder balance test, so I really don't know what the output looks like or why you aren't getting any output from the test.

I know this is really starting to stray from the original posters question, but have you ever tried interupting the cylinder balance test by bumping the throttle during the test? According to my manual, that should yield a code 77 test interrupted/not complete.

 

No I never interrupted the cylinder balance test that way. I only tired it the one time a few weeks ago. But it's too damn hot around here these days to monkey around with anything in the garage just for fun. Supposed to be 116 today. Got to 120 at Lake Havasu yesterday. With that kind of heat I guess you ned a Lake. Thanks to Colorado and their river for that.

I'll check out you suggestion in the fall. And I'll try it with my scanner and then counting volt meter pulses.

Foof - how's it running now? Did youget your codes read?

 

it is running better but still not right. i changed out the upper intake manifold gaskets. in so doing i sliced some of the injector o rings so since i had them out i soaked them in injector cleaner for a little bit and put new o rings on them and put them back in right. got the codes read and here is what i came up with this time. 173,176,181,189. 181 and 189 have to do with the tps i believe. i am pretty sure that i replaced that in the middle of last winter. isnt there a voltage test that can be done on them though to see if they are operating correctly?