During my rebuild I followed Anti's lead and did the twin feed fuel rail from the stock setup like this: This evening I thought I'd check I had plumbed the fuel lines in correctly where they join the hardlines from the rear of the car. The reason for this being I had never identified before I stripped the car which was the feed and which the return. I had them the right way around but I also noticed there was no fuel coming from the return..... So I retraced everything and I'm thinking I might have plumbed the damper in around the wrong way. Would that be a likely cause? Something else I'd appreciate clarification on is my chosen route for the fuel lines. From the hardline feed the fuel goes to a Y-piece, through the lines that go over the plenum to the front of the engine and into the fuel rails from the front, Y-piece at the back, damper, return hardline. In my head it makes no difference which way the fuel flows but please correct me if I'm wrong. Edit: Note that my described route isn't the same as shown in my epic Paint picture.
I am assuming the damper is stock from your wording. The stock damper is activated by vacuum - is that attached? The line on the top returns to the fuel lines - the bottom one is routed into the rail. The damper technically speaking only works one way however fuel can still leak through at a reduced rate if connected around the wrong way This may sound silly but .........also check the lines to the rail are correct - in that you don't have two inputs going into one rail and two outputs going into the other rail - it could also cause no return since the system would be separated instead of joined (pressure to one bank and returns of nothing on the other) Incidentally for info : - If you have an aftermarket reg there's generally three ports available on an aftermarket regulator - if you connect the wrong two you could have fuel flowing from output to output or input to input instead of input to output. In which case you will not get a return of fuel or alternatively any fuel into the rail. Recheck you are using the correct two ports on the regulator if aftermarket. Makes no difference which way the fuel flows through the rails, especially if its dual fed. In single rail fed systems pressure can be greater at the starting injector than the finishing injector even though it can be negligible The pic diagram is fine even though you have a different sort of setup Simple pinching of the fuel hoses for pressure should give you an idea of where your looking - is there pressure before the damper / or after the rail etc....etc... (Follow the FSM if lost) JC :zlove:
I had the issues where i changed the pump and it was spinning in the wrong direction lol. Took ages to work out why i was getting no fuel lol
Just for clarification when you say dampener you mean pressure regulator, right? 'caaaaaaause if you're trying to use your dampener to give you fuel pressure that would be your problem...
Cheers man, yeah it's the stock regulator and it's plumbed into the vac system. I'm not with the car now but with the symptoms and your description I'm sure I've plumbed it in round the wrong way so thanks for that. Out of interest would it make any difference if the regulator was mounted upside down? Previous engine died from a cylinder 5/6 failure on the previous setup and as they're at the end of the rail I wanted to eliminate that as a possible cause when I put those tubs back on. I bet it did! Yeah realise that this morning, I did mean the regulator. Damper has been removed.
Yep, the FPR is plumbed in around the wrong way. Can't imagine it does but does anyone know if the rotation of the FPR is an issue?
If it is back to front you have just found your problem. Also refit the dampener if you are not using a suitable aftermarket reg -pulsation dampening is a big deal.
By rotation I was meaning the physical position of the FPR. Cheers Rob, I swapped the lines around this evening and she now idles steady under 1k, whereas before was at 2k and surging. When I try to blip the throttle though, the engine tries to die like it's choking. When I got her the engine was trashed by massive overfuelling causing bore wash and something crazy like 7 litres of fuel/oil was emptied from the sump. I'm worried it's doing it still so I need to eliminate possible causes. I'm going to order a fuel pressure gauge and test that. I had the injectors cleaned and they were returned with a flow chart showing them all with similar values. If the fuel pressure test comes back ok, what should I look at next?
I presume you used new o-rings when assembling the rail? Did you pressure test the rail prior to install? Can't go wrong with the FSM trouble diagnosis Engine stalls when stepping on the accelerator momentarily
Yep everything was replaced on each injector, o-rings installed with water based lube. No I didn't pressure test the rail.... that's a new one to me. Presumably that to make sure the injectors are seated correctly? Never noticed that in the FSM, I'll have a look when I'm at the workshop, thanks Rob.
