Here they are boys the results are in after a PITA day working on the Z.

I did this to see if it could be the cause of my no start problem!
Compression Test Results:
1.160_-_-_-_-_-_-2. 140
3.137_-_-_-_-_-_-4. 147
5.187_-_-_-_-_-_-6. 160
7.180_-_-_-_-_-_-8. 170

 

car will start with that compression. I believe all numbers should be within 15% of eachother.. And your 170 to 140 and 137-189 difference is just beyond that which could indicate a weak ring maybe a valve problem/adjusted kinda wrong?

But even still the car should start. Describe your no start problem. Does it even crank over? name all hte things u checked. Fuel pressure spark etc

 

Hey my no start problem is that the car just backfires out of the exhaust. Here is a sound clip....

**You have to right click and save target as**

http://www.geocities.com/trickedoutblazer/start.wav

I have check fuel pressure and spark and pcm, pretty much everything.

 

have u checked the cats? do u ahve cats? u check the opti spark? coil resistance?

 

No cats, checked spark at opti, coil, traded pcms, checked injector pulse, fuel pressure, changed all plugs and tried. Im freaking stumped!

 

have u swapped ICM's (ignition control module) also if u dont mind me asking what procedure did u do to test the fuel/opti/coil. Just to see if u were doign it right or maybe forgot something???

Check for constant 36-42lbs cranking of fuel?

BUt you do have spark right?


How/ when did the car die? Going down the rode? after an install on something?

 

I went to start it and it just sputtered out and died. I havent did any installs in the past few months. I check fuel with a Fuel pressure gauge. Checked the spark at the coil, and at every plug. I tested the plugs by taking them out and grouding them out and looking at the spark and tested the coil by arching a spark to a ground. Its a very odd problem. I thought I wouldnt be getting any spark if the ICM was done. I installed a new opti a month or so before the problem.

 

Pull the opti spark connector plug. Its the electrical plug that sends the firing orders to the Computer. Look for BLUE corrosion inside the harnesses plug. Unlikely because you have spark. But check it anyways, easy to see.

Did you order a new vacuum harness with the opti? A vacuum harness that is not working properly can give the opti the full effect of the exhaust/manifold vacuum causing it to distort and die. This is even if u have a vacuum harness on yours.

A bad ICM can keep a car from starting.. but usually it'll kill the car after it gets warm. and yeah.. you wouldnt be gettin any spark

So if u get spark its not the coil , icm . Where did u buy the opti from? Some will give u another one because it should have been sold with a vacuum harness.. Dal at Vandavere would have.. Jason cromer maybe.

But usually if its the vacuum deal you wouldnt get any spark either... maybe its not consistant?

Weird problem.. im saying its opti related.. thats my guess

It has to be fuel or ignition... Has to be.. IF its cranking it has to be.. Cant be VATS, cant be Ignition switch, Cant be clutch switch, cant be starter, cant be battery. Cant be clogged cats, not the fuel pump, not the filter...

Test one of the injector wires to see if its firing? Forget teh signal ur suppose to see...

 

Actually your compression should be within 10lbs on all cylinders which yours aren't. How many miles on your car? Valves could be out of adjustment, Could have some busted top rings, Could be a few other things as well.

 

Miles are at 89k. It ran good then all the sudden the next time i tryed to start it it made the sounds it makes in the clip. Could the timing chain have slipped a tooth?

 

Another thing to check is firing order/timing. The sound link was broken so I couldn't listen, but I'd check the easy stuff before I go looking for a skipped timing tooth (although it is possible). What color was the spark at each of the spark plugs? If it was a dull reddish color, you're not getting enough voltage. Ideally it should be a bluish-white. I assume you checked gap and condition, and they were fine. I don't know much about fuel injection (I'm a carb guy), but are you sure they are firing and at the right time?

And yeah your compression doesn't look that great, something is definately wrong with the #3 cylinder. But if that's the only problem you could probably still start the car on only four cylinders.

Since I couldn't listen to the sound clip, do you hear any ticking noises? How's your oil pressure? Could be hydraulic lifter collapse, but that would probably show up in the compression test more dramatically...

 

The plugs are fine. I think that the timing chain possibly slipped a tooth or something someone was telling me it was common on chevy 350s.

 

Your compression would suck if the timing chain slipped a tooth.
My money is on the opti. Specifically on the rotor in the opti. Mine did the same thing you are describing, I had spark at the wires, but my rotor was torn off in the opti. Drop the opti and shake it around a little it should NOT sound like there are bolts and nuts loose in there.
Change it while you have it off.