no spark please read
no spark please read Im trying to get my 71 chevelle turbo ls1 started. I Have no spark, the pink wires at the coilpacks is getting juice and when i turn the key the pump goes on for 2 secs. Do I have to have a maf sensor hooked up and i also dont have a map sensor hooked up because it broke. Is this my problem? Im using stock computer with wait4me tune and wireharness.
Im trying to get my 71 chevelle turbo ls1 started. I Have no spark, the pink wires at the coilpacks is getting juice and when i turn the key the pump goes on for 2 secs. Do I have to have a maf sensor hooked up and i also dont have a map sensor hooked up because it broke. Is this my problem? Im using stock computer with wait4me tune and wireharness.
Joined: Sep 2004
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From: Downers Grove, IL
I think he means to check individually that the ground wire for each coil does in fact go to ground. (use an ohmmeter to check for a connection between the coil ground wire and ground)
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The black wire at the coil connector is the coil ground. Test from that ground to the pink ign. wire of that same coil. If the test light lights, then the ign. and ground are both good. Check on both banks of the engine, because they are on different ign. and ground circuits. Disconnect a fuel injector wire and use your test light accross the 2 terminals, while cranking the engine over the test light should blink. That will tell you if the PCM is getting the crank signal.
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engine will still have spark with MAP or MAF removed.
Coil Pack Subharness Connector Pin A, Black wire, is engine ground.
Coil Pack Subharness Connector Pin H, Pink Wire, is Ignition 12v+
Check the 3 wires at the crank sensor going to the PCM connector. If power and ground are good to the coil packs, this really is the ONLY thing that will cause a no spark condition. you don't even need the CAM sensor for the engine to run.
Crank Sensor pins A,B,C and the PCM connector they go to. C1 is the BLUE connector.
A. Dk Blue/wht - PCM C1 pin 12 - crank signal to PCM
B. Yellow - PCM C1 pin 21 - ground reference to crank sensor
C. Lt Green - PCM C1 pin 2 - 12 volt+ reference to crank sensor
Last week I went to start my 5.3 swaped caprice and had no fire...a bad crimp on one of the crank sensor pins was at fault. The copper wire pulled right out of the terminal.
Good Luck.
Coil Pack Subharness Connector Pin A, Black wire, is engine ground.
Coil Pack Subharness Connector Pin H, Pink Wire, is Ignition 12v+
Check the 3 wires at the crank sensor going to the PCM connector. If power and ground are good to the coil packs, this really is the ONLY thing that will cause a no spark condition. you don't even need the CAM sensor for the engine to run.
Crank Sensor pins A,B,C and the PCM connector they go to. C1 is the BLUE connector.
A. Dk Blue/wht - PCM C1 pin 12 - crank signal to PCM
B. Yellow - PCM C1 pin 21 - ground reference to crank sensor
C. Lt Green - PCM C1 pin 2 - 12 volt+ reference to crank sensor
Last week I went to start my 5.3 swaped caprice and had no fire...a bad crimp on one of the crank sensor pins was at fault. The copper wire pulled right out of the terminal.
Good Luck.
Last edited by busta9876; Feb 8, 2008 at 09:10 PM.
Put a new map and cam sensor in. Still no spark. When the key is turned on i have power on the injector plug pin. But when i turn the key i dont get a pulse so mabey i think my pcm is not seeing cranking power but should i still have spark? Crank sensor is plugged in, double checked all grounds.
where are you grounding your coil harness's,, make sure you go to a good chassis ground and dont try to ground anything to the valve cover bolts or coil brackets,,
i found out on my s-10 swap that the coil brackets and valve covers are not grounded to the engine,, the thick gaskets and the bolt grommets keep them un-grounded from the block
it will run with the maf unplugged but you will need a working map sensor
also you need a noid light to check for injector pulse, the injectors should have +12 anytime the key is on and when you crank the engine, same for the coils ,, make sure you have power to everything even while you are cranking the engine
-the pcm grounds the injector to fire it
i found out on my s-10 swap that the coil brackets and valve covers are not grounded to the engine,, the thick gaskets and the bolt grommets keep them un-grounded from the block
it will run with the maf unplugged but you will need a working map sensor
also you need a noid light to check for injector pulse, the injectors should have +12 anytime the key is on and when you crank the engine, same for the coils ,, make sure you have power to everything even while you are cranking the engine
-the pcm grounds the injector to fire it
Well i put the 3 grounds on my intake(wieand) alumium intake i just put them though 1 of the mounting bolts, after thinking there is no metal cotact because of the gaskets. I will put them on the motor and see what happens.
Put a new map and cam sensor in. Still no spark. When the key is turned on i have power on the injector plug pin. But when i turn the key i dont get a pulse so mabey i think my pcm is not seeing cranking power but should i still have spark? Crank sensor is plugged in, double checked all grounds.
