replaced distributor now truck will not start

[obs902500]

The bottom of the ICM is made of steel. It rests on a steel plate on the distributor under the distributor cap. It gets warm when it is in use. The new ICM's usually come with a heat sink compound that is put on the steel bottom part of the ICM where it is in contact with that steel plate to dissipate this heat. If you didn't put the compound on the bottom of the new ICM when you installed it, it MAY have overheated. Not absolutely, but possibly.

Check out this reference for what an ICM does. There are things similar to what you are experiencing contained in it:

Ignition Control Module Failures: How to Recognize Symptoms and Estimate Replacement Costs | The Motor Guy

If you’re experiencing problems with your vehicle’s engine, it could be due to a faulty ignition control module.

themotorguy.com

ohhh i see, i did not add any. I’d assume the distributor came with heat sink already but even if it didn’t i haven’t had the truck running long enough to generate that much heat. it’s been sitting for a while since i’ve been trying to find this problem and when i start it its just to let the truck get to open loop to read off sensors but it hasn’t really gotten that hot yet.

 

[H2814D]

ohhh i see, i did not add any. I’d assume the distributor came with heat sink already but even if it didn’t i haven’t had the truck running long enough to generate that much heat. it’s been sitting for a while since i’ve been trying to find this problem and when i start it its just to let the truck get to open loop to read off sensors but it hasn’t really gotten that hot yet.

If your new distributor came with the ICM installed, I would guess the heat sink compound would have been installed with it. But you should verify that with your distributor supplier. If YOU installed the ICM, and you didn't put the compound on it, it needs to be done.

And just so you are clear, "open loop" is an engine that is not relying on the computer for most functions- A cold engine. "Closed loop" is typically encountered at operating temperature, and based on run time, O2 sensor operation, and coolant temperature- A warm engine. Your computer is controlling most engine functions in closed loop.

 

[obs902500]

If your new distributor came with the ICM installed, I would guess the heat sink compound would have been installed with it. But you should verify that with your distributor supplier. If YOU installed the ICM, and you didn't put the compound on it, it needs to be done.

And just so you are clear, "open loop" is an engine that is not relying on the computer for most functions- A cold engine. "Closed loop" is typically encountered at operating temperature, and based on run time, O2 sensor operation, and coolant temperature- A warm engine. Your computer is controlling most engine functions in closed loop.

yes closed loop sorry i keep getting them mixed up. But yea im currently researching to see if davis adds heat sink on the distributors.

 

[bowtie-72]

I’m with the Buick guy that said that maybe the timing is one tooth off. It sure sounds like it. If you have the distributor in correctly, are you absolutely SURE the timing gears are lined up in time?

 

[Russ B]

When all else fails. Put the old distributor back in get back to where you started. I had a 89 K1500 5.7 TBI and the rotor would be dead straight toward the front of the engine, not to #1.

Pulling the valve cover is pretty extreme. You can rotate engine by the crank bolt with finger over #1 spark plug hole until you get compression then line up crank pulley mark to the timing cover tab. Clean both those marks and use white or yellow paint so you can see it. To save the effort, I got a spark plug adapter (from compression tester set) and put finger from rubber glove with rubber band and watched for expansion.

Like above it appears you are one tooth off. So try moving a tooth one way.

If all else fails, the ICM on DIY distributors are not the best quality and could be defective. Swap the one out of the old distributor or get a GM original.

Not to be insulting, but any possibility you messed up the spark plug routing to the distributor. Easy to do.

 

[obs902500]

When all else fails. Put the old distributor back in get back to where you started. I had a 89 K1500 5.7 TBI and the rotor would be dead straight toward the front of the engine, not to #1.

Pulling the valve cover is pretty extreme. You can rotate engine by the crank bolt with finger over #1 spark plug hole until you get compression then line up crank pulley mark to the timing cover tab. Clean both those marks and use white or yellow paint so you can see it. To save the effort, I got a spark plug adapter (from compression tester set) and put finger from rubber glove with rubber band and watched for expansion.

Like above it appears you are one tooth off. So try moving a tooth one way.

If all else fails, the ICM on DIY distributors are not the best quality and could be defective. Swap the one out of the old distributor or get a GM original.

