dini_the_owl Posted January 8, 2008 Share Posted January 8, 2008 im quite sure n/a ones are different as i have an n/a one here you could try,its definately worth a look just to check part numbers etc, its a bit of a ballache to get to but you could always do the bypass line if its knackerd though, cant find any pics at the mo to show you but daryl knows where its situated, its somewhere to start. p.s have you changed your filter? Quote Link to comment Share on other sites More sharing options...
Dash Rendar Posted January 8, 2008 Author Share Posted January 8, 2008 Thanks for the ideas. I'll get Mark to look into it tomorrow. Yes, I've changed the filter, pump, FPR and hoses. Quote Link to comment Share on other sites More sharing options...
Sean1933 Posted January 9, 2008 Share Posted January 9, 2008 Given the amount of things you have changed i would be in agreement with Tricky, sounds like a partial blocked line. If it were me i would try using an independent line thus bypassing any stock pipework and potential blockage. Wouldnt take long to do either Quote Link to comment Share on other sites More sharing options...
Dash Rendar Posted January 9, 2008 Author Share Posted January 9, 2008 Okay, thanks for that idea. Something for me to add to the todo list. The car spent a day with Mark and Matt Harwood at Phoenix today. Alas, the problem still remains. Mark's initial suspicion was that a hose attached to the pump might be leaking fuel. He was pleased to see that this was in fact the case: there's a short fuel hose attached to the pump which appears to have an inner and an outer sleeve. Apparently, when testing, this tube was p1ssing fuel all over the place. He replaced this hose, and they switched the fuel pump to be on 12V permanently. But on driving the car, the problem still remains. The FPR loses over 10psi in pressure while driving, and this appears to be (although still not proven) as a result of it getting hotter. There are no wiring issues and the voltage checks were fine. Matt and Paul think that I may have been unfortunate enough to have replaced my fuel pump with a malfunctioning new unit. Given my luck, this wouldn't surprise me. So, I'll order yet another fuel pump and hope that that's the answer to my problems. I'll also be spending some more money I don't have on an in-cabin fuel gauge, to help with the diagnosis process. On a side note, it turns out that the RLTC I bought a month back isn't quite working properly, but Matt thinks he might be able to resolve this easily enough. (This has no bearing on the FPR problems; I've had the RLTC turned off as it makes the car misfire all the time!) Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 10, 2008 Share Posted January 10, 2008 How are you measuring the fuel pressure, not with one of those el cheapo gauges stuck in a port of the regulator? If so, you have considered the very obvious, that the gauge misreads when it gets warm? If it's a cheap mechanical gauge the clockspring won't be thermally corrected, and its tension will vary with heat. Quote Link to comment Share on other sites More sharing options...
AndyT Posted January 10, 2008 Share Posted January 10, 2008 Sorry this is still an issue mate. Mind you it will be a mega fix when it's sorted. Which I hope it is soon. Quote Link to comment Share on other sites More sharing options...
Dash Rendar Posted January 10, 2008 Author Share Posted January 10, 2008 Yes, that's exactly how I'm measuring the fuel pressure! However, I have tried two different gauges now (both different makes and both behaving the same), and when Ryan was mapping it, he had to constantly add more and more fuel as the car got hotter, which he attributed to a continuing drop in fuel pressure. So it doesn't look as if the gauge is lying. While I'd love to fit a gauge costing hundreds like you told me too, alas I don't have the money. But I'm going to get a gauge in the dash, tapped into the fuel line at the back of the fuel rail. I'm presuming that will not be affected by temperature in the same way, since the gauge is in the dash. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 10, 2008 Share Posted January 10, 2008 OK, sounds like it's unlikely to be the gauge then. Most garages will have perfectly good remote fuel pressure gauge and adaptors, they are used almost daily and very common now everything is FI. Having pipe fed fuel pressure gauges inside the car is a bit dodgy. I have never heard of one leaking, but is it worth the risk? I still think you should try a stock FPR Quote Link to comment Share on other sites More sharing options...
