Wont Start after cam install
I tried the wot to clear the fuel and she started right up but im throwing a p0108 is that normal, also she won't stay at idle I have to keep her at like 1500 rpms to keep her alive is that normal?
Joined: Aug 2007
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From: Turnin' Wrenches Infractions: 005
In the 1970s this advice would be spot on correct. However, with the complexities of todays modern engines and their electrical systems, it is completely useless.
Check the Map sensor at the back of the intake
P0108:
http://www.hotrodlane.cc/New%20LS%20...TC%20P0108.htm
P0108:
http://www.hotrodlane.cc/New%20LS%20...TC%20P0108.htm
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Teching In
Joined: Feb 2010
Posts: 25
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From: Gloucester area Va
Have you checked your ECT sensor yet.Believe it or not it will cause it not to start.Unplug it and make sure you have a 5v reference and good ground.If you have a scan tool check to see what it is reading if it is not close to ambient temp before it starts then something is wrong there.Sometimes when unplugged it will start if it does get a sensor.The same can be done with the TPS sensor.When it is unplugged it will be in a "limp home" type mode and should start if the problem is there.A scan tool will be your best friend if you can get one,NOT a code reader an actual scan tool.Thats what sound like is wrong to me,Good luck.
I might have missed it but did you change your throttle body? if so what throttle body? If you did change your throttle body you can adjust your idle screw a bit higher and relearn your tps. there is a procedure that you do for relearn but you have to search. Or i can get back with you tonight when im off and give you some info then. Hope this helps
I still have a stock TB i saw the article in ls1howto about drilling a bigger hole in the TB but i didn't think my cam was big enough to need to do that. I'll take all the information I can get about the relearn. Thanks.
I don't think so. It is true that the reasons that either spark or fuel is being withheld from the cylinders is now different and more complex, but the fundamentals are the same - if it has spark, fuel, and compression it will fire. I missed what appears to have been a flooded condition in this case but that is because I assumed that when he said the plugs read okay that he was not seeing flooding and that after it sat overnight that any flooding would have been gone.
I'm starting to think that something is majorly wrong with my whole setup.
below is a video of her starting up you can hear the multiple backfires when she starts up. i adjusted the throttle screw so now she fires up with no problem but as soon as i try to let her idle she starts to backfire. I have a small cam i've heard of people running much bigger cams with stock tuning, i tried posting in tuning and diagnostic with no luck, so i was hoping yall might have a few ideas. I have a hp tuner coming on SAT but all i really need is for her to run enough to get to the tuners.
http://www.youtube.com/watch?v=-oXXhhhIn2g
below is a video of her starting up you can hear the multiple backfires when she starts up. i adjusted the throttle screw so now she fires up with no problem but as soon as i try to let her idle she starts to backfire. I have a small cam i've heard of people running much bigger cams with stock tuning, i tried posting in tuning and diagnostic with no luck, so i was hoping yall might have a few ideas. I have a hp tuner coming on SAT but all i really need is for her to run enough to get to the tuners.
http://www.youtube.com/watch?v=-oXXhhhIn2g
9 Second Club
Joined: Aug 2008
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they are still just air pumps with electonics.
I just read your op again and it said you change pump and chain and other stuff. Did you make sure your timing was dead on? Im not a professional but it could be timing. hope this helps and doesnt sound stupid.
Registered User
Joined: Mar 2010
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timing was dead on. the whole build was torqued to specs. it fired fine the first time and stayed idle for around 5 mins. cut it to change oil and exhaust and nothing but the above video. we are both lost right now, We have changed the tps sensor, did the screw method, nothing seems to help with the backfiring.
after you get the tuning software make sure you bring the throttle body back to the way it was before.
idk sounds like it should idle. not knowing much without being there, i would say you should try clearing the pcm and doing the learn procedure once again but really try to get it to get idle on its own. is the MAF facing the right direction?
idk sounds like it should idle. not knowing much without being there, i would say you should try clearing the pcm and doing the learn procedure once again but really try to get it to get idle on its own. is the MAF facing the right direction?
Last edited by disc0monkey; Mar 18, 2010 at 08:58 AM.
Take off the exhaust again and try firing it up. Maybe there is a rag in the pipes or something that is clogging it up.
Take off the sparkplugs and make sure they are all gapped right. Sometimes when you put plugs back on, and if it was difficult to put on, the gap closes. This may cause that. I dont remember if you said that you put new plugs on, but try doing that too.
Take off the sparkplugs and make sure they are all gapped right. Sometimes when you put plugs back on, and if it was difficult to put on, the gap closes. This may cause that. I dont remember if you said that you put new plugs on, but try doing that too.