The Pink Ninja

iTrader: (23)

As above really guys, Went out to shops before and opened it up a little bit but got a warning from the defi`s which are set to differential fuel pressure so should stay virtually static on boost, A quick vid showing a run through 3rd,4th,5th through playback off my defis, fuel pressure drops from 50psi to 40psi on boost between 1.35-1.65bar through 3rd,4th and 5th gear, I`m guessing its the fuel pump on its way as i had a full tank of fuel at the time, Its the original factory pump from 2003 and done 45K miles, Any other ideas incase i`m missing something?

Infected by sti

iTrader: (6)

What car is it gaz? I was reading a thread the other day where the voltage drops across the pump at high boost on a newage, something to do with the alternator and the smart charge system on there iirc

There is a wiring mod that can be done apparently to stop it from happening if that may help?

Believe it was kev from the clinic who mentioned it

The Pink Ninja

iTrader: (23)

It`s a MY 2003 JDM WRX STI Spec-C Limited

To be honest its only just started to do it and has worked fine for the last 12-18 months since the defis have been in and as nothing has changed on the setup of the car/fueling etc to warrant me thinking it could be anything else bar the pump, Yeh i read that too but i think that has more to do with top end power fueling, Mine is as its coming onto boost, at 1.3bar or over, Fuel pressure is dropping about 0.8 bar.

mickywrx

iTrader: (29)

Standard FPR, Gaz? Check the all your vacuum pipes.

Infected by sti

iTrader: (6)

Well it sounds like the defi's are doing their job then tbh, as you said you know your car and if nothing else has changed with the car and the gauge has started to give off a warning then i would be inclined to think pump also tbh, unless it could be something like the fpr breaking down and not holding pressure across the rails? Or would the gauge not pick up on that? Just a stab in the dark really don't know if it could effect it, but was thinking that is the only other thing I can think of on the fuelling side of things that could drop pressure if it was a split line or anything like that you would surely smell it?

mickywrx

iTrader: (29)

Not going to smell air if it's a vac pipe.

It happened to Jeff(Alcazar on here), perished vac pipe to the FPR, he would have been none the wiser without the differential pressure warning from his Defi's.

First thing I'd check, easy to do and cheap to replace.

The Pink Ninja

iTrader: (23)

Yeh standard FPR, will have a look in the morning, The sensor is fitted just after the fuel filter so should pick up any drop in pressure from there to the rails as far as i am aware, Be cheaper if its a vac pipe anyway, will save me £120 for an RCM pump i`d seen.

Defis are expensive worth the price if you know what i mean

Infected by sti

iTrader: (6)

Sorry Micky I meant a split fuel line was typing that reply whilst you posted so didn't see it

And as for a fuel pump gaz the HRC340's are a good bit of kit an are under half that price, think I paid £65 delivered iirc just a thought

The Pink Ninja

iTrader: (23)

I've seen them and they are good for the cash, Even though I won't see it the RCM one looks lovely that's a 340 too

Infected by sti

iTrader: (6)

That's the thing you won't see it

The new black ones hrc have on the go look real nice too such a shame to hide it

mickywrx

iTrader: (29)

Please, never feel the need to apologise to me. We're both trying to do the same thing and give Gaz some pointers.

The Pink Ninja

iTrader: (23)

Well, Checked the vac line and its all good no cracks/holes/perished at all, Was also fitted tightly so not loosing any pressure there, FPR all looks good visually too, So leaves me with the pump and for the cost of them its a bit of a no brainer to risk it after all its a 9yr old pump now.

On a side note, I took it off differential fuel pressure to see if it raises with the boost......Fuel pressure far left, Boost far right



Whats going on here then , Still gonna change pump to be safe as its still dropping a bit compared to the boost

mickywrx

iTrader: (29)

The fact that you weren't going anywhere is of concern, or you have some magical anti-lag.

Did you film the playbacks, Gaz?