No spark! Computer advanceing, ign & grd good, help!!!!!!!!!!!!
07-20-2009, 05:49 PM
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No spark! Computer advanceing, ign & grd good, help!!!!!!!!!!!! Hey everyone,
Ive swapped a '04 6.0L into my iroc-z, im getting no spark on it.
Im watching through HPTuners that te computer is throwing advance, which makes me think te computer is trying to fire the coils.
Ive checked that i have ign+ during crank and key to ign, and my gounds are good.
The 5V refrence circuit is the only thing i can see further that can be wrong. Is this common? Has anyone else had this issue? How do i test the circuit?
Sheldon
Ive swapped a '04 6.0L into my iroc-z, im getting no spark on it.
Im watching through HPTuners that te computer is throwing advance, which makes me think te computer is trying to fire the coils.
Ive checked that i have ign+ during crank and key to ign, and my gounds are good.
The 5V refrence circuit is the only thing i can see further that can be wrong. Is this common? Has anyone else had this issue? How do i test the circuit?
Sheldon
07-20-2009, 06:14 PM
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Did you check the other two parts of the triangle of fire.......Fuel, Air, Ignition?? Fuel pump coming on, got fuel pressure at rail?? MAF connected, air filter not plugged?? Have you turned off the VATS??
07-20-2009, 06:47 PM
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Compression check, fuel check, no MAF atm, but it will run in failsafe if the MAF is unplugged. im just triyng to test fire it. VATS is off, it ran the motor in another car last week, ive already tuned the computer etc
07-20-2009, 07:24 PM
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Alright, to update, i have complete Low Ref circuits, from the PCM pin to the connector, its a complete circuit, so thats not the issue.
Im super confused here.
The computer is showing its advanceing ign 12.5* to get it to fire, there is IGN + at the coils, there is ground at the coils.
What am i missing here?
The computer worked perfect on the same motor in my iroc-z less then 2 weeks ago. It will communicate with HPtuners, its controlling injectors, showing input from all of my sensors, fuel pressure is great etc etc.
Its definately an ign issue. Wtf is the problem here. HELP ME!
Im super confused here.
The computer is showing its advanceing ign 12.5* to get it to fire, there is IGN + at the coils, there is ground at the coils.
What am i missing here?
The computer worked perfect on the same motor in my iroc-z less then 2 weeks ago. It will communicate with HPtuners, its controlling injectors, showing input from all of my sensors, fuel pressure is great etc etc.
Its definately an ign issue. Wtf is the problem here. HELP ME!
07-22-2009, 10:55 PM
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ALright guys, update to this.
Ive checked all through my harness and its perfect. All circuits are correct. All wires power correctly, all grounds are correct.
So to re-run over this.
My Crank sensor is obviously functioning as the computer is telling HPTuners it see's RPM. This would lead me to beleive its functioning correct.
My Coils are fine, ive tried a 2nd set, also had a no-fire condition.
My Computer is fine, i tried a 2nd computer also, but i nkow this one is good, its firing the injectors, i can flash a tune onto it, i can tell it to control MIL, Fuel pump etc etc. How can it just kill 1 circuit?
Im completely stumped here. What the frig else can be bad?
I thought if the crank sensor was good, computer was good, coils are good and wiring is good id have spark?
Grounds are all correct, power is correct.
Obviously my computer is seeing something that it dislikes, and wont fire the coils.
The engine was running in a different engine bay less then 2 weeks ago, now it wont run in this one. Wiring is the only difference, and ive checked that its fine, what else can be wrong?
Does the cam sensor have anything to do with it? I changed the cam in the motor from the MS3 to a XR275R-12 Camshaft (Smaller) but i dont understand how that would have damaged my cam sensor? I thought computer relied on crank sensor only to fire the coils?
If anyone here has advice, im in despirit need to get this damn car running!
Sheldon
Ive checked all through my harness and its perfect. All circuits are correct. All wires power correctly, all grounds are correct.
So to re-run over this.
My Crank sensor is obviously functioning as the computer is telling HPTuners it see's RPM. This would lead me to beleive its functioning correct.
My Coils are fine, ive tried a 2nd set, also had a no-fire condition.
My Computer is fine, i tried a 2nd computer also, but i nkow this one is good, its firing the injectors, i can flash a tune onto it, i can tell it to control MIL, Fuel pump etc etc. How can it just kill 1 circuit?
Im completely stumped here. What the frig else can be bad?
I thought if the crank sensor was good, computer was good, coils are good and wiring is good id have spark?
