No Spark: 87 Cutlass 2.8L

[pokesmot]

I'm helping a friend fix their 87' cutlass cierra cruiser. It has the 2.8L and the ignition system is pretty much identical to the one used on other GM's like the 3.1, 3.3, 3.4, 3.8 and so on.

The car ran fine for the longest time until one day it just wouldnt start in the driveway. It cranks, but does not catch or stumble, anything at all. Just cranks.

There is fuel pressure, because I bled the schrader in the fuel rail, and then primed the pump by cycling the ignition a couple times, so I know the pump is good.

There is no spark on all 3 ignition coils. I'm thinking its the ignition module, and was going to replace it as a whole unit with ignition coils.

I have yet to figure out whether or not the injectors are working as I had no tools at the time I looked at the car so i couldnt pull the plugs to see if they were soaked in gas or not.

I also have yet to hook it up to a basic OBD I scanner and check to see if I get any RPM reading while cranking. If I have an RPM reading then I know the crank position sensor is working.

Just one thing im not sure about is that if the injectors are not firing, it might even be an ECM problem.



Should I go ahead and replace the ignition module for now?

or should I run more tests first?


any advice is appreciated!!

[HeyDace]

Check the fuses for the ECM and injectors. It was common for those to pop occasionally.

[pokesmot]

Originally posted by HeyDace
Check the fuses for the ECM and injectors. It was common for those to pop occasionally.

thanks, will do.

so far I know the IGN / ECM fuse is good, but have yet to test the fuel injector fuse.

I guessing the f/p inj fuse is good as well because the fuel pump runs and primes the fuel rail; will have to double check that fuse anyway though.


if all the fuses are good what would you suggest next?


thanks again!

[HeyDace]

Try swapping a good known ignition module in. If its a no go then consider an ECM.

[SE2000]

While you're grabbing your tools, grab the sparkplug socket and give it a spin. Having fuel pump and sufficient pressure are 2 different things.

[pokesmot]

UPDATE!


so I hooked my scan tool up to it, no communication so I was thinking dead ECM.


checked all fuses and fusible links and they were all good, there was power to the module as well with ignition on.

so I check my scan tool connection, had to push down on the onnector to get it to work, I established communication with my scan tool and wasnt reading RPM whilecranking.

so I assumed module... (also becuase they are easier to replace) Replaced it for $50. no luck.

next tried crank sensor $40 pulled the old one out form the back of the block between engine and tranny (tight fit!) The original crank sensor had no screw holding it in.. and was falling apart when i was trying to pull it out, but it finally popped out and was all cracked / destroyed.

replaced with new crank sensor and it fired right up!

so... for whoever else is out there with no spark or fuel injector pulse with a GM ignition system, check for rpm's while cranking. if its 0 you need a new crank sensor!!