Ok, I finally Had the car running after fixing the 4-prong plug to the dist. It wast twisted and cracked.

Everything in the dist is good, including the module. the ignition coil and pick-up coil is also good.

The car had been running fine. I would go out, start it up and let
it run untill the fan had kicked on a few time and gotten up to operating temp.

I went back out a few days later to start it again and it just cranked.

It set code 42 and 43. Im afraid the ECM is going south.

What do you guys think.

 

some body has to have a educated guess. Looks like I will be tossing the TPI for carb anyways.

 

Code 42 - EST
Code 43 - ESC
Did you make sure your EST wire is connected? It's the tan/black 1 wire connector over by the heater blower motor. It's also part of the 4 pin connector you dealt with.

 

yeah, it is connected. The car had been running fine. I shut it off and left it for a few days and went out to start it up and it would just crank. The dist is too tight to have moved, so it had to have retarded the timming or the computer is going bad one.

This thing is driving me crazy!!!!!!!!

 

Do you have a shop manual? If not, I'll see what I can do about getting my scanner working. If so, I can hook you up with the troubleshooting tree for codes 42 & 43.
Do both codes come back if you reset them?

 

yes I have a chiltons and haynes manual. I have followed every test for code 42. I have not tried to reset it since this last episode. I did notice that the fuel pump seems to run along time now. I may try to start it with the EST disconnected or something.

Right now I am fed up with it. I had it set at 6* timing, so I cant see were the knock sensor would have retarded it. I will do somemore checking as soon as I can. Its pretty cold here.

 

update. Ok, I reset the computer and tried to start the car.
It just cranked. I then turn the key to the (on) position and here a buzz or clicking noise around the TPI. I put my hand on the TB and can feel it. I unplugged 6 of the injectors and nothing changed. Could it be the IAC? Would this cause it not to start at all?

I am going to pull some plugs and see if I am getting spark at the plugs, and also I will check the fuel pressure at the rails and at the main line comming from the tank. If I dont find the problem soon, I am ripping it off and going carb.

Help before I shoot this damn thing.!!!!!

 

Code 33 / 34 tests.

First check air ducts for cracks, holes and tighten clamps.

With the ignition off, unplug the MAF and apply power to ALDL terminal
"G". Check the red wire on the MAF connector for power. If no power,
verify 12v on relay connector orange and white/tan wires. Verify the
connector black/white wire is grounded. Verify black wire from MAF
connector terminal B to ECM connector A11 with an ohm meter. Verify
red wire from relay connector to MAF connector with an ohm meter.
If all is good replace MAF power relay.

Turn ignition on, Check MAF connector dark blue wire for 12v, if so,
unplug MAF burn off relay and check again. If so, check relay
connector black wire for ground. If so, the black wire is shorted to
ground or the ECM is bad. If not, replace MAF burn off relay.

If the dark blue wire at the start of the above test had no voltage,
check the MAF connector dark green wire with ignition on for a 5v
reference signal. If so, and all connectors are good, replace MAF.
If no 5v reference on dark green wire, verify it from the MAF connector
to ECM connector B12 with an ohm meter. If the wire is good replace the
ECM. If the dark green wire has 12v on it, turn ignition off and unplug
the ECM connectors. Turn ignition back on and check again, if so,
it is shorted to power somewhere. If not, and all connectors and
grounds are good replace ECM.

 

Sorry swapmaster, I forgot to tell you that is a Speed Density system. And it is code 42 and 43. Thanks for the help though.

 

Hey bluegrassz,

Are you without injector pulse and still have spark ?

The buzz sound, is it possible that it is actually coming from the right rear of the intake area, may be the egr solinoid ? (normal) If the injector driver circuits bad inside the PCM it could be feed back or the driver for the iac circuit could be bad. Before when I had replied to your post I felt you had a bad PCM then. You can get one from Napa for probley about 75 bucks.

Good luck

 

OOPS, hold on, let me llok it up.

 

What yer do you have?

 

Those are est codes... That is why I was wondering about spark ?

Code 42 : problem in comunication from the electronic spark timing controller to the PCM. a open or short in the ground circuit.

Code 43 is no power from the modual from to the PCM

There is a fuse or a fuseable link involved here also....

Gotta run.. Good luck man

 

Its a 92 motor and computer.

