two dead cylinders need help!
Thread Starter
Driver School Candidate
Joined: Sep 2010
Posts: 20
Likes: 0
From: TX
two dead cylinders need help!
ok first thing i replaced the valvecover gaskets on my 92 ls400 and car ran like it was couple cylinders less. i pulled each spark plug one at a time to see which cylinders werent working and turns out it was the two under the throttlebody #2 #6 i think. so i check the wires to the fuel injectors and find the wires were pinched under the valvecover so i pulled off the valvecover and pull out the wire and taped and made sure the wires werent broken and still dont get anything from those cylinders. i checked and its getting spark and i replaced the spark plugs. i tested the injectors and they are at like 15ohms all across that side so i assume they are good. what else could it be? did i fry the ecu? any help would be appreciated.
Racer
Joined: May 2010
Posts: 1,472
Likes: 154
From: Kansas
I would doubt its the ecu. Something went foul when you put it all back together. My best guess is the wires you pinched off. Or something got down into those cylinders.
I have never done valve gaskets. You may be looking at trip to a auto shop.
I have never done valve gaskets. You may be looking at trip to a auto shop.
Lead Lap
Joined: Jan 2007
Posts: 683
Likes: 3
From: UK
Before considering replacing the ECU have you pulled the EFI fuse/disconnected the battery for 10 minutes to reset the ECU?
What may have happened is the ECU detected a short circuit to those 2 injectors and removed the injector drive pulse to prevent damage to the injector driver transistors in the ECU.
Performing a full ECU reset may provide a cure now the wiring has been repaired.
What may have happened is the ECU detected a short circuit to those 2 injectors and removed the injector drive pulse to prevent damage to the injector driver transistors in the ECU.
Performing a full ECU reset may provide a cure now the wiring has been repaired.
Driver School Candidate
Joined: Jul 2011
Posts: 17
Likes: 0
From: CO
I would also guess you didn't fry the ECU. You said you checked the wires but how well? You should plug a noid light into the injector harness and run the engine it will light up everytime the ECU sends the signal to fire the injector. You should be able to rent the kit from autozone or pep boys. Crossing the spark plug wires is pretty easy on these cars especially if the wires are old or aftermarket. It will still show spark at the plug but it won't fire properly and cause a misfire. I've seen that a few times.
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