can anyone diagnose this problem? Thanks in advance.

1986 740 non turbo Driving to work, the engine suddenly stops, just completely zero rpms instantly. Tried to restart and starter sounds like it is not engaging flywheel, I don't hear it turning over. But why would a starter problem knock out the engine? Timing belt? Clue: drove through some serious high water last night. Any advice greatly appreciated. Thanks
Reply to
MDM
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Sounds like you may have killed the alternator, and flattened the battery due to lack of charging. When you operate the starter with a low battery, the starter motor will rotate but the solenoid doesn't have enough urge to slide the gear into engagement with the starter ring on the flywheel.

Are all the dash lights on at normal brightness? Do the headlights work?

Reply to
Bonnet Lock

I doubt this, the same solenoid that engages the pinion on the starter also closes the contacts to power the starter motor.

Check the obvious things first, look under the hood while someone cranks the engine, does the engine turn over? If it does, open the oil fill cap and peer in at the camshaft, have a helper crank the engine again, is the camshaft rotating? If so, check for a spark. Follow the thick rubber wire from the ignition coil to the distributor cap on the back of the cylinder head, pull the wire off the cap and hold the exposed end about 1cm away from bare metal on the engine and crank the engine, if it sparks then the ignition is working. I would guess one of these steps will narrow things down, could be a coincidence that multiple things failed after getting excessively wet.

Reply to
James Sweet

Sounds like it. It is probably turning over, but there is no compression and sounds much different.

Reply to
Stephen M. Henning

Pull the spark plugs. Let the water out. See if engine will turn over. Hopefully hydrolocking the motor didn't do major serious damage. If you were moving at speed through the water it's not likely that that motor will ever run again. Hydrolocking a motor will bend or snap connecting rods. Running an engine with water in the crankcase will ruin the bearings in a very short time (30 seconds or less).

Bob

Reply to
Robert Dietz

Robert Dietz wrote

I got the impression that this happened the day *after* he drove through the high water, which sorta leaves out the hydrolocking[1]. I'd suspect some electrical connection may have got yanked by the physical shock of the wall of water, and it jiggled loose on his way to work the next day. I'd expect a whole lot of fun looking around for loose wires. Sounds the simplest explanation to me, and Occam makes very good razors.

If, on the other hand, it stopped *when* he drove through the water, I'd agree with Robert, and suspect that the cost of installing a junkyard engine may exceed the value of the car.

[1] I did this to a Plymouth Breeze last year. I drove through about 8-10 inches of water in a car the same way I do with a truck (by which I mean a Freightliner, we usually drive a Century Class), namely, just give it gas and see how large a wave you can make. The air intake for a Century class sits at about 7 feet up off the ground. The ground effects on the Breeze dug down into the water, and pushed some up onto the curve of the bumper. At that point, it turned into a bow wave. I saw that start, and realized the extent of my stupidity and reached to shut the engine off. Too late, it sucked water while turning about 2500-3000 rpm. Total loss (94 Breeze, 124000 miles, worth three hundred less than the cost of the engine).
Reply to
Lane Gray, Czar Castic

You couldn't find a good used motor in a scrapyard? '94 is old enough that a few should be trickling into the U-pull yards by now.

Reply to
James Sweet

Replacing an engine probably doesn't lie outside of my available skills, but it would lie outside of my patience, and time (we don't pay for the rental car coverage on our insurance, and we're landlords, with a heavy maintenance schedule at the time), so I'd have paid to have it put in. Junkyard engine installed%00, car worth 2200.

Reply to
Lane Gray, Czar Castic

I had this problem and it drove me crazy as it was intermittent. The problem: correoded wires to the battery. They looked good, but were actually 90% corroded thrrough underneath the insulation.(small gap between the insulation and the terminal connector allowed battery overflow to seep in)

Definately electrical, though.

Reply to
Joseph Oberlander

Yes, all electrical is normal and it cranks strongly. Thanks

Reply to
MDM

So the engine turns over? Does it have compression?

Reply to
James Sweet

Ah. then it's either the timing sensor(IIRC, it uses an electronic distribitor) or the distributor packs got wet and mangled.

If you get spark but it won't run - or barely does, then it's a soggy and mangled MAF/airflow sensor.

My guess is toasted coil packs. oor the controller/mount underneath them.

Reply to
Joseph Oberlander

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