More '92 NO START
10-10-2014, 12:14 PM
#41
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Pro Mechanic
I may have not been following this thread closely enough, but are we working with "flashing lights" or have we put a scanner on the ALDL to get any stored or history codes?
That can be done by driving by your local AutoParts store and they will pull the codes for you at no cost generally.
That can be done by driving by your local AutoParts store and they will pull the codes for you at no cost generally.
1stVetteFinally has done a few tests that have provided some evidence, but he isn't following a process...he's started at "step #11". He hasn't yet started w/the basics; when it won't start, what is missing; fuel or spark, and also drawing codes as you just mentioned and has been mentioned above. The car can tell you a lot, if you are willing to take a little time to "ask it"...
10-10-2014, 11:58 PM
#42
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1stVetteFinally
Did you check your fuel pressure. As with mine, wasn't just one issue. May be same for u.
True - Service ASR light wont be the fuel pump.
But before you get to crazy under the dash or buying a new ECM CHECK YOUR FUEL PRESSURE. This could be in conjunction with your service ASR issue.
Did you check your fuel pressure. As with mine, wasn't just one issue. May be same for u.
True - Service ASR light wont be the fuel pump.
But before you get to crazy under the dash or buying a new ECM CHECK YOUR FUEL PRESSURE. This could be in conjunction with your service ASR issue.
10-11-2014, 01:24 AM
#43
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Uh, hey, I forgot something. When I unhooked my EBTCM I did drive it around a while before I got the new one and the car was fine, kinda fun without all the traction control and all.
BUT when I finished all the other repairs and still had the issue, then unplugged the EBTCM ............ I ALSO CLEARED all the OTHER codes that became history, still showed the ECM as ERR (of course the EBTCM was now ERR but the codes) and/or potentially logic lock from the serial data not being pulled down by the EBTCM anymore, despite the scan CCM reports as ERR to the ECM, THEY OBVIOUSLY where now able to TALK enough to do their handshake to enable the FEDS.
Try both - CHECKING FUEL PRESSURE and Clear all the history CODES you can.
Then unhook the battery for a few minutes. That is what I remember I had done when I was running around without the EBTCM.
So again each of these cars seems to have its own distinct temper tantrums, So because this worked on mine, does not necessarily mean what another car is doing would work. The only reason I stress the fuel pump is even after a while of no problems with the new EBTCM, when my fuel pump decided to take a dump, it felt VERY MUCH like the months of the first problem.
If you HAVE FUEL pressure, cleared any codes, EBTCM unhooked, then go after the ignition system, insure tach reading, spark all that.
Check fuses for like the SIR (airbag) system too, the FSM says this fuse can inhibit FEDS fuel enable, not serially, but because it shares some portion of power supply to the ECM.
I assume that it does start occasionally the way mine did, when it does do some wiggle testing next to the ECM coming out of the connectors, if you can get audible changes during wiggle tests could be something to address, there's more but not sure if any of this will help. Sure hope it might, but .............
BUT when I finished all the other repairs and still had the issue, then unplugged the EBTCM ............ I ALSO CLEARED all the OTHER codes that became history, still showed the ECM as ERR (of course the EBTCM was now ERR but the codes) and/or potentially logic lock from the serial data not being pulled down by the EBTCM anymore, despite the scan CCM reports as ERR to the ECM, THEY OBVIOUSLY where now able to TALK enough to do their handshake to enable the FEDS.
Try both - CHECKING FUEL PRESSURE and Clear all the history CODES you can.
Then unhook the battery for a few minutes. That is what I remember I had done when I was running around without the EBTCM.
So again each of these cars seems to have its own distinct temper tantrums, So because this worked on mine, does not necessarily mean what another car is doing would work. The only reason I stress the fuel pump is even after a while of no problems with the new EBTCM, when my fuel pump decided to take a dump, it felt VERY MUCH like the months of the first problem.
If you HAVE FUEL pressure, cleared any codes, EBTCM unhooked, then go after the ignition system, insure tach reading, spark all that.
Check fuses for like the SIR (airbag) system too, the FSM says this fuse can inhibit FEDS fuel enable, not serially, but because it shares some portion of power supply to the ECM.
I assume that it does start occasionally the way mine did, when it does do some wiggle testing next to the ECM coming out of the connectors, if you can get audible changes during wiggle tests could be something to address, there's more but not sure if any of this will help. Sure hope it might, but .............