 

I am going to try and run it down. it must be a short or something. This fuel injection wiring drives me crazy. If the computer is going bad, How do I check it specificaly?

 

This is from the '92 firebird helms manual.

Code 42:

When the system is running on the ignition module, that is, no voltage on the bypass line, the ignition module grounds the EST signal. The ECM expects to see no voltage on the EST line during this condition. If it sees a voltage, it sets Code 42 and will not go into the EST mode.
When the rpm for EST is reached (about 400), and bypass voltage applied, the EST should no longer be grounded in teh ignition module, so the EST voltage should be varying.
If the bypass line is open or grounded, the ignition module will not switch to EST mode so the EST voltage will be low and Code 42 will be set.
If the EST line is grounded, the ignition module will switch to EST but, because the line is groudned tehre will be no EST signal. A code 42 will be set.

Try this troublshooting flow chart:
1. Ignition on,
2. Disconnect ECM connectors,
3. Ohmmeter selector switch in the 1000 to 2000 ohms range,
4. Probe ECM harness connector CKT423 (white wire between 4 prong connector at dist and ecm) with an ohmmeter to ground. It should read less than 1000 ohms.
If not; open ckt423 faulty connection or faulty ignition module
If so,
5. Probe ECM harness connector CKT424 (tan/black wire) with a test light to battery voltage.
Light on; disconnect ignition 4-way connector....Light on, ckt424 shorted to ground. Light off, faulty ignition module.
Light off,
6. With ohmmeter still connected to ECM harness ckt423 and ground. Again probe ECM harness ckt424 with the test light connected to battrery voltage. (As test light contacts ckt424, resistance should switch from under 1000 to over 2000 ohms) Does it?
Yes, Reconnect ECM and idle engine for one minute or until code 42 sets. Does code set? Yes = faulty ecm, No = memcal not fully seated in ECM (or intermittents which you don't appear to have)
No?
7. Disconnect dist 4-way connector. Note ohmmeter that is still connected to ckt423 and ground. Resistance should have gone high (open circuit)
Does it?
Yes, CKT424 open, faulty connections or faulty ignition moduel.
No?
CKT423 shorted to ground.

Let me know how this works for you. I'll also hit you with code 43 if need be.

 

You need a new ignition module.
I had the same problem and that is what it was.
I am in a vocational school for automotive and my shop teacher worked as a GM master tech for 14 years and he helped diagnose the problem. Make sure you apply the grease they give you with new module or it will go again. It is a grease that is made to dissipate heat for electronics. It usually comes with it.
Make sure you also clean all connections. If you don't get the grease with the module, it is called dielectrode grease.

 

forgot to mention this before.

I know you said you have a good module, check it again,because they are known to go. I work in a shop and cars come in with a bad module and when replaced they went in a few minutes. When they were replaced again the car was fine. I would try that.

Also, a bad module will cause you to have no spark.

 

Yeah, I plan on getting the module checked, and I will pull a few plugs to see if I am getting any spark.

The sad thing is, I just spent the money on that new accel module. That would suck if it already went bad.

 

UPDATE: The module is good. I had it checked. I have not checked the fuel pressure, or sparks at the plugs. I can pull the codes from the computer, so does this mean the computer is ok?

I really would like to get this thing going. I just dosent make any sense.

 

You need to clear the codes and see what comes back. See if you get a hard code right away and follow the diagnostic routine. I will send it to you directly from all data or the factory manual which ever you prefer if you will do that.

You may not have the same problem as before. Need to idenify if it has injector pulse and spark. Does it have fuel pressure ? that Kinda stuff.. The Computer can be bad and still give codes.. Yes

for instance the injector drivers might be bad....

If it has spark but not injector pulse like you had mentioned before. My responce was that I had never had a car with spark that didn't have injector pulse that didn't need a computer. It is possible but I have never run into it. Had 4 or 5 with the problem in the last couple 3 years.

 

Im going to do somemore checking. Its too damn cold here. The car is on the carport and the wind just whips through.

I just want to find out if it is the computer or not. I am going to change to carb, but I would like to get it going.

I does reset the codes when I clear them. I did two hard resets since this last time it has happend. I will check the connections were I replaced the 4-pin plug in for the module. I will also recheck the fuel pressure at the rail and the main line.

I will let you guys know what I find. Thanks for the info guys.