V70 petrol fuel pressure

[ClassicChris]

2000 V70 (P80) B5244 S2 Manual

I have the CEL on and VIDA gives me the code 'ECM-250A Long-term fuel trim - lower limit'. (A generic reader gives 'P0170 - System Too Rich'). The freeze frame gives the value 0.77 for long term fuel trim, so I am assuming this is (or is close to) the lower limit. There are no driveability issues at all.

VIDA says the fuel pressure should be 3.0 bar. So I check the fuel pressure and find 3.9 bar - problem found, I'm thinking. I also check that the fuel pressure holds up when turned off - to check for leaking injectors - which it does. So I go looking for the fuel pressure regulator which on my car is mounted rather untidily in the fuel line at the back just forward of the filter. The regulator is part 9186277 which is marked 3.8 bar. WTF?

So, if I am to believe VIDA, then I should have a 3.0 bar regulator. Could it be that my car has had the wrong regulator fitted all it's life and the long-term fuel trim has been compensating - until now, when due to accumulated age-related effects, it has run out of range? This would account for my problem very tidily but I am struggling to believe that Volvo would have fitted the wrong regulator. Could they?

Before I try fitting a 3.0 bar regulator (not a trivial task due to the nylon fuel tubing) does anyone have any insight into this? Specifically, should I believe VIDA when it says the pressure should be 3.0 bar?

[Clan]

Originally Posted by ClassicChris

2000 V70 (P80) B5244 S2 Manual

I have the CEL on and VIDA gives me the code 'ECM-250A Long-term fuel trim - lower limit'. (A generic reader gives 'P0170 - System Too Rich'). The freeze frame gives the value 0.77 for long term fuel trim, so I am assuming this is (or is close to) the lower limit. There are no driveability issues at all.

VIDA says the fuel pressure should be 3.0 bar. So I check the fuel pressure and find 3.9 bar - problem found, I'm thinking. I also check that the fuel pressure holds up when turned off - to check for leaking injectors - which it does. So I go looking for the fuel pressure regulator which on my car is mounted rather untidily in the fuel line at the back just forward of the filter. The regulator is part 9186277 which is marked 3.8 bar. WTF?

So, if I am to believe VIDA, then I should have a 3.0 bar regulator. Could it be that my car has had the wrong regulator fitted all it's life and the long-term fuel trim has been compensating - until now, when due to accumulated age-related effects, it has run out of range? This would account for my problem very tidily but I am struggling to believe that Volvo would have fitted the wrong regulator. Could they?

Before I try fitting a 3.0 bar regulator (not a trivial task due to the nylon fuel tubing) does anyone have any insight into this? Specifically, should I believe VIDA when it says the pressure should be 3.0 bar?

There are early and late systems , Yours is later , The early ones had the pressure regulator on the fuel rail , so this may account for your two different figures quoted .

[ClassicChris]

OK, problem fixed - simply by re-plugging the MAF connector a few times. As soon as I had done this the fuel trims started recovering and after about 100 miles had settled to sensible values. Just kicking myself now that it took me so long to try that. I have now gone round cleaning all the sensor connections for good measure.

I didn't change the fuel pressure regulator and I have to conclude that VIDA is wrong for my late-model V70 (MY 2000). Good to know that you can trust the official documentation!

[Luxobarge]

Brilliant - thanks for posting the result, you must be chuffed. I always spray a bit of WD40 on the connectors to ward off corrosion, or better still a little wipe of Vaseline, this seems to work for a long term fix, but the main thing is you're sorted, well done.

Cheers!