1997 Chevy Lumina 6 cyl Front Wheel Drive Automatic 155K miles
3.1 engine cranks but won't start. Fuel circuit is working and stays pressurized. Seems to have a weak spark coming from all 3 coils. It's pretty cold outside (10F) and I wanted to know if it is possible that all three ignition coils could be weakened to the point where when cold, they could all produce weak spark at the same time? Vehicle has always run fine, no misses or failure to starts, except when it's very cold. Have to crank it a couple extra times sometimes. Battery is new and it cranks strong rpms.
I pulled wires from all three coils (plug end) and checked spark to ground with a tester and all three made a weak spark that won't jump the full length to ground on my tester (adjustable tester where you turn the screw to set the length of the air gap for the spark to jump, if you are familiar with this kind of tester). The sae gap on this tester is supposed to be set at 36-40 but my spark won't jump above 25-30 and it's a real thin blue line spark at that, not that flat snappy big blue one.
Since I am getting at least a weak spark that tells me the crank sensors and everything else is working or it wouldn't even spark at all I would assume? Could a bad ignition module cause the coils to produce a weak spark or is it an all or nothing thing there? Wanted some input before I spend 100 bucks on coils as it seems odd that all three could be bad in the same way at the same time. They are the original coils. Primary coils resistance measures.3 -.5 ohms. Secondary coils resistance measures right at 5K on all three at around 10F to 15F degrees outside. My hands are numb!
Oh, when I was done for the day messing with this, I also inadvertently broke (more like shattered in the cold and now don't know where the other end is supposed to go) the plastic vacuum line attached to the fuel pressure regulator. Will the vehicle still start and run (assuming the ignition problem is fixed) with that line off or do I need to have it connected? It should still deliver fuel I think as that is on the return line but please advise also. Again, that happened well after the no start problem.
have the same problem?
Friday, January 29th, 2010 AT 7:04 PM