Ok so I have a 2003 suburban 5.33 flex fuel and I have bad oil leaks my job won't tolerate it. So I got valve cover gaskets And O-rings for the camshaft position sensor and figured I just need to just change them out so I pulled intake cleaned everything up placed what I needed to replace I've installed everything back now and I put the felpro metal gaskets on it that I had bought for a previous truck that I had and it had more problems after a knock sensor went bad never could get it running right so I took the gaskets off of that and hung them on the wall I figured that they would still be good that's the only thing on this truck that came off of that truck and it's causing the same thing is the other truck did I put it all back together I've double checked everything triple checked everything pulled the intake off three other times so far tonight and it's still backfiring through the exhaust. I also had to replace the motor mounts in this truck so I had to take the exhaust manifold off but I've put those back on and I just literally I cannot figure out why it would be doing this unless it's because of the intake gaskets are just warped or bad but I can't for see that that to be happening because I'm barely even was able to get the other truck running when those gaskets were on that other truck I don't know what to do and I'm losing my mind right now.
Engine backfire through exhaust
- Thread starter NO4NSHIT
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There are people on this site, but they're not just hanging out here waiting for somebody to post a new thread, as they all have lives away from the Internet. Be patient, and someone with the knowledge that you are trying to tap into will reply.
It might help us understand what's going on if you separate your thoughts into paragraphs.
Assuming that the engine will run, I would start by using a decent scanner to document the short- and long-term fuel trims at warm idle, and comparing those to ST & LT trims at around 2000 rpm. Run those and post them here for us to see.
Does your code reader show any Pxxx codes (current, history, pending, etc.)?
The way I read it, you re-used intake manifold gaskets from another engine. You can look for vacuum leaks using an unlit propane torch by opening the valve slightly and "sniffing" around the intake gasket areas. If the idle smooths out or you notice it running a little better with the propane in one spot, there's a leak.
How long has it been since the throttle body was cleaned?
Assuming that the engine will run, I would start by using a decent scanner to document the short- and long-term fuel trims at warm idle, and comparing those to ST & LT trims at around 2000 rpm. Run those and post them here for us to see.
Does your code reader show any Pxxx codes (current, history, pending, etc.)?
The way I read it, you re-used intake manifold gaskets from another engine. You can look for vacuum leaks using an unlit propane torch by opening the valve slightly and "sniffing" around the intake gasket areas. If the idle smooths out or you notice it running a little better with the propane in one spot, there's a leak.
How long has it been since the throttle body was cleaned?
Mudsport96
Full Access Member
1. I would get new intake gaskets for one. If the backfire started AFTER you put them on. i would think that it would relate to them...especially it it happened on the previous vehicle they were on.
2. Get a scanner and check codes.
3. Use scanner to check the alcohol content that the flex sensor is reading. If it is going bad it can affect fuel and timing.
4. Sentences with punctuation. Please.
2. Get a scanner and check codes.
3. Use scanner to check the alcohol content that the flex sensor is reading. If it is going bad it can affect fuel and timing.
4. Sentences with punctuation. Please.
Why would you respond this way? you are escalating a sore subject without providing anything of value. That is to say, if you are going to chew on somebody for something you think is stupid, please also add value to the conversation.
It sounds like you have a timing issue. And you indicate resealing the camshaft position sensor... I wonder if there is something wrong with it. Knowing the codes would go along way toward diagnosing your issue.
And a little more patience... It sounds like you used most of yours up on this issue already. However, you are still in the right spot because everyone here knows that feeling.
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