I'm in the process of helping my friend fix his 98 firebird fomula. It cranks, but won't start at all. Here is what i checked so far.

fuel - around 50psi pressure at the rail, I can hear the pump run when the key is turned on so yes it priming. So... Fuel is ok...

Spark. - No spark.

-I checked the relay (swapped the fan and ignition relay). Still not firing.
-15a engine control fuse is OK and has power.
-I disconnected a coil plug and the red wire has power when the ignition is turned on. I believe this means the coils are receiving power.

Still no spark!

Any idea's.

I'm thinking it's either the:

1- crank sensor (doubtful)
2- the little chip in the ignition key (maybe)
3- ignition module in the PCM (possible).

ANY other idea's would be GREAT! Thank you guys.

UPDATE:
I was watching the security light and when I turn the key on, it comes on then goes off. When I crank the car it remains off. If I've ben reading this forum correctly that means that the VATS (key) is not the problem. Correct me if I'm wrong. I'm still trying to figure this out so please help me.

Thanks!

 

I would still say crank sensor. Or bad PCM.

-Geoff

 

UPDATE:

Ok I took a nice scan tool that shows live sensor data and wanted to see If I could see RPM's while cranking the engine (testing crank sensor). Well.... The Scan Tool simply wouldn't connect to the PCM at all! It kept telling me to check my connection and start again.

I then tested the scan tool on two other OBDII cars and it worked flawlessly. Is it too soon for me to assume the PCM is toast? Is this a fairly common problem????

Thanks guys.

 

Don't condemn the PCM just yet. Many scanners are not self-powered, and rely on a 12v power source at the data link connector. Check to see if power is present at the DLC first, and if not you probably just have a blown cigarette lighter fuse. Go from there.

 

The Scan tool is receiving power from the obdII port. It simply cannot connect to the car!

I decided to take the next step... UPDATE:

I got a 98 ls1 PCM wiring pinout skematic and started testing things. All the PCM grounds are grounded, all B+ voltages are fine, and the ignition voltages are ok as well and work with the ignition as they should.

PCM????

Also, the crank and cam sensors are directly fed to the PCM so rather than trying to remove them from underneath, I deceded it would be easier to simply test them from up top. How exactly do I do this? Here is where I got the pinout from.

http://www.ls2.com/boggs/torques/98pinpcm.htm

Again, Thanks.

 

Thinking there's got to be a code - double check the CIG/ACCY fuse. Maybe you can find something here: www.gearchatter.com/viewtopic8646.php

 

Pcm.

 

Can you communicate with any of the other modules?

 

I'm not sure what you mean, but the PCM is entirly unresponsive. No mater how I try to access it it doesn't work. This car is stock with under 100k miles

The car was in motion driving when it died and wouldn't start back up. It showed no signs of problems prior to simply dying.

I ordered up a new PCM and it should be here tomorrow. I also had it flashed with the latest GM update before it was shipped out (according to the VIN).

If anybody can tell me the proper way to test the crank and cam sensors.

Thanks.

 

PROBLEM SOLVED!!

Ok, I bought a PCM and it worked!!!

When I removed the old PCM it was full of water. It looks like the aluminum around the PCM case seal has corroded enough to damage the water tight seal letting water enter.

Thanks.

BUT...... After a 1000 mile roadtrip the car has yet another problem. Help me out here please.:




Thanks!