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Discussion Starter #1
Sorry no booty to look at, but...............

Now that I have your attention maybe I can get some help with this on going prob.

My ASR light came on and car started running like crap. Light stays on then the check eng light comes on too.

Both cooling fans stay on the whole time car is running. (replaced temp swtich) No fix???

Checked codes. 22 TPS and 36 DI.

I know I could use a tune up.

Car runs great till it gets up to temp. Then stumbles and sputters till 2000 RPMs. Smooths and has power after that.

Any ideas????????????

I found the following on the web when looking for an answer->

ASR acting up?
Your situation sounds like exactly what happened to my '94 coupe 3 years ago.
It took me over two years to finally figure out what was causing all of the grief.
I posted my issues a few times on this forum but it seemed like I was the only one who ever had this problem.

See if these symptons are familiar:
ASR service light came on and wouldn't work
Passing kick down gear wouldn't work
Idling was rough

After a few trips to my local garage and two trips to a GM service dealer, replacing the TPS ( throttle body sensor ), the ECM computer, new battery, GM finally found the issue by accident.

It turned out to be the air conditioning wiring harness module that was corroded where it plugged into the engine.
It turns out this wiring harness module, is tied into the idling, transmission and rear axle.
Immediately all of my issues went away.
You might want to have your mechanic investigate this possibility for your car also.

Where would this A/C module be located? :huh:

Please help, summer is around the corner. :nuts:
 

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Discussion Starter #3
I guess I'll change out my TPS and see what that does. Hate to buy parts that I may not need. I found some info on modules that I can look at checking the connections.

The warmer the car gets the more it runs like crap. Sounds like a popping sound coming back out the air intake. Could it be cats getting hot and loosing flow? Origanal cats with 146,000 miles. Would that make the car want to idle at 1200 - 1300 RPMs after it's warmed up?

Still at a loss on the ASR????? Topped off break fluid and new pads in front. Rears need pads still. (read the low break fluid could trigger the service ASR light.) How dose one service the ASR????
 

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I guess I'll change out my TPS and see what that does. Hate to buy parts that I may not need. I found some info on modules that I can look at checking the connections.

The warmer the car gets the more it runs like crap. Sounds like a popping sound coming back out the air intake. Could it be cats getting hot and loosing flow? Origanal cats with 146,000 miles. Would that make the car want to idle at 1200 - 1300 RPMs after it's warmed up?

Still at a loss on the ASR????? Topped off break fluid and new pads in front. Rears need pads still. (read the low break fluid could trigger the service ASR light.) How dose one service the ASR????
by unplugging the ASR fuse. :laughing:


But on a serious note, has it run badly for a while? and which method did you use to find out your DTC's? Did you jumper the ALDL connection from Pins A & B, or did you jumper Pins A & G and view each module?
 

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Asr?
 

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Discussion Starter #7
by unplugging the ASR fuse. :laughing:


But on a serious note, has it run badly for a while? and which method did you use to find out your DTC's? Did you jumper the ALDL connection from Pins A & B, or did you jumper Pins A & G and view each module?
Yea car been running like this (bad) for a few months. I been replacing the other worn out items first like starter, Alt, water pump, OptiSpark and all the interior.

Both, A&B also A&G. A-B gave me the 22 and 36 codes.

A&G CCM Module 1 >>These codes are read through Module 1, Segment 1, on the speedometer display. These codes will direct you to specific chapters
in the GM Factory Service Manual.<< code 72 (LCD Dimming Open),

Module 4 code 22 (TPS Signal Voltage Low) code 36 (OptiSpark High Resolution (Timing))

Module 9 >>EBCS Error Codes - Module 9.1
These codes reflect errors related to the ASR/ABS systems. code 64 (TPS Error)
 

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Yea car been running like this (bad) for a few months. I been replacing the other worn out items first like starter, Alt, water pump, OptiSpark and all the interior.

Both, A&B also A&G. A-B gave me the 22 and 36 codes.

A&G CCM Module 1 >>These codes are read through Module 1, Segment 1, on the speedometer display. These codes will direct you to specific chapters
in the GM Factory Service Manual.<< code 72 (LCD Dimming Open),

Module 4 code 22 (TPS Signal Voltage Low) code 36 (OptiSpark High Resolution (Timing))

Module 9 >>EBCS Error Codes - Module 9.1
These codes reflect errors related to the ASR/ABS systems. code 64 (TPS Error)
Well, from looking at the FSM, the LCD dimming error could be caused by bad connections at the Radio control head, HVAC control head (Do you have the electronic climate control?), or at the CCM. Since both fans are staying on, i'd lean toward the HVAC control head.

Regarding the TPS signal, if you replace the TP sensor, the FSM says you have to teach the EBTCM the new TP sensor idle position voltage, and that the only way of doing that is to do it with a Tech 1. But then you've got the whole Opti issue too.

