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Have a good one for you. 95 camaro 3.4. Vehicle started having problems cranking, sometimes it would lock up motor like hydrolock. Also hard to start sometimes backfiring but once running it ran fine. Had suspicions it was head gasket related. Scoped cylinders and didn't see anything conclusive. Bought kit to determine if was head gasket only to find cylinder #5 filled with water. Ok so I thought I found problem. Did both head gaskets and still have same problem actually worse now. Will not run at all. Backfire through intake and exhaust. Motor still locks up just not all the time. New ICM, and crank sensor. One thing that doesn't make sense is with ICM unplugged the tach operation is fine while cranking. When plugged back in the tach is erratic and jumps around. Rpm on verus is inoperative. If I disconnect fuel pump relay car cranks normal. If both fpr and ICM are connected it backfires and will not start. If ICM is disconnected cranks fine. Will not start on either. Only code was for the 24x ckp sensor which supposedly will not affect starting. Clear flood mode doesn't help either. Did compression test and not all cylinders are equal but there is enough that it should at least start and run. Not sure if anyone has had same issues with this motor. Any help would be appreciated. Considering getting rid of vehicle but would like to know what's going on without spending a fortune on it. Thanks
With everything hooked up do you have spark? Did all the pushrods go back in the right place? I would suspect it wouldn't hardly have compression if they weren't... do you have injection pulse? Backfiring through intake and exhaust sounds like a timing problem which is why I ask about pushrods what were you compression numbers?
Yes it has spark with everything hooked up. It has injection pulse, everything went back the same way. Compression in two cylinders is around 145psi. All the rest are around 110. I know it should be more but it should at least run on those numbers. Not sure if I'm going to tear it apart just to spend more money on it but it's got to be a good one
Ok those numbers are low but it should run and that definitely rules out a misplaced pushrod(I've seen it happen) next thing is verify your ignition wires are in the correct location
Yes wires are in correct location. I've checked it about 10 times just to be sure. Everything is exactly where and how it should be which is leading me to believe its a mechanical problem possibly with the bottom end, or maybe one of the valves is not opening or is staying open when it is supposed to be closed. Just guessing at this point
Pull your plugs and see if it's flooded cranks it with throttle open to clear gas out of cyls (be sure to disable spark) dry the plugs and try again . What is the fuel pressure ? Be sure to cycle the key a few times to prime the fuel system before initial start
HI,
Ok let me review this you know that all the push rods are seated properly and they are not over tightened. The coil wires are in the proper locations. You tested compression. And you have back fire.
1) I would disable the coils and fuel, then crank over the engine listen if it sounds normal
2) Is so, enable coils and fuel, spray brake cleaner in the intake make sure its not in front of a mass sensor. Try and start and see if it runs
3) If so you have a fuel problem
4) No if that did not work you need to check each coil for spark. if not replace coil .
5) Now if this does not work you will need a scope and check for the IC signal that the ignition control module sends to the ECM this is done by the 3x crank signal
6) But you also have a 24x sig on the crank as well. You need to scope this as well.
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