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Discussion Starter · #1 ·
Hello and welcome to my very first post :)

I'd like to share some thoughts related to my recent problem with my Volvo V70II T5. Maybe there's someone out there who might have a good idea :) For thoose who don't know the t5: Its the B5234t3 5-cylinder petrol turbo machine with 250HP.

Appearence:
Engine does crank and turns but doesn't start at all -> battery is full and I have enough fuel.
VIDA does not deliver any problem related codes (only ECM-0093 ECM-0123 related to a additional problem with the yaw rate sensor which is unlikely related - at leat I can't see any relation).

What I already checked:
Fuel pump starts running when I turn on to inction position II (does make a noise for ~2sec when I turn over from key position I -> II). As well I can measure a 12V power supply at the pump connector - sure I was able to hear it. I swop the fuel relais. Changed the fuel filter - it was time anyway and checked if there´s fuel pressure at the fuel rail: I would suggest that there isn't enough pressure... When I press the pin at the valve-access-point there´s coming petrol but far away from 40-50psi, just draining off a little. Unfortunatly I was alone today and I have no pressure gauge so I didn't tested it while starting the engine in the same time. Don't know, what's your experience? Should there be more pessure? Am I wrong when I say that after turning inction on and off several times (this runs the pump always for 2 sec) I should have quite a bit pressure at the rail, do I? This Engine does not have a fuel pressure sensor - fair enough that VIDA doesn't come up with something related to the fuel pressure, but anyway I found quite a few post related to fuel pump issues where there have been error codes delivered... Why there's nothing?! Is that explainable to someone?

Just in case I checked as well the values of the temperature sensors, the Air mass flow sensor, changed the camshaft postion sensor to one I still had in my workshop and was searching for my fuel pump control modul PEM which I apparently don't have?! At least I did't found it neither on top of the tank (I have a plastic version), inside the spare weel area nor behind the weel covers like with the XC models. I just have read that thoose moduls used to fail over time due to the exposed postion outside the car.

What's your thoughts? Where would you focus?

PS: Sorry for my english ;)

Best David
 

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To run, an engine needs fuel, spark and oxygen, delivered at the right time. Is fuel getting expelled from the injectors into the cylinders? Are the coils firing the spark plugs? Could it be the timing?
 

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Discussion Starter · #3 ·
Thanks thaxman :) Meanwhile I'm a step further and yes injektors, coils, spark plugs and timing is fine. Got the engine to run with starter spray today. That means for me it's for sure a issue with my fuel supply.

So I can hear the pump, I measure 12V supply, I have a new fuel filter and changed the fuel pump relais. So its most likely the pump anyway... Or do I have somewhere a corroded PEM mounted? As I said at the beginning I didn't found one...


Best David
 

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Pretty sure that when theschreader valve is pressed the fuel should come out pretty strongly initially. If it's simply dripping out, you've got a problem.
 

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No pem on these cars. That starts in 04.5.

Pump could be toast or lost the feed line in the tank possibly?
 

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Discussion Starter · #6 ·
Thanks ScottishBrick! No PEM is a important Info :)

In the meantime I took out the fuel pump and tested it in my workshop with fuel. Pump was okay and when I bridge/link the line-in and -out the pump builds up pressure. Fine... And the Problem?
Well it took me some minutes to figure out how it works with the fuel transport from the tank reservoir to the fuel pump reservoir which are two seperated reservoirs. I realized that my problem was that I had an empty fuel pump reservoir (however that happened?!?!?) and because you need fuel in the fuel pump reservoir to get new fuel from the tank (venturi princip) the hole system stopped working.
I remember the time I took the pump out of my tank, the reservoir in which the pump sits was empty neverless my tank was at leat 30% filled with fuel...

I put things back together, filled the fuel pump reservoir before closing the tank and voila: Pump is running, fuel pressure is back at the rail and Engine runs perfect. But what the f**k happened? Why could my fuel pump reservoir run empty? Leak in the fuel pipes? Does make no sence to me, because maybe I might loose fuel pressure in the pipes while standing, but the pump reservoir should anyway not be effected to that?! Can someone explain that?



Best David
 

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Discussion Starter · #7 ·
Quick Update: After one night the fuel pump reservoir was empty again and the car didn't started... Well someone has a idea were I might loose the fuel?

best David
 
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