Missfiring 93 J30 HELP!!

[philsShelby]

So I pulled off each one of the coils one by one to see what cylinder wasnt firing correctly and I found it. It is the middle driver side. So I swapped the plug and coil from the first one(good one) into the middle driver side and it still has the same effect. What could this be? It still misfires in the same spot.. Any help would be appreciated. Thanks Let me make sure u know what I am talking about. when pulling off coild from middle driver side nothing happens car dosent lower in IDLE RPM. Every other one except the middle does down when pulling coil!!! Thanks again..

[philsShelby]

ran the car without middle coil on there and had no effect. When reving the car it clears up after 3500 rmps. please help

[yodawill2000]

Sounds like the Injector.Ohm it out.Should be in the 12 Ohm range.Just pull the connector off and get a reading between the two contact points on the injector.

[philsShelby]

I will give it a shot and see how it goes.

[philsShelby]

Well I bought a mechanics stethoscope and all of the injectors seem to be working just fine. Im not sure what else it could be. The compression is where it is supposed to be in all of the cylinders. That one still seems to be acting up a bit. Do you think If i changed all of the plugs out it would make a difference? Input please!!!

[philsShelby]

Well, changed the plugs for the hell of it and didn't do a thing. i used the stethoscope again and they all seem to be making the same tickinh sound. Is there anyway that it could be a clogged cat or somthing like that?

[GerryO]

I wouldn't rely on listening alone, as there are a lot of clicking sounds under the hood and the difference in sound of a working versus a non-working injector (using the screwdriver listening method) is VERY subtle.

I also doubt that the injector is clogged. Things only appear to clear up at high rpms, similar to how the new gas saving programs work with six cylinder engines operating on three or four cylinders at highway cruising speeds.

Check the resistance reading across the two terminals of the suspect injector/cylinder. Just for drill check 'em all. The readings will probably be in the range of 11-12 ohms.

Swap a suspect coil pack with a known good one and see if the issue follows the suspect coil pack.

Plug a noid lamp into the injector harness connectors in order to see if the injector is getting the proper signal from the ECM.

[philsShelby]

i already tried to swap the know problem coil out, but it still had the same issue. I will give the injector the test. Im not 100% how I can do that. I was a little confused by that. Thanks

[GerryO]

i already tried to swap the know problem coil out, but it still had the same issue. I will give the injector the test. I'm not 100% how I can do that. I was a little confused by that. Thanks

So the problem stays with the cylinder.

With the ignition and engine OFF, using a voltmeter set to measure resistance in the range of 10-14 ohms, remove the harness connector at an injector to access the two pins on/in the injector. Contact one meter lead to one pin and the other lead to the other pin at the same time to measure the resistance of the injector. Polarity doesn't matter.

Simpler and easier than everything you've already done, and maybe that's part of the problem. VERY conclusive. Measure a few that are working properly and the one that is not.

I'm beginning to think J30s have only six cylinders/injectors so a different one can't possibly fail every day of the week (one day of rest/peace), when they reach a certain age/mileage.

Modified by GerryO at 8:50 PM 7/3/2008

Modified by GerryO at 8:52 PM 7/3/2008
Modified by GerryO at 8:53 PM 7/3/2008

[philsShelby]

Yeap the problem stays with the cylinder. The car ran the exact same way with the coil off/on(bad cylinder). I am going to give it the test and I will let you know how it goes. Thanks again for all of the help..

Phil

[93jdirty']

For the hell of it put a bottle of lucas injector cleaner with a full tank of gas and see if it goes away. This saved one of my injectors but sometimes they just wont come back.

[yodawill2000]

Redline S!-1 is the best now that BG44k took out the strong stuff they used to include.But before buying it I would ohm the sucker.If its out of spec all the cleaner in the world wont fix it.

[philsShelby]

I already tried the lucas method this past week, no go. I still have to ohm out the injector today. It is still early yet; I am in Hawaii. I will update in a bit.

[philsShelby]

So I did the old ohm check and there was no reading on the bad cylinder. When I checked others they all read around 12 or so. I am in the process of putting a new injector in. I have the screws out, but need to pull injector out. I am letting it soak for a while. I will let ya know how it turns out. Thanks..

[philsShelby]

So yeah, I put the new injector in and while I was jamming it in the fuel rail, I cracked the outside of the injector. i ran it for a while with it in there and it was running much better, but it would die becasue the fuel would leak out of the cracked injector. Now i have to buy another one. that is 200 bucks down the drain.......

[GerryO]

Use a bit of Vaseline to lubricate the two new o-rings that you'll install on the new injector. I was able to seat all six of mine by hand, when installing them with the fuel rails out of the car.

Big ouch and careful with those fuel leaks! Is everything than much more expensive in Hawaii and how many J30s are there in our 50th state?

[fourdrinie]

You're still way ahead of taking it into the "stealership".Take your time, read the previous posts on installing the injectors...there are many of them!

[yodawill2000]

Ive been using the Autozone so called OEM injectors for 89. bux ..Ones been in for two years o so ,, No probs at all.

[philsShelby]

Well good ol Checkers let me exchange it for free. So no worries there. The car runs like a champ now, no more misfire. I am not sure how many J's there are here. There is one for sale for 5700 here on base. I just want to say thanks again for all the help. I sure never want to do that again. I can take all of my injecotrs off of my cobra in about 20 minutes, damn J30.

[yodawill2000]

Now now .. heheEvery injector can come out with ease if you know the dremel trick

Run the Mileage up to 170 K on the cobra and see what ya got