Camaro Crank but no start

[aknight_sa]

suddenly had this issue with my 97 Camaro LT1 V8.

HISTORY
Engine was working normall but suddenly started to loose power.. then the engine went off and wasnt starting at all..

TROUBLE CODES
P0336: Crankshaft Position Sensor A Circuit Range/Performance – had it for some time
P0135: O2 Sensor Heater Circuit (Bank 1 Sensor 1) – due to removed O2 Sensor
P0141: O2 Sensor Heater Circuit (Bank 1 Sensor 2) – due to removed O2 Sensor

DIAGNOSES
1. at the begining suspected that the fuel pump wasnt working properly as it sounded lower than usual while turning the key to the on position, i currently dont have a fuel pressure gauge to check pressure. but when i opened the valve, the pump was pushing gasoline all over the place.

2. while checking ignition by removing one of the spark plug wires and bringing a grounded wire near the coil side.. no spark was jumping out of the coil (number one spark wire).. ofcourse that was while cranking the engine.. i then used an inline spark tester and it was showing spark but kind of looked very weak…

CONCLUSION
i do believe that the ignition is the problem as this type of engine is really known to have bad ignition “Optispark” system. how can i make sure 100% that this is the problem before buying a new coil or new optispark.

Topic

[dreamer2355]

http://www.obd-codes.com/p0336

I would also be looking into the P0336 code.

Did you check mechanical timing of the engine?

The best way of checking cam sensors is with a lab scope, same too with the opti spark system while looking at ignition wave forms for each cylinder.

[EricTheCarGuy]

I agree, ‘pretty sure’ requires some more investigation. As with the above video it sounds like you have checked 2 of the major components for an engine to run but the one thing left out was engine mechanical. Since you have a code for a crank sensor I would suggest you start there as it COULD be a mechanical issue setting that code but more importantly that signal gives the computer information it uses to fire the coils and injectors so before you start looking at the ignition system I would suggest you look into the crank sensor code and also check the mechanical operation of the engine to be sure it’s still in time. Even thought it’s a chain driven single cam it can still jump time. That said it would probably be easier to check the operation of the crank sensor first as to check the mechanical timing without a distributor can be a little tricky.

[aknight_sa]

an update to the situation..

started checking the wiring of the Optispark, Ignition Coil and Ignition Control Module and found some previously cut and repaired wires.. after fiddling with them the engine started normally, then i turned it off after some time at which it didnt start again.. i then reconnected the ignition tester mentioned above and had the engine cranked and there was no spark..

then what happened was following:..
as i was inspected the cables again, my friend cranked the engine again (without me telling him too) there were a few revs with no spark then a spark happened with my hand on the tester AND I GOT ONE GOOD SHOCK!! 😀 and the engine started again..

anyway, i will be checking the signals of all three components as well as the cam sensor and Crank sensor..

i dont want to go to mechanical inspection tell i totally have the ignition system tested as these models are well known to have issues with the dumb Optispark design.

will keep you updated

[EricTheCarGuy]

Glad you’re OK. Ignition systems can pack quite a punch.

I’d focus on repairing that wiring by the sound of it. Perhaps some solder and shrink tube.

Keep us posted.

[aknight_sa]

ok.. here’s an update..

while checking the signals on the Ignition Coil Module one of the cables got ripped off as it was just hardly connected. i did get the connector fixed at which didnt solve the problem as it was there before the cable was cut loose.

[url=http://alfaris.net/up/86/alfaris_net_1352020184.JPG]

i did also change the Coil itself as the one i had didnt supply a strong enough spark and after changing it.. the spark was jumping out of the distributer to the test light while it was an inch away.

i will be doing a proper fuel test now which includes a fuel pressure test and will be checking the fuel injectors for both voltage and control singals from the PCM as per the below diagram

[url=http://alfaris.net/up/86/alfaris_net_1352020281.jpg]

if i still cannt find the exact problem it will on its way to a mechanic..

[aknight_sa]

tested the ignition again and was working fine… resistance continuity between each electric port and injector fuse is fine.. voltage drop between same ports did show a 0.02v drop… but one thing was strange.. i just did a resistance test between the injector fuse and ground and there was resistance of around 240ohms.. i dont know if that is right or not.. but to me it seems that there could be a short somewhere which will prevent the injector from firing..

[johnzcarz]

Would you say that it’s only happening when the engine is warm/hot and you are trying to start it?

[Charles]

I’m guessing that you mean that you made your resistance test with the fuse out or battery cable disconnected. The resistance to ground could be normal. Looking at your circuit, the controller operates the injectors by pulling each wire to ground. Transistors used for this purpose have properties that make them look like diodes and may have feedback circuits that reference ground. Try reversing the meter leads and see if the reading changes. Remember that you are seeing the resistance through all 8 injectors and the controller to ground. If you want to make a true test in this manner you should unplug all but one injector. Then test one at a time, they should be the same.

[aknight_sa]

[quote=”johnzcarz” post=36477]Would you say that it’s only happening when the engine is warm/hot and you are trying to start it?[/quote]

not starting at all

[aknight_sa]

[quote=”Jotmon1″ post=36522]I’m guessing that you mean that you made your resistance test with the fuse out or battery cable disconnected. The resistance to ground could be normal. Looking at your circuit, the controller operates the injectors by pulling each wire to ground. Transistors used for this purpose have properties that make them look like diodes and may have feedback circuits that reference ground. Try reversing the meter leads and see if the reading changes. Remember that you are seeing the resistance through all 8 injectors and the controller to ground. If you want to make a true test in this manner you should unplug all but one injector. Then test one at a time, they should be the same.[/quote]

what i did was removed the battery first, and disconnected one of the injectors.. and did the test between the positive lead and the fuse terminal.. from the diagram above, it should be a direct connection without any ground in the way..

as when i checked from the PCM connection to ground there was no continuity at all..

[EricTheCarGuy]

So refresh my memory please. Is it not getting spark or fuel at this time? I think I remember you saying it had spark since you got shocked but I don’t remember what you said as far as fuel delivery goes.

[aknight_sa]

[quote=”EricTheCarGuy” post=36726]So refresh my memory please. Is it not getting spark or fuel at this time? I think I remember you saying it had spark since you got shocked but I don’t remember what you said as far as fuel delivery goes.[/quote]

what happened was the cable of the IGN broke so i had to fix it..

here is my latest.. was told to spray Carb Cleaner in the intake by ScannerDanner and see what happens and thats what i did today.. and after spraying some in.. the engine did rev and start shortly which means in my opinion that the ignition is working and probably right timing.. but the problem as it seems is a fuel delivery problem..

[EricTheCarGuy]

If you were able to get it started with carb cleaner it’s likely to be a fuel delivery problem as you suggest. Probably the next step would be to check and see if you have fuel pressure and if your fuel pump is working.

[aknight_sa]

the pump is working, as i verified by both hearing it run when i turn the key to the on position.. and by pressing on the pressure relief valve.. but i dont know if its providing the right pressure.. but if its not providing enough pressure i believe the engine should fire up and maybe fail when load is applied..

i do expect that i do have a harness problem which is shorting out the injectors and preventing them from working..

tests will verify it all

[EricTheCarGuy]

Don’t assume that, with as little as a 3psi difference on some systems it can cause a no start. Check the fuel pressure and verify it with a pressure gauge to completely rule that out.

[Author]

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