Ignition Problem Intermittent Ignition/Start
Thread Starter
12 Second Club
Joined: Sep 2003
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From: Houston
Ignition Problem Intermittent Ignition/Start I am having a maddening issue with my LS1 and I need some expert advice to resolve this.
The issue is this: I can go out and turn on the ignition, wait for everything to prime/boot up and then turn over the starter. The engine will spin all day and not fire one single time. If I just shut it off and try again over and over, it will eventually start and run perfectly fine until I shut it off again.
Other times it will start every time I try until I let it sit overnight and then game over.
The problem is that the coils/plugs arent firing at all while the engine is being turned over. Then randomly out of nowhere it will fire and run just fine. It has never started though without cycling the key.
The car isnt throwing any trouble codes and I have collected several minutes of scan logs from EFILive showing that all systems are functioning.
So far I have changed the crank position sensor, cam position sensor and battery. I have performed a CPK Re-Learn and double checked all ground straps and sensor connections for the cam and crank position sensors.
Still nothing
I thought I had it resolved over the weekend because I noticed that where I spliced into the white wire on the PCM for my window switch was a little weak looking. I re-soldered the wire and the car was 100% for about 20 minutes, then the intermittent crap came back and I just put it in the garage.
Any help on this would be greatly appreciated!
2002 Camaro SS M6 9k Miles, garage kept, never used.
Jeremy
The issue is this: I can go out and turn on the ignition, wait for everything to prime/boot up and then turn over the starter. The engine will spin all day and not fire one single time. If I just shut it off and try again over and over, it will eventually start and run perfectly fine until I shut it off again.
Other times it will start every time I try until I let it sit overnight and then game over.
The problem is that the coils/plugs arent firing at all while the engine is being turned over. Then randomly out of nowhere it will fire and run just fine. It has never started though without cycling the key.
The car isnt throwing any trouble codes and I have collected several minutes of scan logs from EFILive showing that all systems are functioning.
So far I have changed the crank position sensor, cam position sensor and battery. I have performed a CPK Re-Learn and double checked all ground straps and sensor connections for the cam and crank position sensors.
Still nothing
I thought I had it resolved over the weekend because I noticed that where I spliced into the white wire on the PCM for my window switch was a little weak looking. I re-soldered the wire and the car was 100% for about 20 minutes, then the intermittent crap came back and I just put it in the garage.
Any help on this would be greatly appreciated!
2002 Camaro SS M6 9k Miles, garage kept, never used.
Jeremy
I'm gonna try the ignition relay. a guy on another LS1 site said that he swapped his with the fan relay and it worked fine....he too said he had no codes
I'll keep you posted, unless you try it first
I'll keep you posted, unless you try it first
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Thread Starter
12 Second Club
Joined: Sep 2003
Posts: 634
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From: Houston
In my testing the fuel pump and gauges wouldnt come on if the ignition relay was bad. So I dont think thats it unless yours is completely dead when you turn the key on.
Something that I found with mine is that if I tug on the crank position sensor harness a little while my wife is turning over the engine it will sometimes start up. This also has inconsistent results so its not a sure fire solution. I just pulled the harness up under the hood this evening and have been fault checking it. Of course everything looks fine so far.
What exactly is yours doing?
I have also considered that the ignition key could be bad. Im not putting a lot of money behind this concept, but it is on my list of things to check.
Something that I found with mine is that if I tug on the crank position sensor harness a little while my wife is turning over the engine it will sometimes start up. This also has inconsistent results so its not a sure fire solution. I just pulled the harness up under the hood this evening and have been fault checking it. Of course everything looks fine so far.
What exactly is yours doing?
I have also considered that the ignition key could be bad. Im not putting a lot of money behind this concept, but it is on my list of things to check.
