I recently put my motor back in with a great header (imagine engineering) But when i started it up, it didnt run right at ALL. I kept checking wiring and spark, but evernything seems to be alright. But the only thing i didnt hookup was my exhaust. No do you think that without the exhaust it could have not had enough backpressure, and cause the motor not to rev above 1500rpms?? It did idle, but when you hit that gas it would die, then comeback but be choppy.
Just an idea

 

i wouldnt think that would do anything too it. Are you running a test pipe or a cat. A good way to build up some back pressure to find out would be to stick a OE cat on there. That should build up some pressure. The only thing i have every heard of not having enough backpressure to do is to take away torque.

 

Backpressure has nothing to do with it - look for the problem in other areas.

Is your O2 sensor hooked up? That's important.

 

O2 doesnt have to be plugged to run, it will run but sputter and just throw a code

 

have you checked your timing

 

that has nothing to do with backpressure.

I ditto the comment on checking timing, and all your wiring.

 

backpressure does not give you torque and it doesnt help you in anyway, you want the least amount of backpressure possible! anyways, what all components did you remove to install the header?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Speedra500 &raquo;</TD></TR><TR><TD CLASS="quote">backpressure does not give you torque and it doesnt help you in anyway</TD></TR></TABLE>

u are the only person i have ever heard say that, but anyways, i had to drive my car about 1/2 mile to muffler shop with ONLY the exhaust manifold, no downpipe, so with the complete header there is a lot more backpressure than what i had

 

having no or too little backpressure will cause extreme exhaust temps at the valves and they will burn up. each car runs well at a certain backpressure, should never be less than 2-4 psi

 

sounds like the tps sensor to me. can be an easy one to over look. its right behind the tb near the fire wall. check it.

 

thanks, im fairly sure its not the tps because i have a vafc and i can read the throttle percentage as im hitting the gas. This problem is stumping me, thats why i thought it was the backpressure. I have a really long 4-2-1 header with no exhaust or cat hooked up right now. Thats why i was wondering bif that was the problem.
If you guys dont think it would cause it not to rev up, i guess thats fine ill keep looking for a solution

 

check you map sensor also. just cause your getting readings dont mean there right. match them up to the helms.

 

you guys are funny..... backpressure never did anything good for anyone. all back pressure does is increase the pumping losses of the engine, making it work harder to push the exhaust gasses out of the engine.

 

twistedbydezign, don't take my word for it, do a little bit of research on your own

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by luda94 &raquo;</TD></TR><TR><TD CLASS="quote">having no or too little backpressure will cause extreme exhaust temps at the valves and they will burn up. each car runs well at a certain backpressure, should never be less than 2-4 psi
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What I think you mean by this is a loss of exhaust scavenging effect due to a lower delta pressure with not enough room for the pulses to create this delta pressure, which is made possible by a small extension of pipe on the end of your header, otherwise known as a test pipe