Not to be insulting, but any possibility you messed up the spark plug routing to the distributor. Easy to do.

i thought about it and am probobaky going to put the old one back in. I see where you guys are saying that i might be a tooth off, but wouldn’t it make my timing bad at all times? The truck only runs “normal” when the advance wire is disconnected. once i turn off the truck and connect it the timing jumps to 40-60 degrees and jumps around.

 

[obs902500]

When all else fails. Put the old distributor back in get back to where you started. I had a 89 K1500 5.7 TBI and the rotor would be dead straight toward the front of the engine, not to #1.

Pulling the valve cover is pretty extreme. You can rotate engine by the crank bolt with finger over #1 spark plug hole until you get compression then line up crank pulley mark to the timing cover tab. Clean both those marks and use white or yellow paint so you can see it. To save the effort, I got a spark plug adapter (from compression tester set) and put finger from rubber glove with rubber band and watched for expansion.

Like above it appears you are one tooth off. So try moving a tooth one way.

If all else fails, the ICM on DIY distributors are not the best quality and could be defective. Swap the one out of the old distributor or get a GM original.

Not to be insulting, but any possibility you messed up the spark plug routing to the distributor. Easy to do.

I checked my wires many times, and placed all wires from cap to cap one by one to make sure of this. I have about 5 google tabs open of the wire diagram but sadly that’s not the problem

 

[obs902500]

al

I checked my wires many times, and placed all wires from cap to cap one by one to make sure of this. I have about 5 google tabs open of the wire diagram but sadly that’s not the problem

so just out of curiosity, could it be a problem with the egr? Like could it be bad, or the solenoid be bad?

 

[H2814D]

al

so just out of curiosity, could it be a problem with the egr? Like could it be bad, or the solenoid be bad?

Could be, but let's make sure of everything else first. Your distributor seems to be back in correctly, based on your comments. It may be time to go backward now. Go back and check every single sensor connection to every single sensor and solenoid (MAP, EGR, TPS, ICM, IAC, etc.) and confirm they are all attached properly. Check EVERY one of them, even the O2 sensor and the cam/crank position sensor.

Check every single one of your vacuum lines and make sure there are no vacuum leaks ANYWHERE and that they are all hooked up to the right places. Recheck the tightness and torque specs of your TBI to the intake manifold.

Make a list of every sensor that has to do with ignition timing. Make a list of every sensor that is connected to your TBI and emissions system. Then one by one, check off that they are connected properly.

If your EGR is not operating properly, you should get a Service Engine Soon (SES) light. You can pull it to check its functioning and cleanliness, or you can do a basic function check while it is still installed, but unless you find something wrong with it, don't just go and replace it yet.

Just curious. How many miles are on your truck? I don't think I've seen that anywhere yet.

 

[obs902500]

Could be, but let's make sure of everything else first. Your distributor seems to be back in correctly, based on your comments. It may be time to go backward now. Go back and check every single sensor connection to every single sensor and solenoid (MAP, EGR, TPS, ICM, IAC, etc.) and confirm they are all attached properly. Check EVERY one of them, even the O2 sensor and the cam/crank position sensor.

Check every single one of your vacuum lines and make sure there are no vacuum leaks ANYWHERE and that they are all hooked up to the right places. Recheck the tightness and torque specs of your TBI to the intake manifold.

Make a list of every sensor that has to do with ignition timing. Make a list of every sensor that is connected to your TBI and emissions system. Then one by one, check off that they are connected properly.

If your EGR is not operating properly, you should get a Service Engine Soon (SES) light. You can pull it to check its functioning and cleanliness, or you can do a basic function check while it is still installed, but unless you find something wrong with it, don't just go and replace it yet.

Just curious. How many miles are on your truck? I don't think I've seen that anywhere yet.

ooooo i have about i’d say 220,000 if i remeber correctly, but i can’t go check right now and tell you because my gauge cluster went out and it’s the moon gauges, while opening my gauge cluster i found out i can play with the miles, i never moved them (yes i did but on accident). so the miles may be higher or lower but it was around 220,000. And how you stated i did check every single sensor, o2 map iac tps egr and ever vacuum line, map vacuum line, basically anything i can see also the coolant temp sensor, battery connections, ground connections.