Grounds are all correct, power is correct.
Obviously my computer is seeing something that it dislikes, and wont fire the coils.
The engine was running in a different engine bay less then 2 weeks ago, now it wont run in this one. Wiring is the only difference, and ive checked that its fine, what else can be wrong?
Does the cam sensor have anything to do with it? I changed the cam in the motor from the MS3 to a XR275R-12 Camshaft (Smaller) but i dont understand how that would have damaged my cam sensor? I thought computer relied on crank sensor only to fire the coils?
If anyone here has advice, im in despirit need to get this damn car running!
Sheldon
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07-23-2009, 07:18 AM
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I thought the computer based the fueling off the cam sensors, so i would have figured it would be good, as im getting fuel? but maybe its only getting a crank input and guessing at everything else which is causing my problems.
Sheldon
07-23-2009, 02:23 PM
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log your cam counts at starting. This will tell you if it is seeing the cam. Also, what is your battery voltage? If it's to low, it might not send a spark signal. Also, have you actually pulled the plug out and watched it not fire? Maybe you are chasing a tune issue.
07-23-2009, 02:55 PM
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Did you remove the harness from the engine at all. I had a similar issue earlier this week, now I currently don't have a OBD2 port hooked up so I couldn't check the PCM for data, but my issue was that teh Cam sensor plug was connected to the Cranksensor and vice versa.
07-24-2009, 04:08 PM
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log your cam counts at starting. This will tell you if it is seeing the cam. Also, what is your battery voltage? If it's to low, it might not send a spark signal. Also, have you actually pulled the plug out and watched it not fire? Maybe you are chasing a tune issue.
Ive replaced teh cam sensor with another cam sensor i have, i tore the harness out, i checked all circuits, and cleaned it all up, and it still has a no-start problem. Cranks & cranks.
Im completely stumped here. Wtf can possibly be stopping spark! Ive had a battery charger on it during start to make sure it has lots of volts. I really dont understand where this is going wrong.
07-24-2009, 05:13 PM
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Have you checked ALL the IGN switched and the battery constant at the PCM connections?
Are you sure that you have it on a circuit that has power during run AND crank? Some circuits shut off during cranking.
I had the same issue, and it was a bad crimp on the +12 constant to the PCM.
FWIW, I've run multiple engines without the cam sensor hooked up at all. It will start hard, but it should start and run just fine.
Are you sure that you have it on a circuit that has power during run AND crank? Some circuits shut off during cranking.
I had the same issue, and it was a bad crimp on the +12 constant to the PCM.
FWIW, I've run multiple engines without the cam sensor hooked up at all. It will start hard, but it should start and run just fine.
07-24-2009, 06:17 PM
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Have you checked ALL the IGN switched and the battery constant at the PCM connections?
Are you sure that you have it on a circuit that has power during run AND crank? Some circuits shut off during cranking.
I had the same issue, and it was a bad crimp on the +12 constant to the PCM.
FWIW, I've run multiple engines without the cam sensor hooked up at all. It will start hard, but it should start and run just fine.
Are you sure that you have it on a circuit that has power during run AND crank? Some circuits shut off during cranking.
I had the same issue, and it was a bad crimp on the +12 constant to the PCM.
FWIW, I've run multiple engines without the cam sensor hooked up at all. It will start hard, but it should start and run just fine.
Sheldon
07-24-2009, 07:14 PM
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Alright, embarrased to post this, but ive found the problem.
Turns out the PCM Ign + feed circuit was going dead during crank
Jumped the wire to another circuit and the thing fired right up without even the slightest hiccup.
I had checked voltage @ the coils, knew the PCM was getting volts during ign etc, but i guess the PCM ign + circuit went dead during crank, which would explain why it would fuel but not spark, since the PCM was still getting battery volts, and the PCM grounds the injectors.
Anyways, the POS runs now!
Thank you everyone for your help!
Turns out the PCM Ign + feed circuit was going dead during crank
Jumped the wire to another circuit and the thing fired right up without even the slightest hiccup.
I had checked voltage @ the coils, knew the PCM was getting volts during ign etc, but i guess the PCM ign + circuit went dead during crank, which would explain why it would fuel but not spark, since the PCM was still getting battery volts, and the PCM grounds the injectors.
Anyways, the POS runs now!
Thank you everyone for your help!
07-25-2009, 08:58 AM
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Check that your injectors are getting + volts during Ign & Crank (Was my issue), as if when you go to crank and you loose power to your injectors, your computer can ground them all day long and they aint gonna be doin anything.
