Boost trouble....

B

Bigrig480

Sunday Drivers
Hi lads,
Just joined today,bought a '99 B4 RSK on friday. I knew the car was well looked after by its general appearance (the owner ran a valeting business),however i was under no illusions to a 14 yr old,turboed cars problems etc,A car like a B4 will always need something!
Anyway,the car has an STi Genome boost gauge and recorder,A HKS blow off valve and an Apexi Turbo timer, Occasonally the car seems to Overboost on Primary,then judder like hitting a rev limiter,then boost through to the Secondary turbo... This morning coming from Cork to Mallow on the N20 it wasn't boosting on the Primary at all,i slowed down,buried the boot,jumped off accelerator blowing the BOV,which seemed to cure it.......
I have a reciept for work done on the actuator on the primary in july,Replaced actuator (second hand) and cleared all pipes in and to both turbos...
Any advice greatly appreciated!

:yellowthumb: :yellowthumb: :yellowthumb:
 
Boost issues on a B4 is a mine field. Complicated system. How was the car driving after the actuator was replaced last month? Has the problem only just started now?
 
I could be wrong so someone please correct me but I think the primary should be 0.5BAR and the secondary 0.8BAR
 
After a few days driving and checking in various gears etc, it seems my problem is when switching from primary to both boosting.
Primary boosting to 1.1 but hesitation before secondary comes in and then boosting to .8/.9....??
 
I think that is none by legacy guys as the valley of death I think they all do it but im sure some of the legacy lads will know more than me
 
Bigrig480 said:
Primary boosting to 1.1 but hesitation before secondary comes in and then boosting to .8/.9....??
Click to expand...

Sounds to me like the VOD(known as the Valley Of Death amongst Legacy owners). Change over from primary to secondary with the drop in power and boost. Got caught on opposite side of the road overtaking with that VOD. Its the reason I sold my legacy. It can be mapped to decrease the drop in power but you'll never totally get rid of it.
 
As above you'll feel a flat spot at 4000rpm as the changeover to twins occurs and if you change gear at the wrong time,for example 4300rpm you drop all boost for few seconds-its a quirk of these cars. Also on my old 01 B4 I has an aftermarket BOV briefly and i found it made the flat spot longer so i removed it.
 
This is happening at 3000-3200Rpm though,Boosting to 1-1.1 then Juddering and Boosting again through to Redline.......?
Thanks for all the feedback though Guys. :thumbsup:

The car is Calibrated to Mph on the Kph clocks so i don't know if it was ever mapped or tuned,Would the HKS BOV be leaking perhaps?
 
Just ran through the process on google,can't see any black or green connectors under the right side of the dash,all that's there is an OBD connector. A friend of mine has his own garage and will hook it up to his diagnostics tomorrow or saturday for me to see what's what...

I'll be on to ya if i've no luck!
Thanks a Million!
 
Those connectors are on the left of the steering column when you remove the lower plastic,chances are Google's guide was for lhd and chances are your mates machine won't read pre 01 Subaru
 
Well lads, just plugged the Legacy into a friends laptop using Autocom,Read a historic O2 sensor fault and an inlet air temp of -40.... is this my MAF ??
 
I had a 97 Legecy RS I had the same symptoms as your talking about,sounds like VOD I brought my car to jomo engineering he put the car in test mode,(good battery needed for this)while in test mode he cleared out the maze of pipes on the boost controller with carb cleaner and blowing until he was blue in the face:)
But it did improve the hesitation between primary and secondary but I believe there is no cure.i found I got use to it and knew when everything would cut in and out!!
Fun car to drive for that reason I thought:)


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Just did the self test on the car,Joined the black connectors and turned on ignition,usual lights went out but the Engine light just flashed on and off at a continuous pace, no long or short flashes just on/off at a constant interval.....?
Don't think it's the VOD because the car is juddering,at 1.1 psi or thereabouts.....
 
Bigrig480 said:
Just did the self test on the car,Joined the black connectors and turned on ignition,usual lights went out but the Engine light just flashed on and off at a continuous pace, no long or short flashes just on/off at a constant interval.....?
Don't think it's the VOD because the car is juddering,at 1.1 psi or thereabouts.....
Click to expand...

Bring it to a specialist as you sound like you don't know what your doing , plus boost would be 1.1 bar not psi
 
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