still having troubles with computer
Thread Starter
Race Director
Joined: Mar 2002
Posts: 12,968
Likes: 0
still having troubles with computer
well, summers almost over here and i still haven't driven my car , this was summer number 3 without driving it 
i have checked everything several times, tried a few computers and several chips, but the computer will still not communicate with either a scanner or myself via the check engine light.
i have asked many times for help here( check my past posts), took it to the dealer, even had it at the dealerships mechanics house for several weeks while he checked it over, still nothing
just thought i would ask again, just in case somebody had some new ideas
greg
i have checked everything several times, tried a few computers and several chips, but the computer will still not communicate with either a scanner or myself via the check engine light.
i have asked many times for help here( check my past posts), took it to the dealer, even had it at the dealerships mechanics house for several weeks while he checked it over, still nothing
just thought i would ask again, just in case somebody had some new ideas
greg
Racer
Joined: Jul 2002
Posts: 313
Likes: 1
From: Dallas Tx
Originally Posted by atotalnincompoop
well, summers almost over here and i still haven't driven my car , this was summer number 3 without driving it
i have checked everything several times, tried a few computers and several chips, but the computer will still not communicate with either a scanner or myself via the check engine light.
i have asked many times for help here( check my past posts), took it to the dealer, even had it at the dealerships mechanics house for several weeks while he checked it over, still nothing
just thought i would ask again, just in case somebody had some new ideas
greg
i have checked everything several times, tried a few computers and several chips, but the computer will still not communicate with either a scanner or myself via the check engine light.
i have asked many times for help here( check my past posts), took it to the dealer, even had it at the dealerships mechanics house for several weeks while he checked it over, still nothing
just thought i would ask again, just in case somebody had some new ideas
greg
Vehicle information? (year)
I might not be able to help but at least I will bump you to the top of the list...
Did you try to contact the scanner's manufacturer for tech support?
Thread Starter
Race Director
Joined: Mar 2002
Posts: 12,968
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its an '85, my mods are listed in my profile.
the car won't idle well and will not rev past 1300rpm, seems to be stuck in "limp home mode" we think, but the comp won't tell us anything. the dealership tried its scanner and got nowhere.
i'm having trouble with the forums new format, so i can't find any links to my past posts ( and there are lots of them ) regarding this problem
thanks for your help
the car won't idle well and will not rev past 1300rpm, seems to be stuck in "limp home mode" we think, but the comp won't tell us anything. the dealership tried its scanner and got nowhere.
i'm having trouble with the forums new format, so i can't find any links to my past posts ( and there are lots of them
) regarding this problemthanks for your help
Racer
Joined: Jul 2002
Posts: 313
Likes: 1
From: Dallas Tx
Originally Posted by atotalnincompoop
its an '85, my mods are listed in my profile.
the car won't idle well and will not rev past 1300rpm, seems to be stuck in "limp home mode" we think, but the comp won't tell us anything. the dealership tried its scanner and got nowhere.
i'm having trouble with the forums new format, so i can't find any links to my past posts ( and there are lots of them ) regarding this problem
thanks for your help
the car won't idle well and will not rev past 1300rpm, seems to be stuck in "limp home mode" we think, but the comp won't tell us anything. the dealership tried its scanner and got nowhere.
i'm having trouble with the forums new format, so i can't find any links to my past posts ( and there are lots of them
) regarding this problemthanks for your help
Maybe somebody that is more knowledgable will speak up.
TTT
Race Director
Joined: Apr 2004
Posts: 17,066
Likes: 3
From: Milpitas ca
If you were in the San Francisco Bay Area I could point your way to an awesome mechanic who specializes in Corvettes.
3 summer seasons without driving your Vette is a crime.
I go bonkers not driving it for a week.
3 summer seasons without driving your Vette is a crime.
I go bonkers not driving it for a week.
Racer
Joined: Feb 2003
Posts: 330
Likes: 0
From: Enon OH
Well, if you've tried both replacement (and known good) computers and chips, you've eliminated both possibilities.
Hate to point out the obvious, but have you checked the harness for continutity and to make sure the pinouts are what they should be?
Hate to point out the obvious, but have you checked the harness for continutity and to make sure the pinouts are what they should be?
Thread Starter
Race Director
Joined: Mar 2002
Posts: 12,968
Likes: 0
Originally Posted by TerryMathews
Well, if you've tried both replacement (and known good) computers and chips, you've eliminated both possibilities.
Hate to point out the obvious, but have you checked the harness for continutity and to make sure the pinouts are what they should be?
Hate to point out the obvious, but have you checked the harness for continutity and to make sure the pinouts are what they should be?
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Thread Starter
Race Director
Joined: Mar 2002
Posts: 12,968
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Originally Posted by Spankyellow
Ive been waiting weeks for good news on this.
Have you called Gordon Killibrew?
Have you called Gordon Killibrew?
