Going lean?

[SUPRALOOPY]

My taxi (r33gtst) is leaning out after 5000rpm on boost?

Thought it was fuel pump but i have just replaced it and its the same? I reckon AFM but I ve been told these are good for 1 bar boost? I'm on stock atm due to the lean issue.

Any ideas?

Thanks

Dave:(

[SUPRALOOPY]

Pretty please.

[bignum]

Could be a few things really, like you say, afm,fpr, injectors clogged/dirty, vacuum leak between manifold/fpr, fuel filter?

[johnd-mkiv]

try borrowing another afm mate, if they are anything like the 300zx it will give you all sorts of readings

[SUPRALOOPY]

Thanks john but from who? They all hate me on the skyline forum. not one answer from them. Gonna get the manual out and check the readings from the afm. I may also try upping the fuel on the safc2 just to see if it does the job as I know you should never add fuel with safc just remove it. But hey if it goes bang it goes bang!! LOL

[SUPRALOOPY]

could it be lambda? as I have AEM only telling me whats going on and not telling the ecu whats its reading

could the old lambda be fooked?

[kylestt]

how old is the sensor? could just be old causing bad readings

[SUPRALOOPY]

gonna replace tha lambda. but I think I can use the wideband sensor to tell the ecu whats going on, as it has another wire to give out narrow band readings I think. Back to the books me thinks..LOL

[D8MOA]

if you had a toyota you wouldnt have silly problems

[johnd-mkiv]

Ill ask me mate dave as he has an r33 might be able to swap a few bits over to try

[SUPRALOOPY]

cheers John

[RedM]

I reckon it's you lambada sensor leading you a merry dance.

[Swampy442]

Id rule out O2 sensor personally, look at the AFM being knacked.

[Chris Wilson]

1 bar is very risky on a GTS-t, you need to do the pump, bigger AFM, bigger injectors and a Power FC to do 1 bar and above, safely. They are very easy to blow up!! Conversely they are very easy to get good power from, done right. If you are saying it's going lean on stock boost pressure you need to monitor the fuel pressure under load. Could be the pump, could be FP control unit in the boot.

[SUPRALOOPY]

could be FP control unit in the boot? Chris can you explain this in more detail? or is it in the rb25 engine manual, also can this be overidden or checked as the fpr I bought was a s**t one and is going in the bin.

I was never gonna run it at 1bar LOL .9 max .85 most of the time. I have changed the pump for a 255 lph and its still the same.

Thanks

Dave

[Chris Wilson]

Are you saying you have changed the fuel pressure control regulator to something other than stock? What? Why? My RB25 ran 460 BHP on a stock regulator, just fine.

[SUPRALOOPY]

No chris, I have not changed anything in the boot apart from the fuel pump and the FPR I did buy was one of those ones with a gauge that replace the stock one on the return side of the rail, but that was rubbish and I'm now back to the stock one. What is this fuel reg in the tank then? and how do I test it? or as I said is there test procedure in the manual.

Thanks

Dave

[SUPRALOOPY]

I've changed the pump. I have got a wideband and narrowband AFR gauge running (very well matched actually) I've checked voltage to the pump (14v) So that just leaves AFM I think? any ideas. I'm now on stock boost and stock FPR.

Thanks

Dave.

P.s a thor fcd could not have anything to do with could it?

[SUPRALOOPY]

Well I've been told I need an ecu? WTF stock boost with just a decat and induction kit.

And I need a ecu? Great tunable car then?

[Steve]

Surely not?

 

[SUPRALOOPY]

Grrrrrrrrr Why did I crash my supra.

[SUPRALOOPY]

Resoldered the AFM and removed the FCD, now overfuels like a mofo and has a loverly flatspot and likes to kangaroo a bit LOL.. but at least its not leaning out anymore..LOL LOL LOL

Thanks for all the replys.

Dave ;-)

[Steve]

Wish i knew more about these Dave

[SUPRALOOPY]

So do I Steve so do I he he he

[SUPRALOOPY]

All sorted...