10-14-2014, 10:33 AM
#44
Pro
Neither.
1stVetteFinally has done a few tests that have provided some evidence, but he isn't following a process...he's started at "step #11". He hasn't yet started w/the basics; when it won't start, what is missing; fuel or spark, and also drawing codes as you just mentioned and has been mentioned above. The car can tell you a lot, if you are willing to take a little time to "ask it"...
1stVetteFinally has done a few tests that have provided some evidence, but he isn't following a process...he's started at "step #11". He hasn't yet started w/the basics; when it won't start, what is missing; fuel or spark, and also drawing codes as you just mentioned and has been mentioned above. The car can tell you a lot, if you are willing to take a little time to "ask it"...
when it won't start, what is missing; fuel or spark
I did pull codes from the car since my last posting, here are the results and their meanings.
ECM codes-
DTC 15 - Engine Coolant Temperature (ECT) Sensor Circuit (Signal Voltage High,Low Temperature Indicated)
DTC 33 - Manifold Absolute Pressure (MAP) Sensor Circuit (Signal Voltage High – Low Vacuum)
DTC 44 - Bank 1 (Left Front) Heated Oxygen Sensor (HO2S) #1 Circuit (Lean Exhaust Indicated)
DTC 55 - Fuel Lean Monitor
CCM code-
Module 1 (CCM)
C25 & H25- Courtesy lamp relay coil circuit open or shorted to ground
C41 & H41 - Loss of ECM serial data communications
Module 4 (ECM)
Err
Module 9 (EBTCM)
H72 - LCD dimming output circuit open or shorted to ground
Something interesting I read in this article- http://tech.corvettecentral.com/2011...trouble-codes/
We have found that when CCM codes 41 or 54 display, it has always been an ECM (Engine Control Module) failure. The first thought is that the CCM would be the culprit, but to date, we have never seen this happen. The law of averages shows that CCMs have an excellent track record. We have only seen one failed CCM (in a 1995 Corvette) in all the years we have worked with them.
Last edited by 1stVetteFinally; 10-14-2014 at 10:50 AM.
10-14-2014, 08:39 PM
#45
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Wow that many codes
so I believe your module 9 code 72 is loss of serial data, the dimming code 72 is CCM only. Because the CCM is reporting ECM sensor codes kinda tells me the ECM and the CCM are talking.
as I found with mine the EBTCM actually would bring down the serial data causing the ECM to come up as ERR, and the CCM was able to report the EBTCM loss of serial data still sounds a lot like the EBTCM.
However, all those sensor codes, those sensors share grounds, I am thinking you may want to tighten the BIG GROUND location shared with a bolt to your transmission bell housing to the engine on the drivers side.
Did you confirm fuel pressure when you have the EBTCM unplugged?
so I believe your module 9 code 72 is loss of serial data, the dimming code 72 is CCM only. Because the CCM is reporting ECM sensor codes kinda tells me the ECM and the CCM are talking.
as I found with mine the EBTCM actually would bring down the serial data causing the ECM to come up as ERR, and the CCM was able to report the EBTCM loss of serial data still sounds a lot like the EBTCM.
However, all those sensor codes, those sensors share grounds, I am thinking you may want to tighten the BIG GROUND location shared with a bolt to your transmission bell housing to the engine on the drivers side.
Did you confirm fuel pressure when you have the EBTCM unplugged?
10-15-2014, 08:13 AM
#46
Pro
Wow that many codes
so I believe your module 9 code 72 is loss of serial data, the dimming code 72 is CCM only. Because the CCM is reporting ECM sensor codes kinda tells me the ECM and the CCM are talking.
as I found with mine the EBTCM actually would bring down the serial data causing the ECM to come up as ERR, and the CCM was able to report the EBTCM loss of serial data still sounds a lot like the EBTCM.
However, all those sensor codes, those sensors share grounds, I am thinking you may want to tighten the BIG GROUND location shared with a bolt to your transmission bell housing to the engine on the drivers side.
Did you confirm fuel pressure when you have the EBTCM unplugged?
so I believe your module 9 code 72 is loss of serial data, the dimming code 72 is CCM only. Because the CCM is reporting ECM sensor codes kinda tells me the ECM and the CCM are talking.
as I found with mine the EBTCM actually would bring down the serial data causing the ECM to come up as ERR, and the CCM was able to report the EBTCM loss of serial data still sounds a lot like the EBTCM.
