Common Subaru Impreza and STi problems

scientist

Blow-off valve (Dump Valve, Air bypass valve) Loud noise between 2-4000 rpm which sounds like someone blowing over top of a bottle. 1997/1998 Turbo

Waste Gate Solenoid can be noisy (clicking), and in extreme circumstances can cause sudden loss of power when accelerating hard All Turbo

Heat Shield Noise from engine compartment caused by cracked heat shield. 1994-6 Turbos

Interior Mirror Interior mirror vibrates lightly, blurring rearward vision All

Clutch Clutch judders when moving off. Worse when cold All Turbo

Brakes Spongy brakes All models

Radio resetting Radio resets when wash/wipe or electric windows activated All 5-door

Brake Pipes Noise from engine compartment caused by brake pipes resonating against bulkhead 1998 Turbo

Porous 15" wheels Loss of tyre pressure 1994-7 Turbo

ECU bug Smile

Jerk when throttling off from full boost 1994-6 Turbo

Engine Engine splutters to a halt. Caused by driver enjoying him/herself so much they fail to notice they were running low on fuel Smile

All Imprezas

Worn anti-roll bar bushes Clonking noise from suspension WRXs

ABS isn't magic Unexpected activation / long stopping distances All ABS cars

Use of low octane fuel? Serious engine damage (melted pistons) STi (4 & 5?)

Piston Slap Noisy (chattery) engine when starting from cold 1998/99 models

Dump Valves (aka Blow off Valves and By-pass Valves)

There seems to be a recognised problem with the 1997 specification car's dump valve. This does not shut properly under boost and thus vibrates giving the sound similar to someone blowing across the top of an open bottle. It has also been likened to a steam train whistle or ship fog horn in extreme circumstances!. Meanwhile the 1998 model seems to have a totally revamped and larger blow off system, but I have had reports that the problem sometimes still occurs.

Waste gate solenoid

The 1997 specification lowered the turbo boost pressure from 1.0 bar to 0.9 bar. The engine breather system vents into the air intake and it is possible for the oil and condensing, burnt oil vapours build up in this valve. This valve is a safety device for detecting overboost and will cause fuel and ignition to be cut if it senses that 1.2bar (97/98 models) has been reached. If it is bunged up, it isn't sensing correctly and will shut down the engine under high boost conditions. The solution advised by Subaru France was not to fill the oil up to maximum but to leave it at half filled only.

If your wastegate solenoid does pack up, the fix is to pull the T shaped supply hose off and fill it with brake cleaner from an aerosol. Then go for a blast before the cleaner evaporates. Tippex thinners also do the job. '98 models have a revised part, which is three port sensing and there have been no reported failures. You can get '97 cars upgraded.

Apparently the fault often occurs just after a service when the oil level may be slightly too high. The 1998 specification engine apparently has revised sensing locations, to over come the above problems but there have been some reports of failure on early '98s.

Sometimes this fault is incorrectly termed as "over boosting". The sensor is designed to detect an over boost situation and is usually so sensitive in normal operation that 1.19bar = ok and 1.20bar = fuel cut routine due to over boost. When it becomes contaminated by oil, this is lost and the sensor can cut in at much lower boost values, cutting in the routine under normal hard acceleration. The effect of this routine is quite disconcerting as all engine power is suddenly lost with some drivers reporting it feeling as if they have just driven into a brick wall!

scientist · Posted: Sat Apr 09, 2005 8:20 pm Post subject:

a lot of these also pertain to the GD STi...both JDM and USDM

mrlantra · Pumpum Conqueror Joined: 10 May 2005 Posts: 1

These problems affect not only the wrx/sti but the legacy and foresters as well, spongey brakes and pinging from poor fuel plauges my ride Evil or Very Mad

Polydor · Posted: Fri May 13, 2005 3:59 pm Post subject:

mrlantra check this out

Have a look @ www.ecutek.com

It has the solution to your problem.

I've been using this for over 1 year in my STI and it outperforms the GReddy waste of money with no support ECU

It's a bit expensive but it has proven and rally tested maps with 100% support from the Techs. @ EcuTek. Kudos to Mike and Peter.

Happy tuning
Polydor.
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