mark3 Posted September 13, 2014 Share Posted September 13, 2014 (edited) Bit of a strange one this but here goes, looked at a non running Supra turbo the other day with big single conversion that wont start, apparently it was fine then cut out when lights turned on, owner turned lights off and it started ok then one day all of a sudden it would no longer start at all so i was called to have a look, it cranks over in pulses for say 2 second then half second gap while keeping the key in the start position, also the fuel pump ran for maybe 8 seconds when IGN only turned on so im assuming after market ECU? Jumped diagnostic box to get fuel pump on constantly and it had no fuel leaving the fuel rail to the pressure regulator but the pump could be heard and was very loud, went back today with new AEM 320ltph pump and fitted that and i noticed the old pump made virtually no pressure, so that's all good BUT now i still have no fuel entering or leaving the fuel rail BUT i do have fuel going to the pressure regulator from the return pipe??? its like the fuel feed and return pipes have been swapped over somewhere but i cant see any evidence of this anywhere. Also the owner said it was running fine then just stopped and no one else has been near it? im wondering how on earth this is possible? This is the car in question, don't spose anyone recognises it? And this is the current fuel supply pipe feeding the regulator The fuel rail is fed from both ends and return comes from near centre of the rail to the regulator then to tank BUT this is being fed from the return pipe! god knows how it was running at all? Edited September 13, 2014 by mark3 (see edit history) Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted September 13, 2014 Share Posted September 13, 2014 Id like to know who built it, that would be a good place to start. Quote Link to comment Share on other sites More sharing options...
mark3 Posted September 13, 2014 Author Share Posted September 13, 2014 Someone in Japan so the importers told me. Quote Link to comment Share on other sites More sharing options...
absz Posted September 13, 2014 Share Posted September 13, 2014 The fuel pressure regulator will be on the return line, the feed from the fuel pump should go to the fuel rail and return line should go to regulator so what you described seems ok. Quote Link to comment Share on other sites More sharing options...
mark3 Posted September 14, 2014 Author Share Posted September 14, 2014 Well yes that's what I was expecting but I have fuel feed into the bottom of the fuel pressure regulator, the hoses feeding the rail are dead????? The question is how was it running before if what the owner says is true? Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted September 14, 2014 Share Posted September 14, 2014 And you're 100% certain the fuel feed is going into the pressure reg? Has the fuel filter collapsed? Quote Link to comment Share on other sites More sharing options...
David P Posted September 14, 2014 Share Posted September 14, 2014 That FPR looks as though it belongs in the bin anyway. Quote Link to comment Share on other sites More sharing options...
mark3 Posted September 14, 2014 Author Share Posted September 14, 2014 (edited) And you're 100% certain the fuel feed is going into the pressure reg? Has the fuel filter collapsed? I have actually removed the pipe from the fuel rail to the regulator and there is nothing there when pump is running, infact its bone dry but if i remove the pipe from the regulator back to the tank fuel pumps out at pressure when pump spins up. Im wondering if someone has fitted some kind of bypass valve somewhere between the tank/pump and the engine bay??? it can be the only reason for it but if they have i cant find it? And i cant see how a collapsed filter would cause fuel to pump round the system the wrong way? Edited September 14, 2014 by mark3 (see edit history) Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted September 14, 2014 Share Posted September 14, 2014 But it ran before, so obviously the fuel system worked fine previously. Quote Link to comment Share on other sites More sharing options...
