89 corvette CODE 42 Need advise
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From: FL
i know that i have FSM
Last edited by rays96in; Mar 11, 2016 at 04:32 PM.
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From: Hartford WI
The car runs beautiful always, injectors have been in for 3 yrs.
This is something new only started last week. Car runs fine until you stomp on the gas. Then when you let off passing gear it runs ok then i went in a store n came out n car would not start. So i thought my fuel pump went put new in that was not it so i tuned it up and that was not it so i changed modular n that not it. so that's why i am asking u guys what's up. I was thinking injectors were dirty or ECM is going bonkers.
This is something new only started last week. Car runs fine until you stomp on the gas. Then when you let off passing gear it runs ok then i went in a store n came out n car would not start. So i thought my fuel pump went put new in that was not it so i tuned it up and that was not it so i changed modular n that not it. so that's why i am asking u guys what's up. I was thinking injectors were dirty or ECM is going bonkers.
Injectors are probably dirty since every 3 years when I clean mine, they have a better "after" result than "before". However, injectors getting dirty are a slower process which is why people always say "My car seems to run fine. Why clean it?". This sudden, either you sucked in a bunch of silt that is fine enough to get past the fuel filter and too big to get past the basket filter in the injector or the coil shorted. If you have Multecs, the latter is more likely since ethanol is supposed to be hard on the coils which use fuel for cooling.
If you think the ECM is bad, try rapping on it when it is hot and does not start and see what it does.
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Joined: Jul 2004
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From: Hartford WI
Timing might be right but when the car is running, the timing goes up when you accelerate. So keep the timing light in the car and when it feels sluggish, hit it with the light and see if it goes up when you rev it. Say it is at 15 degrees with the tan wire, disconnect it and it should drop back to 6. That is to test for ECM advance. You could have a bad module or a bad wire from the ECM to the module.
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From: Hartford WI
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Joined: Dec 2011
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From: FL
Before we start replacing it, if that is your thesis, did you check out fuel pressure at WOT and when it doesn't run?
Injectors are probably dirty since every 3 years when I clean mine, they have a better "after" result than "before". However, injectors getting dirty are a slower process which is why people always say "My car seems to run fine. Why clean it?". This sudden, either you sucked in a bunch of silt that is fine enough to get past the fuel filter and too big to get past the basket filter in the injector or the coil shorted. If you have Multecs, the latter is more likely since ethanol is supposed to be hard on the coils which use fuel for cooling.
If you think the ECM is bad, try rapping on it when it is hot and does not start and see what it does.
Injectors are probably dirty since every 3 years when I clean mine, they have a better "after" result than "before". However, injectors getting dirty are a slower process which is why people always say "My car seems to run fine. Why clean it?". This sudden, either you sucked in a bunch of silt that is fine enough to get past the fuel filter and too big to get past the basket filter in the injector or the coil shorted. If you have Multecs, the latter is more likely since ethanol is supposed to be hard on the coils which use fuel for cooling.
If you think the ECM is bad, try rapping on it when it is hot and does not start and see what it does.
Drifting
Joined: May 2013
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From: Reno Nevada
I had a guy about a year ago that had a 1990 with 10,000 miles on it. He had GM replace his injectors. It ran lean so we logged it and remapped his fuel. These guys claiming 1 injector fits 85 thru 91 is a complete lie. 85 used a 23.8 lb injector rated at 43.5 psi but installed at 39 spi. Yours is a 21 rated at 43.5 but installed at 46 or 47. I've reprogrammed more than 50 cars running Bosch yellow 0280-155-700's. We I change the flowrate to 20 it runs right without a lean stumble.
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From: FL
Ohm the injectors first. A bad coil can overheat the injector driver and in some cases shut the car down. from mid year 88 through the late 90's GM used Rochester Products that are known to be bad.
I had a guy about a year ago that had a 1990 with 10,000 miles on it. He had GM replace his injectors. It ran lean so we logged it and remapped his fuel. These guys claiming 1 injector fits 85 thru 91 is a complete lie. 85 used a 23.8 lb injector rated at 43.5 psi but installed at 39 spi. Yours is a 21 rated at 43.5 but installed at 46 or 47. I've reprogrammed more than 50 cars running Bosch yellow 0280-155-700's. We I change the flowrate to 20 it runs right without a lean stumble.
I had a guy about a year ago that had a 1990 with 10,000 miles on it. He had GM replace his injectors. It ran lean so we logged it and remapped his fuel. These guys claiming 1 injector fits 85 thru 91 is a complete lie. 85 used a 23.8 lb injector rated at 43.5 psi but installed at 39 spi. Yours is a 21 rated at 43.5 but installed at 46 or 47. I've reprogrammed more than 50 cars running Bosch yellow 0280-155-700's. We I change the flowrate to 20 it runs right without a lean stumble.
Drifting
Joined: May 2013
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From: Reno Nevada
Whoa, replace the set. Either get Accel 21's or use the method I previously posted.
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From: FL
NEW 42lbs Green Top Racing Fuel Injector 440CC EV1 0280150558 Turbo 42 lb/hr EV1
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From: Hartford WI
Sure. I bet it will run pig rich and kill every mosquito in your yard, assuming it even runs. Get a set of reman injectors from FIC and be done with it. Clean and test every 3 years.
Drifting
Joined: May 2013
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From: Reno Nevada
Yeah, get these from FIC and run lean.
http://www.ebay.com/itm/Brand-New-Bo...tVfOtf&vxp=mtr
I can reset the flowrate to 20 and they'll work.
http://www.ebay.com/itm/Brand-New-Bo...tVfOtf&vxp=mtr
I can reset the flowrate to 20 and they'll work.
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Posts: 84
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From: FL
Yeah, get these from FIC and run lean.
http://www.ebay.com/itm/Brand-New-Bo...tVfOtf&vxp=mtr
I can reset the flowrate to 20 and they'll work.
http://www.ebay.com/itm/Brand-New-Bo...tVfOtf&vxp=mtr
I can reset the flowrate to 20 and they'll work.
Drifting
Joined: May 2013
Posts: 1,736
Likes: 31
From: Reno Nevada
I can get you a set of 24's for $150.
http://www.ebay.com/itm/7-4L-V8-3500...RTc72f&vxp=mtr
Then send me the memcal (AKA PROM) to be reprogrammed for $65. Check injectors first. If you do buy injectors make sure Martin knows it's for TPI.
http://www.ebay.com/itm/7-4L-V8-3500...RTc72f&vxp=mtr
Then send me the memcal (AKA PROM) to be reprogrammed for $65. Check injectors first. If you do buy injectors make sure Martin knows it's for TPI.
Yeah, get these from FIC and run lean.
http://www.ebay.com/itm/Brand-New-Bo...tVfOtf&vxp=mtr
I can reset the flowrate to 20 and they'll work.
http://www.ebay.com/itm/Brand-New-Bo...tVfOtf&vxp=mtr
I can reset the flowrate to 20 and they'll work.
Your injectors need to ohm 16 or within 1. A job worth doing is worth doing right. Replacing one injector will most likely create an unbalanced fuel delivery system. Your choice though.