Welcome to overboost my friend!

 

had that on my integrale and thought it was over boost but it was the fuel pressure being too low for the boost. didn't break my neck when it did it just exploded the transfer box

 

Expensive fuel shortage PP!!!!!!

 

kippax

it got worse than that!!! got new transfer box, paddle clutch etc fitted then thought I would get the engine setup to stop it overboosting by getting it chipped, on the way home from getting the chip fitted the cambelt jumped and destroyed the cylinder head and 2 pistons!!! it now sits there in a friends car park in pieces

 

bad ****.

 

Kippax-in which range of rpm does it happen?
i had the same problem between 3000rpm and 4500rpm ,first on 5TH gear then in 4TH gear:my dealer discoverd it was a wastegate problem,not exactly a problem...well it was just dirty!
so every regular service my car has, they wash the wastegate valve shooting compressed air inside of it.
they say it's just oil coming from the outside that may obstruct the way.
now my car is ok,running like a beast!!!!
hope this is helpful
cico

 

Cico, what car do you drive?

I'll try what you suggested. There is some good advice in 'Drivetrain' at the moment as well but it seems the other cases, including yours do it at lower revs than mine.

Stu.

 

have you a boost guage? Sounds like you are getting overboost and reaching the boost cut. I would have thought Bob could sort this

 

I've had this problem when I had my Catalunya. Turned out the dealer was overfilling the oil at service time and this caused some oil to blow through the system and contaminate the wastegate / sensor (well summat like that) Any way the upshot was that the engine believes it is overboosting because the wastegate can't act properly and therefore the engine management system cuts the power to avoid the engine thinking it is about to destroy itself.
Wastegate needs cleaning up and the oil level in the sump should not be much more than half full.
Its very scary when u expect full bore round a corner in 2nd or 3rd gear and suddenly you have NO power

 

P1DOG, yeah it's difficult to get round the corner in style with your face pressed against the windscreen

 

Kippax,
Provided the scoobies have a similar overboost setup to the Evos then I suggest you check your wastegate actuator isn't corroded or damaged. If you haven't done any mods recently and its just started overboosting then the wastegate actuator is usually the first thing to look at as it's probably stuck closed therefore developing lots of boost that the car doesn't like.

Andy

 

Cheers Andy and everyone else.

 

Stu (Kippax) as I said when the car was fitted with the LINK ecu it suffered from over boost in 3rd and 4th gears mid /high range boost, basically the same as you are experiencing. It was remapped and the car suffered no more. I did the 1st SIDC Bedford day with no problems at all.

If there has been no modifications done since you bought her to increase boost I really don't know what the problem is sorry. I can only suggest (and I know this is a trek for you) that you take the car back to Branco and Bob and let them plug it in and see if the maps gone off track somewhere. It can only be that in my opinon.

...regards Ian Sutton

 

If driven hard, my engine sometimes cuts out for a split second and nearly breaks my neck. It feels like a fuel shortage but I'm not sure.

Can anyone help?

Edited to say it's an STi5 with a Link ECU, Scoobysport Exhaust, HKS induction kit, HKS plugs, 3 port boost solenoid set up by BR.

Edited to say I just came off a roundabout in second and nailed it to 7500rpm. At 5000rpm in third the power just cut out then came back in again. It does it pretty much every time. I does the same in fourth, can't be bothered trying fifth.


[Edited by Kippax - 1/8/2002 9:59:14 PM]

 

Dave, It came with a boost gauge but it was the dash mounted one and I didn't like the look of it. I'm in the process of fitting a small HKS one in the dash. I agree with you that if it is overboost, a gauge is the first step.

I've tried reading the threads in 'Drivetrain' but it's difficult to read and understand it all. Also, mine happens at >5000rpm which seems different from other cases.

So your saying the ECU detects an unaceptable boost level and cuts the boost?

Why has the problem 'developed' and not always been there?



[Edited by Kippax - 1/8/2002 10:31:03 PM]

 

Hi Kippax,

I too have a similar thing happen.

I've got a linked sti5 as well.

You need to see where and how the engine is being 'cut'.
To check whether its fuel/electrics or boost (am not going to attempt to get technical, as i'm not!)

Mine happened for the first time in 2000 in the winter, normally only happened when i floor it, it just coughs and dies briefly before setting off again quite high up the revs.

Then through the summer it was fine (this was after Bob and Branko had kindly checked the map for me and it was fine), we had also changed the plugs, tried different HT leads and a few other bits and pieces, the problem strangely vanished.

The @ october i started getting the same thing again.
Car is currently with Steve Lawson getting some bits done so will let you know if he finds anything.
We've already tried new plugs again, no difference.

I'm not 100% sure its overboost though (in my cars case) as when Bob first mapped it (on the first visit) the boost was hitting nearly 1.7 on mine and it wasnt a problem.

Now its reliably sitting @ 1.4 but has this cut. Surely if its overboost and being cut to protect, i would have had it when the car was hitting 1.7 nearly?
Tho the wastegate bit does very feasible based on what i've read about such things tryying to educate myself with my own problem.


[Edited by ptholt - 1/10/2002 10:14:59 AM]