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Discussion Starter #1
I have a 6mge with around 100k miles. Compression is good in all the cylinders. Cylinder #4 is dead however. When I pull the plug, it makes no difference to the engine. I noticed it when the car started slowly misfiring and losing power. I took the distributor off to take a closer look at the injectors and when I put everything back together it was still sluggish except this time #4 was dead. I took apart the fuel rail and found yellow flakes that were jamming the injectors which would have caused my initial sluggishness. But still cannot find an answer to the dead cylinder.


It has a compression of around 160psi. New plugs, new wires, new distributor cap & rotor, injectors cleaned & tested by injector company (and i swapped the original injector for #4 with another one), I know its getting gas because the inside of the cylinder looks wet and the spark plug has black juice over it. I tested the injector's wire for #4 and the wire is not cut. I really do not know what is causing me to have a dead cylinder at this point. Anything helps!

oh and no I have not done a leak down test yet.
 

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Whistles
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Tried new plug wire?

If you have good static compression and fuel, ignition is the only thing left.

Edit: I see you added new plug wires.
 

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Take the spark plug out and ground the threads on some metal, start it and see if it's actually creating a good spark. You can also leave the spark plug wire close to some metal and see if it will arc. Inspect the distributor at the #4 connection, and inspect the rotor.
 

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Don't assume that just because parts are relatively recently purchased that they are good. At this point, some of the new Supra parts you may be getting have been sitting in a hot, humid warehouse for 30+ years and some of the recent manufacture are coming off 30+ year old tooling. Its just one of the challenges of keeping an old car.
 

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Discussion Starter #5
Yeah I did all of the above. I also swapped around parts that were working still no difference. Has good spark. Do you guys think one of my valves may be stuck open? Id have to do a leak down test next. As far as timing goes, i havnt check it with a timing light but its not that off. I dont think that would cause an entire cylinder to go out but maybe i should invest in a timing light as well.
 

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Take the #4 plug out start the engine and make sure you ground the thread and see if you have spark. Next I would take a meter and make sure you have 12V at one of the injector terminals on that cylinder. Then I would switch injector positions with a good cylinder. FYI If the plug is wet with fuel its not going to make any spark. If all that fails then I would pull both valve covers and looks at the valves on that cylinder to make sure a lifter hasn't collapsed and the rocker hasn't fell off.
 

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I'm sure you've double-checked so go ahead and triple-check that you're running on five cylinders. You could actually be running on four if you accidently swapped plug wire #four with #three
 

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Since you have 160PSi compression, Use a real spark tester to verify spark. If you have spark, and you ave the wires in the correct firing order, then you do not have the proper amount of fuel if any. In this case, I suggest using a real Noid tester to verify the injector clip is trying to fire the injector. If that is firing, then it sounds like a bad injector.

https://www.amazon.com/Performance-Tool-W89500-6-Piece-Light/dp/B0002KO4I2

If it isnt firing, make sure one side has +12v. If not, a wire is bad somewhere between the injector resistor and the injector. If +12v is there, then a wire is bad between the injector clip and ECU as they are batch fired in sets of 3. If the injector driver was bad, or resistor had a bad output, 3 cylinders would be dead. Not just 1.
 

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Discussion Starter #10
Ok so i was testing the voltage and im getting .17 from the injector #4 (the bad one). But i wws also getting around the same for one thats working?? I made a diy led strip noid light and that wont light up either. Tried to flip the polarity and still no work... meh. Am i supposed to ground the light out on the car battery?

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Did you say .17 on the good and bad injector? What's up with that? Faulty tester? You already said the plugs had black juice ;it, so I assumed you meant it had gas on it. Smell the plug. You hopefully don't have coolant or oil on it as well as gas. You can try putting a lighter to a wet plug, well, I saw an auto tech try it so not sure if it works,.
 

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Discussion Starter #12
I checked again this time grounding the tester on the negative terminal of the battery and got 13-14 volts. So i guess wiring is not the issue. Idk what to do now!!! Ugh.

Oh and just wanted to clarify that all my injectors were cleaned and tested by a local injectoe company. I also swapped the one from the dead cylinder to cyl #1 and it made no difference.

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Read my edited post regarding the plug
 

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Remember Silver MK2 and the valve covers
 

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Discussion Starter #16
Ok, I'll put that on my bucket list of things to do next. I've never taken off valve covers before. How should I know if the valves for cylinder #4 are messed up or not? Anything I should look out for? Thanks.
 

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Whistles
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If the cam lobes are gone, it's not the valve's fault.
 

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The injector driver grounds the injector to fire it. You should have 12v at the injector. The resistor is to limit the current to prevent overheating of the solenoid in the injector.
 

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Discussion Starter #19
Wait a second... am i supposed to have 12+ volts from one of the two wires that go to the injector? Because if i ground my multimeter to the battery and connect the positive lead to the injector wire.... both of the injector wires show the same voltage (13.8). Could the positive be touching the ground somewhere in the harness causing both wires to shoe the same voltage?

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Make sure you are doing this test with the engine off and key on. There should be battery voltage on one pin. It's a pull to ground on the opposite end.
 
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