Background- I acquired a fairly immaculate '84 DL 2.3L w/ LH 2.0 and auto trans one year ago with about 80k original, had been sitting garaged and needed a little help to get up to snuff, but then drove for maybe 7 months without any issues, until last weekend. My beautiful wife borrows it (for the first time ever) for a short trip and when she returns she describes a lurching (maybe limping) effect all the way home that progressively worsened. I attempt to to diagnose and it gets worse and eventually --been out there messing with it in driveway on/off for a few days-- it's so bad now it stalls when you put in gear and attempt to accelerate, or occasionally recovers and lurches forward after nearly stalling without throttle. Starts up and idles fairly nicely every time with maybe a slow cycle of bogging down and almost stalling (every 3-4 seconds or so? but goes away). When you shift to D or 1 or 2 and give a little gas it lurches and stalls. Reverse DOESN'T seem to lurch and WILL accelerate for the 150 feet or so I attempted, but when you apply brakes after reverse, even gently, it stalls.

Main fuel pump making a lot of noise, buzzing and such, and though it is only 8 months old or so, symptom or culprit? It is getting good voltage (checked under rear seat) and visual inspection of connection at pump is good. I have the original which was wrongly replaced- should I go through all that and swap it just to see? I don't have fuel pressure testing equip.

The in-tank is humming along and seemed to test okay (spinning, flowing, submersible tube no holes) a few months ago, but could also be the problem? Gas tank currently about 1/4. Add gas and see if cured?

Done lots of little things chasing issues when I first got the car. New FPR, cap and rotor, plugs and wires, fluids, brakes, belts, main fuel pump & filter, exhaust, flame trap, fuses, cleaned MAF, throttle body.

Any ideas?

 

This morning I thought maybe the alternator, because dash lights Christmas tree'd this morning once the battery ran down from starting and restarting. The battery had dropped from the usual 14V to 12V while idling, and below 12 when off. Trickle charged it for a few hours and took out the voltage regulator and brushes from the alternator. Lots of corrosion and filth, but brushes longer than 5mm and so I cleaned and replaced. No luck Also noticed today that when I returned MAF after spraying cleaner into it yesterday I had forgotten to attach, thought is might ground but then noticed the rubber gromett thing. Could that bolt cause dash light issues-- I don't think so, but when I tried again, dash no longer lit up...

 

Nobody cares, but... I added 4-5 gallons of gas to see if it's the in-tank pump, thinking that raising the level above 1/2 tank would potentially give the in-line plenty to work with. No change. So now I'm thinking electrical problem or main pump on the fritz (even though it is a fairly new Bosch). Frankly, I don't have a clue. When I shake the main pump in its tray a little while car is running (pump still strapped to the tray), idle drops and pump makes scratchy buzzy sounds. This effect is NOT produced when shaking the black and yellow wires attached to the pump. What could that mean? Fuel/injection relays in the mail, so even though I hear at least one of them clicking after I turn the key to II, they're original and maybe swapping them with new will make a difference?

I guess I'm going to swap main pump with the original that I still have that still probably works fine and was replaced for no good reason the last time I was chasing 240 ghosts- see if that tells me anything or is just another onerous time waster...

If anyone IS reading this- wondering if there's anything in the transmission that could cause this problem, because I dropped the pan and drained the ATF and replaced transmission filter last on this car, before this happened. Is there any electrical connection near the pan, or sensor that could produce this?

 

Though it's lonely on this thread of one, I guess I'll consider this my notepad. If someone reads any of this and has had a similar experience, lmk!

Installed the old in-line pump I had that was original. Car fired up and did better, even drove into town and back, but still whining real loud and buzzy in a random pattern like someone turning the volume *** up and down every 1-3 seconds.

Installed 2 new relays to replace original (injector and fuel pump). No changes.

Went for a drive and added 4 gallons to the tank which had been 1/2 full. On the way it was bogging down occasionally, not responding or barely to responding intermittently to throttle, lasting like 2-3 seconds. Seems like its missing but with the crazy sound of the pump and the fact that just putting the old pump back in caused it to run (previously stalled in gear on acceleration), I have to believe it's fuel delivery. Still no no way to check pressure to be sure. Went 60mph for 1/2 mile, but backfired once along the way.

Got back and idle rougher, engine shuddering a bit. Pump sounds horrid. Can still hear the in-tank whirring. Car runs rougher when I pull in-tank pump fuse, so it's doing something. Maybe not enough something.

Checked voltage at harness to in-tank- it's good. Checked in-line at harness under back seat and it's good. bent wires between harness and pump and no new sounds.

Ordered upgraded ipd in-tank. Will install this weekend, but the problems at the in-line pump seem like an obstruction or something between pumps, but how, what? Everything in this car is fairly preserved. There HAVE been some mice living in the engine compartment and they HAVE chewed on this and that a bit, but I don't see how that could lead to fuel starvation in light of all of the other things I've done and checked...

What the heck? SOMEBODY?

 

Have you had a look in your tank yet? It could be crud in the tank is clogging the pickup sock. Or it could be the hose connecting the in-tank pump to the sending unit broken and leaking. Have you checked out this site. Basically tells you all you might want to know regarding fuel pumps for the 240.

In the Tank - 240 Volvo Tank Pump and Sender

Noisy main pump is a clear indication that it is working too hard. However, when I replaced my daughter's main pump ('91 240) the replacement Bosch part was not as quiet as the originals.

 

Thanks. Yeah I’ve read through all that clean flame trap stuff a dozen times. I had pulled the unit and done some soldering to replace some bad connections and tested the pump and inspected the rubber hose last winter.

but

You we’re right. In tank pump was whirring but when I actually pulled it and looked more closely at the rubber tube, actually removing it, it had disintegrated internally and caused a block. This I think was causing the pump or both pumps to draw air from the top clamp which was a little loose on the rubber tube. I discovered this after jumpering the pump and draining supply hose and getting a weak trickle and only 2psi. I replaced the hose with submersible and in process bungled up the tank pump power and ground “suppressor” or whatever that attaches to the poles for the pump. I carefully wrapped up the wires back into coils as best I could and snapped them back into the little plastic housing— thinking Damn, Hope that works! Well, I replaced the assembly and tested for flow again and it shot out at 5psi or so and a steady stream. Between removing the obstruction and possibly jostling a poor connection somewhere back into better shape( couldn’t find any electrical problems but the restriction seemed not enough to limit flow so much) when u put it all back together all issue we’re gone and the pump only made a low hum buzz and cavitation ceased.

So, here’s to being more thorough if you go to all the trouble of removing the tank pump, better to take apart and then re-configure it the flow is low. I really missed an opportunity last winter when I made just a visual inspection. I haven’t read anywhere about the inside of the rubber tube disintegrating.

 

It wouldn't hurt to check your fuel pressure at the rail. I know AutoZone used to lend out tools that you could use to check the pressure but you will have to rig up a T fitting to connect the pressure gauge.

Another thought, have you checked your fuel pressure regulator? Pull the vacuum line from it and if some fuel trickles out then you know it is bad. The only absolute test is to test the fuel pressure though.

 

Fuel pressure regulator is new. I should check the pressure but for now, the Volvo is humming along and driving as good as before the troubles began.

RE: pressure testing, I’m holding out for going to a pick n pull and getting either an old fuel rail (no Schrader valve) or a newer with one and either creating my own tester or if I replace with one that has a Schrader valve I could do testing with a friend’s standard tester.

Thanks for responding. I was beginning to think I was alone! You were right about checking on the in-tank. That was the problem in this case.