paulscoobycallum

hi all newbe here. i have a hesetation problem with my 99 uk wrx. i will start with mods 1st. it has a full ss decat and a bailey d valve thats it. ok the problem is when it gets warm it starts to hesetate between 2.500 and 4.000 revs only when engine is hot and on motorway it feels like its surgeing on steady revs as if the power is constantly on and off. and also when driven hard it tends to pop and back fire when slowing down at high revs. i have cleaned the selenoid changed plugs and leads to no avail. whats strange is it drives perfect when cold and not on the boost. any help please

scooby72

iTrader: (6)

Did you gap the plugs correctly?
Different car but I had major hesitation when my plugs 1)werent in tight enough and 2)were gapped incorrectly.
This was worse when the engine got warmer and the weather got hotter.

paulscoobycallum

hi the problem was there before i changed the plugs and leads they just looked old so i decided to change them anyway. but i did not gap them ib did not know you had to?? thanks for the quick responce..

scooby72

iTrader: (6)

No worries - might not be the cause but its worth a try as its free for starters. You'll find plenty of threads for the appropriate gaps for your plugs on here!!

mozzerscoob

iTrader: (1)

Hi had a simular problem on my 2005 sti and it was the bailey dump valve causing the problem.Refitted the original recirc valve and was perfect after that.Posted a thread on here about it and got the feeling bailey is not the best valve to fit to a impreza.
Hope this helps!!!

alcazar

iTrader: (2)

Put the Bailey DV where it belongs: in the bin.
Go back to a standard recirc valve.

paulscoobycallum

only had the car 2 months and got no standard dump valve with it. i will try to find one. i hate the bloody thing any way it gets anoying. i dont know if it will cure it coz i have noticed it seems to be better at night would the dump valve make a diference
when the air is cooler??? thanks

Splitpin

The popping and banging on overrun is almost certainly a result of the dumpvalve messing up the fuel mixture (and it's more obvious with the decat than it would be on a standard exhaust). It's also eminently possible that the DV is causing the hesitation too if the crack pressure is incorrectly set, or if it's sticking. There are other possible causes for this but in the situation you're in, eliminating the DV as the cause would probably be the best first step to take.

If you have the option you could try increasing the spring pressure in the dumpvalve and seeing if this makes any difference to the latter problem, although in practice obtaining and fitting a standard recirculating dumpvalve is by far the better bet. If you're lucky you might be able to find one for not very much money on eBay or here.

Incidentally, top marks for your first post. You've included all the relevant info - car description, modifications and a good description of the problem - that makes it easy for others to help you. Although, trifling point, your car's called an Impreza Turbo 2000 - not a WRX. WRXes of that era are foreign market models and differ spec-wise, so always better to refer to the model correctly if you can - again makes it easier for us to work out exactly what you've got.

paulscoobycallum

hi i have just bought a standard d valve off ebay from a breakers for £25 posted not bad i think? im not going to increase the spring pressure as im sick of the noise and want it standard as possible. sorry about the wrx mistake as its my 1st scooby. thanks for the reply its very helpful

scooby72

iTrader: (6)

Good move me thinks bud - sadly I still have a fetish for the ol chav horn although like was said earlier I belive the Bailey valve may not be a good option. See how you get on the standard recirc - if the one you get isnt up to holding the boost too well I think youll find FORGE make an excellent aftermarket replacement.
Fingers crossed its all gonna be good!!

paulscoobycallum

im starting to think its been mapped coz i was told its 220 bhp standard when it leaves my mates standard bug eye standing and theres a lot more power than my old audi s3 225 bhp or is it just me any thaughts please