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Discussion Starter #1
Hi guys

Just got back from rolling road centre, put my car on for a power run and asked them to check the fueling.

They ran it up with a motec fuel monitor running (probe in the exhaust), and from idle all the way to 5500 rpm (at 1bar of boost) the fueling was between 0.991 and 0.99 (basicly running lambda one).

At 5500rpm they aborted the run, they did it twice and the fueling was the same both times, so they gave up and told me it's far to lean and if they carry it on then it will melt my engine.

They are not into skylines so they don't really know whats up with it, they said it could be the AFM's or maybe the ECU.

Does anyone have a better idea what the problem could be? or even what I could try next.

The car is running what looks like a std ecu, no chip has been replaced inside it (altho it was sold with the car as being a middlehurst 1bar ecu), uprated downpipes, decat and stainless cat back system and an apexi avcr set to run 1bar, And it's running on optimax.

Is it worth me trying my spare ecu that has a JES chip fitted to it, or is that just going to make things even worse than they already are ?

Any help with this would be appreciated, because at the moment I am running it off boost which obviously means it goes nowhere.
 

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Dodgy MAFs, air ingress somewhere between the MAFs and turbo inlets, faulty fuel pump, boost pipe disconnected from fuel pressure regulator could all be culprits.

Simon
 

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Discussion Starter #3
is there any way to check the mafs ?

And am I asking for trouble if I fit the other ecu with the JES chip fitted ?
 

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Discussion Starter #7
cheers m8

Will check that out first thing in the morning (if it's light enough at 5.30 before I leave for totb). Just glad I hadn't made arrangements to take the liner.
 

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Discussion Starter #9
Just been out and checked, the hose from the FPR to the fuel rail is fine, just struggled like mad to pull it off, and then put a finger over 1 end and blew has hard as I could through it, and then tried the opposite, it seems pretty good to me, I know it's not a great test but does seem ok.

But I have just realised that the blue silicon hose at the back of my engine bay connects to the other end of the fuel rail.

This hose has 2 T pieces in it, 1 to the AVCR, 1 to my Greddy Boost Gauge Sensor, and then the other 2 connect to something on the bulk head and something else near the inner wing.

Sorry I can't describe it any better than that as I can't see what they are propperly as it's dark and raining quite hard.

If it helps I can post a pic of my engine bay and draw circles on where the bits that are T'd in are located.
 

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Discussion Starter #12
ok will have to find a fp gauge.

As this is a pretty simple test, could I use a mechanical boost gauge just to check that the pressure does rise with boost ???
 

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Discussion Starter #15
Ok just got back from TOTB had a word with Mark from Abbey Motorsport while I was there, and he suggested checking the fuel pump to make sure it switches from low to high pressure when it comes on boost.

He said if it isn't the pump then it's the afm's and advised me to get brand new ones, but there around £380 each :eek:

Anyway a m8 of mine has a pair of mint R32 GTR afm's does anyone know if they are the same as the R33 GTR units ?

Oh and mark also said if the pump has had it, then I need to replace it but told me not to use a walbro, anyone know why a walbro should be avoided ? as I forgot to ask him, mind you he was busy trying to get rocket ronny's car ready for it's first run.
 

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I have a pair of R34 GTR AFM's you could use to check? They were working fine when taken off my car a few months ago.

Not sure if they are ok on the R33?

What about using a Nismo fuel pump? Straight replacement item and easy to fit intank. Just remember to have a near empty petrol tank when you change it!


Nik
 

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Discussion Starter #17
NikWilson said:
I have a pair of R34 GTR AFM's you could use to check? They were working fine when taken off my car a few months ago.

Not sure if they are ok on the R33?

What about using a Nismo fuel pump? Straight replacement item and easy to fit intank. Just remember to have a near empty petrol tank when you change it!


Nik

I don't know if the 34 AFM's are any use on the 33 or not, but I have found out the 32 afms are the same, so I can get them from a m8 if it's not a fuel pump issue.

I did try disconnecting the mafs today 1 at a time, both did the same thing, take it off and nothing really happens but when u connect it back up the car nearly stalls before picking up again. Im guessing as it did the same thing with both afm's then they are probably ok ??

Oh and where can I get a Nismo pump from for a reasonable price ?
 
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I have an FP gauge in my car, and the FP rises from 3 bar at idle to 5 bar on full boost at 1.1 bar setting on the AVCR.
Are you quiet sure about this, A fuel pressure will only add the boost the car is running to the base fuel pressure. So if you had 3.0 bar at idle with the vac hose disconnected and then re connect the vac hose and run the car at 1.0 bar you should have 4 bar of fuel pressure.

I think you fuel pressure guage is not correct or the fuel pressure is set up wrong as you say your car reads 3.0 bar at idle it should read a lower pressure at idle as the ca rhas vacuum to the Fuel Pressure reg.


Cossie1

The 32,33,34 AFM,s are the same, But we call these consumable items as I said a new pair are worth 25/40 bhp on the dyno.

Walbro pump are not bad for the price but we have had trouble with them, the dont fit straight in. We just like the Tomei/HKS pumps.

From our experience the prob def sounds like a fuel pump, I am sure Power Station will run the car on the dyno with a fuel pressure guage connected , the pump will only prob show low pressure once the car is running under load i.e on boost.


Mark
 

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Fuel pump

Mark, are the Nismo fuel pumps any good? Sorry for the hijack..:rolleyes:
 
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