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Injector problem?

R

redXJlimited

NAXJA Forum User
Location
Cleveland (Eastside)
I've had a Cylinder #1 miss fire code for the last 3-4 months, truck is running fine with maybe an odd idle once in awhile, but basically runs well.

Shortly after the original CEL came on, had the code read at AZ, then I changed the plugs along with 8mm wires, cap/rotor, MSD 8228, 62mm TB, and numerous treatments of Techron, Lucas and Seafoam. Code went away for a week or so. but came back, and basically stayed. Still runs well, but also still have the CEL. Codes been cleared a few times(during treatments) but comes back.
Here are the plugs after about 3 months. Left is the #1, center is #2(the rest look the same), right is one of the old plugs(not sure if its #1, but they all looked about the same)
DSCN2077.jpg


Im not sure what the color of #1 indicates(the problem cylinder), but it looks like #2(and the rest) indicate a normal lean condition?

Any suggestions? My injectors have about 130k, no leaking, but might be time for replacement?
 
may be totally off here(just a noob) but what color is your coolent? We see redish plugs like that every now and then when the head gaskets are leaking into the cyl.
 
Hi spedly,
Well my coolant looks great as I just replaced my water pump a couple of weekends ago ;) The old coolant looked fine, atleast it didnt alarm me of anything. Ive also been checking the engine oil based on your thoughts, which looks good also.
My 98 head was remachined and placed on a low mile 96 block about 15k ago after chipping a piston. This Cylinder 1 miss fire started about 2k ago.
As mentioned the thing runs great, its just this damn CEL, and funky colored plug.
 
I was leaning toward coolant migration into the cyl. as well, however detergants in the gas (Techron, Seafoam, etc) can also cause a brownish deposit. If that cyl isn't always fireing, it may just not be reaching and maintaining it's self cleaning temp. I would run a compression and a leak-down test on the thing and verify everything is sealed up tight. I would also tighten the intake nots-n-bolts, as an intake leak can cause a lean misfire that may only manifest itself under certain temps and conditions (often, but not always, if yoe rev it and quickly close the throttle, you can hear a poping from an intake leak)

dunno if it helps, but just a thought
--Shorty
 
It was just a shot in the dark. I don't have much jeep experience I come from a land rover background and its a common problem with them. also coolent in the cyl. isn't going to show up in your oil. it would be being burnt causing the orangeish plug. but like shorty said if its not fireing it can cause that too.
 
spedly said:
may be totally off here(just a noob) but what color is your coolent? We see redish plugs like that every now and then when the head gaskets are leaking into the cyl.
Click to expand...

was my first thought as well..
WELCOME-- posts 1&2!!
--Shorty:wantyou:
 
Thanks for the info guys,
A buddy at work has a test guage, hopefully he remebers to bring it in tomorrow(he forgot today).
I'll check the intake bolts, there was work done in that area 15k ago, so that is a good idea.
I'd like to swap #1 and #2 injectors to see if the problem follows. Not something I've done before, more trouble than its worth at this time?
 
Did the compression test today.
Removed all plugs, coil wire, unplugged injector wiring.
#1 125
#2 155
#3 170
#4 170
#5 165
#6 160
The first test was only half warm, so I did it again after getting to full temp.
#1 125
#2 150
#3 165
#4 170
#5 165
#6 155

Seems #1 is a bit below specs... Any thoughts?

TIA
Tom
 
I would replace the number 1 plug and plug wire. Then also swap the number one fuel injector with one of the others and note which one it was you changed, swapped, then clear the codes, drive it and check it again in about 2 weeks.

What is MSD 8228?

Also why are the exterior insulators discolored black like that? What ever that is, is not good from the looks of it, they should be clean and white. You could be loosing spark to ground across that black stuff on the outer insulators. Is it oil, or are they burned somehow?

I would not worry about those pressures at this point, they still OK, still within specs. If you are getting too much fuel from FI #1, it might explain the lower pressure in #1, and the plug deposits.
 
That 125 is troubling, but I would do a wet test before you go freaking out. If the injector is over fueling it could be washing down the cylinder walls. Without oil on the walls the rings can't seal as well so the number will be off.

I would also swap the injector and see if the code follows the injector.
 
Thanks for the comments Lew,

I found a deal on some new injectors, so I am going to swap them all out shortly.
I also want to do that wet test, I have some general maintenance this weekend todo, so I will get that done also.
 
put a small dose of oil into cyl #1 and retest-- if the reading comes up a bunch, you're lookin' at rings being worn (probably caused by injector leaking)
-- if it doesn't change, you are either lookin' at a valve not seating, or a head gasket leaking into a coolant jacket.

--Shorty
P.S. "eastside of Cleveland"-- anywhere near Garfield Heights?? I may be in your neck-o-the-woods in a week or two!:moon:
 
redXJlimited said:
Thanks for the comments Lew,

I found a deal on some new injectors, so I am going to swap them all out shortly.
I also want to do that wet test, I have some general maintenance this weekend todo, so I will get that done also.
Click to expand...

I hope its a deal on NON-OEM, new injectors! I have about 18 OEM, junk yard injector pulls that I use for paper weights now.
 
Shorty said:
put a small dose of oil into cyl #1 and retest-- if the reading comes up a bunch, you're lookin' at rings being worn (probably caused by injector leaking)
-- if it doesn't change, you are either lookin' at a valve not seating, or a head gasket leaking into a coolant jacket.

--Shorty
P.S. "eastside of Cleveland"-- anywhere near Garfield Heights?? I may be in your neck-o-the-woods in a week or two!:moon:
Click to expand...

Yeah not too far, I'm north closer to the lake. You cant be going to Garfield for vacation? ;) What are you up to?
 
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