So about a week ago I went and bought a volvo 740 from a private owner. Basically, he said he just changed the rear axle oil (differential?) and everything. He replaced the radiator with a crisp new one. He said part of the old fuel pump rusted out and was leaking gas on the return so he replaced it with one with plastic parts.

The plates said 2008 when I got it, so I figured it had been sitting. When I was pulling out of his driveway he says the fuel gauge sometimes sticks so flick it to get it to update. I had already paid him, so I'm sitting there thinking that would have been nice to know earlier. I got it filled it with $20 in premium gas (since I had assumed it had been sitting). I got it home and it dripped a small amount of some fluid on the driveway from where the drive shaft starts. I drove it some more, no more leaks. I went on to change the oil with high mileage 10w-30 oil with a new filter. Upon driving it some more I noticed the gas gauge raise very gradually (over the course of several times driving the car) maybe by the 5th drive it showed full. Since then its dropped about 2-3 mm per each time I drove it. Now its sitting a tad above empty, but the tank is full. The car only starts on the first crank if it's hot. But starts on the second when cold. Since owning it I've also experienced two losses of power where you press the gas and the car doesnt accelerate. The car has no self diagnosis (CEL). The car looks nearly mint condition inside and out. The booklet says it was serviced by a volvo dealer every 5k miles up to 45000 and it has 109730 now. It also seems like its shifts sometimes delayed (sticks between 2700-3000rpm for several seconds). I'm not sure if I'm being over-critical or if it really needs some work.

What I'm asking I guess is what problems does this sound like to those of you who are more familiar with volvos?

 

i am unfamiliar with ANY replacement main fuel pump that is plastic. maybe he meant the in-tank pump.

the fuel gauge level problems are unrelated, but the fuel level sender is on the same assembly in the tank as the intank pump.

re: the shifting problems, and the possible final seal leak, i'd certainly check the transmission fluid, and as soon as you can afford it, get a full tranny service (drop pan, clean, flush, new ATF) from a reputable transmission shop thats familiar with AW71 transmissions (these were used on RWD Toyotas of the same era as your car).

the delayed start on a cold engine could be a number of things, like the one way valve in the main pressurized fuel loop may not be holding pressure. a fuel pressure test with a leakdown test would help diagnose this

 

Thank you for the quick response. I love the car, I just don't want to shell a load of money into it if it isn't worth it. I'll try to get some of this stuff done/looked at and get back on it.

EDIT: He had printed out this page saying that he replaced the original with this http://www.fcpgroton.com/product-exe...nuine+Volvo%29
EDIT again: I believe that if he indeed installed this and installed it correctly, it should be giving proper readings ...

 

ok, then if your fuel gauge is still misbehaving, its likely a wire or ground issue. or even the fuel gauge on the dashboard (which is basically a volt meter). Or the new fuel level sensor was damaged on installation (its a bitch to get those things into the gas tank correctly).

thats one of two fuel pumps, sometimes called a transfer pump. the main fuel pump is underneath the car, forward of the gas tank, and boosts the fuel to high pressure, it goes from the main pump through the filter then to the fuel rail on the engine, through he fuel pressure regulator, and back to the tank in a closed loop. There's also a 1-way valve after hte pump, its purpose is to maintain pressure when the pump is off, so starting the car is easier. The pressure regulator maintains 42-44PSI fuel pressure in the rail, so the injectors can squirt the right amount of fuel on demand into the engine.

 

Alright, I checked and that sending unit is indeed installed. I'll look at the main pump' although I'm sure i wouldn't be able to get a whole lot of useful information by looking at the external portion of it.

 

that bit about the one way valve, the way you test that requires a fuel pressure gauge, with Volvo specific attachments, which is something that only a euro specialty mechanic would likely have.... they connect the gauge between the fuel line and fuel rail, then run the engine and measure the pressure. its actually 42-44 PSI above manifold pressure, which at idle is negative 8psi or so so 34-36psi at idle... If the pressure is lower than this, then its likely a defective FPR. Then, you shut the engine off and see if there's still pressure after 1/2 hour, if so the one way valve is working.

 

Alright, well I have pictures of the pump/filter if it'd help at all. I might have to call around to see if anyone around here has the stuff to test it. I'm in southern Wisconsin and I have never seen another volvo driving the streets around here.

 

once you start driving a Volvo, I bet you see more. OTOH, my son has been in northern Idaho for a couple weeks now (summer job), and has only seen one other one (he drives a 940 wagon), but he's -really- in the boonies, working for USFS.

 

I'm sure, my city had a GM plant so of course all you see 90% of the time are GM SUVs and GM cars. There isn't a volvo dealership in 50+ miles, but I'm sure they're out there. Once it's warmed up it drives beautifully, it's hopefully just a few minor things to work out on this.

 

My ball check valve died, but it would crank a bit when cold, but take longer when hot. When I replaced it, it still takes a few revolutions (but not an unusual amount) to start, but when hot, it fires off instantly. If it sat, it probably had alot of gas varnish in the tank. That stuff can build up. I would try maybe Seafoam and get your system cleaner. Higher octane fuel (premium) won't clean it. My car has run 226k on the lowest grade fuel and has never complained once. I don't believe in high test.

