Engine miss/breaking up
Engine miss/breaking up I have a 04 5.3 with a tick cam, BTR springs and a s475 holley 160's holley efi e85 It developed a miss and I cannot seem to find it. I have swapped plugs, wires, coils, map, and wide band sensors. After all of that I am at a loss. I did a compression test and the first revolution it made 120-150 and maxes out at 165-180psi. It started out breking up going into boost. It would idle fine, but now it has a miss at idle and feels like its running on 7 cylinders
Any ideas?
Matt
__________________
Any ideas?
Matt
__________________
The first set looked fine, grayish strap and a little carbon. No signs of detonation I have Holley EFI and the wide band is new. I tested the old sensor and it was working but i decided to upgrade to the NTK My fuel pressure is at 47lbs with a boost sensitive regulator It wants to pull fuel at idle and add everywhere else I was just about done tuning it until this
TECH Junkie
Joined: Dec 2012
Posts: 3,614
Likes: 1,326
From: Iowa
I remember reading a ways back in a thread, that there was a distinct difference in afr between a bosch (maybe denso??) sensor and the ntk. There were different settings in the holly depending on which sensor you were using. Since you had this issue before the switch, I doubt it's the culprit, but it still may be something you want to look at again when you go to finalize tuning.
TECH Junkie
Joined: May 2012
Posts: 3,047
Likes: 713
From: Poplarville, MS
Try unplugging one injector at a time. If the engine starts running bad plug it back and move on to the next one. Keep doing this until you get to one that does not change how the engine is idling. Once you have found the cylinder that is missing you can swap plug wires, spark plugs, coils, and injectors one at a time from a cylinder that isn’t missing to the one that is missing. If you can get the miss to change cylinders then you have found the defective part. I hope this makes sense. If none of this changes the miss to another cylinder then you could have a vacuum leak on that cylinder or recheck the compression on that cylinder.
I ended up pulling the intake and the #1 cylinder was wet. I am having the injectors checked now. I pulled the 5.3 and swapped in a 370 and hopefully it was just that one injector
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