5.0 10

A buddy of mine has an '86 bird with the 2.8 MPFI. UIt's come time for him to go for a sniffer test. We just put the cat back on it and put a new O2 sensor in it. We're having a problem with the engine seting a code a few seconds after the car is started. I was wondering if a pickup coil coild be bad and still allow the engine to run. Also what else could be causeing this? When the engine starts it stumbles a little bit and almost stalls then the SES light turns on and the idle comes back up too 800. Also when stopped at a stop light after about 30 seconds of waiting RPM's will go up and down from 800 to 1200 in drive. It kinda sounds liek I'm revving the engine bu tI'm just holding my foot on the brake in drive.

TomP

We've gotta know the code that the engine is setting first... when that SES light comes on, the computer stores an error code in memory.

1. Key off
2. Look at the ALDL connector under the dash, above the driver's feet, to the right of the steering wheel, covered with a black cap. Remove the cap. Take a piece of wire and strip both ends (or unfold a paperclip). Ignore the bottom row of pins, and just look at the top row. In the top row, connect the rightmost (passenger side) two pins together. As in, x x x x Y Y , connect the Y's in the TOP row.
3. Turn the key to "on/test lights". This is the position right before "crank". Don't start the engine!
4. The SES light will begin to flash, and will display all stored error codes.

It'll flash in a certain sequence. The first sequence goes "flash, pause, flash flash, pause, pause, flash, pause, flash flash, pause, pause, flash, pause, flash flash, pause, pause. That translates into 12, 12, 12. (count the # of flashes).

Each code repeats 3 times, and when there are no codes, it starts over with 12. (12 basically means "computer okay"). For instance:

flash flash flash, pause, flash flash flash flash = code 34.

Let us know the code!

Oh and yeah a pickup coil could be bad and the car will still run, but there's no code for a bad pickup coil. Did he always get this code? Or did it show up after replacing the oxygen sensor? If so, check to make sure the oxygen sensor wire didn't burn on the exhaust; this would cause a short, and set code 44 (lean exhaust).

5.0 10

I cant remember whar code it is but it is 4 flashes then 2 flashes.

TomP

So, code 42? Did it repeat three times?

Here's a bit of a chart I typed up for a kid and never sent him. It'll help you trace out the whole ignition system. If you're unsure of how to work on a car safely, you might be better off bringing this to a mechanic. It's not rocket science, you just need a meter and a test light, but don't get shocked by the spark coil or get pulled into the fanbelts or etc!

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On the distributor’s four pin connector, here’s the wire color/descriptions:

Connector pins facing you, connector clip facing UP. Terminals are labeled, from left-to-right, D, C, B, A. Wire colors from left to right should be D=white (ckt 423), C=purple/white (430), B=tan/black (424), A=black/red (453).

Inside the ECM: D is the EST control wire. C is the spark reference signal. B is the EST by-pass (used to set the timing). D is an internal ECM ground. Don’t check the signals from the ECM unless you know what you’re doing, or you can fry the ECM.

If you remove the negative battery terminal, and then unhook the ECM connectors, you could probe these wires for continuity, to make sure they’re not cut in half between the computer and distributor. The connectors should NOT be attached to the ECM while performing a continuity test. On my ’86 GM book, it shows the following:

423 White (distrib pin D) going into ECM connector B4 (row B is on the smaller 24-pin ECM connector)

430 Ppl/white (distrib pin C) going into ECM connector B5

424 tan/black (distrib pin B) going into ECM connector D5 (row D is on the larger 32-pin ECM connector)

453 black/red (distrib pin A) going into ECM connector B3

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Let me give you some easy stuff to check out before you run the chart.

First: By you continuing to read further, you agree that I am NOT responsible for what happens to you/your car/your friends/etc. Do not attempt anything that you’re not sure of. If you’re not sure, bring the car to a certified professional mechanic.

Second: You know how to check for spark, right? John told me that he showed you guys this. Put a screwdriver inside a plug wire. Lay the screwdriver so the metal of the shaft is NEAR something on the car, like a fender. Then you crank the engine, and look for spark. This way you don’t KILL yourself by getting shocked. Got it?

Third: Pull the gray connector off the ignition coil. There’s two wires on there, pink/black and black/white. Put your ignition key on. Check the pink/black wire for voltage. You should get 12 volts. This is how your whole ignition system powers up! If you don’t get 12 volts to the coil, you don’t get 12 volts to the distributor.

Fourth: (Turn the car off, obviously) Pull off the 2-wire connector from the distributor, and remove the black connector from the ignition coil. I want you to check these wires for continuity; that means, there’s no internal break in these wires. This is covered in step 4 of the chart, but you can eliminate a problem faster by checking this before doing the chart. If the wires are okay, put this mini-harness back on the car.

Fifth: Do the “wiggle test”. NEVER touch a spark plug wire or coil wire while you do this test. Have someone crank the motor while you wiggle the wires going into the back of the distributor, and at the coil. If the motor starts up, you’ve got an internal break somewhere in these wires, and by wiggling them, you’ve made the wires make contact.


