I have a 1998 Jeep TJ with a 5.3 Vortec swap. Occasionally it will backfire through the intake on startup, runs fine otherwise. I have replaced the fuel pump, regulator and plugs. I also replaced the knock sensors and harness twice with Delphi. I still get a code after about 30 min of driving. I need help determining what could be causing both issues. I have attached a log for review, I appreciate any help with this.
We need your tune file, also. Want to know why? Because when I look at the log and don't see a code set for the cam sensor, I cannot assume that some idiot didn't turn that code off in the tune file. Whether the people you're asking for help assume things to be true that aren't, or assume they're not when they are, you get shittier answers and it wastes everyone's time including yours. So please post the damn tune file when asking for help. Like it tells you to do in the 'sticky' post at the top of this very forum, which you ignored. Thanks.
About that cam sensor:
Long crank time means the PCM has guessed wrong about whether TDC is #1 compression or #6 compression, and when it has guessed wrong you will get backfires. Continue cranking and the PCM will flip its #1/#6 identification, and the engine will then start and run normally. Your log does not have any channels in it related to the cam sensor. Please help us help you.There is one normal mode of operation, with the spark under PCM control. If the CKP pulses are lost the engine will not run. The loss of a CMP signal may result in a longer crank time since the PCM cannot determine which stroke the pistons are on. Diagnostic trouble codes are available to accurately diagnose the ignition system with a scan tool.
Knock sensor codes:
Attachment 151923
You done all those things, or just replaced parts and grunted at it like a caveman?
Originally Posted by SiriusC1024
Cam sensor has been replaced also.
So you are just replacing parts instead of diagnosing things. How's that working so far?
The fuel pressure was 26 psi now it is 58 so it appears to be an improvement. You can move on to something else, I can do without your input. Thanks
Actually, you probably can't. He's one of the best diagnostic guys on here.
Just to be clear, fuel pressure won't be fixed by a cam sensor.
Is this a stock motor? Out of what? Did the camshaft change? Are you using the rear sensor which would be stock for that year truck or are you using the front sensor/cover like a later model?
For the knock sensors, make sure they are torqued.. that is key and also only use GM sensors. The aftermarket parts at part stores have been really bad for years now.
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I replaced the fuel pump because the fuel pressure was 26 psi on the rail. I belive it still had the factory Jeep fuel pump. The fuel pressure is at 58 psi on the rail now.
The engine is stock out of a 2003 Tahoe
The cam sensor is in the rear. It has E85 fuel injectors. I bought the Jeep like it is. Thanks
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