car back fires under load. please help.
09-14-2011, 09:06 PM
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Car: 89' camaro RS TTOP
Engine: 92 5.0tpi Bosch III, headers, msd
Transmission: 700r4 built. trans go. 2,300 stall
Axle/Gears: 3:73 posi ls disc brake conversion
car back fires under load. please help.
Some of you know I just completed my engine swap. I pulled a 89 2.8l v6 out and put in a 91 305tpi in. Harnesses and ecm and all. Car runs but what im noticing is when under acceleration or overdrive my car sputters, surges and backfires. Makes driving harsh and embarrassing. Im using original v6 pump cause I was told it was ample capable. V6 was MPFI. I set timing to 0 and this helps soften the back fire from 6 degrees advanced where I had it. Tps is at. 54 and smooth in its action. Im wondering if I have a fuel issue. I noticed some injectors are replaced with ones called tomco rotary disk. All other injectors are black with a green ring around them (original???) FPR is original. What should my pressure be. Im gonna pick up a gauge so I can check. Also under the distributor cap and rotor I noticed the magnetic pick up? (Part that rotates within a metal ring, kinda star shaped) was pretty rusty. It seems to run great sitting still. It might pop if you burp the throttle off idle (might). Ignition coil is brand new. Wires, cap, rotor, plugs new. Any thought? ???
09-14-2011, 09:09 PM
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Car: 89' camaro RS TTOP
Engine: 92 5.0tpi Bosch III, headers, msd
Transmission: 700r4 built. trans go. 2,300 stall
Axle/Gears: 3:73 posi ls disc brake conversion
Re: car back fires under load. please help.
Wanna add, no codes or light. And 02 sensor is unheated in header. (Gotta change) could knock sensor cause any of this? I do have a new one ready to install.
09-14-2011, 11:41 PM
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Car: 89 chevy camaro rs
Engine: 305
Transmission: 700r4
Re: car back fires under load. please help.
play with the timing and see if it fixes it,also timing chain could be really shot
09-15-2011, 08:37 AM
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Car: 89' camaro RS TTOP
Engine: 92 5.0tpi Bosch III, headers, msd
Transmission: 700r4 built. trans go. 2,300 stall
Axle/Gears: 3:73 posi ls disc brake conversion
Re: car back fires under load. please help.
All internals of engine are new. Cam, gears, chain, rods, pistons. Block was bored. Noticed it runs better when cold. Im thinking possibly ICM OR injectors.
09-15-2011, 10:47 AM
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Car: 89 chevy camaro rs
Engine: 305
Transmission: 700r4
Re: car back fires under load. please help.
also could be the egr,did you use the same cam?or different,may require different timing
09-15-2011, 03:03 PM
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Car: 1988 GTA
Engine: 5.7 TPI w/ Bosch III's
Transmission: T56
Axle/Gears: 3.27 Borg Warner 9 bolt
Re: car back fires under load. please help.
The factory injectors are notoriously unreliable. I bet they are leaking.
The fuel pressure for a TPI is supposed to be 42-47 psi.
The factory timing setting is 6* BTC.
Hope this helps.
The fuel pressure for a TPI is supposed to be 42-47 psi.
The factory timing setting is 6* BTC.
Hope this helps.
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09-15-2011, 06:56 PM
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Car: 89' camaro RS TTOP
Engine: 92 5.0tpi Bosch III, headers, msd
Transmission: 700r4 built. trans go. 2,300 stall
Axle/Gears: 3:73 posi ls disc brake conversion
Re: car back fires under load. please help.
Cam is the hotter of the two stock ones offered. I just bought a egr block off plate. Gonna remove it. Will it throw a code? Gonna check fuel pressure and injector resistance. 12-16 ohms seem right to you guys?
09-16-2011, 08:46 AM
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Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: car back fires under load. please help.
I deleted all EGR type crap and have no codes, stock chip.
Check plug wires at night with a spray bottle of water.
spray a fine mist of water on plug wires while engine is running.
Check plug wires at night with a spray bottle of water.
spray a fine mist of water on plug wires while engine is running.
09-16-2011, 11:40 AM
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Car: 1989-92 FORMULA350 305 92 Hawkclone
Engine: 4++,350 & 305 CIs
Transmission: 700R4 4800 vig 18th700R4 t56 ZF6 T5
Axle/Gears: 3.70 9"ford alum chunk,dana44,9bolt
Re: car back fires under load. please help.
If the computer moniters the sensor it will thro a code.
If its just a controlled component it wont. AIR,EGR, EGR temp
If the wire shorts or the controlled part shorts itll thro a light.
So not all components will thro a code if unhooked.
If its just a controlled component it wont. AIR,EGR, EGR temp
If the wire shorts or the controlled part shorts itll thro a light.
So not all components will thro a code if unhooked.
09-16-2011, 07:37 PM
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Car: 89' camaro RS TTOP
Engine: 92 5.0tpi Bosch III, headers, msd
Transmission: 700r4 built. trans go. 2,300 stall
Axle/Gears: 3:73 posi ls disc brake conversion
Re: car back fires under load. please help.
Well....I think I figured it out. I need a fuel pump. Gauge shows 30 psi. Doesn't leak down. Guess the v6 pump can't take it...swappers beware!
09-17-2011, 11:35 PM
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Car: 89' camaro RS TTOP
Engine: 92 5.0tpi Bosch III, headers, msd
Transmission: 700r4 built. trans go. 2,300 stall
Axle/Gears: 3:73 posi ls disc brake conversion
Re: car back fires under load. please help.
Update!!!! CAR RUNS PERFECT!!!! Wasn't fuel pump. Had to purge air from fuel gauge set. Didn't know that. (Fancy snap-on tools) 44 psi car off. 38 psi running. Holds pressure to 30 psi overnight.
So what was the problem you ask?
Spark plug wires to cylinder 5 and 7 were backwards. DOH!!!!
I feel so dumb you guys. I checked wires probably 6 times and missed. Still gonna block off egr valve.
So what was the problem you ask?
Spark plug wires to cylinder 5 and 7 were backwards. DOH!!!!
I feel so dumb you guys. I checked wires probably 6 times and missed. Still gonna block off egr valve.
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