However, all those sensor codes, those sensors share grounds, I am thinking you may want to tighten the BIG GROUND location shared with a bolt to your transmission bell housing to the engine on the drivers side.
Did you confirm fuel pressure when you have the EBTCM unplugged?
H72 code. This may have been caused from someone driving the car with the radio out for service. The code set and was not cleared after repairs were done. If the problem causing the code is fixed, the code must be cleared. The CCM will not display “SYS” if the problem is repaired. However, the code will remain in history until cleared. It’s always best to record all the codes, clear them, and run the engine or operate the system causing the code to see if any codes reoccur.
I'll check the common ground you mentioned.
No, I did not check the fuel pressure with the EBTCM disconnected. I'll pick up a fuel pressure gauge today and check that tomorrow when my mechanic room mate is off work.
10-15-2014, 12:26 PM
#47
Team Owner
Pro Mechanic
With all the connecting/disconnecting that you've done, you may want to clear codes and start again.
10-16-2014, 07:25 AM
#48
Pro
10-16-2014, 10:35 AM
#49
Safety Car
I forget the exact No Start symptoms, but should you clear codes on a car that won't start? I would worry that without it running I couldn't get at a new accurate set of codes.
I would highly recommend a Helms manual. Each of those codes has a detailed diagnostic procedure listed on the page for each code. If you are going to try and work on your car between you and your Roomie, than you will need a Helms to do anything more than change the oil. It also sounds like a good code reader, logger (I use Datamaster on my LT1) and multimeter is in your future. There are a lot of electrical things going on.
I would highly recommend a Helms manual. Each of those codes has a detailed diagnostic procedure listed on the page for each code. If you are going to try and work on your car between you and your Roomie, than you will need a Helms to do anything more than change the oil. It also sounds like a good code reader, logger (I use Datamaster on my LT1) and multimeter is in your future. There are a lot of electrical things going on.
Last edited by pkincy; 10-16-2014 at 10:38 AM.
10-16-2014, 10:43 AM
#50
Pro
Get in, turn ignition on, all lights on system status display light up. Wait for the system to cycle and lights to go out except for check engine and air bag lights to go out. If "service ASR"light does not turn off, the car will not start.
It is sometimes possible to get the engine to start and run extremely rough by pumping the gas pedal when the "service ASR" is lit, but it stop running once the pumping of the gas pedal is stopped.
If the light does go out with the other lights, the car will start and run great until you turn it off.
While driving the car, occasionally the security light in the gauge cluster will blink in unison with the system error where the fuel milage is displayed flashing, and the "service ASR" light will illuminate. The majority of the time, if this is happening, if the car is shut down, it will not restart.
The ECM does get very hot to the touch. Not hot enough to burn you, but it is uncomfortable to hold your hand on it.
It is sometimes possible to get the engine to start and run extremely rough by pumping the gas pedal when the "service ASR" is lit, but it stop running once the pumping of the gas pedal is stopped.
If the light does go out with the other lights, the car will start and run great until you turn it off.
While driving the car, occasionally the security light in the gauge cluster will blink in unison with the system error where the fuel milage is displayed flashing, and the "service ASR" light will illuminate. The majority of the time, if this is happening, if the car is shut down, it will not restart.
The ECM does get very hot to the touch. Not hot enough to burn you, but it is uncomfortable to hold your hand on it.
I would highly recommend a Helms manual. Each of those codes has a detailed diagnostic procedure listed on the page for each code. If you are going to try and work on your car between you and your Roomie, than you will need a Helms to do anything more than change the oil.
10-16-2014, 10:53 AM
#51
Safety Car
OK, if it can start by cooling the ecm in the engine compartment then clearing the codes is no problem.
However, if you have ever seen a Helms you will see why you want it in your hand when you work on the car.
However, if you have ever seen a Helms you will see why you want it in your hand when you work on the car.
11-22-2014, 04:16 PM
#52
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So when your car decides it won't start, does it have trouble lights?
Such as Service ASR, security flashing, or System on the speedo display flashing every few minutes?
If so, like when you stalled before getting into the garage AND IT WILL NOT START - try clearing ALL the codes to get it to start.
I know it sounds dumb but here me out....
