Weird intermittent issue?
Thread Starter
Teching In
Joined: Oct 2019
Posts: 7
Likes: 4
Weird intermittent issue? So I am in the process of finishing up my LS swap on my Colorado. I put a cammed L33 into it. Had it tuned by mailordertuning. I am having an intermittent issue where the truck does not want to pull. Over like 30-40% throttle it just feels like the truck is misfiring. I can switch the key off and start it back up and its gone, pulls like a freight train. I parked it and it happened again. It would not pull at all over 30-40%, once again restarted it and its fine again. Any tips on where to start? The engine is throwing no codes and the tuner looked at a datalog of it doing it and said there is nothing out of the ordinary, it all looked normal. Any help is appreciated!
Running the engine with a E40 ECM, engine is bone stock other than a truck norris cam, springs, lifters and pushrods to match.
Running the engine with a E40 ECM, engine is bone stock other than a truck norris cam, springs, lifters and pushrods to match.
Thread Starter
Teching In
Joined: Oct 2019
Posts: 7
Likes: 4
Gonna be honest, I am not sure why my tuner did not see this but the datalog of it doing it says my O2 sensors are nearly 0mv, when I restart the engine and try again it runs fine and the O2 are reading .35-.45 like they should. Only thing else I notice is when the truck is acting fine the CL - Normal stays lit on VCM Scanner, and when it wont pull under those conditions when it does what its doing as soon as it starts the VCM scanner shows CL - ACCEL/DECEL. Not sure why its intermittent though. Makes not sense that I can just restart it and its fine. Does not even matter if its warmed up.
Thread Starter
Teching In
Joined: Oct 2019
Posts: 7
Likes: 4
I would not have thought it would be intermittent if it was a ground issue. I did check my main ground for the starter because the engine seems to turn over really slow, but i do have a small 650 CCA battery. Have not had a chance to get a new one for the new engine yet. I will check my wiring harness grounds on the back of the head in the morning and report back, the machine shop did put aluminum paint on the block cause it had some corrosion not sure if he did the heads to. The OP - ACCEL/DECEL being the trigger has me scratching me head though. Soon as it goes back to CL - Normal it stops. When I restart the engine and its pulling fine i never see the OP - ACCEL/DECEL. I am gonna do more datalogging tomorrow to but it seems like if the computer switches to that mode its does it.
Thread Starter
Teching In
Joined: Oct 2019
Posts: 7
Likes: 4
Just saw this in my book marks, decided to update the post. The issue I was having was due to running a automatic ECM on a manual truck. The E40 ECMs are finicky about it. The torque management even though I had selected manual in the transmission tab and disable it was still stopping it from going. I could get it to do fine if i waited 5-10 seconds before I started the engine after turning on the key. I ended up sending the ECM off and had a new manual SSR OS put on it. I did try that with HP Tuners but there is code in the ECM HP Tuners just wasn't able to overwrite.
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