NooB Help on a 3.1L ignition

[lsinlv]

Hello all!

I am totally out of my element working on American Metal, so I could really use some of your knowlege.

I was a Factory Porsche Tech, so I know German metal, and can diag issues.

Here's my scenerio: A friends 91 Pontiac 6000 LE 3.1L died while driving...car has fuel, but no spark; it cranks, but won't run.

I have no techanical data to diag the ignition system, or how it interfaces with the ECU...ANYhelp or links to tech specs would be GREATLY appreciated.

Thanks,

Larry

[geoffinbc]

First check would be on the crankshaft position sensor. It is in the bottom of the block on the firewall side. It is a 2 wire sensor right smack in the middle of the block on the lower half. Pull it out and check for cracks. Often it fails and breaks rendering it useless.

[robby1870]

^what he said.

Basically the crank sensor tells the ECM when the #1 is at TDC, then the ECM fires the coils correspondingly. So, if the crank sensor is bad, you wont have spark at all

[lsinlv]

what values should I see from the CPS????

[geoffinbc]

Um I think it makes a square wave signal through the hall effects switch. But just pull it out (1 bolt and 1 wire clip) and check it.

[robby1870]

yeah, square wave makes sense. If you check all 6 wires and they all arent getting any spark, I'd say its bad