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The mkiv Supra Owners Club

Syvecs over boosting problem!


Kaan W

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Right so what I thought was a traction problem and traction control kicking in turns out to be an over boost problem and the syvecs cutting the ignition to prevent damage. I have a low and high boost setting 1bar and 1.6bar on which if I accelerate the boost gauge is displaying around 2.4bar at which point the front of the car lifts and sounds like a jet which for some reason im not happy with. The thing is if im plodding along and I press the throttle sharp and hard all the way down it will only boost to what ever setting im on high or low. So to clarify this only happens if I accelerate softly not gradually but not fast flat to the floor.

 

Also while its boosting at this bizzare pressure im getting alot of chatter and also its cutting out alot for a split second which is the syvecs saftey feature I guess. (Thats what i thought was TC kicking in as my other thread for traction problems).

 

Any know whats giong on?

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Thats what I was thinking but I dont like to bother him too much. Was just wondering if its normal

 

That's what he's there for, mate? Nobody will get to the bottom of the issue quicker. You can log, send him the log, he'll send you a solution and jobs a good'un.

 

The alternative is 20-30 replies based on loads of different theories - and it'll take longer with no real solution.

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You need to plug the lap top into the Syvecs and check what boost the Syvecs is reading under both conditions to rule out an indiscrepancy with the boost gauge. I've heard of this a few times, even on My car also. The Syvecs ready 1.4 bar but my Defi boost gauge has read upto 1.7 bar at 1 point. DanDan also had this issue. If it actually is overboosting, then my money is on a split/melted wastegate line. Are you using the Syvecs boost controller or a seperate boost controller?

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That's what he's there for, mate? Nobody will get to the bottom of the issue quicker. You can log, send him the log, he'll send you a solution and jobs a good'un.

 

The alternative is 20-30 replies based on loads of different theories - and it'll take longer with no real solution.

 

Ok mate thanks i'll do that.

 

Most likely a split pipe or you have plumbed something in wrong when messing with the bay, Ryan won't be able to help with either unless the car is In front of him.

 

You need to plug the lap top into the Syvecs and check what boost the Syvecs is reading under both conditions to rule out an indiscrepancy with the boost gauge. I've heard of this a few times, even on My car also. The Syvecs ready 1.4 bar but my Defi boost gauge has read upto 1.7 bar at 1 point. DanDan also had this issue. If it actually is overboosting, then my money is on a split/melted wastegate line. Are you using the Syvecs boost controller or a seperate boost controller?

 

Now youve said that it could one of the lines to the wastegate as there quite long and messy and have probably burnt or something i'll check it out when I get time. When it boosts to this level tho theres no engine roar like usual just sounds like a real loud turbo noise, when it boosts at the correct amount I get a nice throaty roar and no cutting out what so ever.

 

If I log the data do I need to be driving or can I rev stationary on each boost setting?

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Well my money is on a split/melted wastegate pipe. Have you Thermo-sleeved or heat taped them at all?

 

I havent mate the engines pretty much how I bought the car theres alot that needs tidying. If this was the case wouldnt it be over boosting perminantly?

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Yep I had the same issue as this. There are 2 reasons its doing it and yes its a safty issue.

 

1. Your flooring it when the engine is still to cold..

 

OR (which is what kept happening to me)

 

2. Wast gate vacuum pipe has split somewhere... Your boost will spike, not enough fuel will be supplied, Syvecs will Shi! it self and cut all throttle use.

 

If this happens on the road and you can't pull over, take it out of gear, turn the ignition off while rolling for 1 or 2 seconds turn the key to on then put it back in the correct gear, engine will then come back on and drive sensibly :D

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I'd say the plan of attack would be, rip all the wastegate vac lines out and fit new ones in a nice need manner. Making sure EVERY ONE is correctly insulated.

 

What would you insulate them with or can you buy some braided vac lines?

 

Yep I had the same issue as this. There are 2 reasons its doing it and yes its a safty issue.

 

1. Your flooring it when the engine is still to cold..

 

OR (which is what kept happening to me)

 

2. Wast gate vacuum pipe has split somewhere... Your boost will spike, not enough fuel will be supplied, Syvecs will Shi! it self and cut all throttle use.

 

If this happens on the road and you can't pull over, take it out of gear, turn the ignition off while rolling for 1 or 2 seconds turn the key to on then put it back in the correct gear, engine will then come back on and drive sensibly :D

 

The split vac sounds like the problem but even tho it cuts the engine this is only for a split second, ive never had to do the above it just feels like traction control cutting in but its not.

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