Why Is My 25det Running So Rich

[wessa02]

Hi guys

Since i got my liner its been runnin really rich and I cant seem to find out why. as it sits it has a pod filter 3inch cat back exhurst, turbosmart bov and a fmic. when i got the car it was completely stock and a mate told me when he drove behind me and i gave it a small stab he could smell fuel badly, since putting the exhurst on you can hear it back firing on deceleration, but only when you push it just on boost (so 0 on the boost guage). if you push it right into boost it doesnt backfire on deceleration. Everyone Ive talk to rekons its the bov but the exhurst was the first mod i did and it was doin it back then, the bov was only installed 2mths ago

Has anyone got any ideas on where my problem could lie or have some thing for me to try

Cheers

[R31Nismoid]

Apexi BOV - where the problem begins and ends (usually)

1) Put the stock on back on and you'll have no backfiring issues, or it will at least reduce it based on the below other options

2) Check the timing the car is running

3) Also check the plugs, could be an issue there.

4) And last of all check the fuel pressure, you might have a faulty fuel reg

There are my top 4 for the day

[RPR33]

I agree. how rich you talk how many k's from a full tank I get around 280-300 and I don't drive it to hard to offen..

[wessa02]

It backfired with the stock bov its had new plugs put in 20,000kms ago (platniums - not crappy ones), its just had the timing belt replaced 3000kms ago.

How do i go about checkin the fuel pressure.

thanks so far guys - keep the suggestions comin

[R31Nismoid]

IMO platinums are crappy ones

Just because you spend $120 on plugs, doesnt mean they work.

I will only ever use coppers as with platinums, you can be fooled into believing they wont foul, and they can well before 100,000km's or whatever they are supposed to last for

If the timing belt was changed... then i'd start there.

Fuel pressure, you need a gauge to measure it off the reg, a workshop should be able to help ya out easily and quickly.

20mins tops if you pre-arrange it with them

[wessa02]

I will get my mechanic to recheck the timing as for the plugs just bout everyone i spoke to (including my mechanic) told me to go with the platniums and now i think about it they were only done 2mths ago so theyre only done about 10,000kms max. However it has been running too rich way before the belts and plugs where done and the old plugs where put in when i picked the car up from the yard (i demanded the reciepts for all the work that was done to it so im certain they were changed on compliance) and they werent that bad when i took them out to put the platinums in.

I will give my mechanic a call today to see if he can check the fuel pressure

RPR33 - im getting anywhere around 300kms out of a tank (just below the quater line on the fuel guage) and thats not goin to easy or 350kms if i take it easy. highway drivin the best i got was 450

again thanks for all your help

Wes

IMO platinums are crappy ones

Just because you spend $120 on plugs, doesnt mean they work.

I will only ever use coppers as with platinums, you can be fooled into believing they wont foul, and they can well before 100,000km's or whatever they are supposed to last for

If the timing belt was changed... then i'd start there.

Fuel pressure, you need a gauge to measure it off the reg, a workshop should be able to help ya out easily and quickly.

20mins tops if you pre-arrange it with them

[mad082]

RPR33 - im getting anywhere around 300kms out of a tank (just below the quater line on the fuel guage) and thats not goin to easy or 350kms if i take it easy. highway drivin the best i got was 450

how many litres are you putting in? out of my last tank i got 280km for about 45L, and my car isn't running rich. my AFR's are 12.0 from 3000-5000, then slowly drop to 11.4 from 5000 up to redline. and i don't spend that much time above 5000rpm. it more has to do with the fact that the accelerator meets the floor a bit.

[wessa02]

how many litres are you putting in? out of my last tank i got 280km for about 45L, and my car isn't running rich. my AFR's are 12.0 from 3000-5000, then slowly drop to 11.4 from 5000 up to redline. and i don't spend that much time above 5000rpm. it more has to do with the fact that the accelerator meets the floor a bit.

Im probably putting in about the same amount fuel. excuse my lack of knowledge what do you mean by AFR

[mad082]

AFR is Air/Fuel ratio. that is the ratio on which it is measured to see if the car is running rich or lean.

how much heavy acceleration do you do? also how much driving when the car is cold do you do? alot of my driving is done when the car is cold (only live a few mins from work) and the car only just comes up to temp as i get to work. when the car is cold it uses more fuel to make it warm up quicker.