Dash Rendar Posted January 10, 2008 Author Share Posted January 10, 2008 I've bought a stock FPR, but didn't see much point in putting one on until I have a gauge that can read the fuel pressure... otherwise I might not know if the problem still remains. But it's in my bag of tricks and ready to go on the car. I've got an HKS one to try too. Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted January 10, 2008 Share Posted January 10, 2008 Chris, Mark does have a proper fuel pressure tester, and that was one of the first things we checked. The gauges read within about 2 psi variance at 40 psi. - Sadly, not that. As Darren said, when we first checked the pump, it was clearly leaking from the lower hose connection, but after we replaced that, if you were to restrict the pumps output, you could actually phisically stop the pump and the current draw went massively up as you'd expect it to. The power supply was perfect reading at 13.8 volts minimum. We also replaced a piece of weak hose, but that made no difference either. His regulator is where the charcoal cannister would have been. Exactly the same place as mine, and many others that I've worked on. Yes, it gets warm, but nothing excessive, and I certainly don't have this problem. it's a strange one. Probably something really simple, but until I can find it, it's annoying... Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted January 10, 2008 Share Posted January 10, 2008 Sorry, after proof reading my post it may sound as if I am suggesting you don't have the right gear, whereas my point was meant to suggest he need not buy an in car gauge, adaptors and plumbing as wherever he takes it these days will have their own pressure tester. It is indeed odd, sometimes something which should be easily resolvable proves the trickiest Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted January 10, 2008 Share Posted January 10, 2008 Don't worry, I didn't read it like that. Quote Link to comment Share on other sites More sharing options...
Ian C Posted January 10, 2008 Share Posted January 10, 2008 Wotcha. Just got off the phone with Matt discussing a few approaches to this, so I'm going to write them up here for his reference purposes 1) As you've ascertained that the FPR gauge is accurate enough for the purposes of diagnosing this problem, get Mark's tester on the outlet from the pump cage and compare the fuel pressure there and at the FPR, see if there is any significant variance. Monitor it as the fuel pressure at the FPR changes and note the pressures read by both gauges as the FPR one drops. You should easily then see if there is a difference between the two points as the issue arises. 2) Run up the fuel system using the diag bridge and check the pressure, then stop it, take the return hose off the FPR, put a known good one on and vent it into a jerrycan, then run the fuel system up again. See if there is any difference in the fuel pressure. This should be done while the car is cold. From those two tests we should be able to seriously narrow down exactly which part of the whole fuel system is causing the intermittent restriction. -Ian Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted January 10, 2008 Share Posted January 10, 2008 Quote Link to comment Share on other sites More sharing options...
Dash Rendar Posted January 10, 2008 Author Share Posted January 10, 2008 2) Run up the fuel system using the diag bridge and check the pressure, then stop it, take the return hose off the FPR, put a known good one on and vent it into a jerrycan, then run the fuel system up again. See if there is any difference in the fuel pressure. This should be done while the car is cold. -Ian Ah... So we can see if there's a restriction somewhere along the line back to the pump? Good thinking. Quote Link to comment Share on other sites More sharing options...
Dash Rendar Posted January 18, 2008 Author Share Posted January 18, 2008 I've just had the fuel pulsation dampener bypass fitted. I got charged £65 by the garage, and the bypass itself cost me another £60... so I expecting a nifty bit of kit, not a single piece of braided hose!! Doh! Anyway, the problem still remains. I haven't yet bought the gauges as I'm waiting on a new credit card to arrive to pay for them. When the car goes into Phoenix next, I'll pass on Ian's recommendations for diagnosis. Unfortunately, what with them being so busy, it's going to be quite a few weeks before it goes in again. Bloody car... Quote Link to comment Share on other sites More sharing options...
Sean1933 Posted January 18, 2008 Share Posted January 18, 2008 I thought your car was already in phoenix mate? I would do what Ian suggested earlier in order to check for blockages on the return line. I would also use a new feed line straight to the pump as to bypass the old feed line...also avoiding any potential blockages there too. Quote Link to comment Share on other sites More sharing options...
