Looking for a little insight on this situation. I'm new to the diagnostic field so I'm still learning not very knowledgeable on engines. I had knock sensor codes in this 03 Chevy Tahoe with the 5.3 vin (Z). Replaced the knock sensors/harness, also resealed the intake. After the fix the knock sensor codes did not return but now I am dealing with a long crank start. Smoke tested the intake system thinking maybe I had a leaky intake found a nipple cracked up by the throttle body. Found a used intake and resealed the ENTIRE intake including injectors.. Ive replaced everything from Crank and Cam pos sensors, also replaced Fuel pump, inline filter and the fuel pressure regulator with OEM if not available, then Carquest. Confirmed No intake leaks, or fuel line leaks. But I am stumped now because I don't know whats going on or what to look for, I've swapped the fuel pump relay fuse with the horn fuse, Ive also replaced the ignition switch and I'm still getting a long crank start. When it finally starts the engine stumbles then runs normal. My fuel trims look normal, my Map and Maf sensors TPS reads normally There is nothing that I can physically watch or see that is out of the ordinary but I am still dealing with this problem and am running out of parts to throw at it and sensors to watch. I hope someone can send me in the right direction. Appreciate your time.
2003 Chevy Tahoe long crank start.
- Thread starter TSHAYTAR
- Start date
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Any time a crank and/or cam sensor is changed, a CASE relearn should be done so the ECM knows where the cam is in relation to the crank. Not doing the CASE relearn with a scanner can cause intermittent long crank times.
Let us know how that goes if you decide to do it.
Let us know how that goes if you decide to do it.
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Welcome to the Forum from NH.
Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.
I hope that you will become a participating member in the Forum's discussions.
Pics of the truck, please.
It looks at first glance that you've been through the ringer (in old terms). Given that you have a GMT800 truck, I won't be able to help you a lot with the details of your issue.
The good news is that we have a lot of GMT800 truck owners in this Forum, and they will chime in.
Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.
I hope that you will become a participating member in the Forum's discussions.
Pics of the truck, please.
It looks at first glance that you've been through the ringer (in old terms). Given that you have a GMT800 truck, I won't be able to help you a lot with the details of your issue.
The good news is that we have a lot of GMT800 truck owners in this Forum, and they will chime in.
So I performed the CKP relearn on it. I'm not sure if that's the same thing I didn't see anything on the scanner that relates to CASE, however I may be able to perform this relearn with my j2534 tool using TLC. I will definitely look into it thank you.
That should be the one that was needed, just to rule it out.
