Last winter my daughter ran her car out of gas. It ran poorly after that and got poor mileage. I replaced the filter and problems went away. I just had the car on ramps to change the oil. It won't run now. It actually runs but it will not idle. I'm assuming that having it up on the ramp stirred up the crud in the tank. If it is the tank what can be done to clean it up?
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1980 240 335k 21 years.

I replaced the fuel filter and started it up. It ran better but was still not running smoothly and would barely idle. After a drive around the block it is running fine. Go figure. I think I'll replace the tank pump anyway. thanks for your help.
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1980 240 335k 21 years.

I doubt it is a fuel problem. It is probably a bad pre-fuel pump in the tank. She probably burned up the fuel pump by running the tank dry and allowing the pump to overheat without fuel in the tank to cool it. I recently replaced mine after having rough idle problems and cured the problem. It is not a hard job if you have never done it before.
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1989 240, 1992 745

I thought that too but it happened immediately after we had it on the ramp. It would be unlikely for it to fail at that same moment. It was working fine up to that time. If I do any work on the tank though I'll change it out. I replaced the pump on my 1980 a few years ago but gave away the bung tool to another Brickboarder.
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1980 240 335k 21 years.

Pull the sender/ pump & test. You can also look in to see how much dirt is in the tank. I've never had a tank so bad that it clogges filters.

If it is related to the ramping, I'd suspect a bad hose - the rubber bit attaching the in-tank pump to the pickup line. Add 5 gals gas to the tank. If it runs fine the, the hose may well be your problem.
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240s: 2 drivers and some parts cars

The problem is that she was able to get it to lurch to the gas station and fill it up. So it now has a full tank and does not run. It will start and at high RPM will run but at low idle it is missing on at least one and sometimes two cylinders. I still think fouled fuel filter.
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1980 240 335k 21 years.

What a frustating thing to have to chase down.

If you think you have a fouled fuel line try this. Pull the line off the back of the Fuel pressure regulator and also from the fuel filter. Move the line away from the Filter and blow the line a decent amount of air pressure front to back and see if any crud got past the fuel filter and blocked the line. You will know for sure that is clear then. You can also pull the line off the fuel pump and filter and make sure that is clear by blowing it out.

Then you just have the pickup pump to main pump and fuel rail to trouble shoot if the problem continues. The one sure fire way to check the pickup pump is to jumper the pickup pump with the main pump wires removed. Put the gas line that goes to the main pump down in a bucket and see if steady steam of fuel goes into the bucket. If you do not have a decent stream pull the pickup pump and blow out the line from the tank to the main pump and that you have good solid connections to the pump. Of course all this comes with the warning about the fumes and stuff that goes boom.

Replacing the FPR is the only way I know to see if that is the problem.

One more thing to just get off the list is the IAC and the Throttle Position Switch. If you can crack the throttle body open with your hand and the idle smooths out you might have a issue in there that decided to mask itself in with your work in the back.

Hope this helps,

Regards,

Paul

"The one sure fire way to check the pickup pump is to jumper the pickup pump with the main pump wires removed."

No need to get under and mess with main pump wires. Just remove the tank pump fuse (4) and apply +12V jumper to the Right Side fuse contact. The voltage goes only to the tank pump.

The Main pump can be run independently with that same fuse removed—just apply the +12V to the Left Side fuse contact.

The +12V is always available at the Left Side of fuses 6 thru 10.
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Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Please get back to us about which part actually cures the problem. Very few people do that. I don't know if they give up and sell their cars, or if they are too proud to reveal that their initial diagnosis was wrong. Maybe their too busy posting about their next problem. Who knows?
My car:
Of all the new parts I have installed, the ONLY ones that made a difference are:
1) The new Bosch coil cured my poor acceleration.
2) Changing from my #561 computer to a used #951 computer solved my poor hot start since the 951 pre-primes the fuel line when you turn the key to "on."
3) The new catalytic converter was the only new part that finally made it pass emission testing.



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'89 silver 244DL in Milwaukee WI

Replacing the fuel filter fixed the problem though it took a few turns around the block to get it to run properly,
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1980 240 335k 21 years.

What years and models did the 951 ecu come on? I have hot start problems too, and its not the MAF because that is new. How much did you pay for it, because I am looking on eBay, and they are ranging drastically in price.

Never mind, after close inspection (i.e. actually looking) I have the 951.

Hello,


It is quite difficult to clean these tanks, as there is no drain. One way is to use either a siphon or a
vac-u-suck and empty the tank. After emptying the tank, pour about two gallons of white spirt into the tank and bounce the car

How hard is it to remove the whole thing?
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1980 240 335k 21 years.