89 TPI intermittent low power, no code 12 from ecm, red hot headers
07-30-2008, 09:20 PM
#1
89 TPI intermittent low power, no code 12 from ecm, red hot headers
Working on a 89 Corvette with the 350 TPI auto. We took it out for a spin and it ran fine for about 10 min and then the SES light came on and low power, backfiring, red hot headers, won't idle, avg mpg went from 20.6 to 99 mpg, and range went to 630 miles. I tried to get the codes from the ecm but I got no response when I shorted terminals a&b on the aldl connector, just a solid SES light no code 12. I tapped on the maf and then unplugged the Maf sensor but that made no change.We limped it back home and noticed it ran hotter oil temp and water temp went up from 175ish to 220-230. We got home and I had to move my truck to get the vette inside the garage the all of a sudden the SES light went out and it ran fine. I then tried to see what codes were stored and this time I got a response, code 12, but nothing else. I gave the engine a once over and found nothing obvious. This thing has me stumped, anybody else have any other ideas?????
07-30-2008, 10:07 PM
#2
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Car: 89 iroc
Engine: l98
Transmission: tremec
Re: 89 TPI intermittent low power, no code 12 from ecm, red hot headers
Working on a 89 Corvette with the 350 TPI auto. We took it out for a spin and it ran fine for about 10 min and then the SES light came on and low power, backfiring, red hot headers, won't idle, avg mpg went from 20.6 to 99 mpg, and range went to 630 miles. I tried to get the codes from the ecm but I got no response when I shorted terminals a&b on the aldl connector, just a solid SES light no code 12. I tapped on the maf and then unplugged the Maf sensor but that made no change.We limped it back home and noticed it ran hotter oil temp and water temp went up from 175ish to 220-230. We got home and I had to move my truck to get the vette inside the garage the all of a sudden the SES light went out and it ran fine. I then tried to see what codes were stored and this time I got a response, code 12, but nothing else. I gave the engine a once over and found nothing obvious. This thing has me stumped, anybody else have any other ideas?????
07-30-2008, 11:08 PM
#3
Re: 89 TPI intermittent low power, no code 12 from ecm, red hot headers
Sorry I did forget to mention that we replaced them with a set of accel injectors last year, but I will double check them when I see the car next, the car is owned by a guy I work with.
07-31-2008, 06:00 PM
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Car: 88 GTA "Cocaine"
Engine: 350 tpi
Transmission: 700r4
Axle/Gears: 3.27
Re: 89 TPI intermittent low power, no code 12 from ecm, red hot headers
check the wires that come from the fuse box that give power to the computer
they should be pink w/black stripe
measure voltage and give them a tug
this is the first place I would look in diag
get a helms manual
my car was running on the left bank of injectors last week
I dont know how it was running
even dug it into the gravel getting it into the garage
they should be pink w/black stripe
measure voltage and give them a tug
this is the first place I would look in diag
get a helms manual
my car was running on the left bank of injectors last week
I dont know how it was running
even dug it into the gravel getting it into the garage
07-31-2008, 11:19 PM
#6
Re: 89 TPI intermittent low power, no code 12 from ecm, red hot headers
Im not sure if you have done any work to the engine but I have seen incorrect length pushrods do what your talking about...
but that would only be if you had just replaced them.
but that would only be if you had just replaced them.
07-31-2008, 11:48 PM
#7
Re: 89 TPI intermittent low power, no code 12 from ecm, red hot headers
Engine is totally stock, but i had an extra computer laying around so we swapped them out and so far everything seems fine for now. He took it for a spin for an hour or 2 and it has not acted up, so maybe we have fixed it or just fixed a result of a different problem.
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