another new conversion, no spark
03-31-2008, 09:18 PM
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another new conversion, no spark and I'm out of ideas.
Here's what i've done:
car cranks, but doesn't start. No backfires, no puffs, just a smell of fuel in the air
tried:
unplugging the MAF
jumped all 8 injectors to make sure they clicked, I also pulled the rail and put paper towels under each to make sure it squirted some fuel when the engine turned over
fuel at the rail is 58PSI, solid
checked +12v at the pinks while cranking
checked +12v constant to the oranges, when cranking
the fuel pump is run directly to the battery so it has power during crank
replaced CPK
tested +12 and ground at CPK, wiring is all in good condition
tested +12 constant and ground to ECU
double checked the vac lines, no leaks
checked ground and +12 to coils
the CPS is plugged in
confirmed no spark with a plug
new plug wires
I put a cam in the engine while it was out, I lined up the dots and cranked the engine around like 20 times to make sure it stayed in and every other rotation it came back around and lined up so I think that's OK, it's a small cam and I have comp 7.4" rods in it, I guess the compression check will tell me if the valvetrain is OK. I doubt it's anything to do with my problem.
anything else to look at? I'm quickly running out of ideas. All I can think is it's time to ship the ECM off to someone to try on their car, but I don't know.
VATS was supposed to have been eliminated but I have no way to know it got done.
Here's what i've done:
car cranks, but doesn't start. No backfires, no puffs, just a smell of fuel in the air
tried:
unplugging the MAF
jumped all 8 injectors to make sure they clicked, I also pulled the rail and put paper towels under each to make sure it squirted some fuel when the engine turned over
fuel at the rail is 58PSI, solid
checked +12v at the pinks while cranking
checked +12v constant to the oranges, when cranking
the fuel pump is run directly to the battery so it has power during crank
replaced CPK
tested +12 and ground at CPK, wiring is all in good condition
tested +12 constant and ground to ECU
double checked the vac lines, no leaks
checked ground and +12 to coils
the CPS is plugged in
confirmed no spark with a plug
new plug wires
I put a cam in the engine while it was out, I lined up the dots and cranked the engine around like 20 times to make sure it stayed in and every other rotation it came back around and lined up so I think that's OK, it's a small cam and I have comp 7.4" rods in it, I guess the compression check will tell me if the valvetrain is OK. I doubt it's anything to do with my problem.
anything else to look at? I'm quickly running out of ideas. All I can think is it's time to ship the ECM off to someone to try on their car, but I don't know.
VATS was supposed to have been eliminated but I have no way to know it got done.
03-31-2008, 10:21 PM
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I'm still working mine. DO you have spark when cranking, is the plug sparking? Pull out and ground on exh manifold to see. Is the wiring done right? Is left bank inj wire on the right bank and vice versus? Drivers side should be 1-3-5-7, I think. 
Just a thought, or two.
Just a thought, or two.
04-01-2008, 08:56 AM
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How are you checking spark? With a spark plug laying on the valve cover, or with a timing light? The timing light won't fire if your plugs are fouled. And your plugs are more than likely fouled by now if you've been cranking it over a bunch with no spark. Pull your fuel pump fuse until you figure out the spark problem. Replace the spark plugs, too.
04-01-2008, 09:52 AM
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sounds relly stupid, but I had the same issue a while back, and it turned out to be a shorted o2 sensor. the back of the sensor hit the frame upon install of the exhaust, and was shorting. This may or may not apply, but just throwing it out there as an option. I would have never found it without john's help from speartech.
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04-01-2008, 11:27 AM
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How are you checking spark? With a spark plug laying on the valve cover, or with a timing light? The timing light won't fire if your plugs are fouled. And your plugs are more than likely fouled by now if you've been cranking it over a bunch with no spark. Pull your fuel pump fuse until you figure out the spark problem. Replace the spark plugs, too.
I guess it could be bad plugs :dunno:
04-01-2008, 11:29 AM
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sounds relly stupid, but I had the same issue a while back, and it turned out to be a shorted o2 sensor. the back of the sensor hit the frame upon install of the exhaust, and was shorting. This may or may not apply, but just throwing it out there as an option. I would have never found it without john's help from speartech.
04-01-2008, 02:00 PM
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sounds like a bad sensor if all your power wires and grounds are correct. did you double check the 3 grounds on the back of the driver side head?
04-01-2008, 02:21 PM
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I ordered a cam pos. sensor, maybe mine got jacked. I don't know if a bum MAF will prevent spark, I figured it wouldn't but I dunno.
Sure hate to pull that intake again just for one dumb sensor.
