Engine won't stay running after rebuild
08-23-2009, 07:17 AM
#1
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Engine won't stay running after rebuild I rebuilt the engine in my 02 TA and finished the install yesterday, now it won't stay running. You turn the key and the engine fires but only for a few seconds then dies. A couple times I gave it a little throttle and it would stay running a longer and rev but die after a few seconds. For the short time it runs it sounds smooth,not struggling to run. It does have fuel pressure. I went through most everything during the rebuild, forged short block,cam,rebuild trans and rear,Racetronix pump,etc... A few things I have found are that the gas gauge and tach are not working, the couple times I tried giving it throttle the tach and speedo needles jumped up but then the car dies. My friend has a scanner that he uses on his Camaro, when we plugged it into my car it reads that it can't link, so I double checked connection at the ecm. We connected the scanner to his Camaro to verify the scanner is working and it connects to his car with no problem. Any ideas???
08-23-2009, 12:05 PM
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You get all your grounds? There should be 2 sets on the heads. One passenger side to the block and one driver side to the block, if you stacked the 2 on the heads maybe seperate them. That's my guess any way also there is a fues for the obd port make sure it has power if the scanner wasn't reading
08-23-2009, 08:57 PM
#4
I will say it will be the grounds on the back of the drivers cylinder head. This is the ground for the ECM and as mentioned they should not be stacked. Even if they are tight, make sure that the wires have a good connection with the grounding eyelet.
If the ECM ground is bad it will not power up the ECM or have any data to the ALDL.
You can not check the grounds with a test light either. I had one that the test light should good, but an ohm meter showed 34 ohms. Max resistance is 2 ohms. Put on a new eyelet, then had 1.2 ohms and no more problems.
Good luck
Mike Norris
If the ECM ground is bad it will not power up the ECM or have any data to the ALDL.
You can not check the grounds with a test light either. I had one that the test light should good, but an ohm meter showed 34 ohms. Max resistance is 2 ohms. Put on a new eyelet, then had 1.2 ohms and no more problems.
Good luck
Mike Norris
08-24-2009, 09:30 PM
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Checked the grounds and seperated the ground on the back of the driver side head with no change. Car fires right up but stalls after just a couple seconds. I didn't have the right cable to connect my HPTuners to check for anycodes but will tomorrow night. Any other ideas?What would a bad MAF or crank sensor or can sensor or??????
08-25-2009, 06:25 AM
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sounds like a bad crank sensor cause my car was doing the same exact things your describing yours is doing and it wasn't throwing a code or anything so I can almost guarantee you that's what is wrong with your's. Good luck man and let us know how it goes
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08-26-2009, 06:05 AM
#12
As mentioned, you really need to check for codes and data before you keep throwing money at things. The crank sensor could be it and more so then the cam sensor. A crank sensor relearn issue will not keep it from learning.
So here is what I would do. First ask a couple more questions. You rebuilt the engine, so do you have the same crank?? Do you have the same crank sensor?? Do you have the same block?? Any sensors changed?? The crank reluctor wheel could be damaged or, if replaced, the reluctor in the wrong position.
Next would be for the data or lack there of. If getting no data at the ALDL, you need to check the powers, both battery and ignition to the PCM as well as ohm the four ground cicuits.
Once you have data, what codes are there?? Is there an RPM reference?? Do the injectors show a pulse width?? Is the VATS disabled??
Also, if the gauges are still acting up as mentioned, it could be a major ground issue.
There just neeeds to be more info and diagnosing for sure.
Mike Norris
So here is what I would do. First ask a couple more questions. You rebuilt the engine, so do you have the same crank?? Do you have the same crank sensor?? Do you have the same block?? Any sensors changed?? The crank reluctor wheel could be damaged or, if replaced, the reluctor in the wrong position.
Next would be for the data or lack there of. If getting no data at the ALDL, you need to check the powers, both battery and ignition to the PCM as well as ohm the four ground cicuits.
Once you have data, what codes are there?? Is there an RPM reference?? Do the injectors show a pulse width?? Is the VATS disabled??
Also, if the gauges are still acting up as mentioned, it could be a major ground issue.
There just neeeds to be more info and diagnosing for sure.
Mike Norris
08-27-2009, 11:10 AM
#13
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I tried to connect my HP Tuners and it says unable to connect to vcm. Does that mean there is an issue with the computer? I checked all the fuses and checked the connections at the ECM and there is no change.
08-27-2009, 01:34 PM
#14
You say you checked the connections, but did you check to see if there was actually power with a test light and check the grounds with an ohm meter?
At the blue ECM connector you should have battery voltage on pins 20 and 59. You should have key on or ignition voltage at pin 19. These you can check with a test light.
Also on the blue ECM connector you should also have less then 2 ohms resistance to ground on pins 1 and 40. These must be checked with an ohm meter as a test light can give a false reading.
On the red ECM connector you also need to check the grounds at pins 1 and 40. Same scenario as there needs to be less then 2 ohms resistance to ground and again a test light can give a false good reading.
Now if you have already checked these power circuits with a test light and the grounds with an ohm meter and all is good, just let me know and I will see what would be next.
Hopefully this will help out.
Mike Norris
At the blue ECM connector you should have battery voltage on pins 20 and 59. You should have key on or ignition voltage at pin 19. These you can check with a test light.
Also on the blue ECM connector you should also have less then 2 ohms resistance to ground on pins 1 and 40. These must be checked with an ohm meter as a test light can give a false reading.
On the red ECM connector you also need to check the grounds at pins 1 and 40. Same scenario as there needs to be less then 2 ohms resistance to ground and again a test light can give a false good reading.
Now if you have already checked these power circuits with a test light and the grounds with an ohm meter and all is good, just let me know and I will see what would be next.
Hopefully this will help out.
Mike Norris
08-27-2009, 05:45 PM
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The problem is solved!!! Turns out I had an idiot working on the install....that would be me by the way! I pulled the ECM to trace the harness and be sure everything was connected and I found the blue connector going through the firewall was disconnected. What's weird is that the locking clip was still in place. I appreciate everyones help and sorry I'm an idiot but I'm glad it was something free and easy!!!!