Kind of puzzled on this one. All of these DTC's seem unrelated. This is what i'd do if i were you (if you haven't already) Manually clear all DTC's, then disconnect battery for a couple of minutes, reconnect, and drive the car and see if the DTC's and problems come right back.

I'm actually leaning toward you possibly have a malfunctioning ECM. Those of us who have had a bad ECM know full well it can have you diagnosing and chasing problems all day long with nothing ever being resolved. If you have or know someone with a spare ECM, or if you know someone who might be willing to swap their C4's ECM into yours for a short time for testing purposes, i'd do that first (1992 & 1993 vettes have the same ECM part #). That way, you'll know for sure whether the ECM is bad or not. If after the swap you still have issues, THEN it's really just a matter of the tried and true method of diagnosing each component step by step, could even possibly be a wiring short like you mentioned. Wish i could be of more help, but i'd honestly start with swapping your ECM with a known good one as a first step. Only takes a couple of minutes to swap it out anyway.
 

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Discussion Starter #10
Thanks for the input. :thumbsup:

As for clearing the codes the Haynes manual I have says to disconnect the bat. Is there more to it then just that? I have disconnected the bat and have the same codes. :huh: How would I Manually clear all DTC's?

QUOTE >> Well, from looking at the FSM, the LCD dimming error could be caused by bad connections at the Radio control head, HVAC control head (Do you have the electronic climate control?), or at the CCM. Since both fans are staying on, i'd lean toward the HVAC control head.

:agree: NO CLIMATE CONTROL. So Radio control head as in the car stereo?

I do have a parts car that I think is a 93 also just a bit up graded then mine. I did notice that the parts car does not have the two fuse blocks by the battery like my vette has. Would this ECM still work on mine? Is there any and what / where number matching I would look for on the ECMs to see if they are the same?
 

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Thanks for the input. :thumbsup:

As for clearing the codes the Haynes manual I have says to disconnect the bat. Is there more to it then just that? I have disconnected the bat and have the same codes. :huh: How would I Manually clear all DTC's?

QUOTE >> Well, from looking at the FSM, the LCD dimming error could be caused by bad connections at the Radio control head, HVAC control head (Do you have the electronic climate control?), or at the CCM. Since both fans are staying on, i'd lean toward the HVAC control head.

:agree: NO CLIMATE CONTROL. So Radio control head as in the car stereo?

I do have a parts car that I think is a 93 also just a bit up graded then mine. I did notice that the parts car does not have the two fuse blocks by the battery like my vette has. Would this ECM still work on mine? Is there any and what / where number matching I would look for on the ECMs to see if they are the same?
The ECM will still work, OEM part # is 16159278, remanufactured part # is 88999183. The part # should be labeled on the ECM outer casing, usually just a sticker. When you swap the ECM's though, you'll want to take the PROM chip out of your original ECM and temporarily put it in the loaner ECM. It's a few screws to undo on the ECM, and the PROM chip will slide out like similar it would a RAM chip for a desktop computer.


To manually clear DTC's, take a look at the following post. just go to the section labeled "to clear the codes" and start with #3 after you've jumpered your pins A & G.

http://www.digitalcorvettes.com/forums/showpost.php?p=1061556&postcount=9
 

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Discussion Starter #12
The ECM will still work, OEM part # is 16159278, remanufactured part # is 88999183. The part # should be labeled on the ECM outer casing, usually just a sticker. When you swap the ECM's though, you'll want to take the PROM chip out of your original ECM and temporarily put it in the loaner ECM. It's a few screws to undo on the ECM, and the PROM chip will slide out like similar it would a RAM chip for a desktop computer.
# match on my ECM but the thing doesn't want to come apart at all. I have every screw and bolt out of the ECM housing and can PRY it out about a quarter inch. Just won't slide out to get to the PROM chip. I don't want to screw the thing up though. I can't get away with just plugging it into my car to test it????
 

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# match on my ECM but the thing doesn't want to come apart at all. I have every screw and bolt out of the ECM housing and can PRY it out about a quarter inch. Just won't slide out to get to the PROM chip. I don't want to screw the thing up though. I can't get away with just plugging it into my car to test it????
I'm not understanding what you mean by it won't slide out? what won't slide out? there are only 4 screws located on the bottom of the ECM that you need to unscrew to gain access to the PROM chip. Once you remove those 4 screws, you see the PROM, which is held secure by two simple clips on the outside edges of the chip. The PROM contains all of the information about fuel/air mixture ratios, sensors, shift points, etc. If you want to risk just not bothering with the PROM, that's entirely your call, though i wouldn't recommend it.


This is what you should see, this is the bottom of the ECM; to the rightt = the front of the ECM; to the left = would be where the 4 wiring harnesses attach to the ECM. The blue and white parts in the photo are the clips that hold the PROM chip in place
 

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would anyone else agree that if the engine and transmission combo of the donor car, were the same as the car to receive the known good ecm it would be fine not to switch the prom?

