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Help, New ECM, major loss of power

M

mldpsu

Guest
Hope someone has an idea. About a month ago I had to replace the ECM in my 1990 coupe with a rebuild from NAPA. Of course I kept the chip from the original unit which was the standard GM installed chip. Shortly after I noticed that the car just didn't feel right. Very slow off the line. Not really hesitation, just no low end power. It won't even spin the tires at full throtel. I have a GTech performance meter so I decided to test it and make sure it was not my imagination. I have a good set of baseline runs from a few months earlier. Prior to the ECM swap my 0-60mph was 5.4 seconds. Now it ranges from 6.4 to 6.8 seconds.

The engine seems to run fine otherwise. I don’t even know where to start. Can anyone help ???
 

BigRed

Well-known member
Joined
May 23, 2001
Messages
948
Location
Edmonton
Corvette
1985 Bright Red Rocket
Mabe the Rebuild from Napa it wrong/bad I'd try taking it back and trying another personally
 

c4c5specialist

Technical Advisor
Joined
May 29, 2001
Messages
3,682
Location
New Haven, Ct. USA
Corvette
Nope, but someday.
Computers, DAMN

Hi there,
I would agree with Red here, as sometimes, aftermarket computers are just NOT reliable. I cannot tell you how much I have been burned by aftermarket parts in Corvette.
It could be that your computer is NOT reading sensors correctly, or its NOT putting out correct signals.
There are so many variables that it might NOT be the computer at all. It should be correctly diagnosed before proceeding
Best to you, c4c5
 
A

ArtZR1991

Guest
I agree. The correct GM unit is under $50, and has been upgraded since your car was built. I replaced my 1991 that way, and many minor problems were solved and the car runs better. I would encourage you to return the NAPA as "defective", and get the GM part. The dealer will have the updated one in stock or within a day or so delivery. I only waited overnite for my 91 ZR1 chip.

BTW, the '91 ZR1 upgraded chip is part 16193416, while the original is 1060303. Just carry your original part # in with you, and if the Chevy guy has a different #, then it's the upgrade.

One other comment.... If the NAPA is a "high performance" chip, then you are probably having detonation, and the computer is slowing you down by retarding the timing. This is a common problem with after market modified chips, thou it should not be with an OEM chip.

Good luck.
 

tmkassin

Well-known member
Joined
May 17, 2009
Messages
271
Location
Macomb,MI
Corvette
2009 LS3
I agree. The correct GM unit is under $50, and has been upgraded since your car was built. I replaced my 1991 that way, and many minor problems were solved and the car runs better. I would encourage you to return the NAPA as "defective", and get the GM part. The dealer will have the updated one in stock or within a day or so delivery. I only waited overnite for my 91 ZR1 chip.

BTW, the '91 ZR1 upgraded chip is part 16193416, while the original is 1060303. Just carry your original part # in with you, and if the Chevy guy has a different #, then it's the upgrade.

One other comment.... If the NAPA is a "high performance" chip, then you are probably having detonation, and the computer is slowing you down by retarding the timing. This is a common problem with after market modified chips, thou it should not be with an OEM chip.


Did you say that you put the original Prom (chip) back in? If so the disconnect your Neg battery cable and let the ECM reset. If you don't have the original Prom in the ECM put it back in.
 

rlg

Well-known member
Joined
Feb 28, 2009
Messages
232
Location
Broken Arrow, OK
Corvette
1990 White Coupe
Did you remove battery cable before replcing the ECM?

If not I agree with tmkassin, Disconnect for 10 minutes then reconnect and drive it for about 30 or 40 miles, long enough for it to send some sidnals out a relearn.

