Cylinder 1 misfire.

[2GEEZEY]

My car is misfiring, when i start it up it idles at reall low vac, idles all over the place and it wants to die.

I figured out it was a misfire, now im trying to figure out why.

Brand new spark plugs and wires, coil looks good too.

maybe my timing jumped a tooth? what could it be?

 

[gofer]

Try unplugging the #1 injector while its idling and see if the idle changes, if it doesn't you found your culprit.

You mentioned new plugs/wires but do you know if your getting spark to that cylinder or are you just assuming because you just recently replaced that stuff? How do you know its a cylinder #1 misfire?

 

[2GEEZEY]

I scanned it.

thanks for the help! If i unplug the injector wont that mess it up?

 

[gofer]

Your not going to hurt anything by unplugging the injectors connector while the cars idling. Thats great you scanned it but have you checked for spark on that cylinder, I suggest you do this first if you haven't.

 

[2GEEZEY]

theres a tick coming from the cylinder #1 which seems to be the plug. I unpluged that injector, and it didnt really affect it that much.

this is weird, all for cylinders are getting spark, coil is firing as it should, injectors seem to be fine. Before it would idle really low and fluctuate up and down, bouncing off the bottom, this is when i heard the ticking. Then after it was warmed up it would idle at 1000k-900k and stay there and only move a tiny bit sometimes.

 

[gofer]

Your post doesn't make much sense and this really isn't that hard to troubleshoot.

How did you check spark?
What happened when you unplugged the injector while it was idling?
Have you done a compression test?​

 

[boostforfun]

If you unplug injector and the idle doesn't drop or get worse, then that injector is bad or its not getting signal. If the idle doesn't drop when unplugging, get a noid light to check the signal at the injector. If its getting signal to the injector, replace injector. Simple.

 

[2GEEZEY]

Compression test came out perfect.

and yes I unplugged the injector, the idle dropped a little bit, but still idled, and sounded like it did when it was plugged in.

 

[gofer]

To be 100% sure its the fuel injector you need to pull the fuel rail and move injector #1 to a different location on the rail, then move that injector to the #1 spot. See if the cylinder misfire follows that injector after you reinstall everything and start it up.

 

[2GEEZEY]

changed the injector....still misfiring..

 

[gofer]

You changed it with a new one or you moved it to a different location on the rail?

 

[2GEEZEY]

changed with a new one

 

[gofer]

Quoting myself from a few posts up then.

How did you check spark?​

 

[2GEEZEY]

I unplugged the wires will it was running and it was arcing in there fine, and i pulled out all the plugs and checked the gap on them.

I forgot i had a autozone giftcard, so i just got some new ones. and threw those in and its still doing it..

 

[Jankenshank]

if your getting spark, fuel and comp your not missing.


you mentioned low vac, possible hose? (this would also explain the erratic idle and wanting to die)

 

[2GEEZEY]

yeah no clue, did a BL test and came out fine. I seriously have went over everyline looking for leaky vac. Im pretty sure the timing jumped, that seems to be the only thing.

 

[gofer]

Your not going to get ONE cylinder misfiring from a jumped timing belt, its just not possible. If your sure thats what it is, a single cylinder misfire, you need to troubleshoot the spark and fuel in that cylinder. I don't care what you've done to check it either, start over...

SPARK
With the car off pull the plug wire and the spark plug out of the cylinder thats misfiring, we'll go with cylinder #1 since thats what you said it was in your OP. After the spark plug is out of head plug it back into the plug wire and hold it against the valve cover, squeezing the rubber boot on the wire so you don't electrocute yourself. Now have someone crank the engine over while your hold it to the valve cover and look for spark between the two electrodes on the spark plug.

FUEL
Turn the car off and pull the connector off the injector then check for resistance across the two terminals, it should read 2 or 3 ohms. If the resistance checks good plug it back in and start the car up.

When you start the car listen or feel the injector pulse on the cylinder that isn't firing as the engines idling, its a TICK-TICK-TICK and should increase as the RPM's increase with the motor. Just remember even if the injector isn't operating you might think it is because you mistake it for the sound of the other injectors.

If it IS NOT pulsing while the engines idling you need to troubleshoot the injector driver circuit. That means pulling out the multimeter again and checking for resistance at your injector resistor box thats mounted on the firewall.

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[2GEEZEY]

thanks so much gofer, i will do that now and see what happens!

 

[2GEEZEY]

okay so i checked the resistor and everything still the same.

Checked the timing, it jumped 2 teeth like what i thought...

 

[volcomsnow245]

Sorry to bring back this thread but I have the exact same problem. I've done everything you've tried except change out the injector in the misfiring cylinder. I measured the ohms in my injectors all of them were fine except cylinder 1 there was nothing does it mean that injector is bad?

 

[Jeremytf12]

Hi, so I'm kinda having a Similar issue 6 bolt in a 2g I'm getting light spark in cylinder one put it on another plug wire and it's good changed the plug wire still light spark in that on of the coil do you think that's the coil pack going bad?

 

[spyderdrifter]

Replace your coil and plug cables.

 

[Jeremytf12]

Already tried that

 

[spyderdrifter]

Replace the PTU.

 

[Jeremytf12]

What's the ptu?