bad backfire after lt install please help....
Thread Starter
Staging Lane
Joined: Jul 2006
Posts: 67
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From: indianapolis
bad backfire after lt install please help.... The car is a 98 formula with just gears and now full exhaust. The lt's are stainless and of unkown origin got them through a trade with a 3" pacesetter ory. During install I broke the ect and second to last header bolt on left side. Just replaced the ect with a napa echlin unit and brand new wires with tr55's gapped at 50 thousand's. Am going to replace the head's before to long and solve the header bolt issue. Now onto the issue The car will run but barely and will backfire hard every couple of second's out of the exhaust and the left side header will be extremely hot after only ten second's of running while the right side will be cool to the touch. I had a extra set of coil's laying around that I threw in off a 99 and it made no difference. Please try and guide me somewhere I am clue less is it possible I got a bad ect or what?
Correcto... The backfire sounds like fuel is being dumped into that side of the engine, and igniting in the pipes..
An incorrect ECT sensor could be causing hi fueling as it's telling the pcm that the ect is -40*
A header leak due to broken bolts isn't going to help the situation, either, once the engine temp is up and in closed loop.
Now's the time for a scan and a datalog session.
Thread Starter
Staging Lane
Joined: Jul 2006
Posts: 67
Likes: 0
From: indianapolis
thanks for the reply I will be trying a new ect and going over all plugs and wires this evening I will post up the result's. If I have a issue with the header bolt I will be throwing on a set of ported 241's that a buddy has figure that would be easier that fixing that bolt.
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OP is there an SES light on? If you have access to an OBD2 scanner (own or at the local napa) have them get you the codes it is throwing. Given that this is fresh off an LT install, my guess is you either a) didn't connect something properly or b) fouled an o2 sensor. You may as well have a bad o2 extension. Swap it with the other side and see if the issue swaps over.
Everything else is just re-checking plugs, wires, coils, fuel injector plug wires, and other such things of that nature.
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Thread Starter
Staging Lane
Joined: Jul 2006
Posts: 67
Likes: 0
From: indianapolis
Just installed a new ect and the backfire is gone but still has bad miss and after only 10 seconds the left side header is to hot to touch and right side is cool. I do not have access to a scanner or anyway to pull the code's. This weekend I will try to switch out the 02's and switch my extensions from side to side. All wire's and plugs are hooked up correctly. Any more suggestion's?
One side is running too rich because the o2 sensor isn't properly reporting the mixture. Swap your o2's to different sides and see if the problem changes sides. if so the o2 is bad and needs to be replaced.
Thread Starter
Staging Lane
Joined: Jul 2006
Posts: 67
Likes: 0
From: indianapolis
ok, I switched out the 02 sensor with brand new one's and swapped the extensions side to side with no change at all being the result. I did how ever notice that where the header bolt is broken it is ticking very bad and has a noticeably bigger leak than i thought. Will a leak like that cause any sort of misfire?
