As the title states, my 80 has had this seemingly totally random cylinder 6 misfire. It comes and goes as it pleases, no real determining conditions. Truck still has egr. I have replaced cap, rotor, plugs and wires, fuel pump, compression tested (within 8psi across the board). I am losing my mind with this thing. Somedays it will run flawlessly, others like today, it just will not go away. Occasionally i can restart the vehicle during misfire, and it corrects itself. Wiring tests good, good spark. Replacing the fuel pump helped for a long time, but it has restarted with the miss again, which leads me to believe it is a fuel delivery issue. Im torn down to injector or ecm, but maybe the mud gurus can give me some more insight as im new to the 80 series world.
Intermittent cylinder 6 misfire- 97 1fzfe
- Thread starter TaterGt
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- #2
Jesus i just realized how jumbled that is. Now that i have sat down, let me re-explain.
P0306 consistently.
Occurs at totally random times with no real pattern. Will appear and disappear while driving. Will go lengths both with and without misfiring.
Have replaced:
Plugs
Wires
Cap
Rotor
Crank position sensor
Fuel pump (helped for a while, miss has returned)
Compression has been checked and determined to be good.
I am thinking its an injector, but before i devote the energy to yankimg this intake, i wanted to see what the mud guys had to say. I searched extensively and read many missfire thread, but did not find one that met my symptoms.
P0306 consistently.
Occurs at totally random times with no real pattern. Will appear and disappear while driving. Will go lengths both with and without misfiring.
Have replaced:
Plugs
Wires
Cap
Rotor
Crank position sensor
Fuel pump (helped for a while, miss has returned)
Compression has been checked and determined to be good.
I am thinking its an injector, but before i devote the energy to yankimg this intake, i wanted to see what the mud guys had to say. I searched extensively and read many missfire thread, but did not find one that met my symptoms.
inkpot
SILVER Star
I had a similar situation on my #1 cylinder. No coolant lost, no change when wiggling the main wiring harness above the injectors, tested and/or replaced just about everything. Tried a fresh set of injectors, no help. At 190,000+ miles the original injectors were all at 95% or better on the -pretest. They were all at 99% or better when I put in the fresh ones. No change. Ended up being the negative/ground wire from the #1 injector that goes back to the ECU. There is a single wire that branches out and supplies a constant 12 volts to all 6 injectors. The ECU grounds each injector separately to trigger them. That wire from #1 was heat damaged up around the heater valve and down around #5 injector also. It was a royal pain to figure this out as the wire was bad in several locations. Put a meter on the lead from your #6 injector plug and check continuity to the corresponding pin in the clip on the ECU, after you remove the plug from the ECU. Wiggle the harness as much as possible and watch the meter for changes in resistance. Unbolt the heater valve and loosen the harness from the firewall so you can really get mad at it. Wiggle, twist, push, pull, whatever it takes to make sure that there is no damage inside of that big wiring bundle. It is a lot easier than pulling the injectors. Of the dozens of 1fz rigs I have worked on, only ONE ever had a bad injector. If it wasn't for Tools R Us, I don't know if I would of ever figured my rig out.
- Thread starter
- #4
So interesting tid bit more info, this has all happened this evening.
I had to make about a 70 mile round trip tonight to pick up some furniture. The truck misfired the vast majority of that. I stopped with the wife and kiddo to have some dinner. Parked the truck missing, truck sat for roughly 30 minutes. Came outside to leave, no miss for about 5 minutes, then it returned and remained the 20 minute trip home. I have been home about 20 minutes now, went outside to move the furniture, fired up the truck and no miss again. This is driving me insane.
Inkpot, i will be taking your advice and doing some digging into that. I dabbled with the wiring some and did a small relocation to get the harness away from the egr tube. The wiring appeared to be ok, but i will reinvestigate for sure!!!
I had to make about a 70 mile round trip tonight to pick up some furniture. The truck misfired the vast majority of that. I stopped with the wife and kiddo to have some dinner. Parked the truck missing, truck sat for roughly 30 minutes. Came outside to leave, no miss for about 5 minutes, then it returned and remained the 20 minute trip home. I have been home about 20 minutes now, went outside to move the furniture, fired up the truck and no miss again. This is driving me insane.
Inkpot, i will be taking your advice and doing some digging into that. I dabbled with the wiring some and did a small relocation to get the harness away from the egr tube. The wiring appeared to be ok, but i will reinvestigate for sure!!!
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Most often a dead injector is dead, intermittent is usually electrical. Get one of these; https://www.amazon.com/Lisle-52500-Mechanics-Stethoscope/dp/B0002SQYSM Put the probe on the body of one of the good injectors, listen to the even click it makes. When the miss is happening, listen to the suspect injector, if it's clicking, not the problem, if it's not clicking found the problem.
Start doing the electrical tests. My quick and dirty first test; when missing, move the wiring pigtail the comes out of the harness to the injector around. If you can move it and make it miss, move it another way and have it run, it's likely there is a broken wire/bad connection in the pigtail. by doing this can often pinpoint where the problem is.
Start doing the electrical tests. My quick and dirty first test; when missing, move the wiring pigtail the comes out of the harness to the injector around. If you can move it and make it miss, move it another way and have it run, it's likely there is a broken wire/bad connection in the pigtail. by doing this can often pinpoint where the problem is.
Check wire harness behind glove box at ecu,
Buy some new adhesive thermal tape and take the old stuff off the main wire harness where it goes by the EGR... Inspect those wires for any melted plastic or damage.
Did the OP figure this one out yet?
I just got the P0306 code and the car is shaking slightly.