ANY READERS WITH A NO START -- TRY THIS
On the ALDL (Key off) put a little 3" jumper wire between slot "A" and "G" into the ALDL connector under the drivers side knee bolster.
Depiction of ALDL plug:
- - - - - X < HERE
HERE > X - - - - -
Now turn key on engine off
The speedo display will go into onbaord diagnostic mode.
display will begin cycling through all the modules and their codes.
You can watch them through or any any time begin:
Using the buttons just to the right of your IP gauges this is how you navigate:
This side This side
curses back curses FWD
Fuel info Eng Met
Guages Trip ODO
Fuel Trip
Press "trip ODO" to navigate to "1.7"
Press and hold "Eng Met" till you see "---"
Press and hold "trip" untill you see "4.0"
Press "trip ODO" to navigate to "4.7"
Press and hold "Eng Met" till you see "---"
Press and hold "trip" untill you see "9.0"
Press "trip ODO" to navigate to "9.7"
Press and hold "Eng Met" till you see "---"
You have now cleared all the codes
Recap: Module 1 is CCM, 4 is ECM, 9 is EBTCM
If you have digital HVAC their will be an additional module (not sure what number I'll use X)
and you would press "trip ODO" to "X.7" Press and hold "Eng Met" till you see "---" for that number module as well
TURN OFF KEY, Remove the pigtail jumper from the ALDL
Try tyo start the car NOW ( Note: turn key on wait about 3-4 seconds before engaging the starter)
If this does not work DO THE WHOLE CODE CLEARING AGAIN
On 92/93 Vettes being FUSSY and stranding you I found this to work near 90% of the time to get you going.
This does NOT fix the source of your problem but will trick the serial data into the fuel enable to get it to start.
the 10% of the time this does NOT work is when the situation is related to the ignition or fuel pump.
Good luck
Such as Service ASR, security flashing, or System on the speedo display flashing every few minutes?
If so, like when you stalled before getting into the garage AND IT WILL NOT START - try clearing ALL the codes to get it to start.
I know it sounds dumb but here me out....
ANY READERS WITH A NO START -- TRY THIS
On the ALDL (Key off) put a little 3" jumper wire between slot "A" and "G" into the ALDL connector under the drivers side knee bolster.
Depiction of ALDL plug:
- - - - - X < HERE
HERE > X - - - - -
Now turn key on engine off
The speedo display will go into onbaord diagnostic mode.
display will begin cycling through all the modules and their codes.
You can watch them through or any any time begin:
Using the buttons just to the right of your IP gauges this is how you navigate:
This side This side
curses back curses FWD
Fuel info Eng Met
Guages Trip ODO
Fuel Trip
Press "trip ODO" to navigate to "1.7"
Press and hold "Eng Met" till you see "---"
Press and hold "trip" untill you see "4.0"
Press "trip ODO" to navigate to "4.7"
Press and hold "Eng Met" till you see "---"
Press and hold "trip" untill you see "9.0"
Press "trip ODO" to navigate to "9.7"
Press and hold "Eng Met" till you see "---"
You have now cleared all the codes
Recap: Module 1 is CCM, 4 is ECM, 9 is EBTCM
If you have digital HVAC their will be an additional module (not sure what number I'll use X)
and you would press "trip ODO" to "X.7" Press and hold "Eng Met" till you see "---" for that number module as well
TURN OFF KEY, Remove the pigtail jumper from the ALDL
Try tyo start the car NOW ( Note: turn key on wait about 3-4 seconds before engaging the starter)
If this does not work DO THE WHOLE CODE CLEARING AGAIN
On 92/93 Vettes being FUSSY and stranding you I found this to work near 90% of the time to get you going.
This does NOT fix the source of your problem but will trick the serial data into the fuel enable to get it to start.
the 10% of the time this does NOT work is when the situation is related to the ignition or fuel pump.
Good luck
03-01-2015, 01:02 PM
#53
Pro
UPDATE:
Well I went against the common thought here of thinking my problem was in my EBTCM (I just couldn't agree with the ECM throwing a error code like it was). I sent my ECM off to SIA ( http://www.siaelec.com/index.aspx ) to have it tested. They ended up reflowing the ECM's solder. While I haven't had much chance to drive it because of weather, my car ran great in the few hours I did drive it.
