2001 v70XC Fuel Pressure Bleed Down

userjg · Post by **userjg** » 18 Jan 2011, 11:40

When the car is left overnight in the cold it has difficulty starting, turns over but does not fire.

The "Engine System Service Urgent" message occasionally comes up during the cold start, but it tends to go away on its own or I can force a reset by disconnecting the negative cable from the battery. When it is on the power loss experienced is pretty minimal, not the typical 'power reduced' state that comes with ETM failure (replaced at 50K, car currently at 108K).

I replaced the plugs (NGK platnium) and fuel filter, did not help.

I cycled the key from the I to the II position a few times, I can hear the fuel pump engage, and it starts fine. This leads me to think that the fuel pressure is dropping off. When the car is warm it starts fine.

This began a few weeks ago around the time that I had the alternator and timing belt replaced, and an oil leak in the turbo drain back seal and gasket fixed but I suspect that is coincidence.

A couple of suspect areas would be the fuel injector leaking or the pressure regulator on the main pump but I'm not sure how to proceed in troubleshooting further.

As I'm not ready to give up on this car yet (despite the many challenges I still really like the car) - any thoughts on this would be greatly appreciated.

RaymanSean · Post by **RaymanSean** » 18 Jan 2011, 12:59

It is possible that some varnish has built up on the check valve in the pump or on the injector seats. Usually not all injectors fail at the same time so I doubt it is your injectors which leaves your check valve in the pump. You could test the pump by removing the fuel line that comes from the pump at the fuel rail and applying a static pressure to the line and watching to see if the pressure drops. You could also do the same thing to the fuel rail with it out of the car. However, before you go too far it may be worth your while to send a couple heavy doses of injector cleaner through the gas tank to see if the cleaners will clean the valve/injector seats up. Take a long weekend trip to somewhere that is ~400 miles away and every time you fill up dose the fuel tank with injector cleaner. Seafoam seems to have a large following so you might give it a try.

FCPEURO · Post by **FCPEURO** » 18 Jan 2011, 16:39

I would try running some sea foam through the engine and fuel system. That could be enough to clean out the system and get her running well again.

Also, check to see if there are any codes stored in the computer. That would tell us if it was a sensor of some kind.

userjg · Post by **userjg** » 19 Jan 2011, 23:41

Thanks.

I am running seafoam through the fuel system, hopefully this will correct the cold start prolem (so much for my new plugs :->)). I have read a number of posts on putting seafoam into the intake mainfold through the brake booster line and into the crankcas through the oil fill. I am concerned about the potential negative consequences.

Any thoughts on whether the risks are outweighed by the potential improvements at 108K miles?

Post by **JRL** » 20 Jan 2011, 06:28

You indeed may have a check valve issue.
Common on 2000 Volvos but usually not on 2001s
However if you determine fuel may be your problem, I sell aftermarket check valves for $69.95 shipped.
It's about a 1/2 hour install and WILL fix this, if it proves to be the problem.
Better than spending $1500 for a new fuel pump!

Post by **jimmy57** » 20 Jan 2011, 08:23

Do 2001's still have the fuel pressure regulator in the T in fuel line just in front of the filter or was it already moved to sender/pump cap on that car?
Fuel pressure regulator and the fuel pump check valve both have to be good to hold fuel.
I have always had complaints of hot restart "vapor lock" type symptoms with engine starts, runs briefly then dies or runs very rough for 1-3 minutes when the fuel pressure regulator or FP check valve is bad. The cold start longer crank time may or may not be a complaint also.
Do you have any problems with the way the engine runs if the car is driven for a distance then stopped long enough to fuel it up or do a quick (45 min or less) shop stop?
The CEL coming on while cranking needs to be looked into. That may be a clue to something completely different from fuel delivery problems that is preventing easy start.
A battery with a bad cell will crank an engine over well enough but the voltage for control units can be too low while starter is running.

userjg · Post by **userjg** » 20 Jan 2011, 17:03

There is a T above the filter, I don't know if there us a regulator in there.

In terms of the warm performace of the car there are no issues. It runs very smoothly and has no trouble starting up when left for afew minutes or a few hours.

With the CEL I had a mechanic read the codes and what he came back with is that he saw 4 codes 'related to the TPS'. I did not get the specific codes. He did some additional investigation with the diagnostic tool and found no problems with smooth operation of the potentiometer in the TPS. Since I have started pressuerizing the lines by engaging the fuel pump a few times before trying a cold start the light has not returned.

Thanks for the input.

Post by **jimmy57** » 20 Jan 2011, 17:18

OK ,out on a limb a little bit here but, The fuel injection has it's greatest fuel delivery in the first few revolutions of cranking and then settles to a lesser amount. This does a few things but one of those is compensation for the fact that the sealing of fuel system is not going to be prefect.a good many brand new cars will have 0 psi when they sit overnight. An ETM that goes to a greater opening position and dilutes (leans) the enrichment for cold start will give long crank with rougher start up.
Cycling the key a few times may be building pressure and cycling the ETM and giving it a chance to set to correct position.
The codes may be a very relevant bit of info.
That car has to be close to its ETM ext warranty expiration (hopefully not past 10 yrs or 200K already).
You may want to pursue that at a dealer.

userjg · Post by **userjg** » 20 Jan 2011, 18:12

Unfortunately I am past the 10 year mark by a few months.

Would there be value in removing and cleaning the throttle body?

In terms the ETM potentially failing I gave a close read to the thread below and for what it is worth I am not seeing these kind of symptoms:

https://www.matthewsvolvosite.com/forums ... 12&t=17252

otis44 · Post by **otis44** » 20 Jan 2011, 18:32

For what its worth my fuel pump in a gmc yukon exhibited symptoms similar to yours, particularly when cold or when in cold weather. It would be hard to start or would not start at all without some coaxing. Needless to say the pump finally failed completely. On this vehicle, (not sure if it will work on your Volvo) a crude means of testing was to have someone rap on the fuel tank with a rubber hammer while cranking. If the car starts using this method you can almost be assured the fuel pump is faulty.