Hi all I'm new to the forum. Apologies if this has been asked/answered before but I couldn't find anything using the search. I picked up my 1998 uk turbo 2000 wagon today, all seems well apart from occasionally if I am cruising along quite slowly (only happened in 4th gear so far but not had it long enough to say its only in this gear) and put the throttle right down, its almost like the engine loses all power and jerks the car forward, almost like applying the brakes very hard. It doesn't happen every time and at no specific rev range so I don't believe it's the gearbox. Has anyone else experienced this? if so how did you go about fixing it?

any help much appreciated

 

Could be your boost control solenoid needs cleaning...

https://www.scoobynet.com/technical-...-solenoid.html

 

Thanks for the link I shall try to clean it out tomorrow after work, R.E the boost my gauge doesn't read bar but its approx 15psi. not sure what that converts to. on the way home tonight coming down the motorway i put the foot down a bit in 5th to try and force the problem to narrow it down a bit and couldn't get it above 85 as it kept jerking, almost like it was cutting fuel. then if i ease back to about half/ 3 quarter throttle it boosts up and pulled on to 100 no problem at about 10 psi boost.

Sorry if I'm asking anything stupid but its my first turbo car so not sure where to start

 

15psi is about 1.03 bar, so high for your car.

It it modded at all?

 

the only things I am aware of being non standard is the dump valve (which manages to dump while the boost gauge reads its in vacuum, not sure if this is normal lol) and an aftermarket back box, the rest is standard as far as i can tell

 

Dump valve could be the problem . Use the search to ask why. Hot subject on here im afraid. And by the way, welcome.

 

sounds like your hitting the fuel cut off, check the pipe which goes to the waste gate is on - and double check you havent got a manual boost controller installed you never know! i had this problem on my blob when i got it, was the waste gate pipe that wasnt on - prob because the previous owner messed around stripping the easy bits off before sale

 

Hi L3YMS excuse my late replay not had access to the computer, I couldn't see the ecu in the footwell so can't confirm a part number, but the symptoms you describe are exactly what I was experiencing, it used to happen only in 4th and 5th when boost gauge showed approx 15psi, I since replaced the vacuum lines and t-piece connector as they were knackered, I used fuel line as my local factors didnt have vacuum line. since replacing it it now happens in all gears and boost climbs worryingly fast (And yes I remembered to put the restrictor pill back in lol) It has me totally stumped I cannot think what else to check

 

xdevil666 I just had a check and there is no MBC in it, and I just replaced all vac lines from all 3 ports on the t piece,
Kevo10 I have tried 2 different dump valves on it and no joy with that either im afraid :/

 

[QUOTE=gee423;11034558]xdevil666 I just had a check and there is no MBC in it, and I just replaced all vac lines from all 3 ports on the t piece,
Kevo10 I have tried 2 different dump valves on it and no joy with that either im afraid :/[/QUOTE contact neilgray1972@yahoo.co.uk

 

[QUOTE=Neil type r;11034627]

 

Hi gee, if your still having problems,
Contact me on 01253 871188

 

Run it on standard actuator pressure to test (put hose straight from turbo compressor to actuator - bypass ecu boost controller etc) should run and hold actuator pressure then at 7psi. Then if that solves ur prob u no its down to the boost controller or vacuum lines there and u no actuator is ok.. If youve swapped all the vacuum lines one usually has a boost pill and without it they usually overboost anyway. Mine did when swapping to silicone lines.
Aaron

 

Hi mate thanks for the suggestion, do I keep the pill in for running between compressor and actuator? I put the pill back in the same place it came out of the old hose, between the compressor and the t-piece, from what I have heard so far on this year of impreza without the pill it will underboost rather than overboost, so I was considering trying to get a small enough drill bit and drill it out?

 

No just put a nirmal vacuum hose straightfrom actuator to turbo compressir with no pill. Then it should run around7psi see how it runs then. I wudnt get drilling that pill mate cos it probably isnt the cause. And u xant un drill it if it isnt lol

 

thats very true lol, I disconnected the hose to the solenoid and blanked it off when I went for petrol, but still had the pill in, and it boosted to 7psi with no fuel cuts like normal, will cut the spare hose to length and try again with no pill tonight and post back after dinner lol

 

Hey everyone just an update, I believe I have narrowed it down to faulty boost control solenoid, as when run hose between turbo and actuator it boosts at 7psi, and when i put the t piece back in and I cleaned the solenoid out slightly with carb cleaner it got slightly better, but is still overboosting, and struggles now to hold a constant boost (needle on the boost gauge flutters rather than staying steady)

I have started a new thread for a bit of advice on how to plumb in a 3 port instead as I hear these are easier to deal with and control boost much better thanks for all the help everyone

 

Just to throw a spanner in the works! I had the same problem and changed a lot of things. I eventually took it to a specialist who took it out for a couple of runs, changed the coil pack with one from a working car a bobs your uncle the problem was gone

I got a second hand coil pack and now everything is fine. You can get them for about £25 from the breakers on this site.

Best bet is to take it to a specialist before you start spending a fortune on things that don't need changing.

 

Hi mate thanks for the input gave the solenoid a damn good clean with carb cleaner, used about half a can lol, hooked it all back up and its much better, still boosting a bit high but im not convinced that the restrictor pill is the right size, I will dig out my precision drill bit set another day though and see if the 1.2mm bit fits it

 

is the exhaust standard? CAT still fitted etc? because i had similiar problems with overboosting with just an exhaust fitted and had to drill the pill out slightly to get it under control

 

it is aftermarket mate, its a scorpion exhaust. Not actually sure if the cats still there, but I believe so because its pretty quite for a subaru, until I put the foot down anyway lol

 

yeah a mate has a scorpion exhaust on his P1, subtle at idle but sounds nice on boost, the perfect scooby exhaust IMHO. i suspect you may have the same issue i had, i replaced all pipes, cleaned the solenoid and tried a replacement, but my car always overboosted. I drilled the restrictor out to 1.3 or 1.4mm and problem solved, it holds 0.9 bar (standard boost) rock solid all the time

 

yeah think that will be the problem mate, I replaced the pill with a welding tip drilled out to 1.3 (in order to prevent ruining the pill drilling it as a test lol) boosts strong now but doesnt overboost anymore running 15psi if my boost gauge is to be believed