If this doesn't fix it take it back.
 

gmjunkie

Well-known member
Joined
Nov 11, 2004
Messages
4,538
Location
Old Fort NC/Vero Beach FL
Corvette
03 Z-51,78 L82 Coupe
:boogie:boogie:boogie:boogieI think he either has it fixed or junked by now,theres nothing quite like opening a 8 year old thread!!!:thumb

:D:D:D
 

gmjunkie

Well-known member
Joined
Nov 11, 2004
Messages
4,538
Location
Old Fort NC/Vero Beach FL
Corvette
03 Z-51,78 L82 Coupe
I guess I need to figure out how to use this site better
We've All done it,thats what makes it funny!
I must have opened 5-6 old threads when I came here!!!;LOL;LOL;LOL
I had a computer for 3 weeks and typed in HillBilly!!:boogie:boogie:boogie
Welcome to CAC!!:CAC :thumb:thumb:thumb
Keep reading the old threads,theres a ho-lotta information here!!:thumb

:D:D:D
 

tmkassin

Well-known member
Joined
May 17, 2009
Messages
271
Location
Macomb,MI
Corvette
2009 LS3
You seem to have a good bit of knowledge about these cars. What do I need to program a Hyper-tech chip on my LT-1? I want to change the fan temp and maybe adjust some performance issues. The only other mods so far are a K&N air filter with the air box opened by drilling 8, 1" holes along the side and a Borla exhaust. Do I need to buy a DRB or a program and cable for my laptop or....?
 

gmjunkie

Well-known member
Joined
Nov 11, 2004
Messages
4,538
Location
Old Fort NC/Vero Beach FL
Corvette
03 Z-51,78 L82 Coupe
You seem to have a good bit of knowledge about these cars. What do I need to program a Hyper-tech chip on my LT-1? I want to change the fan temp and maybe adjust some performance issues. The only other mods so far are a K&N air filter with the air box opened by drilling 8, 1" holes along the side and a Borla exhaust. Do I need to buy a DRB or a program and cable for my laptop or....?
I know some excellent tuners,but I'm not a tuner!:L:L:L
If came with it from the factory,I can fix it!!:thumb:thumb:thumb
If mine ran any better,I'm afraid I'd give up sex!!:boogie
 

Curious George

Well-known member
Joined
Oct 31, 2008
Messages
290
Location
Orlando, Florida
Corvette
'92 Red Convertible / '99 Red Convertible
You seem to have a good bit of knowledge about these cars. What do I need to program a Hyper-tech chip on my LT-1? I want to change the fan temp and maybe adjust some performance issues. The only other mods so far are a K&N air filter with the air box opened by drilling 8, 1" holes along the side and a Borla exhaust. Do I need to buy a DRB or a program and cable for my laptop or....?
Hello,
To burn chips for your 1992 LT-1 you'll need an "Autoprom" from "moates.net". It comes with (almost) everything you'll need except the laptop w/ USB connection. I purchased one back in November and have been tuning my '92 LT-1 and '87 IROC. With the Autoprom purchase, you will receive TunerPro also, which will allow you to collect data, so you know what to tune. Another program that is compatible with the Autoprom is "Tunercat". You have to pay for this one though. ($100 I think).

You also need to modify your OE memcal header because it is soldered in a socket. If you send an email to moates he will answer all your questions. Tell him want you want to do and he will tell you what you need. Nice guy. Also, if you want to learn everything you can about prom burning, join "thirdgen.org"

CG
 

tmkassin

Well-known member
Joined
May 17, 2009
Messages
271
Location
Macomb,MI
Corvette
2009 LS3
Hello,
To burn chips for your 1992 LT-1 you'll need an "Autoprom" from "moates.net". It comes with (almost) everything you'll need except the laptop w/ USB connection. I purchased one back in November and have been tuning my '92 LT-1 and '87 IROC. With the Autoprom purchase, you will receive TunerPro also, which will allow you to collect data, so you know what to tune. Another program that is compatible with the Autoprom is "Tunercat". You have to pay for this one though. ($100 I think).

You also need to modify your OE memcal header because it is soldered in a socket. If you send an email to moates he will answer all your questions. Tell him want you want to do and he will tell you what you need. Nice guy. Also, if you want to learn everything you can about prom burning, join "thirdgen.org"

Thanks:cool:beer
 

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