The PO had the engine rebuilt due to #6 cyl HG problem. He had some thermal tape around the wiring loom in that location.
I won't have any time to look at it till this weekend.
I just got the P0306 code and the car is shaking slightly.
The PO had the engine rebuilt due to #6 cyl HG problem. He had some thermal tape around the wiring loom in that location.
I won't have any time to look at it till this weekend.
I had a similar issue with #6 misfires, and it was due to corrosion on the #6 connection. My heater valve had been slowly leaking (on my to do list, and now done) and built corrosion on my #6. You may want to unplug your #6 injector and confirm it is corrosion free
How do you get in there? From under the car? There is so much stuff up on top of the engine I can only fit a pencil through.
I ended up just pulling all my injectors and sending them off to rc engineering to get cleaned. So I am of no help there. Far right injector was #6.
Well, it appears my #6 injector died. 500 ohms across the leads. Also have a seeping coolant leak above it, thought the connector itself does not appear to be corroded. Could the coolant have killed the injector? I assume it cannot be repaired? Recommendations on where to purchase a replacement? Local dealership is $126. I will pull the others and have them cleaned while I have everything apart.
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Original lasted 22 years. So, $126/22 = approx $6 per year. I'd buy a new OEM one...
There are refurbished injectors for $25 - $40, up to you if you want to save some money.
My #6 failed a bunch of years back, replaced with new OEM, not had a problem since. I did send in the dead one as a 'core' to rock auto and got a refurbished one back as a spare for $25 or so.
Here's my writeup when I replaced mine -> Injector Service
cheers,
george.
There are refurbished injectors for $25 - $40, up to you if you want to save some money.
My #6 failed a bunch of years back, replaced with new OEM, not had a problem since. I did send in the dead one as a 'core' to rock auto and got a refurbished one back as a spare for $25 or so.
Here's my writeup when I replaced mine -> Injector Service
cheers,
george.
COYS
SILVER Star
I'd just get new OEM injectors myself to avoid having to send back and forth. Love your write-up. Do you have part #s handy for all the stuff you replaced with new? Thank you.
Thanks, George. Am ordering a replacement that should be here Tuesday. No one seems to stock them. I will send the core into Rock Auto to get a spare - thanks for the idea. I'm going to replace the remaining hoses on the firewall (just to the left of the injector connector in the photo, which is where the weeping is coming from.
Which seals did you replace with OEM after you received the injectors from RC? Appears there is a 23250C (9048013005 ) and 20250B (9030107001 (9030117001)) grommet and ring on the rail side of the injector and 23250D grommet (can't find the PN), 23250B oring (same as outside), and 23291 (2329141010 (2329102010)) vibration insulator on the head side of the injector.
I assume that grommets in the intake manifold I can't find the PN for will be hard and need to be replaced?
Thanks,
Rod
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I ordered new OEM grommets, orings etc, but can't remember the part numbers. Likely I ordered them from Cdan prior his slack retirement - at which point he would have just sent me the right ones without me trying to figure it out
Yeah, I'd replace them just to be safe. I had sent my other 5 out for R&R and they came back with new grommets, orings, but kept them as spares, preferring to use the OEM ones I bought to be 'safe'.
Make sure to lube all of the seals etc before pushing into the rails etc (you don't want to pinch them -> leaks). I used dielectric grease (silicone) as lube.
It's not a hard job, just lots of steps and you want to take your time to get them right. Given you have a bunch of stuff disconnected, probably not a bad time to replace the fuel filter unless you've done that previously.
Also, I'd be triple checking the condition of the plastic heater valve - that POS if original is likely on its last legs anyway (brittle and waiting to break).
cheers,
george.
I ordered new OEM grommets, orings etc, but can't remember the part numbers. Likely I ordered them from Cdan prior his slack retirement - at which point he would have just sent me the right ones without me trying to figure it out
Yeah, I'd replace them just to be safe. I had sent my other 5 out for R&R and they came back with new grommets, orings, but kept them as spares, preferring to use the OEM ones I bought to be 'safe'.
Make sure to lube all of the seals etc before pushing into the rails etc (you don't want to pinch them -> leaks). I used dielectric grease (silicone) as lube.
It's not a hard job, just lots of steps and you want to take your time to get them right. Given you have a bunch of stuff disconnected, probably not a bad time to replace the fuel filter unless you've done that previously.
Also, I'd be triple checking the condition of the plastic heater valve - that POS if original is likely on its last legs anyway (brittle and waiting to break).
cheers,
george.
Yeah - I really miss just having Dan send me what I need. Have not found a replacement for that yet...
Replaced the original heater valve about three months ago, right after I replaced the radiator and right before I replaced the water pump.
I did not replace ALL those firewall hoses (including those in the photo coming to that dead ended piece of pipe) because I became just too frustrated trying to access them. I did the valve cover gasket, spark plug wires, gaskets, wires; distro o-ring, cap and rotor this spring.VSV and etc were replaced a couple of years ago, so I have done the plenum before. Looks like I get to do it again.
Just don't want to pull those injectors and have a bunch of brittle grommets in the intake manifold that I don't have replacements for. Been on the phone five times today with various dealerships trying to find those grommets but no luck so far. Did the cleaned injectors come back with those intake manifold grommets, orings and vibration isolators or just the ones on the fuel rail side?Did you replace the vibration isolators with new OEM as well? They are about $3 each.
I don't mind doing PM on the truck when I want to, but this year has had a LOT of "got to" items (like this injector) that are beginning to wear on me.
My neighbors have been commenting on how often my hood has been up lately.I also managed to smash in my rear lift gate on Rubithon and am now looking find a used one. Happy happy...
Cheers,
Rod