I would, check the main fuel pump (so a pressure test like earlier suggested) and check the ground and harness plug for the fuel sender/pump in the trunk under the rug (assuming it's a sedan). Make sure contact haven't backed out in the connector and that the ground is secure. Maybe all your problems are a lousy ground. But maybe not. Also, the dash on these cars are known to sometimes loose a good contact on the printed circuits on the back of the gauge cluster. You can loosen the contact screws on the back and re-tighten then to ensure good contact if nothing else seems to fix you gauge. I would do that last of all.

I agree with what Pierce said too.

 

B230FT's ping like crazy on a warm day with the crappy regular we get around these parts, they just about have to have premium IMHO. a regular B230F, sure, regular is fine.

 

It is indeed a sedan, and I'm running a bottle of lucas through it, then seafoam, then another lucas then trying a lower grade of gas. It'll take a while, sure, but why not?


EDIT: Interesting find. I took a look at where the wires come through the trunk and there isn't a connector, there's a splice. So it could be likely that one of them is bad, also, what is the hose for that is cut?
Edit Again: Started this car this morning, and fuel gauge jumped up to completely full (moreso than last time i filled it). This is after I moved the carpet so the wires are positioned differently, I'm guessing its a short that was temporarily cured when I moved the carpet?

 

Cut hose, maybe a trunk lid drain? Follow it, see where it goes. As for the splices, some people should be allowed to touch their own cars. Whom ever did that, probably didn't understand how to pull apart the connector and cut it out. They connect quite tightly. Or maybe the new sender didn't con with the connector. What ever the case, they chose a cheap way out. I would get a new connector (maybe a generic one with enough connections and solder it all up. It would be a better than OE fix. Just don't mix them up. That whole area looks suspicious to me. If you do take these wires apart, don't mix them up. A good re-crimp would probably be sufficient. Also tug on the wires and see if you can't get them to pull out of the crimpy thingys.

I've never had mine ping on low test, but I don't disbelieve you. It's just surprising to me. How hot does it get?

 

I guess I can go get some basic connectors from radioshack and hopefully knock one problem out of the way.

By weak starts I also mean that if you get it started itll kind of sputter (sometimes die). To remedy this I usually press the gas and hold it at 1500 rpm for almost half a minute then put it in gear and apply gas quick again or itll stop again... Once you get rolling its perfect. It's just the initial start and idle. I ordered plugs/wires a few days ago simply because they guy said he never touched them since he had the car (1991 @ 76k miles) so it's had the same plugs since 91. One of the 4 plug wires looks different than the others too.

 

indeed, that does look like the drain hose. on a 240 sedan, its normally connected to a Y, one leg goes to a sunroof drain hose that comes down the C pillar, and the other leg is connected to a drain hose from the airvent under the back window. there's one of these on each side. oh, if you don't have a sunroof, delete the Y, and the C pillar hoses

put a towel or something under that hose, and dribble some water into the drain vent under the window, see if it comes out that hose.




those blue crimps are pretty ghetto. I don't like using crimp connectors, but I find the marine ones sold in boating stores tend to be better quality than the stuff from the hardware store or auto shops. given my druthers, I often use heat shrink insulation, and solder the wires... if its in a hostile environment, I'll put some dielectric gel, or 'liquid electrical tape' over the joint, and while its still wet, slide the shrinkwrap over it and hot-air shrink it. then I'll put a piece of plastic wiring loom over the whole bundle of joints for mechanical strength and general neatness. I generally make my splices inline rather than Y, and I'll stagger the lengths of the wire so the splices aren't all in the exact same place

 

Yeah it is a sunroof, I think I'll try the in-line solder+shrinkwrap, that looks really nice and reliable to me... and more professional.

 

Update on the fuel gauge thing, It seems that when full the gauge says full, but now I've driven 50 miles since filling up and now the gauge is reading close to half. I know for sure its only used 2-4 gallons... not half a tank. It just starts dropping dramatically once some of the gas has been used.

 

In general, gas gauges drop fast and hover around empty longer, or so they seem to.

 

Well I mean in the last 20 miles its gone from completely full to 1/4 or less. I know empty is still usually a couple gallons.

 

New Update: I changed plugs/wires and put on a new fuel filter. When i got about 100 miles on the tank of gas, the car failed to respond to the gas pedal (seemingly). Press gas to the floor--nothing, let it up, press again, nothing, then it will kick in again. The engine drops to 1000 rpm, but doesn't die. Sputtered and sounded like it might die taking off from a complete stop. This was after a 20min drive going between 55-80mph. I also noticed an oil leak under the distibuter cap when changing the wires. I believe its the valve cover gasket, which I'll order. Is it as bad as a head gasket leak where you have to replace oil & probably coolant or not?

the unresponsive gas pedal happened about 15 times in 2 hours without a topped off tank, I refilled it and it hasnt happened since