91 chevy won't start

[s1lv3r]

OK, Need a little help.

The truck is a 91 with 350. It has a new module in the distributor, new plugs,cap,rotor,coil and a new "pick up"(the ring inside the dist.)

After replacing all, the truck started and went down the road and then died.
We hooked up the "light bulb" on the fuel injector harness at the injector plug and no light. Also tested for spark and none.

Any ideas would helpful.

Thanks, Larry

[s1lv3r]

Can anyone direct me to an online wiring diagram?

[ChevyTech]

The computer needs to receive a distributor reference pulse from the distributor module to trigger the injectors.

Did you put heat sink compound/grease under the module when you installed it? Without it, the module will fail.

[s1lv3r]

Originally Posted by ChevyTech

The computer needs to receive a distributor reference pulse from the distributor module to trigger the injectors.

Did you put heat sink compound/grease under the module when you installed it? Without it, the module will fail.

Will the motor still receive spark if the computer doesn't see the pulse from the distributor module?

As for the heat sink grease, I'm not sure. My dad had already installed it before I got there to help him. The truck hasn't ran a significant amount of time since it's been installed.(couple minutes at best)

[ChevyTech]

Yes,
It is possible for the module to produce spark without the computer getting a reference pulse.

As for the heat sink compound/grease under the module it depends on many factors such as; was the new module set in the old grease, was the grease wiped off, was dirt and grit knocked lose doing the job and got under the module compromising the contact with the distributor so no heat gets transferred…

The new module could have failed already for quality issues even if it was installed correctly.

[s1lv3r]

Originally Posted by ChevyTech

Yes,
It is possible for the module to produce spark without the computer getting a reference pulse.

As for the heat sink compound/grease under the module it depends on many factors such as; was the new module set in the old grease, was the grease wiped off, was dirt and grit knocked lose doing the job and got under the module compromising the contact with the distributor so no heat gets transferred…

The new module could have failed already for quality issues even if it was installed correctly.

I'm a little baffled. After my initial post, I went and tried to start the truck and it cranked and ran for about 3 seconds and then died. Then once again, I had no spark and no injector signal to fire. The fuel pump is priming also.

I ohm'd the wires from the module to the ECM and they checked out good.

However, I did notice that when the truck has cranked that it's taken a fair amount of time before it starts.(2 to 3 sec).

If the module is bad, does it typically not allow spark or fueling? Or does it even work like that?

[cayoterun]

Similar problem on a '97 454 brought me to this site. Without the looong story, it turned out to be a faulty NEW distributor cap.
It was suggested by this board to go back and put old components on one at a time. By then, I had taken it to the local dealership. Loong story short, I have a $800. NEW FAULTY distributor cap laying by my chair as a reminder.

Mine was running, but was due a tune up. I did it myself, started it up, it ran about a minute, then quit.
Good luck & hope you find your problem soon.
Cayoterun

[ChevyTech]

Did the vehicle have this problem before you put in the new parts?

Did you use Gm original equipment parts?

Cayoterun’s thought of putting the old parts back on is not a bad plan.

Work on the lack of spark problem first. The injectors not being triggered is most likely a result of the ignition problem.

It would be a good idea to look under the distributor module and see if your dad put heat sink compound under it. If not you should replace it. If he did you may want to take it out and have it tested. NAPA stores in my area will test them for free. If the old module was working ok you may want to put it back in.

I would rather have a used working gm module then a new after market module.

[s1lv3r]

Originally Posted by ChevyTech

Did the vehicle have this problem before you put in the new parts? YES

Did you use Gm original equipment parts? NO

Cayoterun’s thought of putting the old parts back on is not a bad plan.

Work on the lack of spark problem first. The injectors not being triggered is most likely a result of the ignition problem.

It would be a good idea to look under the distributor module and see if your dad put heat sink compound under it. If not you should replace it. If he did you may want to take it out and have it tested. NAPA stores in my area will test them for free. If the old module was working ok you may want to put it back in.

I would rather have a used working gm module then a new after market module.

Yes the heat sink compound was used.

No, the parts are not OEM.

[71/454]

Curious why you replaced the module and pick up coil. Did the truck die previously and these parts were bad so you replaced them? If so the reason the may have failed may be due to the bushings in the distributor being worn. If this is the case and you didn't replace the bushings or distributor it will continue to take out the new pickup coil.

[ChevyTech]

71/454 has a valid point.
On these distributors the housing/upper bushing area gets so worn out that the shaft will move sideways so far that the points on the pickup coil pole piece get hit by the reluctor points on the shaft. When this happens the ECM receives compromised signal for RPM and timing issues.

The ignition coil could also be failing causing the system to lose spark. But that should not stop fuel from being injected.

The symptoms alone it almost sound more like it is running out of fuel.