Car 1990 Volvo 740 wagon turbo 160k

So over the past 3 months roughly the car has runs fine but a few times over that span of time the car has died. It stumbles then dies, and if you let it set it will restart. I noticed that the times it has died it has been on 1/4 tank of gas or less.

So today the car will not start at all. I drove to work and parked the car. When I went to drive home the car would not start. I checked for spark which it had.

I listened for noise at the intank pump and the main pump and get no sound from either. I checked the fuses 1 and 11 and the fuel pump relay. All the fuses and relays are good.

What I think happened is that my intank pump went out and over time the strain on the main pump killed it too.

Do you all think this is a plausible theory, and if so is there a good way to test the main pump?

(i have a prepump, filter sock, fuel line, and gasket to do in tank pump but still would need to buy main pump. I have been meaning to do intank pump but am intimidated by that whole string maneuver deal).

Thanks in advance,

Chris
Portland, OR

now that i think about it I think i only looked at the face of that in tank fuel hose for cracks.

i think i am going to have to pull the intank again. BOOOOOOOOOO!

ok so i changed out the main pump today with a bosch unit and the fuel filter. the car now starts. i am trying to hear if the in tank pump is working. i can hear the fuel returning and trickling in but i can't tell if the pump is running. I have the parts to do that job so plan to do it tomorrow.

i hear you about throwing parts i got to refine my trouble shoot.

How many miles? For $35 from FCP Groton, I would be happy to pre-emptively replace the in tank pump.

I did the job after my main pump died - it sounded like a beehive for a year before it died. I found the string trick completely unnecessary and just put the sending unit in upside down, turned it right side up at halfway and put it in the rest of the way. The bung nut is a little stubborn, but you can use a hammer and long screwdriver or make a special tool to make it move.
It took me about 10 tries to make sure it was seated, but I think I had it as of the third or fourth time. I just wanted to make sure it was right before I put it back together.

Shortly after, my fuel gauge stopped working >.< but that was just my car.

Good Luck, you can do it! It'll just take time, patience, and maybe a lot of posts to the brickboard :D
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1990 740 Turbo, on its way to stock specs, maybe beyond

okay so i was able to get the in tank pump to seat in. I used the string trick put the point of the sender toward three o clock then rotated counter clockwise. The gasket went in first and i lubed it with vasoline. I needed to put some pressure and it popped into place. I hooked everything up and I can hear the pump running plus fuel coming back into tank.

When job was finished i had about 4 gallons of gas in the tank. I have a new symptom now. when i am turning and accelerating (intermittent) I get a lag like it is stumbling out of fuel. I filled the tank up a little over half way and symptom went away. I have not yet ran the tank low on gas.

Does this seem like i might still have an issue with my prepump. If so what could it be? I was thinking that when i popped the assembly into place it knocked off the sock or maybe it is sitting funny in the bowl.

I have pics of the inside of the tank if anyone would like to see. However, need to figure out how to post pics to this site. Do I need to host the pics somewhere else?

Anyway, the other thing I was thinking is that maybe the fuel system needs to have some fuel run through it to get it functioning correctly?

When i put in the intank I set up the pos and negative wire and made sure they corresponded to the correct terminals. Then i put the sock on. It just snapped on. Did I need to do anything else?

BTW -- thanks for the support!

I used the string trick put the point of the sender toward three o clock then rotated counter clockwise.
hello
do you mean clockwise?

one thing i did before i removed the sender unit is mark the outside with whiteout so that when I put it together i new it was in the same location.

i am kinda thinking that my problem might just be my fuel gauge. Can anyone enlighten me on how the fuel gauge gets it's reading?

hello
there is info in the FAQ that explains how to test gauge.
i cant tell you exactly how the gauge works but the resistance changes as the float rises or lower in the sender.
good luck
Mike

okay, i must have missed the FAQ. I will take a look for that. I thought the gauge had something to do with a float. I could here it sliding around when I had the assembly out. Hopefully I don't need a new assembly. If I do I am going to try the junk yard.

If you are referring to the stalling in turns below 1/4 tank, a faulty fuel gauge or sending unit is not at fault. Unless of course it says you have fuel and you are empty. Bite the bullet. Still guessing its the short piece of hose. If you notice the short hose is above the filter sock. So when below 1/4, in a turn. The hose gets exposed to air, with a crack or hole, sucks air, cars wants to stall. Get out of turn, hose gets covered again, car runs again.
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Post Back. That's whats makes this forum work.

yes, that is what i am thinking is that it says i have fuel when I actually do not. I filled the tank up a little over half and the needle on the dash went to a little over half. But then when it got low i lost the accuracy on the gauge and actually ran out of gas. The needle was not even into the red. I got a can and put 4 gallons in the tank and the car started back up. I am leaning between this and that fuel hose.

looks like i am going to need to open it back up. there is a possibility that the hose has a hole on the back side of it. i just looked at the face and said hmmmm this is good.

If i bite the bullet and open her back up. Replace that line and am still have issues. At that point it seems like I am just running low on gas and not realizing it because of the fuel level gauge.

I never had a problem with the fuel level gauge before. So, i am thinking I must have knocked something when I removed the in tank pump.

Unfortunately you have the classic symptom of the short piece of rubber hose has a crack or hole in it. Normally below 1/4 tank and usually left hand turns sucks air. All covered in the FAQs.
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Post Back. That's whats makes this forum work.

From reading the FAQ that is what I was thinking when I first removed assembly but I checked the hose and it was fine. The sock was so old thought that it just crumbled when i was looking at it. However, sock has been replaced.

hello
i use a piece of 3/8 id or 1/8 id flex pipe to stick down there and use as stethascope.
it works.
good luck
Mike

There is a FAQ entry about jumpering from one side of fuse 1 to a specific side of fuse 11 to test the in-tank pump. DON'T DO IT WITHOUT READING THE FAQ FIRST. You can cause serious trouble if you jump to the wrong side of fuse 11.

Your symptoms sound almost exactly like mine when my main pump failed on my 1991 745 turbo. Is your main pump making any unusual noises? Mine sounded like rocks tumbling in a cement mixer when it failed.
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1955 Human, Scott; 1991 745 Turbo, Brunhilde; 1990 745GL, Snuggle Bunny

i really did not notice the pump making any weird noises but then again I never really paid attention. Now the car will not run so listening is not an option. However, I am fairly convinced that it is a main pump and pre pump prob and when I replace main pump car will start again. I then plan to do in tank.

Before you throw parts at it, use the suggestion by N7SC gave you about jumpering around the relay and see if your pumps will run. You are not trying to start it, just seeing if you can hear the pumps run.
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Post Back. That's whats makes this forum work.

Try reaching under the car and tapping on the main pump. You may get it going for a while. You can also test it by running some jumper wires directly from the battery to the pump connection. Have you ruled out the relay?

You could spray some starter fluid in the throttle body and if it starts you'll know that you're not getting fuel. I have a 1990 regina with just 1 fuel pump in tank and was a bit intimidated, but thanks to art bensteins excellent pictorial, I successfully changed it.