Thoughts about driving on 7 cylinders for 130 miles?

Hi all, 1987 951 with 2000-ish LS1.

Short question: Would driving the car 100+ miles on 7 cylinders hurt anything? Engine shaking like a mofo.

Long story: My car has been stranded for over a week now in a tiny farming town in Central CA about 130 miles from my home.

First the serpentine belt broke and tore the lines to the heater core so the engine was given an unplanned steam bath. So we put a new serp belt on the engine, and did a loop/return for the heater lines.

Then, a couple hours of driving later, the engine simply died, and we saw that the fuel pump was getting no power. So now the fuel pump is hooked up directly to the battery with a manual switch.

That setup works fine, but when we got the car started it was running crazy rough.

It turns out the #3 coil is not getting power. Zero volts from from the ignition harness.

The local mechanics in this little town are all hotrod/lowrider type guys who love the idea of a chevy engine in a 951, but all they seem to be really busy and it's been over a week now and I think I need to get the car home to fix it.

The mechanics seem to think it wouldn't hurt anything to drive the car home on 7 cylinders.

What do you guys think?

when fuel isn't getting ignited that means its getting washed into the oil which affects your viscosity and lubrication. I don't think it's an ignorable thing for that long of a drive of fuel bathing your oil.

every once in awhile i get stranded on a failed coil in my daily driver which is a turbo'ed scion frs (gt86), and the one time i got caught way out of the city i limped it back home for 20km and with my aggressive tune that dumps fuel to keep on top of any detonation my oil smelled mighty premium after that.

immediate oil change as well change out the crappy aftermarket coils. will never buy expensive "quad fire" coils again. bunch of snake oil, tonnes of research into oem products and on coils i'm hard pressed to think there's a reason to stray from what's intended.

in summary, i think it's too far. i'd see if you get voltage at the ecu pin and if you do jimmy a wire to get the control signal to that coil so you can drive home on all 8 firing.

also have you swapped a coil to make sure the problem doesn't move? if it moves, it's the coil and then swap that out and you might get your 8th back real quick.

If you do, I'd unplug the fuel injector for that cylinder. Then it's just pumping air. No fuel, no spark.

Thanks guys! The mechanic said to unplug the harness connector to the coil, he said there'd be no fuel then.

And yes, I installed a new coil and there is no power to it.

And I agree, I should have the mechanic chase the no voltage from the coil connector back to the the ecu to see where the problem is.

unplug the injector for that hole. the pcm isnt smart enough to shut the injector of when the coil isnt firing.

are you missing the 12v switched power to the coil or the 5v trigger signal? if your missing the 12v switched power its an easy fix, get another coil harness. the coil harness has one 12v wiring at the 8 pin connector and splits in the coil harness, if it has 12v on all but one coil on that side its a problem in the coil harness. the 12v doesnt come from the ecm, it comes directly from a switched power fuse in the efi harness.

That is very helpful, thank you.

From what I saw when I was up there last week, one of the previous mechanics was getting zero volts from the coil connection. I think, but am not sure, zero volts from both the switched power and the trigger signal.

I did get a text from the current mechanic this evening, he said that there wasn't enough power to one of the coil banks and that once they added power the miss went away. He said he could do a "manual jump to add power from the other side" as a temporary fix to get the car home.

Still waiting on confirmation that the manual jump works.

Well, the mechanic says it's running. So I'll go get it tomorrow.

Then I'll start going through the harness to see if I can figure out what the problem is.

I wonder if some of the harness wires got water damaged when the heater core hoses got torn off and the engine got steam cleaned on the side of the freeway?

Well, for those that are following this drama, the car is home, finally!

The fuel pump is still powered directly from the battery by a manual switch because the fuel pump isn't getting power.

The last mechanic spliced in power to the driver side coil bank to solve the miss on cylinder 3 which previously was also not getting power (actually the whole bank was getting 7 volts or less, as sharkey correctly suggested above), and with that I was able to get got home.

But...during the entire 2.5 hour trip home the turn signals did not work.

And then, just a block from my home, they started working again. wth?

And...today I drove it while doing some errands, and at a stoplight the engine suddenly died. As far as I could tell, there was no power to anything.

I got out and lifted the hood, and as I stood there I heard  the radiator fans turn on and, lo and behold, there was power again!

I was then able to start the car and get it back to my home with no problems, but of course I am very frustrated.

Anyway, as far as I can tell, the start of all my problems was a week before when the serpentine belt broke and tore off the heater core lines. There was a huge cloud of coolant steam that poured out from under the hood. I've never seen anything like it.

I'm assuming the car did not appreciate getting all it's engine wiring steam-cleaned?

Of all things car-related, electronics are the most difficult for me.