Help needed, dead cylinder

Digitalchaos

Registered User
After a long drive of perhaps 2 hours today, I briefly parked my SC, perhaps 1o minutes. I then drove again to a local store, visiting for perhaps half an hour. Upon starting it after leaving the store, I heard what sounded like a constant miss.

We removed wires to test cylinders, and then proceeded to run a balance test. On what should have been the 4th test (cylinder?), there was no drop in RPMS when the EEC attempted to shut fuel and spark to the cylinder.

What order does the EEC run the balance test, 1 through 6?

I assume this is either a dead 3rd or 4th cylinder, depending on testing order. DIS? Coil pack? What could be behind the cause of this sudden problem?

Also, most importantly, I have no options for transportation, and the vehicle must be driven, in the morning. Could I be risking further damage?

Thank you for your time;
Kevin
 
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Any advice you can contribute for this issue would be greatly appreciated. I assume this is related to the ignition system, but I am unsure how to test the coilpack.

Thanks again..
 
Digitalchaos said:
Any advice you can contribute for this issue would be greatly appreciated. I assume this is related to the ignition system, but I am unsure how to test the coilpack.

Thanks again..
well, i never had to do it on this car, but i presume that you could check for spark the same way you could on a car with a distributor. Take the spark plugs out, and hold the threads against the block, and check for spark across the gap.

On second thought, this could be a real nuisance, with how hard these plugs are to get out.
hmmmm...
In that case you could get a spare plug wire, and a spare plug, and pull the plug wires out at the DIS and test all 6 the same way as listed above. Then you can at least be sure that it's spark and not gas or something.
If you do the test this way you don't eliminate the chance of a fouled sparkplug, or a bad wire.
 
Do a compression test

My 94 SC had a bad rough idle problem for almost a year. I, like you, did the cylinder balance test and #4 and #5 cylinders would always fail the test. So I finally did a compression test. Here is what I found. #1 - 90lbs, #2 - 140lbs, #3 - 150lbs, #4 - 0, #5 - 20 lbs and #6 - 40lbs. I'm surprised the engine even run. So I pulled the heads off suspecting blown HGs. The HGs were perfect. The engine was a Ford reman with 35,000 miles on it and they did use FELPRO HGs. I took the heads to a machine shop and they poured water down the intake and exhaust ports. The intakes were fine but 4 exhaust valves leaked. Guess which ones. So after replacing all of the exhaust valves the SC runs great.

Bottom line: do a compression test. That will tell you what is happening inside the motor.

Hope this helps!

Ed Springer

94 Red SC Auto: 70mm TB, Fresh Air Intake, Stock 90 SC Pulley, Accel 36# injectors, Scorpian 1.73 Rockers, ARP Head Studs, 190 l/h fuel pump, 180° Stat, Raised SC Top, I/C Fan, Headers, Raven Muffler (no cats) with stock resonators, 3:73 Gears, 76 C&L MAF (Gold Tube), Magnacore Wires, NGK Iridium Plugs, MSD Ignition, TRANSGO Shift Kit, Haydon Auxiliary Transmission Cooler, ProTorque 2500 TC, Tokico Struts & Shocks, Royal Purple Synthetic Lubricants, Optima Yellow Top Battery, American Racing 17” Sniper Wheels, Michelin Pilot Sport A/S.
 
wires

i had the same problem driving home from work one day i lost a cylinder i checked the wires pulled them all off and put them back on and the problem was solved. if its the same for you it should be easy if not mabe a bit of grit got passed your fuel filter and clogged one of the injectors.
 
Digitalchaos said:
Any advice you can contribute for this issue would be greatly appreciated. I assume this is related to the ignition system, but I am unsure how to test the coilpack.

Thanks again..

The coilpack going bad should drop two cylinders. I would check the wires and plugs like mentioned earlier and if they check ok, the compression test would be next, like Ed said.
 
NCredSC said:
The coilpack going bad should drop two cylinders. I would check the wires and plugs like mentioned earlier and if they check ok, the compression test would be next, like Ed said.

Thanks for the responses everyone. I was afraid I had previously observed this on the forums, it definately appears to be one cylinder by the complete lack of rpm drop when the balance test disengages a cylinder the forth time.

Like I said, the car has operated with full power and no trouble for the nearly 3 years :eek: :D (its been that long?) I have now owned it, until walking out of Menards and starting it back up. The cylinder was completely dead.

Ed, you mentioned exhaust valves. About 2 weeks ago, my exhaust broke :confused: immediately after the resonator. I have driven it daily like this. Is there any chance that by some function of the change this may have caused that it could have damaged an exhaust valve?

If the coil is in pairs, could the DIS module still be responsible? Do you think an injector could have stopped working this suddenly?

I have made about 5 trips with the car now, nothing further has occured.

Anything else is welcome.
 
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