Ok, i have a 1993 Chevy Cavalier Z24. I have had the clutch replaced and a new block put into it at the beginning of the year. A couple weeks back, the car just up and died. No spark. I changed the igintion module(5 times), 3 new coil packs, knock sensor, crank sensor, and went through all the wires that deal with the ignition system. All the grounds are solid and where they need to be. Now this is where i confuse everyone i have taken the car to, even a chevy dealership. Once I replaced the ignition module the car would start and run for a day. The next day i would start it up and it would run for 10 seconds and then die. No spark again. If anyone can tell me what is wrong with my car, I would greatly appreciate it.
Any ideas would be helpful.
Nick
Why did it need a new block? Did you replace the entire engine or just the block and re-use the top end? It sounds to me like the coil pack keeps getting fried due to faulty wiring somewhere. Maybe a short to hot.
dead as in wount crank? or click click in the start? maybe you are looking at a mouse that really hates you cause you have a cat? is it 5-speed could your clutch not be fully ingaded? have you looked in the dash board for the wire problem? fuel? air? ect
I was thinking bad wiring too.....but I'de also check the computer.... do ya get any trouble codes? If it has a cam sensor, that would cause you to loose spark if it went out, because the car would think the timing chain was broke, but I don't know if those cars have them.
check the connection on the clutch solendiod. theres 2 or 3 wires on a relay box behind the clutch pedal. one of those possible came off and its not swtiching like it should and not letting you start the car.
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Ok i had to change blocks because i blew the oil pump in the old one and warped the crank. I threw a new block in and kept from the block up. Every wire dealing with the ignition system is good, all the grounds everything. I have run through every wire under the dash to the engine and still no spark.
i also replaced the ECM too. When you try and start it it will turn over but not start. the clutch pedal and sensor are ok.
is it getting fuel? when was the last time u had the fuel filter changed and how's the fuel pump? also what about compression? did u crack the head when u warped the crank?
i'd run a compression test in your car. see if you have any leaks that wouldn't let it start.
it may not be clutch related.
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Guys, there are a few key pieces of information being given, now to disseminate.
The ignition module won't start sparking until it sees 400 rpm cranking speed. While you say you've replaced both the CPS, and the module several times, i'm wondering if maybe the small 3 wire lead that runs between them has rubbed up against the belt or otherwise frayed. A faulty crank signal (or one that is fine, but with a signal that is grounding out against the nice shiney new block) would cause this condition.
While its generally understood that most people don't have DSO's (or a regular oscilioscope for that matter) at home, the only real correct way to make sure the CPS is working is to connect the scope up to the ground and signal wires and see if your getting the 5v waves your supposed to. If you are, then theres another issue with the other connector going to the ECM (in your dashboard).
It should be noted that the 2.8/3.1 ignition module has three sets of connectors. the three wire connector is for the crank position sensor, the two-wire connector is the power connection, and the 5 or 6 wire (i forget) connectors for ignition control via ECM.
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Basically, you can see that the ECM shouldn't really have anything to do with the deal, it should start spark on its own as long as it is getting power. That diagram shows you what color wires should be doing what.
The 6 wire ECM connector does nothing more than provide a 'tach' signal to the ECM so that it can begin to figure injector timing so it can spray fuel.
The harness from the CPS to the Ignition module is routed near the belt, and near moving parts -- check that none of the wires have pulled out of either end and that you've got continuity between the ends if your still unsure. jiggle the connectors and try starting again, my bet is that is where the issue lays.
If not, check the fusible link going to the IGN module. Does your tach rev up at all during cranking?
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My mechanic gave me that diagram and that wasn't the problem. The car has normal fuel pressure i had fuel lines replaced and the fuel filter. I just took the car to my buddy that had a z24 and he found out the problem. None of you will believe this. I couldn't even believe this. THE ABS MOTOR. He disconnected my ABS motor and the wires for it that go to the fire wall, replaced the iginition module and the car ran and never died. I couldn't believe it. So if anyone that owns a 91-94 Z24 that is getting no spark disconnect the ABS motor wires and replace the module and you will have no problem. I want to thank all you guys for the ideas. I really appreciated it. If any of you have a problem don't be afraid to ask. I'm always online.