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Verdad Gallardo it just cranks. forever. according to all of the t/s i did with the multi-tester and the book, my ECM took a ****. I'm not a happy camper right now. Even if i could buy a new computer tomorrow...I still have to have it tuned, nothing in my car is stock except the ignition.
first, when the engine still ran, I took a scanner and I cleared the codes. once I did that, I idled the car and then slowly brought the rpms up until the SES light popped on. Once that happened, I checked the codes. only one coil showed up, three times in a row, so I assumed that coil was bad...and I was guessing that if one went bad, maybe it effected the others -- sounded stupid to me, but I never owned an LSI. On a hunch, I swapped the coil with another one on the engine, just to back up my thought process and repeated the scanner test. Sure as ****, a different coil popped up and then after 6 subsequent tests, the same coil never popped up twice as the first coil to fail. Now I look in the service manual and it tells me to take a test light and stick it in the 'ignition control' terminal in the plug going into the coil. the IC terminal is next to the 12 volt supply terminal on the same plug. I got +12 to show, but I could never get the light to flash (indicating a signal from the PCM) when I touched it to the IC terminal. Finally, i swapped coils with another vehicle and nothing changed, no codes on his car, same ignition coil primary/secondary failure codes on mine. after checking the relay and putting my coils back in the car, checking the plug wires for resistance and blah blah blah, I finally conceded to the fact that the manual stated in the troubleshooting section...the PCM is bad. I'm lucky, though...the PCM is less than 200 dollars (plus a $200 core) and my tuner is going to re-flash the new one for nothing...
Thread Starter
12 Second Club
Joined: Sep 2003
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From: Houston
Interesting
Well mine is not giving any codes, and once I get it to start it runs perfectly until I shut it off.
Let me know if swapping computers works for you Im not sure what to try next on mine.
My car has always had funny little electrical glitches. Noting serious, but sometimes when I am going down the track my brake lights will flash and my reverse lights will come on. I would have never noticed this except my buddy videoed one of my runs up close so I could see it.
Does the PCM control the lights directly?
Let me know if swapping computers works for you Im not sure what to try next on mine.
My car has always had funny little electrical glitches. Noting serious, but sometimes when I am going down the track my brake lights will flash and my reverse lights will come on. I would have never noticed this except my buddy videoed one of my runs up close so I could see it.
Does the PCM control the lights directly?
On The Tree
Joined: Aug 2006
Posts: 106
Likes: 0
From: eldersburg MD
i had the same exact problem with my car today. i just bought it and it only has 4000 miles and i got to start it and it just cranks....... so i pulled it into the shop and it would start fine over and over again. so i checked the rpm when i was cranking it with a scan tool and nothing was funny so the guys said the crank position was good. and they started to bang on the relay boxes and when he hit the ignition relay box it started. so I swapped it with a cooling fan relay and it seemed to start every time. so i drove up to the nearest chevy dealership and bought a relay and a fuel filter and it seems to be good now.. wait till tommorow it seemed to have the biggest problem when it sat in the heat.
Thread Starter
12 Second Club
Joined: Sep 2003
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From: Houston
Originally Posted by 2001sunsetmetalss
i had the same exact problem with my car today. i just bought it and it only has 4000 miles and i got to start it and it just cranks....... so i pulled it into the shop and it would start fine over and over again. so i checked the rpm when i was cranking it with a scan tool and nothing was funny so the guys said the crank position was good. and they started to bang on the relay boxes and when he hit the ignition relay box it started. so I swapped it with a cooling fan relay and it seemed to start every time. so i drove up to the nearest chevy dealership and bought a relay and a fuel filter and it seems to be good now.. wait till tommorow it seemed to have the biggest problem when it sat in the heat.
I checked those relays first but never tried swapping them around.
Originally Posted by jermstyle
Side of the brake pedel? What are you talking about? I'm sure that's not it because I have tried to start the car 100 times in the last couple of weeks.
On The Tree
Joined: Aug 2006
Posts: 106
Likes: 0
From: eldersburg MD
yea i swapped them out and it worked fine so i went up and got a new relay and replaced the bad one never had the problem since, dont forget wich one is bad though you do want your cooling fans to come on!!