Hi all. Back again for more help i am affraid.

I recently purchased a 4 Bar Fuel Pressure Regulator as i was advised it would be a good mod and as it was only 40 quid delivered i thought, why not. I already have a Custom Re-Map (done by TR Racing, Essex), ABD CAI and Forge 007p DV. I am also having a custom Cat Back Exhaust fitted next friday (09/04) by Power Flow.

Now been trawling through threads on here about the 4 Bar FPR and cannot decide if i should fit it or not as worried i am going to do more harm than good.

Could someone pleaseshed some light on this one for me please? Should i fit it or not?

Only worth fitting if your mapper advises it. Revo usually do with their stage 2 as that's what the software was mapped for.

I personally wouldn't bother. If you're not having any issues such as leaning off at high rpm etc then all you'll do is increase the rail pressure, which in turn will make the engine management see that more fuel is going in and then pull back the injection duty.

The only thing you'll notice is that your economy has "suddenly" jumped up, because the intruments thinks you're injecting less fuel, when you're actually injecting the same, but at higher pressure.

Higher rail pressure = more load on fuel pump. Say if you're running 1.3bar boost and 3bar FPR on full throttle that's 4.3bar from the pump, but if you put a 4bar FPR on then you're talking 5.3bar which is close to the standard pump limit really.

Just my 2p worth. Quite simply, if the mapper recommends it do it, but if it's already mapped and you thought you'd see some kinda gain from fitting it, dont..

Kev

Only worth fitting if your mapper advises it. Revo usually do with their stage 2 as that's what the software was mapped for.

I personally wouldn't bother. If you're not having any issues such as leaning off at high rpm etc then all you'll do is increase the rail pressure, which in turn will make the engine management see that more fuel is going in and then pull back the injection duty.

The only thing you'll notice is that your economy has "suddenly" jumped up, because the intruments thinks you're injecting less fuel, when you're actually injecting the same, but at higher pressure.

Higher rail pressure = more load on fuel pump. Say if you're running 1.3bar boost and 3bar FPR on full throttle that's 4.3bar from the pump, but if you put a 4bar FPR on then you're talking 5.3bar which is close to the standard pump limit really.

Just my 2p worth. Quite simply, if the mapper recommends it do it, but if it's already mapped and you thought you'd see some kinda gain from fitting it, dont..

Kev

Thanks very much for that Kev. Makes a lot of sense when explained like that.

It sounds like i am experiencing the same common problem a few people have on here with hesitation / flat spot between 2500 and 3000 rpm. The FPR had been suggested to me, not by my mapper, asa possible solution to this. Another thing which has been suggested is the H type N75 valve (the type which Awesome sell) but not really sure on this either to be honest.

taz sounds more like the 17705 is occuring

clean the throttle body

taz sounds more like the 17705 is occuring

clean the throttle body

Tried that mate and made no difference which is why i have been looking into other possible solutions

could need a new one buddy. i have sold a couple to people with the same prob and it then cleared i also had the same issue put new throttle body on cleared.

if you know someone close with a vrs borrow there throttle body 2 min job and then you will see.

I'd be tempted do so some VCDS logging.. From that using the right measuring blocks you'd be able to see if there was a lean point around that rpm, or if there's a bit of ignition timing pull etc.

Kev

I had same problem with hesitation and when i fitted a ECS N75 race valve few years back ( which is the N75 H type) hesitation went.

I also fitted a yellow forge spring to my DV which also made a difference holding boost on my remapped car.

Perhaps you should also replace the fuel filter and check condition of your air filter.

P.S forget fitting the 4bar FPR , not worth it.

Edited 31 March, 201016 yr by Bowders1

Cheers Westalic and Kev.

I will speak to a guy i know who also has a vrs and see if he is open to letting me borrow his TB. Not sure how i will get on with that as he is a miserable **** most of the time lol!

If this does not work then will try the logging route Kev to see if this throws up anything. Are you able to suggest anyone in Kent who is any good with this?

Des ("ThePelletWaggler" on here) is probably your nearest VAG-Com owner depending on what part of Kent you're from. Mike from Impossible Performance would also be able to do it but is impossible (LOL ) to get hold of.

I'd let you borrow my throttle body but would need to get a couple of gaskets first as the gasket should really be replaced when you take the TB off.

Cheers for taking the time to reply guys.

Definately not going to bother fitting the FPR now. Currently arranging to borrow a TB to rule that one out.

Only recently fitted the ABD CAI i got from vrs_si, which was in perfect nick and it was having this problem before i fitted it so i know it's not the Air Filter.

Think i will carry on following the process of illimination until problem is solved.

Thanks again

Edited 1 April, 201016 yr by TazD

Do Somebody Know where is the Location of Fuel Pressure Regulator Valve in my Octavia 2008 TDI A5

with photos if possible