fuel gauge or sensors ??? car 1999 xc v70 won't start

cindiana · Post by **cindiana** » 26 Mar 2011, 06:46

I have a 1999 Volvo xc 70. About a year ago, my car died while I was driving. Turns out it was out of gas but the fuel guage did not go below the 6 oon the indicator. Okay, so I have been driving by the tripometer and average miles per gallon. A month ago, I went out to start my car in the morning. It was very cold around 0 degrees F. I thought that the battery was low so charged it up, still no start. So I thought maybe it ran out of gas, although by my mileage indicator that could not be true. Anyway, I ran and got my lawnmower gas and added about 1 1/2 gallons. The car started right up. I went and got gas and found that, indeed there was still about 6 or 7 gallons in the tank when the problems accurred. It has run fine and started fine until last night. I had filled my tank earlier in the day and made 2 more starts and stops. Then last night I went to start it, cold again but still in the 20's. And it is the same sort of feeling. The engine is not getting gas or thinks that there is no gas for some reason.
Recent work-changed out blower motor myself. Had tires rotated, antifreeze changed, oil change and had the heat shield over the drive shaft refastened into place (it had come loose and was rattling a little for about a week.
Right now, I am jumping the battery as I wore it down a little. Am hoping that as the sun warms things up it will somehow make the car realize that it does have gas!
Any ideas, and is it something I can do myself? I have changed out the ABS module, blower motor and a few other things but am not a mechanic. Can fix lawnmowers, computers and stuff like that, but do not have all the tools, guages and cool things you need to diagnose these problems. Dealer is about 1 1/2 hours away.
Thank You.

cindiana · Post by **cindiana** » 26 Mar 2011, 06:54

A little update-just went out to try again and it didn't start, but when I turned the ignition off it still was trying to run and I could even remove the key and it kept 'running' Put key back in, turned it on and off and it stopped!

Post by **Pauloil** » 26 Mar 2011, 08:55

when you turn the key to pos. II, you should be able to hear the fuel pump priming the motor. you may be lucky and have a bad fuel pump relay, and you can read a lot about that on this site. you can jumper two of the plug ins for the relay and see if the fuel pump runs. it is also poss. to check if you have fuel pressure by pressing the schrader valve at the end of the fuel rail: after priming the pump, you should get a squirt of fuel out.

https://www.matthewsvolvosite.com/forums ... =1&t=37456

cindiana · Post by **cindiana** » 26 Mar 2011, 09:07

Hi Pauloil,

Thank You. Since posting, I have removed the relay and jumped the two posts indicated with a paper clip. I am not hearing anything when I move my key to pos II . I do not know where the fuel rail is, or what a schrader valse is, although If I could see it I would probably be able to figure it out. And is access to the fuel pump through opening up the cargo area removing rugs etc and the round thing with 4 bolts holding it in? I enjoy workinng with my car, but the learning curve is kind of steep on some items!
Thank You

Post by **jblackburn** » 26 Mar 2011, 09:31

From what I understand, changing the fuel pump on an AWD models pretty much means cutting through your floorboard or dropping the entire tank; I don't think they made an access panel in the floor for you guys.

Here's the schraeder valve, at the end of the silver rail on top of the engine.

You'll probably have to remove the triangle-shaped piece of black plastic with a single screw on the drivers side of the engine to gain access to it. I can't remember if 99's have that there or not.

cindiana · Post by **cindiana** » 26 Mar 2011, 10:04

My schraeder valve is exposed, at least that was easy. When I first opened it, a little gas came out-perhaps left over from yesterday when car ran fine. Subsequently retried starting with the relay in and with the relay jumped and now no gas comes out. I am hoping/wondering though in how this happened once before and was easily remedied, with no problems since, and now once again, and after a pretty cold night, it has happened, with no apparent remedy. My feeling is that it is electrical and somehow related to the failure of the gas float or sensor to accurately register the presence of gas. When I try to turn my car on, all the lights are fine, gas guage is at full (which it is), and everything kicks into place, except the engine. Is there anything else electrical or control wise that could be causing this problem? Or do I just have to face the facts? Thank you for answering my questions. There is no way, that would feel comfortable cutting a hole in the bottom of my car

. Maybe it is the fuel filter, please?

Thanks Again,
Cindiana in the Temple of Doom!

Post by **jblackburn** » 26 Mar 2011, 10:20

Since you're sure there's gas in the tank, and dont hear any noise from it, it sounds like the fuel pump just died outright. I know, it's never a fun experience - but at least yours didn't go as you were trying to merge onto the highway filled with trucks

Here's how to go about replacing the pump on an AWD model from the top (without dropping the tank). Once you gain access to the pump and replace it, you can find a piece of sheet metal or something to rivet back down over the opening.

https://www.matthewsvolvosite.com/forums ... =1&t=20367

The contacts on the float sensor are probably gummed up and not giving you an accurate reading when the tank drops below a certain level. Gasoline with ethanol in it (most of it now contains at least 10-15%) will cause that to happen to the sensors.

cindiana · Post by **cindiana** » 26 Mar 2011, 10:39

Thank God, I told my teen-agers I would take them shopping today. Gonna take a shower, start up the old Jeep (registered farm vehicle and very glad that we didn't junk it), and go buy some nail polish or something girly. I will have to think through this before attacking my car with my sawzall, or just leave my house before I attack with the sawzall before thinking i through!
What about that FPR thing I have read about?

Thanks to everyone for their help!

Post by **jblackburn** » 26 Mar 2011, 12:12

I am not hearing anything when I move my key to pos II

Not the regulator. If you jumpered the relay and still aren't getting anything, the fuel pump has just quit on you. Sometimes they'll work again for a bit if you hit the underside of the tank with a 2x4 or something (especially if it's super cold), but it's not something I would trust to keep working.