Ric Posted September 14, 2014 Share Posted September 14, 2014 JMimports? Quote Link to comment Share on other sites More sharing options...
mark3 Posted September 14, 2014 Author Share Posted September 14, 2014 (edited) But it ran before, so obviously the fuel system worked fine previously. But how it is now it will never run which is where the confusion lies! It's all very very odd? JMimports? No idea? Customer called them and although I spoke to them I didn't ask the name of there company, all they said was clean the spark plugs which wont help with a dry fuel rail! Edited September 14, 2014 by mark3 (see edit history) Quote Link to comment Share on other sites More sharing options...
absz Posted September 14, 2014 Share Posted September 14, 2014 If it was running fine before then you have wired the polarity wrong on the new fuel pump. Quote Link to comment Share on other sites More sharing options...
mark3 Posted September 14, 2014 Author Share Posted September 14, 2014 If it was running fine before then you have wired the polarity wrong on the new fuel pump. Im not that stupid! and i have cracked the banjo bolt on the fuel feed hose on the pump hanger at top of the tank with pump running and it squirts out everywhere from the flow so it IS pumping down the flow from the tank its just not getting to the engine bay in the same pipe??????? Quote Link to comment Share on other sites More sharing options...
absz Posted September 14, 2014 Share Posted September 14, 2014 Im not that stupid! and i have cracked the banjo bolt on the fuel feed hose on the pump hanger at top of the tank with pump running and it squirts out everywhere from the flow so it IS pumping down the flow from the tank its just not getting to the engine bay in the same pipe??????? I'm not saying you are stupid,Just trying to help if its coming out the feed line from the pump then all you can do is follow the pipe from tank to engine bay and that should answer the question to Why its not getting to the rail. Quote Link to comment Share on other sites More sharing options...
mark3 Posted September 14, 2014 Author Share Posted September 14, 2014 (edited) The problem i have is its pumping out of the return at the engine and the supplies to the rail are bone dry? been underneath and found "some" fuel pipes running from tank (hard to tell whats what though) then they disappear above the rear subframe, then a 25mm steel braided hose appears and runs to the front of vehicle that splits into two and both these connect to front and rear of fuel rail, it all looks normal apart from there is no fuel in these pipes? i thought maybe a blockage but why would that cause it to pump out of the return pipe in engine bay? there not linked! Also not keen in dropping the rear subframe and/or fuel tank just to see what going on above as it may show nothing and be a waste of my time and that the customer isnt happy to pay for? but it looks like maybe the only option? Edited September 14, 2014 by mark3 (see edit history) Quote Link to comment Share on other sites More sharing options...
David P Posted September 14, 2014 Share Posted September 14, 2014 Take the pipes off at both ends and blow through them, that will identify which goes where. Quote Link to comment Share on other sites More sharing options...
mark3 Posted September 14, 2014 Author Share Posted September 14, 2014 Trouble with that is I can't blow into one end and be up the other end at the same time lol Anyhow I know what goes where cos pumping fuel into the fuel supply pipe at the rear of car makes it come out of the fuel return pipe at the front of the car, thus my assumption that the two are somehow connected lol Quote Link to comment Share on other sites More sharing options...
absz Posted September 14, 2014 Share Posted September 14, 2014 If it was me I'll just reverse the polarity on the pump wires and see what it does to the fuel flow:) Quote Link to comment Share on other sites More sharing options...
mark3 Posted September 14, 2014 Author Share Posted September 14, 2014 Pump is pumping the correct way as it spurts out when 17mm headed banjo bolt is cracked open on top of pump hanger Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted September 14, 2014 Share Posted September 14, 2014 If it was me I'll just reverse the polarity on the pump wires and see what it does to the fuel flow:) That would just draw fuel out of the fuel lines. Quote Link to comment Share on other sites More sharing options...
mark3 Posted September 15, 2014 Author Share Posted September 15, 2014 That would just draw fuel out of the fuel lines. That's what I thought Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted September 15, 2014 Share Posted September 15, 2014 I suspect the regulator is plumbed in backwards. Should be pump out to fuel rail inlet, rail outlet to inlet of regulator, output port of regulator back to return stub on tank top. Got to be something simple, I am guessing you are a trader for some reason, and you ought to know never trust people when they say "it was fine before...." Is there fuel pressure at either regulator hose?? Maybe as you say, return and pressure lines are reversed? Just re plumb it using basics. Quote Link to comment Share on other sites More sharing options...
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