black smoke

[daveb]

hi all, i thaught i would run a problem by you all before i start stripin my engine . when the engine comes back to idle it sort of coughs for a second then puts out a large puff of black smoke . when driving slow at constant speed eg 20 when i ease of and on throttle slightly again it puffs out black smoke . even if it stands on idle for couple of minuate and then i slightly touch the throttle and let off again it does the same. it doesnt smoke when its accelerating hard or at constant high revs or even from high revs going back to idle ????? i thaught it would be the valve stem seals .? dont think it the turbo . its only done 2000 miles since new. all intercooler pipes are clean and not oily. i have checked oil seperator and that all breathers are clear. have done compression test and all for read 140 to 145 psi. plugs go really black in 200 miles . thing is it goes like a bat out of hell and pulls like an horse. no problems running at all . ive got a fmic, induction, blitz bov, blitz dsbc, apexi avcr, performance plugs , leads, uprated fuel pump, 3 1/2 " stainless straight through pipes ( no cat) and 1.2 bar boost . so i guess about 280 bhp ish ?? any ideas please

 

[Mr GTiR]

sounds like it's overfuelling. If the plugs are black after 200 miles then the mixture is too rich.

 

[daveb]

that did cross my mind . i have got a air fuel gauge that reads well near the top end of rich constantly. except when i take foot of throttle and then it disserpears. all the time driving its showing rich .nemesis performance only set up my avcr about 2000 miles ago which was last year . can the avcr loose memory ??? . the car does only do 130 miles to a tank. but i got a constant heavy right foot. why would it be overfueling . i have checked ecu and its not throwing any codes up ??? is there a way i can check overfueling . would it do any dammage to the engine ???

 

[Olly]

Blacks fuel someone been playying with your apexi? or is maf sensor on the way out, get it checked on the rollers are data log the maf voltage down the road and all the times it running and being drivern and see if it's right. See the nissan manuals. Over fuelling.. may have a pipe off and have a air leak also.

 

[Fast Guy]

Pop down your local garage and ask them to check the emissions, that will tell you if you're running rich or not.

Other causes could be a faulty coolant temp sensor, AFM problem, or lambda sensor. All 3 can cause overfuelling.

 

[daveb]

i have checked all pipes every where and no holes no leaks nothing . so i guess i will have to go to the rolling road . my local is a place called clive atterhowe in norwich. i think he is good. but i am sure nobody has been playin with the avcr . even i dont touch it coz i dont no how to work it . it has shown the revvs and max revvs since the day i got it lol

 

[daveb]

have just got a new coolant temp sensor coz the fans didnt work . dint put the code up but i still replaced it . fans still didnt work so i got myself a kenlowe automatic fan kit that sorted that problem . have had new lamba sensor 1000 miles ago and nemesis rewired it for me . what is the afm ??

 

[JIMMYBACK]

have just got a new coolant temp sensor coz the fans didnt work . dint put the code up but i still replaced it . fans still didnt work so i got myself a kenlowe automatic fan kit that sorted that problem . have had new lamba sensor 1000 miles ago and nemesis rewired it for me . what is the afm ??

afm= air flow meter it right next to the air filter

 

[antgtir]

Id sort out the over fueling problem out first before you start stripping things down, get someone to set up the mixture correctly before you decide to go the full hog :?

At 1.2 bar i would be expecting a bit more than 280bhp too. I get on standard running about 230+ miles to the tank, im sure even the 1 bar lot get close to 200 so i would defo query the fueling issues first mate.


Ant.

 

[daveb]

so with all my mods what would you expect my bhp to be. i was only guessing at 280 . never had it dynoed. is it dangerous for me to use the car if its overfueling ?? what could it do to the engine ???

 

[Anonymous]

would someone fiddling with the avc-r be the cause of overfuelling :?:

i thought that the avc-r only dealt with boost and it was the saf-c that dealt with the mixture side :?

at 1.2 bar i'd be expecting approx 320bhp.

if it's very rich,you'll be very poor filling it with fuel and you might get bore wash which could cause major problems :shock:

 

[LOU ROB]

would someone fiddling with the avc-r be the cause of overfuelling :?:

i thought that the avc-r only dealt with boost and it was the saf-c that dealt with the mixture side :?

Your right, you can't adjust fuelling with the avcr, only boost an start duties.
Like you said, its the Super Air Flow Controler that adjusts the fuelling

 

[herbie]

When my car was running like that, the connection to the MAF had came a bit loose.
Put it back on properly then it was back to normal.

 

[ki_saj_ng]

if i were u, stop fiddling about with it and get some1 to have a proper look at it mate before its too late.

get it on the rollers and get everything running right.

if it is over fueling, i wouldnt use it until its sorted as u gradually gonna mess up the engine (bore wash)

saj