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All codes had the "H" in front of them. I cleared the codes and went for about a 15 minute drive, and let it idle for 5 minutes. Turned it off, and no codes set. Let's hope it stays that way for a while. Left BLM is 140, is that too high?
Would this vacuum line from the EVAP cause it to run lean? I wanted to double check for vacuum leaks, so I started the car. Engine cold. Starts up great, but bad idle. Like the video I posted, "LT1 running bad". This time, the car died on me. Scanned codes and none. Code C12, but that's normal.
Last pic is from the air filter. Would that cause un-metered air to come in?
Thing is, it's a 50/50 shot if the car will run fine when cold.
Last edited by 1993C4LT1; Dec 1, 2015 at 11:55 AM.
I'm pretty sure everyone is annoyed with this thread. Sorry about that. I keep wanting to check for vacuum leaks, but the car stalls on me in like 10 seconds. Any ideas?
It's weird Patrick. Sometimes it runs fine cold, other times bad cold. Or it could be running bad when warmed up. But as of late, seems to run like **** when started cold.
Honestly, it's hard to follow the thread since there are so many issues.
If it is running so lean from a vacuum leak somewhere that it stalls you would be getting a lean bank code.
Recently I went through a similar saga with my 93 running lean. You can read the details in the link below but it ended up being a combination of leaky header gaskets and a small vacuum leak which was only found by a smoke machine at a local shop. The tell tale sign of a vacuum leak is 0 IAC counts at idle. I'd suggest looking at those.
I also started getting an intermittent H41 during this time along with some other random serial data codes, until one day it turned into C41 and would barley run.
After tearing the dash apart and checking all the wiring between the ECM/CCM/EBTCM, it could only be the ECU. I broke down sent it to SIA electronics and they found solder issues on the circuit board. That ended up being the the problem.
What i'm saying here is it could be the beginning stages of a failing ECM, but you should investigate it in efficient, detailed manner. If not your going to drive yourself nuts and keep going in circles. READ that FSM it's full of valuable information you just have to find it.
From: Las Vegas - Just stop perpetuating myths please.
Well it reads like u have multiple problems - ign and vac leaks and maybe fuel injectors. From what i can read u never corrected for the larger injectors w/lower resistance solenoids. Now the ECM does try and correct the fueling with long term BLM. But everytime u disconnect the batt and de-energize the ECM it returns to its default base map.
If it were my car i would go to the boneyard and pickup some used injectors from even a B body car and if u cant afford to have them recalibrated then just install them for trouble shooting. Then u can move to the other problems.
Honestly, it's hard to follow the thread since there are so many issues.
If it is running so lean from a vacuum leak somewhere that it stalls you would be getting a lean bank code.
Recently I went through a similar saga with my 93 running lean. You can read the details in the link below but it ended up being a combination of leaky header gaskets and a small vacuum leak which was only found by a smoke machine at a local shop. The tell tale sign of a vacuum leak is 0 IAC counts at idle. I'd suggest looking at those.
I also started getting an intermittent H41 during this time along with some other random serial data codes, until one day it turned into C41 and would barley run.
After tearing the dash apart and checking all the wiring between the ECM/CCM/EBTCM, it could only be the ECU. I broke down sent it to SIA electronics and they found solder issues on the circuit board. That ended up being the the problem.
What i'm saying here is it could be the beginning stages of a failing ECM, but you should investigate it in efficient, detailed manner. If not your going to drive yourself nuts and keep going in circles. READ that FSM it's full of valuable information you just have to find it.
IAC counts were at 0, replaced the 2 way check valve, and it's no longer at 0 Glad you found the problem! You are correct about finding the info in the FSM.
Well it reads like u have multiple problems - ign and vac leaks and maybe fuel injectors. From what i can read u never corrected for the larger injectors w/lower resistance solenoids. Now the ECM does try and correct the fueling with long term BLM. But everytime u disconnect the batt and de-energize the ECM it returns to its default base map.
If it were my car i would go to the boneyard and pickup some used injectors from even a B body car and if u cant afford to have them recalibrated then just install them for trouble shooting. Then u can move to the other problems.
I still have the factory injectors. Guess I could swap those in, and see what it does. Thanks
Glad you found the problem! You are correct about finding the info in the FSM.