I don't know it for sure about this ecm, but I know that it works that way with the trucks.

good luck fixing this,
~wd-40:buhbye:
 

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Discussion Starter #15
HA MY BAD! I was thinking / trying to slide it out from the end the plugs are at. 4 screws also. :thud: Hope nothing got cracked.

I see now from your pic the plate to remove to get to it.
 

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hello there,


i stumbled upon this forum post and i got exactly the same problems for some months now on my 93.

i had to replace the optispark and the ignition control module earlier this year and then replaced the EVAP solenoid, that fixed a good amount of the issues i got. but i still have the asr and sometimes service engine soon lights coming on and deactivating the asr (not so good in winter now to drive without asr), so i ordered a brand new original ac delco TPS. i was about to replace it, but got an instruction on how to reset the idle volt value with a tech scan that i don't own myself, so i searched the net.

the interesting fact, i got all the same issues and now watch: i got a defective a/c, the cooler of the climate got a hole and the fluid went out of it, so it won't work anymore, maybe this is related to the problems somehow and gives wrong data to the same data bus so it behaves like a corrosive harness. btw, did anyone find the "a/c harness going into the engine", so i could check on it if it's corroded and spray some wd-40 on it ?

i'll try the new tps tomorrow and check if the problems are gone then.
 

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Discussion Starter #17
BUMP...BUMP.
It's been almost a year and tried a few things and still the same probs. WTF.. HELP! :spanked: :toilet

Same ol' codes still. Same sputtering and stalling at stops like it's loading up after car warms up. Over 2500 RPM runs great.

Changed the fuel pressure reg. It started leaking. Tune up.

Swapped ECM with another - same codes and run condition. :huh: So I put mine back in.

Found two vac leaks and fixed- still nothing.

So the other day I bought a INNOVA 3120 CanOBD 2&1 tool kit scanner from O'Reilly Auto. Wifey gets discount. YEY ME! Well it read the code her car had thrown that morning on her way to work / hence the reason I should get 1 I told her. :smack BUT... When I hooked it to my Vette Carma hit. It looks for my ECM and dash lights and heat blower fan comes on. Then a few seconds and stop and reads couldn't link. :WTF REALLY!
Codes I had got before was by jumper wire. Why can't this bring ANYTHING up?

I missed some Corvette GTGs cause of this last summer. NOT again. Do I need a new ECM? It's one of those you can't take back if that don't fix the prob. $$$ waisted. Rainbow run is coming up and I'm not trying to miss it AGAIN.

Any ideas welcome. More details in earlier posts from me too. like my A/C use to work too till this stumbling prob. Cooling fans still on all the time too.... TRADES for a C3 welcome too. :laughing:
 

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Hey RottNRobs93.....
Reading your post is just like being in my garage for the past 10 mos. :smack I have the same ASR light on, Check Engine light and yes both cooling fans fire up. :WTF
I see a few differences in our problems but have not been able to find any help with just WHY the HELL this is happening.
I know this is not going to make things better, but my buddy House's down the street has a black 93 vert that is doing the same thing. Just know we are all looking for a solution, and soon as we find it we will post it up and let the C4 community just how to fix this bullshit.....:cheers:
 

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BUMP...BUMP.
It's been almost a year and tried a few things and still the same probs. WTF.. HELP! :spanked: :toilet

Same ol' codes still. Same sputtering and stalling at stops like it's loading up after car warms up. Over 2500 RPM runs great.

Changed the fuel pressure reg. It started leaking. Tune up.

Swapped ECM with another - same codes and run condition. :huh: So I put mine back in.

Found two vac leaks and fixed- still nothing.

So the other day I bought a INNOVA 3120 CanOBD 2&1 tool kit scanner from O'Reilly Auto. Wifey gets discount. YEY ME! Well it read the code her car had thrown that morning on her way to work / hence the reason I should get 1 I told her. :smack BUT... When I hooked it to my Vette Carma hit. It looks for my ECM and dash lights and heat blower fan comes on. Then a few seconds and stop and reads couldn't link. :WTF REALLY!
Codes I had got before was by jumper wire. Why can't this bring ANYTHING up?

I missed some Corvette GTGs cause of this last summer. NOT again. Do I need a new ECM? It's one of those you can't take back if that don't fix the prob. $$$ waisted. Rainbow run is coming up and I'm not trying to miss it AGAIN.

Any ideas welcome. More details in earlier posts from me too. like my A/C use to work too till this stumbling prob. Cooling fans still on all the time too.... TRADES for a C3 welcome too. :laughing:
Wish I could still help you, but I got rid of my piece of crap C4 several months ago. I don't have anything to reference any more. :nuts: :laughing:
 
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