what are these for?
06-01-2010, 10:44 AM
#1
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Car: 1972 GMC
Engine: 355
Transmission: 700r4
Axle/Gears: 4:10
what are these for?
Does anyone know what the extra harness connections are for located by the ecm? many of the wires are cut off?
06-01-2010, 01:56 PM
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Car: 1981 Camaro; 1986 Z28
Engine: LT1; LT1
Transmission: 6 speed; 6 speed
Axle/Gears: 3.73; 3.42
Re: what are these for?
It looks like somebody did a harness modification and just left the connectors attached.
06-01-2010, 03:59 PM
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Car: 1992 RS
Engine: Carbed 350
Transmission: 700R4
Axle/Gears: 3.42 posi
Re: what are these for?
Maybe for the cruise control module? It's located in the same area as the ECM box, and has plugs like that. Does your car have cruise?
06-01-2010, 07:05 PM
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Car: 2003 Hyundai Tiburon GT
Engine: 2.7L V6
Transmission: 6-speed
Axle/Gears: 4.41
Re: what are these for?
Looks like maybe someone switched from TBI to TPI, or the other way around... The other set of connectors looks like it is for a 165 ECM.
06-01-2010, 09:39 PM
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Car: 1972 GMC
Engine: 355
Transmission: 700r4
Axle/Gears: 4:10
Re: what are these for?
I talked to the previous owner, he wired in a performance programmer of some sort, which he says didn’t work out so he just left the wires in place. I have cut out the extra harness and in the process of taking apart every one of the connections to see if I can find the problems. He used a wire stripper that pulled the jacket apart; it looks like it stretched the wire in several places.
06-01-2010, 10:02 PM
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Car: 89 IROC-Z
Engine: L98 5.7 liter
Transmission: TH700r4
Axle/Gears: limited slip 3.23
Re: what are these for?
That ECM looks like the same brand I have in my car currently. I have not been able to tell who it is manufactured by though. Do you know who manufactures that ECM and is the one in your car a re-manufactured unit? What kind of problems are you having with the car?
06-04-2010, 12:13 PM
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Car: 1972 GMC
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Re: what are these for?
I got it ECM O'Reilly auto parts, I also have the original.
Turns out that the Prom is bad.
Turns out that the Prom is bad.
Last edited by 91TTOPZ; 06-04-2010 at 07:15 PM.
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06-04-2010, 08:27 PM
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Car: 89 IROC-Z
Engine: L98 5.7 liter
Transmission: TH700r4
Axle/Gears: limited slip 3.23
Re: what are these for?
Thanks, how did you find out that the prom was bad? The problem I'm having is that my IAC valve is being sent a constant signal which has been draining my battery. I already replaced the IAC valve but I still have a draw so I thought it was a bad ECM, but now I'm thinking about the prom.
06-04-2010, 09:03 PM
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Car: 1972 GMC
Engine: 355
Transmission: 700r4
Axle/Gears: 4:10
Re: what are these for?
I sent it to
Brian at
Harris Performance INC
PO BOX 1447
Randleman, NC 27317
336-471-2827
www.harrishighperformance.com
John
Brian at
Harris Performance INC
PO BOX 1447
Randleman, NC 27317
336-471-2827
www.harrishighperformance.com
John
Thanks, how did you find out that the prom was bad? The problem I'm having is that my IAC valve is being sent a constant signal which has been draining my battery. I already replaced the IAC valve but I still have a draw so I thought it was a bad ECM, but now I'm thinking about the prom.
06-11-2010, 10:52 AM
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Car: 1972 GMC
Engine: 355
Transmission: 700r4
Axle/Gears: 4:10
Re: what are these for?
It turns out that the other connectors were from a performance programmer the previous owner installed, I removed them and repaired the wires and installed a new ecm, from OReilly’s, I have checked the continuity and ohm of the tan w black strip wire from the distributor to the ecm and it checked out ok. I sent the prom out and had it check and it was bad so they flashed it with the stock settings. When I installed everything it still ran bad but if I install the prom with performance piggy back it doesn’t give me the SES light, if I remove the piggy back and install the stock prom it runs the same and the SES light comes on (code 42). So I am thinking that the stock prom is the problem.
Also I have checked all the wires for the ecm and several of them show an ohm reading to ground not sure but that doesn’t seem right?
Any input is greatly appreciated.
Thanks
John
Also I have checked all the wires for the ecm and several of them show an ohm reading to ground not sure but that doesn’t seem right?
Any input is greatly appreciated.
Thanks
John
06-11-2010, 07:11 PM
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Car: 2003 Hyundai Tiburon GT
Engine: 2.7L V6
Transmission: 6-speed
Axle/Gears: 4.41
Re: what are these for?
There are several wires going to and from the ECM that are grounds. Some are black/white, and there is also a tan one for the O2S ground. There may be a problem with a connection for the factory PROM in the MEMCAL. If you can, try a different MEMCAL.
06-16-2010, 10:01 AM
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Car: 1972 GMC
Engine: 355
Transmission: 700r4
Axle/Gears: 4:10
Re: what are these for?
Repalced Prom, checked out coil, and ignition module, fixed wires, still runs the same.
John
confused:
John
confused:
06-16-2010, 12:17 PM
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Car: 89 IROC-Z
Engine: L98 5.7 liter
Transmission: TH700r4
Axle/Gears: limited slip 3.23
Re: what are these for?
I just saw your most recent post about all the things you have replaced trying to find the problem, I can sympathize with you... trust me! I finally found the source of my problems with my 89 IROC. I had a constant battery drain coming from the IAC valve, so I started the cheap way and replaced everything before I finally went to Advance and bought a re-manufactured AC DELCO ECM. This entire time my ECM was the issue, but it never popped a code and the car didn't run rough. All I'm saying is when in doubt, get a new ECM. A guy I work with was telling me about how he bought a IROC new in 1988 and that after a couple years it was running rough. He said one day he had the car running and grabbed the ECM and twisted it after he heard that the mother boards were cracking. Sure enough, from him twisting the box it started idling normal and no check engine light. His story was what convinced me to pony up the cash and just go buy a new ECM. I'm glad I did.
06-16-2010, 12:29 PM
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Car: 1972 GMC
Engine: 355
Transmission: 700r4
Axle/Gears: 4:10
Re: what are these for?
Thanks for for the feedback, but I already replaced the ecm, twice, once with a used one and once with a referp from Oriellys
John
John
I just saw your most recent post about all the things you have replaced trying to find the problem, I can sympathize with you... trust me! I finally found the source of my problems with my 89 IROC. I had a constant battery drain coming from the IAC valve, so I started the cheap way and replaced everything before I finally went to Advance and bought a re-manufactured AC DELCO ECM. This entire time my ECM was the issue, but it never popped a code and the car didn't run rough. All I'm saying is when in doubt, get a new ECM. A guy I work with was telling me about how he bought a IROC new in 1988 and that after a couple years it was running rough. He said one day he had the car running and grabbed the ECM and twisted it after he heard that the mother boards were cracking. Sure enough, from him twisting the box it started idling normal and no check engine light. His story was what convinced me to pony up the cash and just go buy a new ECM. I'm glad I did.