a CHALLENGE!! ('93 5.7 Intermittent no-spark)

God, I'm glad I finally found this forum!!

OK, so we've got a '93 wagon with the L05 engine (5.7), and it's been having intermittent no-spark problems for a long time now (>1yr).

It cranks most vigorously, but won't catch. I've checked the wire from the coil to the distributor with one of those pen-type inductive spark testers (while someone else cranks) and, sure enough, no spark.

Now, here's the kicker. Ether gets it started. I have no idea why. My only guess is that it's got a very WEAK spark when it's in this state, and the ether is just volatile enough to go off with what spark it has. Once the engine catches, it runs just fine.

Shortly after the problems began, I swapped out just about all the ignition components I could think of (cap, rotor, wires, and even the coil and ignition module). Thought it helped at first, but didn't. Even took it in to a local (yes, and reliable) shop this past week to have it looked at.

The guy found a no-start condition, but said it was the fuel pump. (It was definitely getting fuel requested from the engine, but not delivering to the injectors. >2 bills later, I have a new fuel pump. Pulled out of the shop and she runs like new. Stopped for gas and it started right up again afterward. But when I left work tonight, it wouldn't start again. 2x with ether and it cranked right up. (I couldn't check for spark as I was by myself.)

So I'm back to square one.

Now it doesn't seem to be a cold/wet/or any other kind of weather-related problem. I recently changed out the cap & rotor again, but the problem persists. (Oh, and yes...they ARE a big pain in the a** to get to!) I've even checked the engine for codes and found nothing.

I know how much intermittents suck to diagnose. I'm here because, quite frankly, I'm at the end of my rope. I'm hoping someone else has run into this before because, short of taking it to a dealer and having them faff about with it, I'm not sure what else to do.

Bueller? Anyone?

Cheers,

---chris

It kind of sucks that this has been out for over two months without even so much as a peep.

Has *no one* else ever run into this problem on one of these things? :^(

There have been 83 views of this thread with no replies, so apparently no one has had a similar problem, so let’s start with the basics and do one test at a time.

· Next time it will not start, pull the coil wire out of the distributor cap and place it within 1/4” of the block (ground) while someone attempts to start the engine. Do you see a crisp blue spark, pale yellow, or no spark?

Note: Be sure to check to see if you have a continuous 12v from the ignition switch to the primary side of the coil when trying to start. You can check this at the coil.

Let us know what you find, then we can move on to the next step.

I haven't come across this issue with my '95, but one thing I thought of , I wonder if perhaps one of the items you replaced might be bad right out of the box,(i.e. ICM,coil). I've seen it happen before to others including myself. So if you get further along with troubleshooting the issue without any luck, perhaps you might want to look at those components again.