My 1991 245 130k will not run and this has me stumped.
Here's a list of symptoms:
If I let it sit for a day or so it will restart.
When it starts, it runs fine, unless you open the throttle wide-open, then it dies. If you gradually open the throttle, it will rev fine. It will not restart unless it sits for a day or so. I tried unplugging the AMM and restarting but this does no good. The fuel pump fuse is good. The battery is good. No fault codes. It seems to be getting spark (otherwise it wouldn't start in the first place?) Anyone have any ideas?(other than an oily rag in the gas tank and a lighter) Any help would be greatly appreciated.

Here's an update:
Now it won't start at all.
I am smelling a lot of gas when I turn it over.
I am getting spark to all the plugs.
I tried resetting the ECU (unplugging Neg. terminal for 2-3 mins)
I unplugged the AMM.-No dice
The last thing I have to check before I blow it up is the Coolant Temp Sensor...
If this fails...what else can I check. I have narrowed it down to an air/fuel ratio problem but I am yet again stuck.........

Thanks to all of you who answered this post.

I'd check the fuel pressure regulator first. Pull off the little vacuum line going to it and see if the line smells like raw fuel. I forget, have you changed the plugs yet? If they are totally fuel fouled, even if you get it "fixed", it's not gonna start.

Chris

Always go back to the basics. The cap and rotor...new? old? one of those blasted black aftermarket ones that I hate so much? The plugs, white indicating lean? black indicating rich? When it won't start back...do you hear the pumps running? Do you have spark? Does the fuel pump relay click? And just what is the date on that fuel pump relay? How about the crank sensor, yellow banded? falling apart? white banded and pretty? Your fuse panel, does it look like a corrosion experiment, or are the fuses all clean, connections all tight?

Next time you get it to start...and then it dies...you need to figure out what you are lacking. You need three things for your car to run...fuel, spark, and compression.

Chris

Stalling out when you open up to full throttle is one of the classic symptoms of a dirty fuel filter. Then it gets worse and starts to stall out at regular operating speeds and when it's really bad it won't even idle. When did you replace yours last? It's supposed to be a 60K interval item, so perhaps yours was replaced at 60K and is now overdue?

Among the other things to isolate, check the fuel pump relay and if it is bad it can heat up the coil after driving for a while where re-starting is a problem. Next check the ECU part # If it is the Bosch xxx561, it could be the ECU signal to the fuel pump relay that fails the ground connection. This seems to get worse the longer you drive the car, will work OK at cruise, but cuts out the engine if you step on it. This is a well known failure of these ecu's.
I had the same type of problem, with both the fuel pump relay and the 561 ECU, but at different times.
--
'89 245 Sportwagon, '96 960 sedan

My 91_240 had a similar problem. It took 5 days at a good shop to isolate the problem to intermittent connectors at the fuse block. Most of the time was spent waiting for the car to start. Car would start, would run, but once shut down would not restart. Once in a while would just stop. Seems the bad connectors would get hot, expand a bit, and let the connection get loose. Then either ignition or fuel would quit working.

Make sure all the connectors at the fuse block are clean and tight. This is cheaper and quicker than changing all the other stuff that could be wrong.

Good luck.

91_240

P.S. the shop only charged for the connectors they replaced, not the time. About $60 as I recall.

Sure, I know this one, it's a classic textbook case of failed LH-Jet coolant temp sender.

Sender is open, leading the ECU to believe it is -40 degrees outside. So it makes the mixture REALLY rich. That's why your car will start, then not re-start - it's flooding out. 3 days later, when the flooding gas evaporates, it'll start again.

Proper test procedures can be found in your Bentley manual.

You need to isolate Fuel vs Ignition

Ignition problem will prevent Fuel operation

Ignition problems can be intermittent

Force Fuel Pumps by jumping fuses 4 and 6 (left side contacts), then try starting.

If it starts, the fuse jumper compensated for a Fuel circuit problem — or a failing signal from Ignition, which is basically OK if it runs. Further diagnosis needed.

If still no-start, it's probably an Ignition problem (RPM sensor or Power Stage possibly). Further diagnosis needed.
--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

Hi
Try the distributor first. I had about the same symptoms with my '87 780 and tried a lot of tricks, checked and changed a lot of electronic devices. About three months later, a guy from brickboard and my father had the same idea: have a look at the distributor. With all the electronic devices and all the troubles, nobody looks for the simple things. Inspecting the distributor with the b230 is a little bit tricky, but its worth the time. (In our family, we have 5 bricks and 4 of them had a distributor in bad shape, number 5 is a diesel...).
Good luck
David