Engine Misfire Question
Der Postmeister
Joined: Sep 2006
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From: Long Beach, Calimexiforia
Compression bleed down times & Fuel pressure test w/ bleed down time.
Compression b/d= immediate =valve
fast = ring
Fuel pressure = high = F/P regulator
Fast b/d = injector hanging open
Compression b/d= immediate =valve
fast = ring
Fuel pressure = high = F/P regulator
Fast b/d = injector hanging open
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Senior User
Joined: Dec 2009
Posts: 374
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From: Portsmouth, Va
Along with the tons of other parts I've replaced on this truck (ymeski knows), I installed a new FPR in June/July when I attempted a trip to North Carolina that didn't quite work out.
I'll double check it. Compression's good and there was no immediate or fast bleed down, but I'm gonna remember that post just for good reference ymeski.
I move on to testing fuel components next. Will report back when I complete those tests.
I'll double check it. Compression's good and there was no immediate or fast bleed down, but I'm gonna remember that post just for good reference ymeski.
I move on to testing fuel components next. Will report back when I complete those tests.
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Senior User
Joined: Dec 2009
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From: Portsmouth, Va
I've tried my best, but I still have not solved this issue. It came about so sudden one day while I was reading vacuum, and hasn't gone away.
Recap
-Very bad vibrations and regardless of RPMs. With no load it smooths out a little as rpms increase. Removed old plugs, #3 and #5 wet with fuel. Truck sounds like a loping V8.
-Idle is steady, vac gauge needle is steady at about 21 in Hg, it reacts to throttle correctly
-Swapped in some injectors I had, no fix. Swapped on new cap, rotor, wires, and plugs, no fix.
-Compression test is good.
-Swapped old ecu back in, no fix.
-Timing is good, and adjusting timing doesn't fix.
-Removed my cat, no fix.
-Only code is an EGR code but engine responds appropriately to using hand vac gauge on EGR valve. NO misfire code.
The only thing I could see now would be the junkyard distributor acting up but not throwing a code. I don't see this as being mechanical.
Recap
-Very bad vibrations and regardless of RPMs. With no load it smooths out a little as rpms increase. Removed old plugs, #3 and #5 wet with fuel. Truck sounds like a loping V8.
-Idle is steady, vac gauge needle is steady at about 21 in Hg, it reacts to throttle correctly
-Swapped in some injectors I had, no fix. Swapped on new cap, rotor, wires, and plugs, no fix.
-Compression test is good.
-Swapped old ecu back in, no fix.
-Timing is good, and adjusting timing doesn't fix.
-Removed my cat, no fix.
-Only code is an EGR code but engine responds appropriately to using hand vac gauge on EGR valve. NO misfire code.
The only thing I could see now would be the junkyard distributor acting up but not throwing a code. I don't see this as being mechanical.
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Joined: Oct 2009
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From: ct
did you ever put a noid light on the the injectors to make sure they are getting a good signal from the pcm? Also most compression testers out there will not give you a bleed down reading of the cylinders, the compression from each stroke is stored in the tester with schrader valves. Two do a proper bleed down test you need to bring which ever cylinder is being tested to tdc on the compression stroke and fill the cylinder with compressed air then watch the gauge for bleed down times. Also it would be good to pull the vavle cover and turn the motor over and watch the rockers and push rods for proper motion. you could have a bad lifter or sticky valve.
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Joined: Dec 2009
Posts: 374
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From: Portsmouth, Va
EDIT-Feel free to cuss me out.
I just came to the realization that I have the firing order wrong. 15, 36, 24 is correct. I know mine right now is 13, 56, 24, which is why 3 and 5 are near dead but in great condition.
I'll walk outside tomorrow and see this, correct it, and she'll be great, but I'll feel like ****. I'm supposed to be good at this by now, but I know I am not the only one who's made this mistake. Blame the creators of the distributor....
I just came to the realization that I have the firing order wrong. 15, 36, 24 is correct. I know mine right now is 13, 56, 24, which is why 3 and 5 are near dead but in great condition.
I'll walk outside tomorrow and see this, correct it, and she'll be great, but I'll feel like ****. I'm supposed to be good at this by now, but I know I am not the only one who's made this mistake. Blame the creators of the distributor....
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