I recently uprated my headers and up pipe.

Ever since doing this, ive noticed on the air/fuel gauge, that the car is running lean!

I drove it for a week or so not putting my foot down, and noticed over time that once the car was warm, (but not when cold) it would struggle low down the revs but was fine when you put your foot down, almost like a poor spark or lack of fuel.
I also noticed the knocklink light lighting up on high revs.

This problem got worse over days and made the car a bit of a pain to drive round town, so I went with the cheap option first and put some new super 7 plugs in. Fixed it momentarly, (around 40 miles) then resorted back to the same problem.
I also notice that the knocklink light's up sooner, around 4-5 rpm since I replaced the plugs.

Has any one got any idea what the f**k is going wrong!

Im wondering if a lack of fuel is causing knocking in the engine!?

Or is somthing else wrong!?

Scooby Clinic are going to get it on the rollers next week for a remapp and sayed they'll work out whats going wrong.

Any ideas would be great, the cars a version 3 STI Type R.

Cheers Shimy.

 

headers will allow more air into the mixture, without the necessary increase in fuelling with it, surely thats the cause of your leanness?
remap should sort it no worries.
could be wrong though...

 

Yeah I was thinking the same thing peanuts!

I do find that if I sit at a steady speed for a while the mixture increases and gose back to normal, but then when I stop it gose back to lean.

Cheers Shimy.

 

Remap will sort it.

It will be expelling exhaust gas quicker and more efficiently than before, which means mr turbo will be kicking in a bit earlier, and you will also find the headers require extra fuelling at high rpm (did on mine while being mapped)

MB

 

i had my 1st re-map without my aftermarket headers
then fitted them and went to bob for 2nd re-map
car was also running lean
but sorted now , so you should be ok after re-map bud
daz

 

as a short term- if you have an adjstable fuel pressure regulator (and guage!) turn up the fuel pressure a bit...
it's only a band aid tho.

remap is the safest route imo.. just resist the urge to nail the car until its done



did the clinic lads advise this would happen?
I expect from past experience that they would have done

did you listen to them is the question..

 

No mention of an Uprated fuel pump !!! Get one fitted to enable the pump to supply enough fuel, The standard one could be at it's limits

Dean

 

It wont be on an unmapped STi3. Close, but not near the limit.

MB

 

sorry- my comment was to shimy..

 

Cheers for the reply's lads!

Yeah the Clinic did advise me on saturday to wait until next week to get it mapped on there rollers, and to take it easy until then.

There going to fit an uprated fuel pump to her aswell, cause as said before, its just about on its limit.

Fingers crossed for the re mapp then .

Do any of you guys know if the fact of it running lean is the cause for the knocklink sensor to be going off?

Cheers Shimy.

 

My STi5 has headers, full 3" decat and uprated panel and didn't need an uprated pump. Not saying you shouldn't, but it doesnt "need" one. Any further mods and I have to have one

Primary cause of det is lean mixture, so more than likely the headers is the cause. See what SC say when its on the rollers.

MB

 

Cheers Mark.

I had a feeling that this was causing detting.

Scooby clinic will have the rollers all set up by the end of this week so i'll see what they come up with.

I'll report back and let you lads know what the out come is.

Cheers lads, Shimy.