backfiring problem continues (long)
 

maybe some of you guys can help me. i am still having backfiring problems with my sefi converted 67. i have found out that it doesn't do it so much if i have the fuel pressure around 50-52 and the timing quite advanced. however, i don't want to do this because the idle surges and spits out raw fuel (makes it look like i burn oil).

i do have a jms chip for my computer but it doesn't seem to be helping. i am thinking of sending it back for a reprogramming.

also, the other night when i was cruising around, it would backfire at pretty much any rpm. i turned my heater on to try to keep the engine temps down and it didn't backfire once, so i have a question. does anyone know if bad ect or act (temp sensors) that read too hot could make the computer retard the timing or lean out the air/fuel ratio. i have a 180 deg stat and was thinking of going to a 160. i am thinking it is detonating from being lean, but am not quite exactly sure what detonation sounds like.

if anyone has some kind of info or experience with a problem like this, i would really appreciate it if you could leave some info. i won't be able to reply back though until after 5:00 pm central time.

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shawn hill
1967 ford mustang coupe, red w/white stripes, hood scoop, front and rear spoiler, sefi and c4, trickflow intake, 70mm mac tb/egr, billet fpr, 24# inj, c&l maf, heavy duty c4 w/transgo shiftkit, msd 6a box w/tfi blaster coil, flowtech longtubes w/turbo mufflers, t-rex inline pump, ported and polished E7TE heads w/1.94,1.60 valves, lunati 292 cam, harland sharp 1.6 rollers, conventional 8" with 2.79 gears (soon will be gone)

Any codes?

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Retired Moderator
MustangNet

My site: JimPorterRacing

RACECAR spelled backwards is RACECAR

HEY !!! Are you ASE Certified ??? If you are, ask me about iATN. The best tool you'll ever have, and it's free !!!

i cannot get any engine running codes for some reason, but the koeo and continuous codes wouldn't cause any of that to happen.

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shawn hill
1967 ford mustang coupe, red w/white stripes, hood scoop, front and rear spoiler, sefi and c4, trickflow intake, 70mm mac tb/egr, billet fpr, 24# inj, c&l maf, heavy duty c4 w/transgo shiftkit, msd 6a box w/tfi blaster coil, flowtech longtubes w/turbo mufflers, t-rex inline pump, ported and polished E7TE heads w/1.94,1.60 valves, lunati 292 cam, harland sharp 1.6 rollers, conventional 8" with 2.79 gears (soon will be gone)

Replace your ECT sensor. Your problems fit a bad ECT scenario, and the fact that you can't get KOER codes convinces me even further.

Take care
~Chris

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Retired Moderator
MustangNet

My site: JimPorterRacing

RACECAR spelled backwards is RACECAR

HEY !!! Are you ASE Certified ??? If you are, ask me about iATN. The best tool you'll ever have, and it's free !!!

guess what, i just bought a new one yesterday and was going to replace it today to see if that was the problem. i am going to go out there now and see if that fixes it, i'll post what i find out.

thanks chris

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shawn hill
1967 ford mustang coupe, red w/white stripes, hood scoop, front and rear spoiler, sefi and c4, trickflow intake, 70mm mac tb/egr, billet fpr, 24# inj, c&l maf, heavy duty c4 w/transgo shiftkit, msd 6a box w/tfi blaster coil, flowtech longtubes w/turbo mufflers, t-rex inline pump, ported and polished E7TE heads w/1.94,1.60 valves, lunati 292 cam, harland sharp 1.6 rollers, conventional 8" with 2.79 gears (soon will be gone)