Hi. Still got my 1990 240DL Wagon. My wife uses it for her job as an urban gardener. Perfect for that purpose and we'd like to hold on to it forever.

For the past year or so, it was having problems starting up after a rainfall. And it would stall out and some very inopportune times. Engine cold or hot: didn't matter. After one rainfall it didn't start up at all. This was eventually fixed by replacing something within the starter relay. Sorry, but I don't have the receipt for that one available and I don't remember the part. But we were very happy after that repair...

...for about a month.

Then it started to hesitate/hiccup at stop lights/signs. And then it started to stall out at the lights and signs.

Back to the garage. He ran a diagnostic on the computer and came up with a 1-2-1 code. "Check for Vacuum Leak. Check Mass Air Flow Sensor". He removed and replaced that unit but couldn't find the a replacement for the Intake Tube (which he repaired instead). Then he cleaned the Throttle Body.

I asked about the Intake Tube and he said it was air tight.

I picked the car up and didn't warm it up. Hesitating and stalling all the way home (10 city blocks). Next day I let it warm up 5 minutes before driving to work. No stalling but hesitating a lot. I played the accelerator pedal gently to keep it from stalling.

It's back in the shop, now. No word, as of yet.

Any advice/knowledge imparted would be greatly appreciated.

No such thing as a starter relay. On the starter motor is the solenoid component.

As more stalling in rain, though not fully dteailed in this FAQ article, yet may help you (copy and paste URL into new browser tab or window). Mucho Info on stalling sumptoms and corresponding causes.

https://www.brickboard.com/FAQ/700-900/EnginePerformanceSymptoms.htm

Or click FAQ as open in new tab (Ctrl+Click or Right-Click or Shift+Click)

Test the OBD Yourself. Why pay the mechanic to do so?:

https://www.brickboard.com/FAQ/700-900/EngineOBDCodes.htm


1. Diagnostic Test Mode 1: Fault Code Retrieval

Socket 2 (Your 1990 has Bosch LH-Jetronic 2.4 fuel injection test) AND 6 (Bosch EZK116)

Where the red light flashes out anything other than the all's well 1-1-1, record that code and repeat the DTC code check until no new DTC codes flash out.

I don't trust mechanics. I used to be an uncertified mechanic in the 1980s. Maybe you use an honest repair service I hope.

Post back should you encounter DTC fault codes other than socket 2 (fuel injection) and DTC fault codes in socket 6 (ignition).

Read the tables so marked for your engine control versions for the meaning.

Questions?

Afternoon Earl Grey Tea Person.
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as mentioned -- the CPS Crank Postion Sensor. Did your shop check that. It's a wire and with age the insulation breaks down.

Art's post on turbobricks

https://forums.turbobricks.com/showpost.php?p=3459318&postcount=10

FCPEur Blog
https://blog.fcpeuro.com/how-to-install-a-crankshaft-position-sensor-rwd-volvo

121 always means needs a mass meter. hope you found a bosch unit and not the chinese parts that seem to be everywhere-as opposed to bosch which appear to be extinct.

won't start, stalls, etc. is usually cap rotor and wires. bosch or bremi only on the cap and rotor, bremi, bougicord or karlyn on the wires-no bosch wires. had a few bad out of the box and won't try again.

1 other problem as i recall was the CPS wire..for a temporary i used aluminum heat tape that I got from my hardware store...I wrapped that around the wire & wasable to drive again,,,!!!my keyboard is infected w pelo de gato!!!

If all your repair efforts fail you might want to consider going back to a good old fashion carburetor. I'm in the process of doing it on my '79 244. My car had sat for many years before I bought it. After installing a new fuel tank, both pumps, accumulator, filter, injectors, pump relay, etc. it will run but not like it should. I've had 2 good mechanics look at it but they're both stumped. So for the sake of simplicity and economy I'm going back to a carb. Another thing I did was replace the original ignition module with a Chevy-GM module like they used back in the late '70's & '80's. Again super-simple & cheap.

FYI re: Carbs

your 79 B21 uses a Bosch Breakerless ignition...which can be used with a Carb.
The FI system is a Mechanical K-Jet Constant Injection (CI)System, with no computer system involved.
The only 'computer' is for the Lambda Emissions system.

a 1990 with B230 uses a LH electronic FI system, A computer 'fires' the injectors (they pulse on an off) and controls the ignition.

To Carb any LH System -- you would also have to replace the Ignition system.

And frankly I don't understand why you would want to do that. Nor do I get why you want to replace your K Jet FI with carb.

The KJet is a very reliable system...used in older BMWs, Porsches, Mercedes. As long as you drive/use the car regularly, it is rare to have problems.

I'm sooo glad Carbs along with the Points and Condensor ignitions are long gone.
In the wayback the Bosch Breakerless system was the first great improvement on Carbed engines.

ALL the vac lines should be replaced w new & made tight,,I think there are tiny metal clamps that shouldve been replaced but many are lost over the years..as the engine warms up that would create a vac leak..so make sure those lines are tight & secure
Any problems w rain is definitely aan electric problem NOT a fuel supply & going backs to carburetors would cause another raft of problems.

NO!! Never go back to the carburetor!!most likely this in the elec .circuit,,replace the cap & rotor,,.All grounds should be cleaned & tightened.this is an electrical problem,,if you need a good rubber intake hose I have 1 908-343-1939

NO!! Never go back to the carburetor!!most likely this in the elec .circuit,,replace the cap & rotor,,.All grounds should be cleaned & tightened.this is an electrical problem,,if you need a good rubber intake hose I have 1 908-343-1939