Ignition issues
Ignition issues Wasn't sure where I should put this thread cause it covers a wide range of things.
Car: 93 T/A
Engine: LQ9 6.0 408
PCM: 411
Trans: TH400
I really need some help here!
My car has been giving me ignition issues since I got this setup in the car, I haven't even had it off jack stands in 3 years since I started this whole idea.
I have gone back and tested for spark on every cylinder and I'm at a loss.
All cylinders have PWR and GRND.
PCM has GRND and PWR at the right times.
All wires ohm out from the PCM to corresponding Coil connector.
All cylinders have spark but #5 & #8 they have no spark at all.
I change the Driver to Passenger main harness plugs for the coils then I had spark on #8 but it was going off cylinder #1 signal.
Anyone have any idea what my issue could be?
Next to buying expensive tools to check a few things I don't know what to do??
Car: 93 T/A
Engine: LQ9 6.0 408
PCM: 411
Trans: TH400
I really need some help here!
My car has been giving me ignition issues since I got this setup in the car, I haven't even had it off jack stands in 3 years since I started this whole idea.
I have gone back and tested for spark on every cylinder and I'm at a loss.
All cylinders have PWR and GRND.
PCM has GRND and PWR at the right times.
All wires ohm out from the PCM to corresponding Coil connector.
All cylinders have spark but #5 & #8 they have no spark at all.
I change the Driver to Passenger main harness plugs for the coils then I had spark on #8 but it was going off cylinder #1 signal.
Anyone have any idea what my issue could be?
Next to buying expensive tools to check a few things I don't know what to do??
I did then I swapped plugs and got spark so I know the coils are good it's just not getting signal for some reason on 5 & 8.
I'm thinking there is something up with the PCM but I'm not sure about that either.
I'm thinking there is something up with the PCM but I'm not sure about that either.
On The Tree
Joined: Feb 2014
Posts: 102
Likes: 0
Ok good. Are you certain that your pcm is flashed for a V8 and not a V6 or that it's flashed for the correct year engine? (24 vs. 58 tooth reluctor wheel)
http://easyautodiagnostics.com/gm_co...oil_test_1.php
Perform test 6 or 7 to verify that the PCM is sending trigger signal to the coils.
I would also take an ohm reading from the coil trigger wires to the pcm to make sure the wires are going to the correct pcm pin.
While you're in there take a good look at your crank/cam position sensor connectors to make sure you don't have any bare wires or shorts.
http://easyautodiagnostics.com/gm_co...oil_test_1.php
Perform test 6 or 7 to verify that the PCM is sending trigger signal to the coils.
I would also take an ohm reading from the coil trigger wires to the pcm to make sure the wires are going to the correct pcm pin.
While you're in there take a good look at your crank/cam position sensor connectors to make sure you don't have any bare wires or shorts.
PCM is flashed as a 2000 F-body with current mods taken into consideration and all VATS and DTC codes turned off.
I don't see the place where I had it tuned in the sponsorship adds but I know he is on here.
Thanks for the link
I don't see the place where I had it tuned in the sponsorship adds but I know he is on here.
Thanks for the link
K, I did the test that you posted.
Everything checked out but 5 & 8 are not getting signal from the PCM.
I'm going to e-mail my tunner and see what he suggest but it looks like I need a new PCM.
Everything checked out but 5 & 8 are not getting signal from the PCM.
I'm going to e-mail my tunner and see what he suggest but it looks like I need a new PCM.
On The Tree
Joined: Feb 2014
Posts: 102
Likes: 0
Thats a bummer. I would try a reflash of the pcm first. My pcm had no program in it when I first got it from the junkyard(must have dropped from having the bat. disconnected for so long). I found a tune on the HP tuners vault and loaded it and all was good.
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...and how do you know the PCM is good, have you tried another? I had an intermittent cylinder 5 misfire on a car that was 100% stock. I did all the typical troubleshooting and finally loaded a spare 411 PCM I had lying about which fixed the issue. Ironically this car that has been garaged it's entire life, never been changed or wrecked with just under 100K had a bad coil driver in the PCM. I've had PCMs in vehicles with double that mileage hit trees (and one hit by a train) and be just fine. Just an idea.
I haven't tried a different PCM.....I'll have to buy one or see ifsome one would let me try mine in there's.
Checking spark with a spark tester in the end of the plug wire.
Checking spark with a spark tester in the end of the plug wire.
The problem with buying one is it will still have VATS enabled which you won't have a way to disable without some sort of tuning software. The simpler thing would be to try your PCM in a different V8 vehicle with a Red / Blue 411 type PCM and see if the problem follows. Even though the engine calibration will be way off from your 408, you could at least see if it runs enough to determine if the problem followed.
Well the PCM wasn't the issue as I still have a no run issue yet.
Now I'm going to start by checking spark again then Crank Sensor and then the reluctor to see if it's not running true.
I'm at a real loss with this whole thing
When I did have a small run like 2sec it had codes P 1336, 0335, 0336.
From what I was told this is normal since the PCM isn't from the "same car".
A crank relearn.......Not unless I can get it to stay running
Now I'm going to start by checking spark again then Crank Sensor and then the reluctor to see if it's not running true.
I'm at a real loss with this whole thing
When I did have a small run like 2sec it had codes P 1336, 0335, 0336.
From what I was told this is normal since the PCM isn't from the "same car".
A crank relearn.......Not unless I can get it to stay running
Well I believe I found my issue........my CKP has been rubbing ans has a notch on the front (mounted in motor) side so now I have to pull my motor out I think to fix the issue.
Last edited by Phantom383; Mar 7, 2014 at 08:41 PM.
