willsy369

hi all, need some advice on a acceleration problem, i have a V5 JDM CLASSIC (98-99) and when driving and wanting to put the foot down i get to about 4500rpm and it backfires and misses (hessitats/holds back) as if its hit the rev limit, if i drive say more normally and gradually go up revs i can get full use of the revs with no problems at all, it doesnt do this in 5th gear for some reason but is worse in the lower gears on hard driving, i am getting full 1.2 bar boost and no idle issues, and like i said drives normal in all revs if not driven hard, i am running a new MAF, and a pipercross induction kit, revolution cat back exhaust and baileys dv, it was all on the car when i bought it, i did put OE air box back on but it was worse, i then put induction kit back on and its been fine for weeks untill last 2 days, am i looking at another MAF, or could it be the crapy dv or am i looking in wrong area? any help apprieciated guys

willsy

edited to mention MAF is green stripe type is 3 months old as carnetix had to change it due to a similar fault before i bough the car as it was only fueling 5% instead of 25% on acceleration, this cured that fault, and i have an uptaed fuel pump also, which is very noisey but is also new and has been checked by carntix as to be running correctly, i may try re fitting old stock fuel pump and oe air box and borrow my mates MAF and re circ dv, is this a good plan?

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addi monster

iTrader: (6)

sounds like its overboosting ie cutting out your fuel!! could just be down to the freezing cold air its running on this time of year,.

willsy369

ayup addi!! yeah could be but its running stock boost for an import and doesnt do it in 5th at all but 1st - 4th its a git around that rev range, but doesnt always do it and did it few months back when was warmer, i know the mods it has i.e induction kit and the **** baileys are poo but at the mo got nothing to swap them for.

TonyBurns

iTrader: (3)

With a cat back exhaust I wouldnt say it was overboosting, not at 1.2bar, i would say you may have broken your maf again due to the induction kit
Has the ecu been mapped for UK fuel or your mods? especially that induction kit?
Also what fuel are you running and do you have any form of det detection (for example a KS3 or a knocklink?)

Tony

PS have you tried seeing if there are any error codes or resetting the ecu?

stedee

iTrader: (4)

i think it maybe your dv is sticking ,try spraying some wd down it

willsy369

Hi Tony,

no form of det detection, as far as im aware no map has been done to the car with the cat back exhaust, induction kit and uprated fuel pump fitted. im running v power as i have a shell garage on my doorstep, however i did need to fuel up yesterday on a long drive and all i could find was bp ultimate but as far as im awre they are ok to use? im also thinking maf due to the induction kit and my first job is to fit the oe air box and borrow a maf to eliminate that, would anyone recommend that i swap the dv also? and what kind off price do uprated injectors go for and is it worth it?

although carnetix have said fuel pump running o it does make one hell of a high pitched noise to the extent that a scooby meet thought i had a flamer kit! tis is also new so is this worth fitting my stock fuel pump back on as well?

many thanks for the replies

TonyBurns

iTrader: (3)

Oooooh! think that could be your problem, BP ultimate isnt very good, your ecu is mapped in japan for a minimum 100 ron/102 ron fuel map, so your best using shell or tesco 99 and octane booster, you really also need a KS3, 220 quid, get one before the vat goes up, its cheaper than your engine going up

Injector wise, you cant change them without a remap, your standard ones will see you to 330bhp happily, I would suggest that would be your first port of call (the remap), forget about the injectors, try the brakes Godspeed have some very nice 2 peice discs in, ok not cheap at 250ish quid but with a good set of pads it will make a difference

Oh and definately swap that DV to a recirc one

Tony

willsy369

cheers Tony, am i best to drive sensibly until the bp ultimate is used up or add some booster? i will change the dv anyway and i guess fitting the air box will prolong the maf as well just for safe measure

TonyBurns

iTrader: (3)

Millers octane booster is normally one of the most common available, just shove a bottle in per tank, its the Millers octane Plus your after (yellow sticker)
It looks like this http://cgi.ebay.co.uk/MILLERS-OCTANE...a0e520fcdf3766
Check your local car parts distributor as they may hold it

Tony

willsy369

is that just if i need to use another fuel to v power or use it with that also?

TonyBurns

iTrader: (3)

Yup V power is good but its always better to run a JDM on the highest octane fuel AND octane booster if you have not mapped the car, and also fit that KS3 just incase you get a bad tank full, seen it before in my first Spec C, slight flick to red on the knocklink, but they retard much better than the classics, the classics wont retard, they will just blow themselves to bits (hence I have a lambda link, knocklink AND KS3 in my V5 STI type R )

Tony

TonyBurns

iTrader: (3)

I should mention that the KS3 has an audiable alarm and you can set it to what you want, though it does recommend a limit, see here >>> http://www.phormula.co.uk/KnockDetection-KS-3.aspx
They have a demo vid on there showing how it works, available from Aztec performance on here, just searh for KS3, was in the group buy section, definately worth having!!

Tony

willsy369

thank you again for your advice, will look into the KS3 definatly

JK99

iTrader: (5)

I'd say it's the knock sensor if you've checked everything else.

willsy369

hopefully going to get round to changing some bits tomorrow and will let you know if its back to normal, cheers for all advice guys