Hello folks- I've got one that's kickin' my butt big time.

The car: 87 244DL, B230F, AW70 auto, 230K +/-

The symptoms: driving at highway speeds, stalls and dies. SOmetimes stalls momentarily and recovers, usually has to be restarted. Does sometimes stall at idle. Sometimes goes for hours without reoccurring. Sometimes stalls again in 1 minute, or 5, or 30. Does occasionally seem to not want to recover from releasing the throttle, but usually does come back up to a proper strong idle without stalling. Historically, as in for the last year or more, stalls when you put it in reverse- sometimes. Never stalls when you put it in drive.

Tonight the symptoms got quite bad and frequent. The car stalled on her 5 or 6 times over a 1/2 hour trip. She finally pulled over and called us, we drove up to see what the trouble was. I unplugged, cleaned and tightened the AMM connection (a previous problem on this car) and it fired immediately. It did not stall for several minutes there on the side of the road so we called it good and headed out, following her. Drove 1/2 hour, no trouble. After another stop, the second leg of the trip didn't go so well. The car died out multiple times in 20 miles. Each time it was able to recover and restart, only to die again 1-5 miles down the road. WIth a high-speed highway section coming up, it seemed prudent to leave it in a parking area and come back tomorrow.

What's new on the car: dist cap, wires, rotor, plugs <5000 miles. Fuel pump relay, 25A fuseholder. Coil (a long story). In tank pump, fuel filter.

I swapped my fuel pump relay with hers, and drove home on hers, no problem. Her car kept acting up even with my new fuel pump relay installed. I had a spare AMM in the trunk so I replace the rebuilt unit that was in this car with it. No luck, still dies 2 miles away.

I can't find a loose connection anywhere, though the red lead to the 25A fuseholder looks like it could use a new crimp. Reading the 700 FAQ, it seems to maybe point to engine ground points. I'll check this out tomorrow.
Also, after a stall, I've checked for spark immediately- and it has strong spark. I was hoping perhaps I could isolate it to the Ignition Power Stage but that doesn't SEEM to be thr problem- I'm not ruling anything out yet.
Meantime, anyone got any ideas? Thank you in advance.
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Rob Bareiss, New London CT ::: '87 244DL/M47- 221K, 88 744GLE- 202K, 91 244 181K, 88 244GL 145K

My guess? Sounds like an electrical failure in the ignition system, to wit:
-Hall connector or wiring to it (and recall that these cars suffer from harness rot all over)
-power stage internal fault
-ECU

Let us know what happens.

Check/clean ground wire [located under the rear seat] for the fuel pump.

The symptoms point to a common problem, which is, as mentioned earlier, the ECU. The ground path for the fuel pump relay is the ECU, and the control unit fails in that manner alone. So the relay trips, engine stalls, restarts as the relay resets due to a new start sequence. Some have rewired the system to use an external timer relay like from a VW Rabbit, and bypassed the control unit altogether, as the ECU is fine in other respects.

Thanks Rhys, I'm definitely going to try the ECU if it doesn't turn out to be something simpler. It's easy enough to check in any case.
IF it was a later car, I'd immediately suspeect the ECU, but these 85-88 cars don't often have ECU failures. I suppose anything's possible on a car of this age. Fortunately I've got a good running car to test things on, and swap parts if necessary.
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Rob Bareiss, New London CT ::: '87 244DL/M47- 221K, 88 744GLE- 202K, 91 244 181K, 88 244GL 145K

Rob, I am surprised to see a man of your stature on the Brickboard stumped. With the symptoms you described and if it were a 740 I would say bad Hall sensor or it's connector, but not the case here unless something fishy in the 240's dizzy. But that would be unusual.

If you had a no start situation it would be much easier to troubleshoot. Intermittent stalling with immediate restart can be tough. I think power stage is a prime suspect here. What about ignition switch?

I have always believed in answering that ultimate question (you know the one about spark or fuel) by carefully observing the tach. You may know tach pulses are fed right off the coil negative.

Therefore:
Engine cuts out at speed, tach jerks down immediatley and rapidly to 0 even before the engine winds down means you have lost spark.

Engine cuts out at speed and tach continues to track engine rpm as engine winds down means fuel problem.

Tach can even be observed while cranking during a no start. The ignition pulses at coil are reflected at the tach with very slight needle movements.

Of course all of the above assumes that rotor, cap, wires and plugs are all good.

What about gently jiggling various wiring connectors and harness sections to see if you can induce a stall during idle.

Just my thoughts. Good luck, be sure to post progress and results.

--
David Hunter

Thanks David, I am trying to figure out if it's a fuel or spark problem.
That's the "chicken or egg" question here... I do have a timing light so I ought to be able to see if the spark goes away when the stall occurs. I almost wish it was worse so I could find a definitely bad component- but every time it restarts, everything is back to normal.
The 240 doesn't have a track record of hall sensor failures, but it does behave like one... identical stall to the effects on our 88 740 a couple years ago, when I had to replace the distributor.
In checking it out I did find a loose plug at the throttle switch, but securing this didn't seem ot change anything, and I wouldn't really expect it to prevent stalling... might help with idle recovery though.
It's weird, I haven't come across a car that would stall at idle like this. This car, in fact, had a stalling problem before from the plug at the AMM, which made it die under hard throttle- I could make it do it in the driveway regularly, by holding the brakes and applying power in drive. Tightening up the plug made the problem go away, until this event today.
I think I will plan on doing a power stage anyway. I have to rule that out. Usually my experience with those is, all or nothing- no start once it goes bad. But a 740T I saw recently had an intermittent stall before it came to the shop with a no-start. That one was the power stage. I'll try it and let you know what I find.
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Rob Bareiss, New London CT ::: '87 244DL/M47- 221K, 88 744GLE- 202K, 91 244 181K, 88 244GL 145K

I too would suspect the hall effect thingy. If not that, what about the wiring to it?

What about the ignition switch? Any chance it's worn down to the point of intermittently causing the ignition to cut out?

What about the fuel pump ground points (which I believe are on the intake manifold)?

Are you getting fuel when the car stalls and you try to restart? If no, is there pressure in the fuel rail?

The friend with the Peugeot was tracking down a starting problem with the diesel. Sometimes it would start, others it wouldn't even click. It would take a jump just fine tho. Apparently he got pretty good at push starting it by himself(!). Turned out to be a poor connection at the starter.

Can you push or jump start your car out of a stall?

- alex

'85 244 Turbo

I had your exact symptoms and after much frustrating chasing, the culprit was the ECU. I wish I knew how to diagnose it, because I ended up replacing the AMM first (though I think the AMM was bad, too).

Fortunately I have a running car to test parts on, and I hope to nail it down tomorrow. I'll post back with what I find.
Thanks!
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Rob Bareiss, New London CT ::: '87 244DL/M47- 221K, 88 744GLE- 202K, 91 244 181K, 88 244GL 145K

I once had a very similar problem to this on my 86. Turned out to be the ECU. The circuit board near the harness connection was cracked and became intermittent. I was able to get the car to stall at an idle by applying some pressure to the ECU wire harness connection.
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1986 240, 230K, Original owner, Boulder, CO.