Yeah exactly, normally if I'm doing a rail reassembly after plenum pull I'll dunk the thing in water and run compressed air through it (the fuel rail would see up to 60psi fuel pressure on a lightly boosted car, so set the reg on the compressor to 60) -if you don't see any bubbles you know you're OK. One of those things that saves you chasing your tail later No worries man and good luck! Checking fuel pressure is one of the steps in that procedure, but it's good to have a sequence to work through. I'm sure you'll figure it out.
So I just plumbed in my new gauge and got a reading of 41psi at idle. It should be about 37 according to the FSM, do you guys think that could be the cause of the overfuelling? Also just noticed I should have plumbed it straight after the fuel filter but it was just before the regulator...
Depends on your definition of over-fuelling? Over fueling is normally related to too much fuel going into one cylinder - this is normally as a result of a faulty injector or injector seat / o- ring which allows more fuel into one cylinder Pressure only affects over fueling to all cylinders and this you state is not your problem. The pressure is close enough to be almost right and you stated the injectors were tested for flow - did you use new injector seals for the lower intake plenum ? It should be at 43.4 PSI for a stock regulator - something is wrong with your fuel line setup/ regulator or gauge. (I suspect its your gauge and the stock reg/ lines and pressure is right). You really need to draw a diagram of your lines - lol There is not enough information here.... Is this a manual and does it idle correct at start and also after 5mins? Who says its overfueling now and why? Is there a AAC problem is what I am trying to ascertain..............or something else........ JC :zlove:
Is that with the vacuum line connected? Actually the car doesn't run does it? Sounds ok to me -pressure will lower due to manifold vacuum once you start the car.
Have you check the TPS voltage since ? Its good time to square that away if you haven't since its a crucial part of the fuel control system...time to check basics off I cannot see a fuel problem at this stage..... JC If I had to guess.....an air leak somewhere..(AAC?)........more info on idle is needed as he stated idle steady at 1k - is it firing on all cylinders etc.
Just re-read -OK so yeah with the car running and vacuum tube connected to the FPR it will read lower than if the tube is disconnected as the manifold vacuum will lower the pressure (and then increase it as you come onto boost). I checked one yesterday with an AWB gauge, readings weren't exactly as quoted in the manual but within 1-2psi, I think you have to allow some margin for error depending on the quality/calibration of the gauge.
The reason I thought it was overfuelling was just the stinking rich fumes out the back, I will fire it up and run up to temp next time to see what happens. Yes it is a manual. Yes, new O-rings installed all round with water based lube. I got my mechs stethoscope and turned the CAS listening to each injector. They all fired and I noticed the fuel pressure gauge maintaining 43psi. So as far as I'm concerned that no longer a cause for concern, right? Yes the vac line is connected Rob, so if it lowers once started it seems to be good. I just set my throttle bodies and noticed the left adjuster on the linkage was replaced with a nut and bolt that's way too short to do the job so I'll get one ordered tomorrow. Throttle bodies are now just snug but the return spring doesn't seem to want to shut them properly, it takes a light push on the linkage to close the last mm. Is this an error I've made or down to the fact the linkage isn't is missing the adjuster? Instead of this... I followed this guide for setting and testing the TPS: http://z32.wikispaces.com/Throttle+Position+Sensor With the hard idle switch set to just open (continuity), I got the following from the oval connector: Pin A (black wire) to ground should be 0V. Mine was 0v Pin B (orange/blue wire) should be 5V. Mine was 4.59v Pin C (black wire) to pin E (red wire) should be about 9,000 ohms. Mine was 9.97 ohms Pin C (black wire) to pin D (white wire) should be 1,000 ohms. If you slowly open the throttle, this resistance should climb to about 9,000 ohms. Mine was 1 rising to 8.51 ohms Wire into the back of white pin to ground was 0.45 rising to 4.27v I don't know if there is any leeway but that definitely doesn't look right to me, what do you guys think? I started her and she caught straight away, idle sat the lowest it's been at about 800rpm for a minute then started rising to 1100 and falling again.