Well I went against the common thought here of thinking my problem was in my EBTCM (I just couldn't agree with the ECM throwing a error code like it was). I sent my ECM off to SIA ( http://www.siaelec.com/index.aspx ) to have it tested. They ended up reflowing the ECM's solder. While I haven't had much chance to drive it because of weather, my car ran great in the few hours I did drive it.
03-01-2015, 03:24 PM
#54
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1stVetteFinally
We've been lucky with the weather here in Balmy Seattle WA, SPRING will certainly be a welcome turn 4 sure...
You'll be happy - right choice.... ECM....
So I went through the System/Security no start as this thread explains and it would start with the EBTCM unplugged with all past codes cleared through the onboard diagnostics.
Replacing the EBTCM after many tests and serial data wire recrimps and such ran good for a time. Been using my '92 daily driver. (and love it!!)
Then, a similar situation began to occur after only a few months....
This time, unplugging my EBTCM and clearing the codes DID NOT WORK. Hmm
So it had ALL THE SAME TROUBLE CODES as before, (but the LED one, that repair still works) But now would not start.
Perhaps even Accidentally -
The first time it did this... I needed it to start.
Opened the hood, and wiggled my coil wires (Because the MSD deletes the latch mechanism), but that wasn't it. check the plug to the Opti nothing, fuel pressure shrader - good, no start.
I got back out from the seat ..again.. and went straight to the ECM and KNOCKED ON IT with my knuckles - like loudly knocking on someones front door - WHILE I asked it - "Why won't you start??""
It STARTED.
Turns out, couple days later, I got to test the theory, no start, went out and "knocked" on the ECM's door, (sort of speak) bam - starts.
I did not get all that overthinking on it this time and ordered a ECM on ebay, making sure I got THE EXACT part number:
SERV. NO. 16159278
and even matched the 16173881 at the bottom of the label.
Then put my CAL chip from the original ECM to the one I got.
While waiting for the ECM to arrive (shipped ground), the condition began to occur more and more often. Funny, when it did, the Knocking on it like a door thing worked... every time. so, even though once early in the thread I suggested the ICE thing was maybe overthought, knocking on it is probably just as unlikely, but .... here we are.
Guess if you do something to the ECM to make it start, that's a good place ton start. Just make sure you get a compatible used one or a reputable re-manufacturer for the ECM.
I hope your weather gets better and your vette is now doin' OK - been several months now that mine has been running very nice.
We've been lucky with the weather here in Balmy Seattle WA, SPRING will certainly be a welcome turn 4 sure...
You'll be happy - right choice.... ECM....
So I went through the System/Security no start as this thread explains and it would start with the EBTCM unplugged with all past codes cleared through the onboard diagnostics.
Replacing the EBTCM after many tests and serial data wire recrimps and such ran good for a time. Been using my '92 daily driver. (and love it!!)
Then, a similar situation began to occur after only a few months....
This time, unplugging my EBTCM and clearing the codes DID NOT WORK. Hmm
So it had ALL THE SAME TROUBLE CODES as before, (but the LED one, that repair still works) But now would not start.
Perhaps even Accidentally -
The first time it did this... I needed it to start.
Opened the hood, and wiggled my coil wires (Because the MSD deletes the latch mechanism), but that wasn't it. check the plug to the Opti nothing, fuel pressure shrader - good, no start.
I got back out from the seat ..again.. and went straight to the ECM and KNOCKED ON IT with my knuckles - like loudly knocking on someones front door - WHILE I asked it - "Why won't you start??""
It STARTED.
Turns out, couple days later, I got to test the theory, no start, went out and "knocked" on the ECM's door, (sort of speak) bam - starts.
I did not get all that overthinking on it this time and ordered a ECM on ebay, making sure I got THE EXACT part number:
SERV. NO. 16159278
and even matched the 16173881 at the bottom of the label.
Then put my CAL chip from the original ECM to the one I got.
While waiting for the ECM to arrive (shipped ground), the condition began to occur more and more often. Funny, when it did, the Knocking on it like a door thing worked... every time. so, even though once early in the thread I suggested the ICE thing was maybe overthought, knocking on it is probably just as unlikely, but .... here we are.
Guess if you do something to the ECM to make it start, that's a good place ton start. Just make sure you get a compatible used one or a reputable re-manufacturer for the ECM.
I hope your weather gets better and your vette is now doin' OK - been several months now that mine has been running very nice.