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
WOW, I've been wondering if you had solved your problem. Here we go again.
Fuel, air , spark, of course you need compression-not trying to be facious.
I know you must have checked the accuracy of the plug wire routing.
I'm beginning to think-since you replaced the ECM-just maybe you have a damaged prom-or not properly installed prom. Thats the part you remove from the old ECM and install in your new ECM-and it's very sensitive, you actually need a special tool to remove it.
Fuel, air , spark, of course you need compression-not trying to be facious.
I know you must have checked the accuracy of the plug wire routing.
I'm beginning to think-since you replaced the ECM-just maybe you have a damaged prom-or not properly installed prom. Thats the part you remove from the old ECM and install in your new ECM-and it's very sensitive, you actually need a special tool to remove it.
Pro
Joined: Dec 2002
Posts: 522
Likes: 3
From: Rolling Meadows IL
I saw in your sig that you have a new cam and heads. Did it ever run good after you did the mods? Can you put back your original chip.
Did you check that the plug to test the base timing is making contact.
Did you check that the plug to test the base timing is making contact.
Safety Car
Joined: May 1999
Posts: 3,651
Likes: 5
From: Atlantis
Cruise-In I Veteran
I am an awsome mechanic that specializes in Corvette's.
I'll make it run for you, guaranteed.
You anywhere near Columbus, Ga.?
FYI: I'm actually an awsome Software Engineer that is an awsome mechanic that specializes in awsome Corvette's.
I'll make it run for you, guaranteed.
You anywhere near Columbus, Ga.?
FYI: I'm actually an awsome Software Engineer that is an awsome mechanic that specializes in awsome Corvette's.
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
are you still running the stock 85 ECU? have you considered updating to an 87 ECU? They are much faster.
Ok... does the SES light at all?
I am not convinced it's a ground problem. I am thinking it's an ALDL connection problem.
If you have a known good ECU and a known good chip... what about BOTH chips. Are they BOTH good?
I wish I could be closer to help... but alas, I cannot.
Ok... does the SES light at all?
I am not convinced it's a ground problem. I am thinking it's an ALDL connection problem.
If you have a known good ECU and a known good chip... what about BOTH chips. Are they BOTH good?
I wish I could be closer to help... but alas, I cannot.
Melting Slicks
Joined: Dec 2000
Posts: 2,719
Likes: 60
From: Fremont Oh
I had an issue with a 89 where the connector coming through the fire wall to the ECM was corrodded to pieces, and I found that one of the wires was corroded in half... just a though... also I have seem MAF probelms cause that sort of probelm as well try disconnecting the MAF connectr, start it and see if that helps.. if not I would look into the timing to be sure you have the distributor jutst a couple thoughts...
Mo
Mo
Burning Brakes
Joined: Dec 2002
Posts: 1,088
Likes: 0
From: Lakeland fl
It looks like we have a few pertinent questions pending answers.
1) this "new" ecm- was it brand new or used?
2) did you reuse your same old chip in the new ecm?
3) if yes to #2, were you carefull when you changed it? I have an 85 chip listed in the for sale section for $6 shipped, BTW.
4) does the SES light ever come on? is the SES light bulb blown?
5) Have you tried to locate the ALDL wire right at the ECM and check it for voltage? Voltage here=communication.
It does sound like you are in limp mode. In limp there is no communication, and poor running as you described. I can invoke limp mode by installing my chip backwards, or removing the chip altogether. Check your chip orientation, even if you suspect that it is undamaged. I would also recommend an ECM upgrade, to the '165 used in 86-89 Vettes and Camaro's. You will need the ECM #12277165 or equivalent, and a memcal for your application (like an 86 model- that has no VATS), and a few relays for the MAF. All the info on the swap is available on the web, It took me about two hours to do mine. This wont, however, cure faulty or shorted wiring. But if you need to buy a new ECM, buy the better one. Theyre all about $100 anyway.
1) this "new" ecm- was it brand new or used?
2) did you reuse your same old chip in the new ecm?
3) if yes to #2, were you carefull when you changed it? I have an 85 chip listed in the for sale section for $6 shipped, BTW.
4) does the SES light ever come on? is the SES light bulb blown?
5) Have you tried to locate the ALDL wire right at the ECM and check it for voltage? Voltage here=communication.
It does sound like you are in limp mode. In limp there is no communication, and poor running as you described. I can invoke limp mode by installing my chip backwards, or removing the chip altogether. Check your chip orientation, even if you suspect that it is undamaged. I would also recommend an ECM upgrade, to the '165 used in 86-89 Vettes and Camaro's. You will need the ECM #12277165 or equivalent, and a memcal for your application (like an 86 model- that has no VATS), and a few relays for the MAF. All the info on the swap is available on the web, It took me about two hours to do mine. This wont, however, cure faulty or shorted wiring. But if you need to buy a new ECM, buy the better one. Theyre all about $100 anyway.
