My Car Is Running Lean?

[shaunvlc]

Hey guys,

Have made a similar post in the past however misread the dyno print out.

They were doing free power runs in town so i thought i would go down and see what my car is making.

It made 239.5hp atw. however from about 5000rpm onwards the afr's are reaching 13.5. is this normal?

The mods i have are as follows:

- FMIC

- Running 10psi boost

- 3.5 Turbo back exhaust

- Pod with CAI

- Iridium plugs

- HKS FCD (found it by accident one day ahah)

From what i understand is the AFR's should sit around 12 or below?

Is there anything i can do to fix this?

Obviously by getting a decent ECU but i want to avoid that for now, there must be something causing this? dead fuel pump? bad coil packs?

Help boys!

[2gceffy]

what turbo and engine would help too mate? also u say decent ecu so what are u running now? is it tuned ?

Edited May 4, 2009 by 2gceffy

[shaunvlc]

sorry. its an rb25, turbo is stock. when i say decent ecu i refer to pfc, haltech etc.

currently running stock ecu. but should be pumpin out a bit more then 240hp i would presume?

had a nice big flat spot around 5000rpm too. also noticed a lot of unburnt fuel (black cloud) coming out of exhaust at that time.

[Beer Baron]

that puff of smoke and miss at 5,000rpm could well be detonation.... considering it's running 13.5:1. it's not stupid lean, but yes it is too lean. any time you change the amount of air going into the engine you push it outside of what the ecu expects too see. sometimes it works ok, sometimes it doesn't. it could well be a dud fuel pump so it's worth checking that. it could also be a damaged afm. but most likely it's just the way to stock ecu is behaving with the increased boost over stock.

[femno]

What increased boost?

You should be seeing around 11.5 at the top end with your mods and a healthy EFI system, so yes its quite lean. I would guage it as unsafe.

Could be your fuel pump as stated, could even have dirty injectors or busted fuel reg (reg unlikely). You need to monitor fuel pressure while doing a dyno run as a start.

[_Ryan_]

FCD set up correctly?

[shaunvlc]

i havent touched the fcd as i no nothing about them other than they are named "fuel cut defender's" ahahha.

it was there when i bought the car. I can see that whatever is causing the car to lean out is affecting the whole rpm range. I have a air/fuel meter and it also indicates the car running lean at 3000+ rpm's. i can see i have several options.

I can replace most of the consumables such as fuel pump, fuel filter etc, if that doesnt fix the problem i will look at getting some better/bigger injectors put in as i plan on doing a turbo upgrade and running more boost down the track.

I also have a feeling my coil packs are cracked and a not performing to their full capacity so i will do a quick fix on those to see if that helps. if it does then i will also replace those with some new ones.

[Guilt-Toy]

Start looking for a new engine. You will need it in a matter of weeks.

[KiwiRS4T]

Check to see you have an adequate fuel supply (flow and pressure) and if you can't afford an aftermarket ecu get rid of the fcd and get an safc instead.

[Guilt-Toy]

FCD = Broken engine. Simple.

[STATUS]

FCD set up correctly?

bingo, we have a winner.

excellent little fkrs if set up properly on a std car, killers if not.

Edited May 5, 2009 by URAS

[shaunvlc]

well guilt toy instead of being a dik maybe you could offer advice?

URAS can i simply remove the fcd without any modifications needing to be done or will the wires going to the fcd need to be re-connected correctly?

My questions are:

a) Are there many people out there that know what theyre doing when it comes to tuning these little devices?

b) Would it be worthwhile removing the fcd or getting it tuned properly?

c) Could this unit be entirely responsible for the car to be running lean?

d) Does anyone recommned a setting for it to be set at?

[Beer Baron]

a) yes, any competent tuner can.

b) yes

c) that's a big 10-4. yes.

d) yes, one that is not harming your engine and causing that detonation at 5,000rpm. there is no magic setting. it needs to be tuned to each application. get it on the dyno and get it adjusted.

[Guilt-Toy]

well guilt toy instead of being a dik maybe you could offer advice?

URAS can i simply remove the fcd without any modifications needing to be done or will the wires going to the fcd need to be re-connected correctly?

My questions are:

a) Are there many people out there that know what theyre doing when it comes to tuning these little devices?

b) Would it be worthwhile removing the fcd or getting it tuned properly?

c) Could this unit be entirely responsible for the car to be running lean?

d) Does anyone recommned a setting for it to be set at?

Most of the people who ask for advice on this site do not listen, but here goes.

a: There are a few people who use them, most people choose not to. (smart ones)

b: Removing it is the best option

c: yes, as long as the fuel system is in order

d: no

Get rid of it. buy a power FC, i have one for sale with $1250 with hand controller. and then get it tuned and the issue will be fixed.

[_Ryan_]

bingo, we have a winner.

excellent little fkrs if set up properly on a std car, killers if not.

as a prize want to diagnose the whistling noise my car is making?