S40 V40: No start after changing fuel pressure regulator

[druid]

Originally Posted by ww1dm1

Because I'd prefer to figure out what is going on instead of throwing money at a 16 year old car. "Buy the OEM part" is the boring answer nobody wants to hear. Especially when the OEM part is a most basic 5 EUR pressure regulator priced at 150 EUR. OEM parts aren't special anyhow besides having certain specifications, but if you're too lazy to think a little they're perfect. Might as well recommend taking it to a service shop. If you don't want to help me figure this out then simply don't, it's no big deal.

If you figure it out many, well a few people will be chuffed if it saves money!
Good luck to you!

[ww1dm1]

Forgot to post how it all ended. Eventually I learned that FPR is the same for P1 turbo models and most P2 models (though strangely the way it is connected differs), so it wasn't hard to find a reasonably priced used one. Gave up on the one I got before, good thing it was cheap. I noticed that it couldn't be blown through, while the original Volvo one could (good unit tested). My guess is that some FPRs are "normally open" and closed by the vacuum pressure, and some are "normally closed" and opened by the vacuum pressure.

So lesson learned - FPRs can differ not only by maintained pressure. Don't get the Audi/VW one.

Though unfortunately that didn't completely solve my problems, it seems as the fuel pump is catching air when I turn the ignition on (the pump sound is "dirty"). I'm starting to think that the other FPR is completely dead, or the pump is dying somehow. Need to find myself a fuel pressure gauge.

[skyship007]

Originally Posted by ww1dm1

Because I'd prefer to figure out what is going on instead of throwing money at a 16 year old car. "Buy the OEM part" is the boring answer nobody wants to hear. Especially when the OEM part is a most basic 5 EUR pressure regulator priced at 150 EUR. OEM parts aren't special anyhow besides having certain specifications, but if you're too lazy to think a little they're perfect. Might as well recommend taking it to a service shop. If you don't want to help me figure this out then simply don't, it's no big deal.

Once you have confirmed the routine service items have been done if the fault persists it really is worth buying a code reader or figuring out which Indy has got a good one. Otherwise you will often waste time and money guessing what is wrong.

Once you know what needs replacing it's worth using a VIN & engine number specific web site like Skandix to figure out the part number and find out if there might be an alternate part. The HP pump is probably a Bosch unit, so the FP regulator will almost certainly be from the same company (The MAF sensor is a Siemens). List of Skandix FP regulator parts:
http://www.skandix.de/en/suche/?q=fuel%20pressure&k=849
(You need to register and use a VIN for the correct part, BUT they don't send spam)

Obviously if you have the current Volvo software that will also ID the part number and fitting a used part which does seem to fail is a gamble.
A faulty FP should throw a hidden fault code, BUT you can also get the same code cos of a blocked feed (Fuel filter or LP feed pump if fitted). If it's sucking air in then the engine will probably stall or fail to start.

[ww1dm1]

Originally Posted by skyship007

Once you have confirmed the routine service items have been done if the fault persists it really is worth buying a code reader or figuring out which Indy has got a good one. Otherwise you will often waste time and money guessing what is wrong.

Once you know what needs replacing it's worth using a VIN & engine number specific web site like Skandix to figure out the part number and find out if there might be an alternate part. The HP pump is probably a Bosch unit, so the FP regulator will almost certainly be from the same company (The MAF sensor is a Siemens). List of Skandix FP regulator parts:
http://www.skandix.de/en/suche/?q=fuel%20pressure&k=849
(You need to register and use a VIN for the correct part, BUT they don't send spam)

Obviously if you have the current Volvo software that will also ID the part number and fitting a used part which does seem to fail is a gamble.
A faulty FP should throw a hidden fault code, BUT you can also get the same code cos of a blocked feed (Fuel filter or LP feed pump if fitted). If it's sucking air in then the engine will probably stall or fail to start.

I'm using Vol-FCR for error reading, sadly such problems as incorrect fuel pressure do not give a code, so I have to go with mechanical means of fault finding. The FPR is made by Weber.

It started to run really poorly lately after developing a slight vacuum leak at the throttle, now whenever the engine reaches it's working temperature it is barely able to maintain idle. RPM drops down to almost zero, shoots back up to ~700 and drops again, forming a hunting oscillation. Sometimes stalls after throttle is suddenly released. My thoughts is that at low temperatures the cold start rich mixture keeps the engine somewhat well, but when the working temperature is reached it becomes too lean because of insufficient pressure and atomization.

By the way, do the x40s have a dedicated fuel pump filter on the sender, like the v70??

[grow junkie]

Originally Posted by ww1dm1

Because I'd prefer to figure out what is going on instead of throwing money at a 16 year old car. "Buy the OEM part" is the boring answer nobody wants to hear. Especially when the OEM part is a most basic 5 EUR pressure regulator priced at 150 EUR. OEM parts aren't special anyhow besides having certain specifications, but if you're too lazy to think a little they're perfect. Might as well recommend taking it to a service shop. If you don't want to help me figure this out then simply don't, it's no big deal.

960kg thinks he's a wise guy.....don't take it personal.

[skyship007]

http://www.volvoforums.org.uk/showthread.php?t=147630

That thread is about the T4 in-tank fuel feed pump.
If you really are fault code free, then it's probably a forked LP fuel pump (Might just be gummed up) or a bad fuel filter.

PS: 960kg does know one end of a V40 pump from another!

[ww1dm1]

Originally Posted by skyship007

http://www.volvoforums.org.uk/showthread.php?t=147630

That thread is about the T4 in-tank fuel feed pump.
If you really are fault code free, then it's probably a forked LP fuel pump (Might just be gummed up) or a bad fuel filter.

PS: 960kg does know one end of a V40 pump from another!

I replaced my fuel filter a couple of months ago, couldn't believe it went so fast. Will take a look at the pump this weekend, hopefully the inner filters are clogged and everything will go back to normal after cleaning those.

It even sounds a little a little higher tone during ignition phase, besides sounding odd in general. I remember running out of fuel in an old Audi once, won't forget the high pitched starving fuel pump sound, does not bring back good memories.

[ww1dm1]

Cleaned the fuel pump and sender filters, turns out they are metal mesh filters. Still seemed a little dirty, so gave them a good spray. This gave me an idle fuel pressure increase of 0.1bar, which seems negligible, but it sounds a lot better now and I no longer have a poor running issue, strangely.