1988 744Ti 175K? M46

Son on the way to work during a snowstorm this morning slid into a curb landing fairly flat against the passenger's side wheels (from the looks of the wheels).

Drove the final quarter mile to work from there and the car started cutting out. Stalled and wouldn't restart.

Some time later by coaxing and feathering the throttle it would finally start and I was able to get it to about 2500 rpm and could hold it there. Thinking it might drive if I could keep the RPM's up I took off down the street only to have it start to break up and slowly lose cylinders until it was only running on one before it died.

At that point it would not restart. Only an occasional pop when trying to start.

Everything looks normal under the hood. Distributor cap is in place. All the hoses involved with the intake are in place. I was running out of light and standing in freezing rain at this point so there was not much incentive to linger at the scene.

Did a little tap dance with a screwdriver handle on the fuel injection relay as well as the radio suppression relay with no effect. I can hear the pumps cycle when turning the key on.

I did try disconnecting the AMM simply because it was there and of course it made no difference.

I was unable to determine tonight if I was dealing with a spark or fuel issue and it has hints of both in its behavior.

So I am looking for ideas on things to try. The rain is supposed to turn back into snow so my current mood calls for a few gallons of gasoline and a match, but we need the car.....

Suggestions on what might be amiss in association with the impact with the curb?

Thanks as always.

Randy

What components other than the coil do I need to look at to strive for a blue white spark?

I put the towbar on the car today and towed it home.

I verified that the main pump was running but when I put a pressure gauge on the fuel rail it registered zero. Tried to run fuel into a container from the open fuel line and got nothing.

When I listened at the filler neck when someone tried to start the car I could hear the intank pump running. What was more interesting was that I could hear gasoline draining back into the tank as though it was being poured out of a container!

The only thing I could think of was a failed connector hose on the fuel pickup. I added five gallons of gasoline and with the hose at the fuel rail disconnected into a container I cranked the car and eventually fuel showed up. I replace the fuel line to the rail and after a few more cranks it shows 40psi on the pressure gauge and the car started.

It ran for about 15 seconds but when I tried to let it idle it died and would not restart. I checked for spark at the coil. The coil will jump an orange spark about ¼” to ground. I removed the sparkplugs and they were all fuel soaked but would also only deliver an orange spark.

I ran a quick compression test and got 90 psi on each cylinder. This is way down from the last test and I think part of the problem is perhaps the excess fuel washed the oil off of the cylinder walls. This is the point where I ran out of light.

Tomorrow I will squirt oil into the cylinders before replacing the plugs and trying to start the car again.

You may wish to check timing marks, all you need to do is line up the crank mark and remove the dist cap and look at rotor position. I have replaced many a t-belt after running a Volvo into a snow bank although most commonly without the presence of of a belly pan,worth looking in to all the same.
good luck

Randy, don't get too excited. :)

It sounds to me like a fuel issue, because of the way you describe the popping. The igintion would not fail in such a fashion, one after the other. You probably disturbed some junk in the tank that may have restricted the pumps.

Tommorrow, make sure that the pumps are indeed operational. It might be wise to bypass the relay and fire them up yourself.

I wish the best of moods to you, this holiday season!!!

I have a 1987 740 and when I once hit deep snow there was enough force to break the semi-rusty in the area where a passenger would place hit feet. So there may have been force applied in other places under the car at the fuel filter or along the fuel lines, depending on where snow and ice may have impacted under the car. Could the cat have been crushed? Just an idea. Also, I have a rotted harness insulation and it seems that a sideways engine shift would upset things in ways that normal engine movement would not.