long crank time Topic is solved

bigern · Post by **bigern** » 24 Aug 2005, 11:45

have a big dilema.... 2000 volvo v70 xc awd.. after sitting for an hour or two, there is a very long cranking time, five, maybe six seconds. Checked fuel pressure, and it is 54-57 psi (375-395 kpa) at all times when running, but as soon as the key is off, it drops to the floor, like to 10 psi within 8 seconds, therefore the long crank time to build the fuel pressure back up.My customer brought the vehicle to me with a volvo dealership diagnosis of a bad fuel pressure regulator. This is a 7 hour job, so my customer asked me to do a preliminary diagnosis. This is where it is sticky. the fuel pressure regulators job is to keep the pressure at the stated pressures above. so why would the pressure regulator work while the vehicle runs, but then show signs of something ruptured during ignition off, to allow fuel to run back to the tank? there is another fuel pressure test port before the filter, so i removed the filter, blocked the fuel flow, and found that again, as soon as the key is off, the pressure fell to the floor, and this is checking it with the regulator out of the equation. which leads me to believe that there is a valve in the pump that is allowing pressure to be released once the fuel pump is not energized, thus the car needs a pump....... anybody out there have a motion that i am right, or another clue as to what is up?
thanx

dpauto.com · Post by **dpauto.com** » 24 Aug 2005, 15:21

bigern,

Residual pressure dropping to quickly, YES, will cause hard starting. FIRST thing to check to make sure none of the injectors have leak down problem. That can easily done by removing the fuel rail with injectors attached and connected. Then energize the pump by switching on key multiple times. Watch the injectors closely to see they are not leaking. If ok ... then your problem with residual pressure is the FUEL PUMP. The pressure regulator is only to regulate the pressure. The pump has a one way check valve built in side which can effect the residual pressure when it goes bad.

Anyway, the pump should be replaced in this case. HOWEVER ... to prevent future come back, since it's not easy to drop the fuel tank, I would replace the regulator as well while at it. I have seen quite a few bad pressure regulators causing high fuel pressure.

Regards,
Dave

bigern · Post by **bigern** » 25 Aug 2005, 07:42

i did already check the injectors, as well as everywhere else there could be a leak (various connections at filter and such). i thought that i would see if anyone else had an idea. i called the volvo tech and they stand by their diagnosis of a pressure regulator. the problem is trying to convince my customer that volvo is wrong, and i have to put a 650.00 pump in their vehicle instead of a 280.00 regulator. know anywhere that i can get a cheaper pump for this volvo? the part number is 9470674.. the regulator # is 9445512.. i thought of just changing them both, but at the costs of parts its hard to convince customer

AJU · Post by **AJU** » 25 Aug 2005, 07:59

You can find it here for $510: http://www.fcpgroton.com/CSV70/volvocsv70fuelsystem.htm

That's damn expensive for a fuel pump. I guess there is no aftermarket unit yet for the AWD.

Does priming the pump several times - by turning the key back and forth to the on position - before starting change the crank time? If not, I would think the trouble it elsewhere.

dpauto.com · Post by **dpauto.com** » 25 Aug 2005, 13:06

bigern,

I would like to correct my mistake. I spoke to the Volvo Factory Field Tech, he said on this model XC AWD, the check valve is built inside the regulator NOT the fuel pump. Most other models have a check valve inside the pump.

Regards,
Dave

bigern · Post by **bigern** » 30 Aug 2005, 12:09

installed a new fuel pump and residual fuel pressure problem is resolved. apparently, there is a non-return check valve in the fuel pump, not the regulator thanx to all that viewed and gave a reply.. bigern

polygaryd · Post by **polygaryd** » 20 Jun 2007, 23:24

hey guys i have a 2000 volvo xc awd and it does exactly the same thing.. i was thinking there is a check valve in the pump as well. so this confirms my theory. is there any way to have the pump rebuilt for much cheaper so they can just replace the check valve inside the pump rather than put a new one in ? also dpauto.com i saw you wrote that the check valve is in the regulator itself so why when bigern replaced his pump and not the regulator it fixed his problem? what big ern said and what you said doesnt coincide. my thought was it is in the pump and that was big erns fix so should i leave it at that and try to get it rebuilt or get a new pump and leave the regulator alone?? also if i should change the regulator how do you get the lines off of it so i can spend only 100 dollars on one from eeuroparts.com and not 300 from the dealer with the lines since i dont need them..

Post by **JRL** » 21 Jun 2007, 06:01

Guys, gus,
I've posted this before.
You can replace the check valve with an aftermarket valve that fits next to the pump, this part costs about $65.
You will still have to drop the tank and get at the pump, (4 hours)
but you save the 6-$700 cost of a new pump.
Contact me for the part, if you want to save money.
I did this on mine, sold the part to several others and it has been working just fine for 6 month now and seems to work just fine for them too