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Alright, here’s the chart. You need a multimeter (can be analog, but DON’T measure ECM voltage using an analog meter- use a digital for that)

1. Check for spark on TWO spark plug wires. This makes sure that one of your wires isn’t ****ed up.
1a. Got spark? Check fuel, plugs, etc
1b. No spark? Go to 2.

2. Disconnect the 4 terminal distributor connector, and check for spark.
2a. Got spark? Pull the distributor and replace the pick-up coil. This means that
the pick-up coil output is too low for the ignition system to operate. In
case you don’t know, the pick-up coil is NOT the spark coil. The pick-up
coil is internal to the distributor. A Haynes manual from Pep Boys would
show you how to replace this.
2b. No spark? Go to 3.

3. Reconnect the distributor’s 4-terminal connector. Pull the spark coil wire off the distributor end (center wire, of course). Check for spark.
3a. Got spark? Check/replace distributor cap & rotor.
3b. No spark? Go to 4.

4. Disconnect the two terminal connector from the distributor. Turn the ignition switch to “on”, but don’t crank the engine. This is the switch position right before crank, where your dash lights come on. At the distributor HARNESS 2-pin connector, check for voltage between each of the two terminals and ground. As you look at the distributor harness 2-pin connector, with the terminals FACING you, and the connector clip UP, the “C” terminal is on the left. The “+” terminal is on the right. They might be labeled on the connector.
4a. Both terminals at 10 volts or more? Go to 5.
4b. The “C” terminal is under 10 volts? Check for an open or short-to-ground
in the circuit from the “C” terminal to the ignition coil’s black connector,
terminal “A”. These –ARE- marked on the black coil connector. This
means your distributor isn’t giving a “spark!” signal to the spark coil.
4c. Both terminals under 10 volts?? Repair wire from the “+” terminal (distrib
harness side) to the “B” terminal on the ignition coil’s black connector.
Then, re-do this step #4! This means your distributor isn’t getting any
power from the spark coil.

5. Reconnect the two terminal connector. With ignition on, check voltage between the tach terminal to ground. In case you don’t know, this tach terminal might be taped back in the engine harness. Don’t bother finding it. It comes off of the GRAY spark coil connector, and it’s the black/white wire, pin “A” on the gray connector. Pierce the insulation and probe the wire that way.
5a. 1 to 10 volts? Replace the module, and check for spark again. If no spark,
then replace the spark coil too, it’s probably faulty.
5b. Under 1 volt? You didn’t pierce the insulation enough; you’re not making
a good enough contact with the tach wire.
5c. Over 10 volts? Go to 6.

6. Connect a test light from between the tach terminal (gray spark coil connector, pin “A”) to ground. Crank the engine and watch the light.
6a. Light blinks? Replace the ignition coil and re-check for spark. If no spark,
reinstall the original spark coil, and replace the distributor module.
6b. Light on Steady? Go to 7!

7. There’s much more to type, but it’s all basically testing out the ignition module and the pick-up coil further. There is ONE thing left on the chart that your buddy could check out- make sure the module is grounded properly.
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Let us know how it goes (or what you do to fix it!)

5.0 10

I haven't got a chance to check the continuity of the wires yet. I just thought I'd clarify a few things. My buddy went for his sniffer test today and passed with flying colours. We still have a problem with the ignition though. When we first start the car the light stays off now. Whenever the light is off the car has no power and feels like the timing is too far retarded. Right now i think we have the base timing set at 12 degrees. Any lower than that and it is way down on power. The car has 230,00 km on it so we think the timing chain is stretched causing us to have to avance the ignition timing more to make decent power. Anyway. when driving with the SES light OFF there's no power and the tach needle likes to jump around. It'll jump from liek 1000 rpm to liek 3000 rpm sometimes with out the engine going to 3000 rpm. The needle is also generaly unstable when the SES light it off. When I watch with a timing light with the SES light off as the engine is revved the timing appears to retard like 5 or 10 degrees until about 2000 rmp depending how how quickly you open the throttle. Is this normal? With the SES light OFF the car also doesn't accelerate very smooth and can sometimes be a little bit jerky and seems to jerk in tune with the tachb needle jumps. Now after a while of driving sometimes the SES light will turn on. When this happens we get back most of our power and the tach needle while no longer jump and is perfectly smooth. The car also accelerates smoothly. But at stop light with the SEs light ON the rmps will go form 600 RMP to like 1200 rpm and back down again. It will only do this in drive at a light. We suspect we have a broken wire somewhere because of how intermittent this problem is or maybe a bad ignition module.

TomP

Glad he passed the sniffer! Have you checked the TPS voltage? Is the IAC pintle/passageway and throttle body cleaned out? Is all the regular tuneup stuff okay (plugs/wires/dist cap/rotor/filters)?

5.0 10

plugs, cap, rotor, filters. dist cap are all new. I'll get him to check the TPS volatge an dcheck his IAC valve and passageway. We're think it's dist/wiring related because sometimes his car wont do any of the stuff I mentioned an dother times it does it really badly.