[wessa02]

AFR is Air/Fuel ratio. that is the ratio on which it is measured to see if the car is running rich or lean.

how much heavy acceleration do you do? also how much driving when the car is cold do you do? alot of my driving is done when the car is cold (only live a few mins from work) and the car only just comes up to temp as i get to work. when the car is cold it uses more fuel to make it warm up quicker.

I have never mesured the AFR (how do you do that if i dont have a guage or a after market ecu).

I generally drive easy but accelerate hard on the odd occasion, and for as drivin if cold one of my jobs its only just warm by the time i get there but the other one is 30min drive which is my main job (5days a week)

[mad082]

the only way to check the AFR's is with a wideband o2 sensor. if you put it on a dyno they will be able to check them.

as for fuel economy, you aren't getting that bad economy. next time you fill up work out how many litres per 100kms you get.

e.g if you do 300kms to 45L then you divide 45 by 3 = 15L per 100k's.

i get about 16.5L/100k's in my skyline and about about 11.5-12 in my missus SSS pulsar.

[O.I.C Napster]

I have the same problem as this first lad, and have fitted the same BOV, can someone tell me why it pops and farts at low boost when ya take ya foot off? is it because my car is running a airflow meter and not a map sensor?

or how can i still use the new BOV without changing back to the old one?

[wessa02]

mate, my mechanic got me to take the 02 sensor out and clean it with white vinegar and that seemed to help alot, although if your o2 sensor is totally screwed this wont help. Theres only 2 ways to find out if its stuffed, find someone with the nissan diag software to monitor it as you go for a drive or just simply bite the bullet and buy a new one

[MBS206]

You guys have shocking fuel economy! I get around 11.5 - 13 L/100km!

That's in an R33, 3" turbo back, 7psi/11psi (adjustable on switch) FMIC, induction pipe on turbo...

Mind you, I generally keep the revs below 2500RPM, which if you do, you get alot better economy, I don't even meet normal atmos pressure half the time (Aftermarket guage too BTW)

As for popping and farting.

The AFM is measuring X amount of air, then you let off the gas and vent to atmos, hence, AFM thinks you have a shit load of air, motor has no air... Basically, it's going really rich as the BOV vents as the ECU thinks there's more air in there!

Edited October 16, 2006 by MBS206

[The Mafia]

holy shit I am getting sick of these

"I just installed a fulleh sick swooshy twirly trumpet sqwarky BOV and my car stalls and runs rich" type threads.....

Can we get a full explaination done up and made a sticky?

[Munna1]

Have a look at the tuning guides from the site bellow it explains why.

cheers

[AdamsR33]

firstly, are you sure its your car that smells of fuel and not your mates???

and secondly, if your car smells that bad of fuel it usaully indicates a leak somewhere.

thirdly, your car ain't running that rich if thats your fuel economy. Stockers run rich from the factory, nothing you can do unless you start changing to a fuel controller or an aftermarket ECU such as a PFC.

I regularly get 400 to 500kms from a tank but i don't boost it most times and do my racing at the track, where i did 250kms to a full tank!!!

[mad082]

where you live also plays a bit of a part in it. where i live is rather hilly, so there is a lot of taking off up hills, etc. even though you drive down the hills as well, so you use more fuel at times, and less at others.

[MotoMan]

You guys have shocking fuel economy! I get around 11.5 - 13 L/100km!

Mind you, I generally keep the revs below 2500RPM, which if you do, you get alot better economy,

I wouldnt call everyone elses economy shocking if you dont even drive on boost

its like saying

"MBS206" you have shocking fuel economy! i get around 9.3L/100km!

Mind you, i was on the hume highway

Edited October 17, 2006 by MotoMan

[MBS206]

I wouldnt call everyone elses economy shocking if you dont even drive on boost

its like saying

"MBS206" you have shocking fuel economy! i get around 9.3L/100km!

Mind you, i was on the hume highway

But this guy is jumping up and down about bad fuel economy. 90% of fuel economy problems are how people drive. If you want to boost the car every gear change, expect to fill up every 200-300KM.

Basically, it's a different way of saying HAVE A LOOK AT YOUR DRIVING STYLE!

And I'm not talking from just one tank on the hume, I was giving how I generally drive, each time I'm in the car. It's driver attitude as I said 90% of the time, that controls fuel economy.

If I said my fuel economy, and nothing else, heaps of people would be like "WTF, why's mine so bad" whereas, IF they think for themselves, they might take a look at there driving style.