A mechanic replaced the fuel pump and fuel filter and also a sensor on my '84 240 GL. It now idles at 1500-2000 rpms -- an increase of more than approx. 500-1000 rpms from normal range. There is also a high-pitch whinning sound from around the fuel pump area.

Can any give my any insight, please? Is this a safety hazzard? It is going through fuel fast, which is a concern.

Thanks!

 

a whining main fuel pump usually suggests that the in-tank booster pump is dead.

idle should be 600-700rpm when the motor is warmed up. its computer controlled.

if the coolant temp sensor says its really cold when its actually hot, it will idle way too high, and run way too rich, wasting fuel. verify this is correct before proceeding by measuring the CTS resistance at the ECU connector, per one or another of the volvo 240/740/940 troubleshooting FAQ pages...

if the CTS is good, then....

you should verify the throttle closes completely, no cable hangups, remove and clean the inside of the throttle body and make sure it fully closes when released, clean the idle air controller, insure the hoses to the idle air controller aren't cracked and replace them if they are, reassemble. verify the throttle idle position switch closes when the pedal is at idle and opens as soon as it gets any gas (use an ohm meter on the switch contacts). if all this is good, and the idle is still high, you pinch off the idle air controller hose, the idle of a fully warmed up engine without the idle controller should be about 500 rpm, there is a bypass air adjustment screw on the side of the throttle body for this (its NOT the idle position screw, that should be set so the switch is closed and opens on the slightest crack of throttle). once thats adjusted down to 500rpm (which is almost stalling), unpinch the IAC hose, and it should idle properly.

 

Thanks so much for the very helpful information! Your answer makes a lot of sense. My mechanic says the car is fixed, and I should pick it up, but obviously it is not fixed. What is the risk of driving like this? Know any mechanics in the Dallas/FW area that could assist?

 

I only know mechanics here in Santa Cruz, California

_if_ your in-tank pump is dead, your main pump will have to work harder when the gas tank is low. if you keep the gas tank above 1/2, it should be fine. when you get down below like 1/3rd tank, and you accelerate briskly in 3rd gear, you may find it bogging down and suddenly loosing power. at least, thats what mine did. I'd back off for a few seconds, and the power would came right back.. you can use a alligator jumper wire to test the pumps separately... lets see, 1984 240... greenbook TP 30678/1 says... . wait, it says you only have one fuel pump ? hmmm.

do you have a b21f or b23f engine ? thats 2.1 vs 2.3 liter. the parts catalog is a bit ambiguous about older models like this.

 

ok, hmm, I just checked the 1984 wiring diagrams, and teh 1984 parts catalog, you only have one fuel pump. dual pumps came a couple years later.

the fuel pump shoudl be a very soft smooth quiet hmmmmmmmm if all is good and happy.

here's the parts diagram,



that box '1', thats whats inside the fuel tank, its the fuel pickup sock on the bottom, a bit of fuel hose up to the tank seal on top, and the fuel level sender, which drives the gas gauge on your dashboard.

2-tank cars have an additional 'booster' fuel pump on that assembly. yours doesn't.

'2' is the fuel pump, '8' is the fuel filter.

 

Thanks again Pierce. You are correct. My car does have an in tank fuel pump and your first suggestion sounded right. That sounds expensive to replace. Is it?

 

ok, there's an easy way to test the dual pumps. the tank pump is on a fuse, I think its fuse 5? turn ignition off, and remove that fuse. now, the 'input' side of the fuses is on the left, and the 'output' side of the fuses is on the right. the 'main' pump is /before/ that fuse, so its on the left tab, while the tank pump is after the fuse, so its on the right tab. fuses 6-10 are /ALWAYS/ powered, directly off the battery. take a jumper wire, and jumper the left side of fuse 6 to the right side of fuse 5, and the tank pump should be powered. if you remove the gas cap and listen at the fuel filler pipe, you should hear it whirring in there.

disconnect that jumper, and now jumper the left side of 6 to the LEFT side of fuse 5, and the main pump under the car should be powered, without the tank pump, you should hear it whirring, and if your gas tank is low, it may well be complaining.

the final test is to remove the jumper, then put the car up on jack stands, crawl under it, and disconnect the fuel line from the front of the main pump, stick it into a catch container, and do the first jumper left fuse 6 to right fuse 5 for a few seconds, gas should come out in profuse quantities, unjumper it before your container fills up



tank pumps aren't that hard to replace, there's an access panel on the floor of the trunk of a sedan under the carpet mat, or under the floorboards of the wagon behind the front seat. open up that access panel, and you can see the gas tank flange, with the 2 gas lines (output and return) and wiring for the gas gauge sender, and the in-tank pump.

Volvo only sells the whole assembly, but aftermarket will sell you just a pump and sock, which you can install on your existing assembly, much cheaper that way.

Do note that many after market assemblies are coming mis-wired such that the tank pump runs BACKWARDS. if you could hear the tank pump run, but no gas came out, then odds are good the pump is wired backwards and sucking instead of pushing.

In the Tank - 240 Volvo Tank Pump and Sender everything you could ever want to know about it.

 

I suggest doing fuel tests away from any source of ignition such as water heater pilot lights in the garage.




bring it back to the mechanic and see what he says and then post it here.

Tank pump is about $50 for a good one and 30 min labor.