scotts40 Posted September 15, 2015 Report Share Posted September 15, 2015 Hi everyone, iv got a couple of annoying problems i trying to sort out with my 1998 s40 20t, ill give you a quick rundown on it first then my 2 problems 1998 modelB4204t5 speed2.5" exhaust from the turbo back and 1 rear muffler no cat convertersDigital boost gaugeMbc problem number 1 is what i suspect to be low fuel pressure, my reason for thinking low fuel pressure came from hours of searching google. Thats how i found this awsome forum. So far ive replaced oil filter and oilCoils PlugsLeads Fuel filterGenuine volvo fuel pressure regulator Brand new fuel pump and intank filtersSecond hand fuel rail and injectors The symptoms my car was showing where taking to long to start and when my tank gets to around 20 litres left it feels like its running out of fuel, when i fill up the tank i get 40 litres in so gauge is working properly. Im not sure where to go from here with this problem.My second problem is low boost, i installed my boost gauge and mbc on the weekend, i bypassed the factory bcs/tcv. When I went for my test drive and boost adjusting fun my car was only makin 3.5psi, i screwed the mbc in 1 turn and boost increased to 4.5psi, i pulled over again and adjusted the mbc 2 more turns and it was then screwed all the way in. Im now making 7 psi, the car pulls alot better now but im still not even making the factory boost levels. All mbc adjustments where made after 3rd gear pullsThe reason i posted both these problems together is i think they might be due to the 1 issue, i know that they have 1 thing in common wich is vacuum lines. At the moment my boost gauge isn't t'd into the cbv vacuum line, its hooked straight up to the nipple for the cbv on the manifold. Any help or guidance would be greatly appreciated. Thanks in advance, regards Scott Link to comment Share on other sites More sharing options...
1clean00 Posted September 15, 2015 Report Share Posted September 15, 2015 Can you smell any fuel around the engine compartment? The long cranking and low boost pressures would make me think you have a vacuum leak. The long cranking can also be fuel injector leakdown, have you checked the rail pressure after the car has been off for a extended period? Like in the morning if you press the fuel rail valve will any fuel come out? Also, the fuel pump assebmly itself could be the cause of the low pressure. If its not getting the fuel, the boost isn't going to come on as it should. The fuel pressure regulator should hold 3.5 bar at idle and from there work as a rising rate with boost. Link to comment Share on other sites More sharing options...
theForgottenone Posted September 15, 2015 Report Share Posted September 15, 2015 I'm also going on a limp to say you have a vacuum leak somewhere Link to comment Share on other sites More sharing options...
scotts40 Posted September 15, 2015 Author Report Share Posted September 15, 2015 Hi thanks for the quick replys, i sometimes get a wiff of raw fuel when i take off from a giveaway sign. Thats what I was thinking about the injectors because when i push the valve on the end of the fuel rail it only spits a little bit of fuel out at low pressure. I'll have a poke around the engine bay and suss out the vac lines. I'll grab another fuel pump assembly. Thanks for your suggestions and ill do an update of my progress Link to comment Share on other sites More sharing options...
scotts40 Posted September 22, 2015 Author Report Share Posted September 22, 2015 Ok so i had a look for any vacuum leaks today using soapy water in a spray bottle but didn't find anything, im going to try the smoke method on the weekend. im still trying to track down the fuel pump mechanism aswel. Cheers Link to comment Share on other sites More sharing options...
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