Napster134

Hi all,

I'm having an issue with my car (1991 Pontiac Firebird TBI) where I have no spark. I do have fuel coming out of the injectors into the TBI but no spark from the coil/wires.

Here is what I've done so far:

1. Replaced distributor.
2. Replace coil.
3. Replaced spark plug wires. (I was going to do this anyways)
4. Verify 12 volts exists at coil.
5. Verify that while cranking the injectors pulse and fuel is sprayed into TBI.
6. Tested for pulse at the white wire on the coil. I found no pulse exists. I then replaced the distributor to rull out the pickup coil and ignition module)
7. Replaced connector between the 2 wire connector between the distributor and the coil.
8. Disconnected the 4 wire connector at distributor and checked for spark yet still no spark.

I'm very curious what else is needed to get spark to output from the distributor or what else could cause no spark to output from the distributor/coil?

Any help/suggestions appreciated!

Thank you!

RBob

iTrader: (1)

First thing to do is to either pull the two injector fuses, or disconnect the connectors from the injectors. Otherwise swapping spark plugs will be next once spark is back.

Since the ECM is activating the injectors it is getting distributor reference pulses (DRPs). Can verify this by doing a key-on, engine-off until the fuel pump stops. Then do a short crank, the fuel pump should again run for 2 seconds.

Can also observe the tachometer on the WUD during cranking. If it shows RPM (100 - 200), then the ECM is getting DRPs.

Does the vehicle dash tachometer show RPM while cranking? Likely not as spark is required for RPM to show.

So if the above checks out regarding getting DRPs to the ECM, that means: the ICM is getting power (via coil power via the pink wire on the two wire pigtail). That the distributor is rotating and the pickup coil is OK.

At this point put a spark checker on the output of the coil. Any spark while cranking? If so then move on to the coil to cap wire, along with the cap and rotor.

If no spark at coil, then either the coil is bad or the ICM is bad or the two wire pigtail white wire is bad. The white wire from ICM C- is what dwells and fires the coil.

Note attached ignition system check from the FSM.

RBob.

Napster134

RBob,

Thanks for all the help!

This was my problem:

"or the two wire pigtail white wire is bad. The white wire from ICM C- is what dwells and fires the coil." - RBob

Basically, the two wire connector had the terminals pushed out. Somehow, I think the wires got yanked and the terminals were not pushed out far enough to make it obvious that there was no connection being made.

Anyhow, I replaced the two wire connector and bam! I had spark!

Thank you once again for all of your continuous help and support!

RBob

iTrader: (1)

Glad you got it going. Those 2-wire pigtails are troublesome.

RBob.