No start on 94 z28
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No start on 94 z28
My car is almost back together after a timing set broke. I have had it started and running well in the garage. Tried to start it again about a month ago and it would crank and crank, but would never hit til i let off the key. It would hit a couple times and then quit. I stopped cranking on it and then started again and the starter housing broke in half.
I just got back after being gone for a month and put a new starter on it, but i still have the same weird problem. It won't hit until i let the key off. Then i get smoke out of the intake. The exhaust is the only thing that isn't hooked up. (Just headers) The passenger 02 bung is in the y so it's not hooked up. Don't know if that could be the cause.
I just got back after being gone for a month and put a new starter on it, but i still have the same weird problem. It won't hit until i let the key off. Then i get smoke out of the intake. The exhaust is the only thing that isn't hooked up. (Just headers) The passenger 02 bung is in the y so it's not hooked up. Don't know if that could be the cause.
#2
When the timing set broke, did you replace valves/pushrods? Were the timing gears lined up dot to dot when you put the new timing set back on? How did you set your valve lash? Just some ideas on where to start trouble shooting. The fact that it is backfiring out of the intake and cracked the starter in half tells me that it is most likely not timed right and trying to fire at the wrong time. I would take off the valve covers and turn the motor over by hand, watching the rockers and making sure that the proper valves open as you turn the crank.
Also, having the passenger side 02 sensor not hooked up will not cause the car to fail to start. The sensor is only used by the ecu in closed loop and that doesn't happen until the car has been running for a few minutes. It will make the car run bad, but it should still start.
Good Luck,
Bill
Also, having the passenger side 02 sensor not hooked up will not cause the car to fail to start. The sensor is only used by the ecu in closed loop and that doesn't happen until the car has been running for a few minutes. It will make the car run bad, but it should still start.
Good Luck,
Bill
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It was just a stock replacement that came with my cam. Was supposed to only have a couple dyno sessions on it. It's dot to dot. Valve lash set. Took the heads to a machine shop and they replaced 5 valves and checked everything. It's been running already and it ran smooth , so the timing is good. I'm gonna recheck all the ignition connections and check all the rockers.
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Just checked everything. Rockers are moving correctly and everything on the coil and opti is snug. Anything else i should check? I'm suspecting it's the opti at this point
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Did you test the coil itself?
I had the same symptom out of my 93. Worth checking before chasing down an opti.
http://shbox.com/1/coil_testing.jpg
http://shbox.com/1/how_tos.html
In case you don't already know about shoe box. it is well worth searching through.
Would definitely get that O2 hooked up just in case.
Ben
I had the same symptom out of my 93. Worth checking before chasing down an opti.
http://shbox.com/1/coil_testing.jpg
http://shbox.com/1/how_tos.html
In case you don't already know about shoe box. it is well worth searching through.
Would definitely get that O2 hooked up just in case.
Ben
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This is the meter i'm using. I had it set to RX1K and It was reading between 20 and 30. I'm not really sure what that means. It was consistent on all the terminals though. There was an adjustment **** with the "omega" sign on it. Turning that changed the reading about ten units. does any of this sound right? This electrical stuff is not my thing ha.
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Sorry, I think I read too many posts yesterday. I missed the part about the smoke from the manifold and this could also correlate with timing or vacuum.
Chances are you know all this already, but here goes a few suggestions.
To start with, test for spark at the plug, test for fuel at the rail. Be certain to double check all wired connections just in case.(not just on the opti) If it were running you could obviously check timing and for vacuum leaks. So, check all vacuum lines for cracks and connection. You did have the intake off during the recent timing chain swap. Are you certain the gasket is correct?
What did the meter say on the RX1 setting? I'm pretty certain that all your rx settings are ohms just kilo ohms and so forth. Then again, it has been awhile since I have used an analog meter. You should read 8500 ohms or lower on that setting. Ohms are resistance so higher numbers aren't necessarily favorable. http://shbox.com/1/coil_testing.jpg
PCM failures are somewhat rare but it couldn't be ruled out all together.
If you don't have access to a pressure gauge:
Can you hear your fuel pump cycle when you turn the key, have you checked for fuel pressure at the rail? Might sound stupid, but if there is no fuel and you don't hear the pump cycling then hit the tank with a rubber mallet a few times and try starting. This has actually worked for me multiple times with dead pumps. I'm guessing by the smoke in the manifold that you do have fuel but it is worth a few minutes to rule things out.
Spark: Test the spark plug with a flat head. If spark is the issue I would figure out the coil readings for sure and the ICM next before going after an opti. However, there is a test for the opti, butI'm not certain if there is one for the ICM. Again, this info can be found on shoeboxes website.
Diagnosis can be arduous. Keep in mind that the more detailed the info you share the faster the forums can help. Be certain to check all your ground straps as you had the car apart recently.
Again I apologize if I added steps to your diagnosis but this should give us more to go off of.
Ben
Chances are you know all this already, but here goes a few suggestions.
To start with, test for spark at the plug, test for fuel at the rail. Be certain to double check all wired connections just in case.(not just on the opti) If it were running you could obviously check timing and for vacuum leaks. So, check all vacuum lines for cracks and connection. You did have the intake off during the recent timing chain swap. Are you certain the gasket is correct?
What did the meter say on the RX1 setting? I'm pretty certain that all your rx settings are ohms just kilo ohms and so forth. Then again, it has been awhile since I have used an analog meter. You should read 8500 ohms or lower on that setting. Ohms are resistance so higher numbers aren't necessarily favorable. http://shbox.com/1/coil_testing.jpg
PCM failures are somewhat rare but it couldn't be ruled out all together.
If you don't have access to a pressure gauge:
Can you hear your fuel pump cycle when you turn the key, have you checked for fuel pressure at the rail? Might sound stupid, but if there is no fuel and you don't hear the pump cycling then hit the tank with a rubber mallet a few times and try starting. This has actually worked for me multiple times with dead pumps. I'm guessing by the smoke in the manifold that you do have fuel but it is worth a few minutes to rule things out.
Spark: Test the spark plug with a flat head. If spark is the issue I would figure out the coil readings for sure and the ICM next before going after an opti. However, there is a test for the opti, butI'm not certain if there is one for the ICM. Again, this info can be found on shoeboxes website.
Diagnosis can be arduous. Keep in mind that the more detailed the info you share the faster the forums can help. Be certain to check all your ground straps as you had the car apart recently.
Again I apologize if I added steps to your diagnosis but this should give us more to go off of.
Ben
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If I did the test correctly it was reading 25000 OHMS (reading 25 on the RX1K setting) across all the terminals. Fuel pump cycles. I know the intake gaskets are correct. I'm 99 percent sure the ground straps are well connected, but i'll check one more time. I'll check for spark/vacuum leaks today and see if i can get ahold of a pressure guage. Thanks Ben
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I just checked the spark with a dummy plug on a couple of wires both checked out fine. I did find an injector that is leaking from the rail. Fuel was everywhere after turning it over a few times. I don't have any of the fuel rail injector clips on them. I guess i'll pick some up and see if that fixes things. I guess it's bleeding all the fuel pressure off? Could this be the problem?
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Update: I fixed the injector issue and still no start. When I tested the fuel pressure It would spike to 40 or so when the pump primed, and when cranking, but immediately go back down to zero after I stopped. Shouldn't the pressure bleed down very slowly?
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Anybody have any idea what I should do next? After I try to start it all the fuel pressure is gone within 10 seconds. Won't hold pressure like it should. Still can't get it to fo anything but sputter.