just got my uk99 with ppp, fitted with ;

3" roger clarke downpipe[no cat and heat wrapped ]

3" revolution centre section and backbox.

headers and up pipe ported and heat wrapped[done by harvey]

knocklink and lambda link.

and got my engine cleaned as well.

all fitted by gossy ,who has been very helpfull and flexible both with price and service.cleaned the car before he gave it back as well-nice touch,thanks gossy.

but on the drive home i noticed the revs at idle [at traffic lights etc. ] fluctuated badly up and down,sometimes nearly conking out!

what could the cause be?
maf?
ecu?
do i need a better air filter?

goes without saying didnt have any probs before the above mods.
HELP!! will i damage the engine driving like this?

 

sounds like MAF failing

did the ECU get unplugged or the battery disconnected for an amount of time

Chances are your MAF was failing anyway, but the ECU had 'learnt' to cope , until it got reset

Happened to a mate, after I fitted his gauges, and we had the ECU disconnected

New MAF sorted it out, you could try leaving the engine idling, and disconnecting the MAF, IIRC the engine should then stall if the MAF is ok

edited to add, get it changed ASAP

 

battery was disconnected i think as the time clock was reset
how much are those buggers then?
is it easy to fit?
cheers mate

 

If you take it to Subaru they'll probably try and stiff you for about £320 (housing et al). But the sensor can be bought on it's own for about £72

 

£72, cheers but are we sure its the maf.

ill have to try and disconnect it as 2nd post suggested

 

I disconnnected mine & the car still idled fine.
Replaced it and all was back to normal - so you cannot be sure just by the disconnection method.
Bear in mind however, £72 is much less than a new engine if the MAF is dead/dying.

 

MAF MAF MAF MAF MAF MAF MAF.......I promise you...get it changed, asap, voice of experience.......If you in the Wycombe area I got one you can try.

 

Here and here

 

MAF

 

Mine did the same after I swapped the ecu to a ppp one. Definately maf.

 

After I bought Scoobymoos PPP ecu for my MY99 (Thanks again - It's improved the car no end) Mine done exactly the same. New MAF sorted it - I still have the recipt in the car: Part No 22794AA010 £77.19

 

thanks lads will check ecu codes and then reset it and take it from there.

must emphasise it only fluctuates from 1000 rpm [around normal idle revs] to 0 revs.[not all the way up to 2000revs or anything.]

could it runing weak on tickover how do i increase the tick over and richen the mixture?

the funny thing is i have a lambdalink but can anyone tell me how to interpret the lights? [it was flicking 2 reds at 70-80mph]

 

If it fluctuates downwards from normal idle speed i would deffo say your maf is stuffed.
Even if it ain't - you would be well advised to replace it anyway. It's not really a case of "if" it will go, it's more the case "when" - A simple fact of MY99 life

 

Fault codes won't necessarily show a failing maf. Will show if the maf is knackered, but may not show if it's on it's way out. As already suggested, change to be on the safe side. Also, if you're still on the original maf, a change will be worthwhile as the replacements are said to be slightly more restistant to failure, so an upgrade, if you like.

If you're still not convinced then take : eek: up on his offer.

 

MAF MAF MAF

This time last year MAF died on PTMW! resulting in the requirement for a new engine Bloody happened @ Brands on my birthday treat

Richard Gledhill had his go a month later.

Both costs ££££ to fix in new engines


On MY99 they are a WEAK item that should be replaced on an annual basis, otherwise expect a £2k+ bill

Replace the Lambda sensor at the same time.


Don't fanny about, just do it and if it is not the problem, then at least you know you're safe from that particular fault for a year. It is a false economy to not do it.

 

Oh & don't give your engine WOT until its sorted, thats when det occurs & mullahs all that work you've just had done.

I'll have a word with Gossy tomorrow at work...

 

Derpil

As i said to you on the phone 2 hrs after you picked up the car i would almost gaurentee your maf was on the way out as you described the symptoms to me

As the battery had been disconected i would hazard that that was your problem I have a maf i can also get a maf from eek so if you bring the car over i will change it for you

All i can say is that as far as i am aware all the work that i have done should not have affected it.

I have left a message on your ansa phone too

Gossy

 

Maf , changed mine today, No more fluctuating idle.

 

MAF
Has to be said again, the very day i fitted the PPP ECU to my MY 99
the MAF went belly up.
Fluctuating idle gave it away, bought the sensor only (£70 ish) and with correct tool i fitted it in minutes and et voila problem solved

 

oh and if you need anymore proof read this thread http://bbs.scoobynet.co.uk/showthread.php?t=371439

 

Gossy the only way the work you have done that would affect the car, is the pure and simple fact that the battery/ecu had been disconnected, resulting in the learning of the failed maf to be lost

But I guess you knew that anyway

70 quid is better than a new engine , no matter how anyone looks at it

 

thanks for every ones input.much appreciated.
i bought the maf sensor today .will be fitted on the weekend.
thanks to eek for offering his maf
and thanks to gossy for his advise and texting me with the part number.

the original post may have unintentionaly implied that gossys work related to the problem .so i would like to state that the problem is not related to gossy in any way. what i was trying to put across was wheather ,if the mods themselves caused the maf failure[ie decat downpipe etc.] or whether it was already going/gone.

thanks again peeps!

 

My fluctuating idle was an O2 sensor.

 

See you saturday morning then

 

changed the maf sensor this morning. the idle is steady at 800 rpm .seems to have done the trick .
thanks everyone