165 ECM question
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Joined: Jun 2005
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From: Lexington, IN
Car: 87 IROC Z-28
Engine: 305 TPI
Transmission: AT
165 ECM question
I have tried a number of things to clear a Code 33 (MAF sensor) and sometimes a code 34 at the same time.
This is the 3rd MAF sensor I have had in the car- new TPS and set to various settings. New relays, fuel filter, cap & rotor, checked voltages, grounds, and vacuum lines.
I am about ready to swap ECM's. A friend of my son's who works at a Chevy dealership suggested to replace the ECM with a new one, that the new ones have this fixed.
I was going to go with a used one, but if this is a manufacturer problem, maybe I should get a new one. Is this the case?
This is the 3rd MAF sensor I have had in the car- new TPS and set to various settings. New relays, fuel filter, cap & rotor, checked voltages, grounds, and vacuum lines.
I am about ready to swap ECM's. A friend of my son's who works at a Chevy dealership suggested to replace the ECM with a new one, that the new ones have this fixed.
I was going to go with a used one, but if this is a manufacturer problem, maybe I should get a new one. Is this the case?
Joined: Feb 2000
Posts: 1,855
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From: St. Augustine, FL
Car: 89 GTA
Engine: 383
Transmission: 4L80E
Axle/Gears: 12 bolt-3.73
Do a search on those 2 codes and see what you come up with.
I will get a code when my tps sensor voltage is higher than .62 at idle, so I keep it lower. Other than that, I don't know. Is your maf sensor gutted?
I will get a code when my tps sensor voltage is higher than .62 at idle, so I keep it lower. Other than that, I don't know. Is your maf sensor gutted?
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Junior Member
Joined: Jun 2005
Posts: 17
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From: Lexington, IN
Car: 87 IROC Z-28
Engine: 305 TPI
Transmission: AT
No, the maf sensor has not been gutted- it is a Bosch (was that stock?), and it is the third one that has been installed on the car trying to eliminate this problem.
I reset the minimum idle. My TPS sensor was set at .54 and I took it to .61, thinking that maybe by comparison the maf readout would not be so high to the ECM. Still sets the code, and once it is set, the car runs like crap.
It usually sets a code 33, (high voltage), but sometimes it will also set a code 34 (low voltage). This should not happen at the same time. That is what has got me thinking that maybe it is the ECM.
You can pick a used ECM up pretty cheap. I guess I am wanting to know if there has been a change by the manufacturer that would make a new one better than a used one.
I reset the minimum idle. My TPS sensor was set at .54 and I took it to .61, thinking that maybe by comparison the maf readout would not be so high to the ECM. Still sets the code, and once it is set, the car runs like crap.
It usually sets a code 33, (high voltage), but sometimes it will also set a code 34 (low voltage). This should not happen at the same time. That is what has got me thinking that maybe it is the ECM.
You can pick a used ECM up pretty cheap. I guess I am wanting to know if there has been a change by the manufacturer that would make a new one better than a used one.
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From: Doghouse ······································ Car: 1989 Formula 350 Vert Engine: 350 L98 Transmission: 700R4 Axle/Gears: B&W 3.27
Car: 87 Formula T-Top, 87 Formula HT
Engine: 5.1L TPI, 5.0L TPI
Transmission: 700R4, M5
Axle/Gears: Sag 3.73, B&W 3.45
Here are some things to consider.
When I was getting 33 & 34 I too thought MAF, but it was fine. My problem was one of two things, probably both. My temp sensor for the ECM on the front of the intake was faulty. This also caused some interesting cold starting issues that would not allow the idle to level out until the car had warmed up. Also a leak in my intake tube between the MAF and the intake was happening at the same time.
Like you mentioned, a Faulty ECM will really mess with readings and our heads. I believe the NEW 165 ECM number is 16198259.
John
When I was getting 33 & 34 I too thought MAF, but it was fine. My problem was one of two things, probably both. My temp sensor for the ECM on the front of the intake was faulty. This also caused some interesting cold starting issues that would not allow the idle to level out until the car had warmed up. Also a leak in my intake tube between the MAF and the intake was happening at the same time.
Like you mentioned, a Faulty ECM will really mess with readings and our heads. I believe the NEW 165 ECM number is 16198259.
John
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