Dash Rendar Posted January 18, 2008 Author Share Posted January 18, 2008 It did go to Phoenix, but I could only get it booked for the day. I'm now waiting till end of Feb for my next slot, and I'll certainly get everything done that has been suggested, thanks. Quote Link to comment Share on other sites More sharing options...
kylestt Posted January 18, 2008 Share Posted January 18, 2008 Just speaking out loud here....but If the return line is blocked or stuffed, wouldn't this cause the FPR to not lose pressure? Because the line will be blocked causing the fuel to stop in the line, which in return shows pressure up until the blockage point? Just speaking out loud here as i'm bored, someone tell me to hush if i'm in left field Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted January 18, 2008 Share Posted January 18, 2008 The theory is that if there is a movable blockage in the feed or return pipe, (i suspect the return) then whatever the pressure is set at, is either going to increase or decrease, depending on if the pipe was partially blocked, or free flowing when it was set, if that makes sense. Quote Link to comment Share on other sites More sharing options...
Dash Rendar Posted February 26, 2008 Author Share Posted February 26, 2008 A quick update on this. The car spent a couple of weeks at AFR Tuning. Matt had a theory that the symptoms might be caused by a compression problem. So they did a full leak-down test on the engine. Fortunately, it came back fine, so that's a relief. However, they did notice a lot of what appears to be steam coming from the exhaust. I've noticed this before, since a lot more steam seems to come from the exhaust in this car than in my old one. I mentioned it to Mark when I was at Phoenix last time, and he said this was common in Supras, as the long exhaust system leads to a lot of condensation. But I was still a bit puzzled because this happens even after the car is hot, and I would have only expected condenstation while the car is warming up. Matt and another guy at AFR Tuning said that the amount of steam coming from my car was far from normal, and said a small puddle had formed behind the exhaust while they had it on the dyno. They reckon that coolant must be getting into the system; one of the guys there is sure it's the head gasket. They did do a coolant contamination test, and it showed up clean, but he said that's not conclusive at all. I guess it might also be coming from the water cooled turbo. The weird thing is, I very rarely have to top up my coolant... Maybe an inch every couple of months. Could that really account for all the steam? And why would a coolant leak into the engine system cause the fuel pressure to drop so much? I didn't really get that. The car will be going back into AFR Tuning again soon to carry on the diagnosis, but if anyone has any suggestions in the meantime, please let me know. Quote Link to comment Share on other sites More sharing options...
gaz1 Posted February 26, 2008 Share Posted February 26, 2008 no suggestions but hope it gets sorted for you, was great meeting you mate;) Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 26, 2008 Share Posted February 26, 2008 Doesn't sound like a coolant issue to me, if you are hardly using any water, also the coolant cant get into the turbos and be burnt as the water jacket doesn't come into contact with the spindle, even if coolant was entering head through a crack etc it could have no effect on fuel pressure, other than perhaps a very slight variance due to idle fluctuation, as said feed and return lines need to be checked, along with pump, cant remember was the voltage to the fuel pump monitored during the pressure fluctuations?? Quote Link to comment Share on other sites More sharing options...
Muffleman Posted February 26, 2008 Share Posted February 26, 2008 Feed and return lines aswell as tank breather were checked. Not being an expert, I got a little bit lost when it was being explained, but apparently if there is a problem with the head gasket it can cause a lack of vacuum in the intake manifold when the engine is cold. When the engine warms up, the vacuum increases thus pulling the fuel pressure down. I will try and find out more about this tomorrow. However, there was a LOT of water coming out of the exhaust. We put the car on the rollers to try and simulate the problem, and we ended up with a large puddle at the back of the car. If you turned the car off for 5mins and then re-started it, you got plenty of steam out of the exhaust again. The leakdown test results were good which is a relief but the water issue needs to be sorted first. Matt Harwood has checked the pump wiring so I wont even look there as i KNOW Matt will have done that all properly. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted February 26, 2008 Share Posted February 26, 2008 For the vacuum to vary enough to cause the sort of pressure variation he described the leak would have to be quite substantial, and in any case leak-down would have showed that up along with the sniffer test on coolant, I get a fair bit of condensation from mine at times, humidity also plays a big part in the amounts of vapor issued from the exhaust. Did Matt check for voltage variation over time to the pump? Quote Link to comment Share on other sites More sharing options...
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