Hi All

I bought a car from a friend who sold it cheap b/c the car wouldn't start. A couple months previous he had a shop go through the car and get it dialed as a reliable daily driver. He drove it for a month w/no issues, then it started to randomly stumble, and a couple of days later it would not start.

So I got the car home and started going through all the fuel and spark components to look for anything obvious. I pulled the fuel line at the filter and turned the key to On and fuel flow looked normal. The guy mentioned that the coil was stock and had a new one that he didn't install yet. So I change the coil and put everything back in. Try to start the car and the battery is pretty much dead. Charge up the battery, and then try to start again. It fired right up! Ran for a good ~5minutes, then would stutter randomly. I turned the car off but then it won't start back up and sounds just like it did before I touched anything. The fuel pressure is good at the check valve on the rail.

The car cranks fine, but just wont fire. If it was the opti how did it run good for awhile the time I got it started? I am thinking there is a loose/damaged connection somewhere at/near the coil...?

Any ideas???

Thanks in advance.

-Neil

 

Have you checked the charging system????? Bad Battery/Alt??????????


PS: It helps with alittle info on the vehicle also..... Z/28 ???? 1st gen??? 2nd Gen????

 

Sorry, it is a '97 Z28 M6.
So when I got home from work I went out to try to start it again but battery dead. So I put the charger on it. The only thing that I touched while it was charging was jiggling the wires/plug on the ICM. Charge gets enough to crank, and the car starts right up! I turn it off, and now it won't start again! WTF?

 

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Battery dead??????? Have the battery load tested. Most local part stores have the equipment to check this and its free.... If bad, get a new one, then check the alternator with a multimeter... Normal running engine at idle with a good battery will normally put out around 13.8~14.2 VOLTS.... If not, then it might be bad.....

PS: Check connections for worn/corrosion/loose/etc......

 

Have you checked for spark while it is being turned over?

First thing i would do is crank it and have some one shack the wires that go to the ICM and coil around and see if it will fire. If it does then you have to mes around with each wire untill you find the one that is the problem.

Also might be the ICM its self, you will have to check and see if they just go out like that or not.

 

As suggested, check the battery on a load tester first to see if it is good or not. If it tests good, check the alternator at a parts store, simply testing it with a multimeter for voltage isn't accurate, you have to monitor amperage flow through it. IIRC, 124 amps is ideal? Maybe I'm mistaken.

Didn't thoroughly read the thread, but it sounds like maybe the ICM... if it's bad, or going bad, it can randomly cut in and out. Has the car ever died in mid-drive? If so, it's probably the ICM, when it gets hot it just shuts off.

 

I was thinking it was the wires to it or the ICM itself as well. I plan to thoroughly check those tomorrow.
Thanks for the input!!
-Neil

 

check the wires going to the coil too!

Also maybe check the conector for the opti, its on the pass side of the intake