1998 V70XC Fuel pressure

rhd · Post by **rhd** » 07 Nov 2015, 11:24

I recently bought a 1998 V70 XC with a diagnosis of needing a fuel pump. The owner had all the repair receipts for the last decade, and the price was very reasonable. Checking the fuel rail showed no fuel pressure at all. All the fuses are good, and I replaced the fuel pump control module with a known good unit.
I replaced the fuel pump, but it still wouldn't start. There was almost no pressure at the fuel rail. I changed the pressure regulator, and now there is some pressure at the fuel rail, but not a lot. There is spark, and it turns over but doesn't fire up. The "check engine" light does not come on.
Other than this problem, it is in great shape and a neighbor wants to buy it from me. What should my next step be?
Thank you in advance for your help!

Post by **kahl** » 07 Nov 2015, 11:31

When you turn the key can you hear the fuel pump kick on? I know you replaced the pump but it is a good place to start.

jcdillin · Post by **jcdillin** » 07 Nov 2015, 11:53

Keep in mind that if the car is AWD the main fuel pump is actually on the passenger side and is not accessible unless you cut a hole in the car, or drop the rear subframe. The unit on the drivers side is just the injector assembly that transfer fuel across the saddle.

When I got my AWD it was showing over a half of tank of gas, but in reality it had more like a quart, this was because all the gas was stuck on the other side of the saddle tank. May be worth adding some more just to be sure. I was able get the system to re balance by adding a few bottles of techron fuel system cleaner.

The other suspect would be a failing fuel pump relay, should hear the pump kick on for a few seconds after turning the ignition on.

rhd · Post by **rhd** » 07 Nov 2015, 13:00

The fuel pump does hum for a couple of seconds when the ignition switch is turned on, and also when it's turned off. I replaced it by cutting an access panel behind the passenger seat. The fuel pump relay has been replaced. There is now gas at the fuel rail where there was not any before.
I researched the project on this site before doing it. By now it should be running! Hopefully someone here has had this situation come up and found something else that causes the problem.

Post by **kahl** » 07 Nov 2015, 18:27

I wonder if you have lawnmower syndrome. Try putting a half cap of oil in each cylinder. If you have spark, gas and compression it should pop. There are many posts about this lawnmower syndrome. Worth a shot.

rhd · Post by **rhd** » 02 Dec 2015, 10:54

The trick to get it running again was to squirt some brake cleaner into a vacuum hose at the front of the engine. I'm not sure what the hose is, a mechanic friend of mine did it and explained it afterwards. I had tried ether in the air cleaner box, but apparently that's not enough to get things going. Now it runs like a top.
Looking back, it may have helped to just hold the Schrader valve on the fuel rail open and run the fuel pump to purge the air out of the fuel lines. If anyone has this problem and finds that that works, please post it here.

Post by **cn90** » 02 Dec 2015, 12:33

How old is the fuel filter?

rhd · Post by **rhd** » 02 Dec 2015, 22:48

The fuel filter was changed last at 163K, and it now has 235K.
The fuel pump was the original, and it had finally given up the ghost.
Now it is running fine... the next project is to replace a front half-shaft.