First of all let me start by saying thank you, in advance, for any of your help. And let me apologize if this thread is repetitive but I spent 6 hours trying to find an answer to my problem without any results that jumped out to me as a solution.


Long story long, my car has been acting up with increasing regularity. The symptoms as I see them are that it seems to happen after I've been driving several short trips throughout the day or on a longer trip after about 70 miles or so.
The car will begin, for split seconds, to hesitate as if I have taken my foot off the accelerator with moments in between. This moment between will decrease until the car is practically not running. Once I pull over the car will idle okay, at first, but each time I depress the accelerator it just stalls as if it is getting no gas. As I continue to press the pedal the stall gets worse and misfiring is included until it just stops running altogether. If I start the car it starts fine but again, any press of the gas pedal causes it to stall again.


Once I wait about 10 to 15 minutes, the car starts and runs just fine for the rest of the day/trip.


Sometimes when this happens, I get codes usually 121 and 232 but today they were 121 and 223. This does not happen but maybe a third of the time the issue arises.


I'm concerned now because the issue has gone from happening once every few months to recently a couple of times per week.


I'm writing here in order to find a solution I can fix on my own, or just be more informed if I have to take it to a shop (last resort... I'm SOOOO broke)


Again, thank you all for your help folks


Long time guest reader converted out of necessity

 

my first guess is fuel pump and/or relays.

but, 121 is a mass airflow problem, the ECU sees a wiring fault, or its a bad MAF/AMM. check the wiring, make sure the MAF cable isn't going too close to spark plug or distributor-coil wires, that its not damaged, that the connector is firmly seated. if thats all OK, I'd find a friend with a LH2.4 car (volvo 240/740/940 from 1989+) and swap the MAFs, if the problem moves to the other car, give him back the good one, and get a new one.

232 is too lean or rich, that could easily be caused by a bad MAF.

223 is an electrical fault in the idle air controller circuit, thats something completely different, and would only effect idle.

there's no magic bullet, you're gonna have to test stuff and figure out whats wrong, throwing expensive new parts at something is a lousy way to fix it.

 

Thanks Pierce, I've got a MAF that I've already swapped out so I'm pretty certain that's not it. Same as you, I'm quite suspicious of the pump/relay too so I'm gonna do a 6 to 4 fuse test as soon as I can find a donor ear for the inner pump.


Just to verify test, I should remove fuse 4, take jumper wire from fuse 6 terminal and touch to left side of fuse 4 contact to hear outer pump and right side to hear in-tank pump, is that correct?

 

i'd have to look at the 1991 diagrams, they made some changes on later years.

the *FIRST* thing I'd do to ANY 240 is replace ALL the fuses with brass/copper european ceramic fuses... the tin plated ones they came with stock (and are all you can find in US car parts stores) suck. these are often sold in bulk kits as 'mercedes w123 w124 fuses' (w123 and w124 were two generations of the Mercedes 300E/300D family from the same era as the 240's, and they use the same fuses). for instance, Mercedes Fuse Kit W124 W201 190E 16V 190D 300E 260E 300D 300CE 300TE 300TD 2 5 | eBay

 

I had the same symptoms. Your in-tank fuel pump will fail soon (atleast that's what happened to me). Get a new o-ring and lock nut from the dealership - they are very cheap. This is in the trunk on that "step" under the carpet.

Also, change the fuel filter - under the car on the driver side below the rear seats. If finances permit, change the main pump also. Its right next to the filter in the same cage. Being a student, I didnt bother changing my main pump. Car runs fine. Taken it to Toronto and Atlanta last year

 

Take a look at this link as it clearly shows how to check the in-tank pump.

In the Tank - 240 Volvo Tank Pump and Sender

 

That's an excellent link by act1292. That's what I used too in my case.

The case where your car is running bad seems like the fuel filter to me. Also if your in tank pump fails the main pump below the car will become very noisy and buzzy.

Took my car to Chicago right after I bought it. Ended up changing the fuel Filter as it became almost undrivable in my case. Oh also my brakes failed - had to change the master cylinder also. Both were done in auto zones parking lot as only they had the parts in stock. Boy that was a fun trip