Hey, I bought a 96 sti import a few weeks ago, its occasionally overboosting in 3rd, 4th and 5th and fuel cut comes in at 1.5bar its 50/50 though as it also holds 1.1bar when it wants too.??

It has the following;
Decat downpipe straight through exhaust
Bailey Dump valve

I was advised to get it dyno'd which i have and when they looked at it the boost vacum hoses where plumbed in wrong. Also had a bleed valve which i have thrown in the bin lol.

They did a test run and it hit 235bhp.

Re plumbed the hoses and added the missing pea from vacum lines (homemade pea with a 1mm hole)

Ran at 265 bhp better but not right.

Changed the pea to a 8mm hole and did the final run
Hit 275.3 bhp at the flywheel and 213 at the wheels.

Had a slight missfire caused by leads which i have now changed.
Any help would be much appreciated?

 

On which run did it hit 1.5 bar? thats 300+bhp territory on a TD05 turbo if the car is a version 2?
Your decat wont help matters, neither will the misfire (is it still there after you changed the leads?).
Also who tested the car? did they give any fault diagnosis out???

Tony

 

Its a version 3

Veysport in Bournemouth was where i had the 3 power runs and vacum hoses rearranged.

1st run was how it was when i bought it, no missfire but underpowered
2nd run more power after pea and hoses where sorted
3rd run hit good bhp with different sized pea but developed missfire at the end of the run (showed on the graph) and i felt it on the drive home

Ive borrowed my friends leads until my magnecors turn up and missfire was cured

it never overboosted on any off the power runs only on the road.
but its tempermental sometimes she holds 1.1bar and the next minute overboost and fuel cut?

So no fault print out apart from missfire

 

Just to clarify, was it overboosting/fuel cutting 'before' you had it dyno'd? ie when you first got it?

 

So VF23 if its a version 3, 1.5 bar is quite high, something not quite right there, though its still overboosting, your first call would be the boost solenoid, cheap to clean out, look in the tech archives area for info on how to do it

Tony

 

Was wondering if the pevious owner was using the bleed valve to limit the boost/prevent over boost, hence why the plumbing was a bit

And surley you mean a 0.8mm 'pea' not 8mm

 

before dyno it didnt overboost it was only running 0.7 bar

Ok great il have a go at cleaning it tomorrow thanks

Maybe why he had the bleed valve as he did seem over cautious

and yeah 0.8mm lol

Thanks peeps
will update when ive cleaned the solenoid

 

Had a go today, fired some break cleaner through in test mode and it came out yellow for a few swuirts then clear, gave her a run and so far so good :-D

feels like a different car! Thanks for the help guys

 

Glad it's sorted, I did laugh though, 'only' 3rd, 4th and 5th...

 

Well it was only 3rd 4th and 5th lol