Thread: Cyl #4 No Go...

Alright so I've been getting CEL #304 = Cylinder #4 miss-fire.

I pulled the spark plug, it what completely black and fouled.

While car is idling, when I pulled the #4 wire completely out and the car idle did not change.

I did a compression test, about 120 psi all the way around (this is a DET so lower compression).

I tried swapping out the spark plug with another one, but it doesn't seem like it did much, but I will see for sure tomorrow if Cel # 304 comes up again hehe.

Another thing that I noticed is the fact that every single spark plug that I would screw in would have the ground electrode perfectly facing the intake side. Maybe the spark plug is not going into the cylinder all the way in thus not in the fuel to give a good spark.

Either way the car has much more pre boost torque then it did when the sludge monster was in, the only way I noticed something wrong is by the weird idle jerking

Also, I must mention that I am running stock 99 ECU, with a stock DET (370cc injectors). I don't recall having this problem for the first week the car ran thought.

Sorry for the long post and thanks for looking

Sounds like it isn't firing, make sure spark is getting all the way to the plug. I am sure you have though. Next step would be to clean the plug and put in a new one. Then try disconnecting the injector for that cyl and start the car. It will run really rough but it won't foul with the injector not getting power.

Then plug in the injector and see if the engine smoothes out. Maybe there is an injector problem? Process of elimination I guess.

Its probaby the #4 injector failure. Ohm Test the injector across the pins per FSM spec. Replace the injector if out of spec.

Also as a test for the spark plug wires, swap the #4 wire with the #3 wire. If #3 stops firing, then you know your #4 wire is fried.

If the idle did not change it is going to be one of 2 things.

Bad inj or stuck piston rings.

I would first start with getting a bottle of Marvels Mystery oil. Put it in all 4 cylinders by removing the spark plugs and let it sit over night. You have a turbo motor so you will have to put alot in each cylinder to make sure the oil spills over the top of the piston, since the DET piston has a large dish.

In the morning get a towel and put over the spark plug holes without the sparkpugs in to make sure not to hydrolock the motor and crank the motor. This will get whatever remaning oil out. You want to use a large towel or shirt and put over the open spark plug holes so that the oil does not go all over the hood and engine bay. Put in spark plugs and start the motor and see if all is well.

Check back in and see if that works.

If not we will do a wire to injector test to make sure the wires are pulsing properly. if yes then we will do an injector test.

Thanks for the suggestions guys

Alright so the injector seems to be pulsing fine because the cylinder was wet when I pulled the plug out this morning. I was blowing a massive amount of smoke too, thus fuel was being unburnt and running into the exhaust.

I talked to my coworker and he suggested something that makes perfect sense, take the plug out and keep the plug wire plugged up and see if there is a spark going from plug to ground.

I replaced the plug last night and replaced the plug wire, and the car ran even worse today. So I'm thinking before it was bad because of being rich, and now the cylinder is actually not working because of a weak spark.

I'm going to test it out right now while on lunch break



Thanks for the tip , I actually did that when I first got the motor, and the cylinder does seem to move, when I did a compression test it moved from all the way down to all the way up. I think it says 54c on the pistons hehe.

I say the injector is stuck open

Alright I pulled the spark plug and tried starting the car, GAS WAS EVERYWHERE!

It's like the injector took a piss after drinking all night!

I could not check to see if the spark plug had a spark, but as I was driving home, I did notice that the O2 sensor was stuck in Open Loop, son of a gun, it no wonder, it has been just throwing fuel in. Not to mention that the timing is probably too low, thus the ECU is dumping fuel left and right.

I think the O2 sensor went capoop when I did the compression test and it got too much fuel all over it. Luckily I used my old sensor not the brand new 15727

I just replaced the plug, and wire, now resetting ECU and will try to go back to work, if not then the car will have to sit until ECU arrives

How can I make it close, because it seems exactly that!

But I did hear clicking from it while motor is running, pull the wire, clicking goes away, put the wire back in clicking comes back hehe.

To fix it, replace that injector. Its dumping fuel.
A leak-down test will prove it by simply removing the rail and turning the ignition switch to ON w/o starting the car..
If any injector leaks fuel, you've found the problem.

Oh.. I would put a towel under the rail during the test, to catch the fuel.
Wouldnt want u to blow up yourself!!

^^^

Yep that makes sense. I'm probably going to hold off on driving the car until the ecu gets here and I can get some kind of a DET tune on it. After that will start replacing things...