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The mkiv Supra Owners Club

Not making any boost HELLLPPPPPPP


Scott

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i popped an itercooler pipe and lost all boost but she did continue unning ok just no boost at all but i could hear the whosh when she popped so knew it was that, before i went single i popped a small pipe at the back of the the metal pipe cluster and lost nearly all boost but heard nothing, just seems strange that you lost boost after fitting a new bov insert, you sure you havent knocked something while doing so

 

I don't think so, well i can't think of anything as i only took out 4 allen screws. It was working fine for a few quick bursts, to see what it sounded like, and then nothing.

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I missed the part about fitting the BOV :rolleyes:

 

Could be it's faulty or getting a bad vacuum signal. It might be worth reverting it back to how it was before, just to eliminate it

 

I tried taking it off and blocking up the relief pipe bit. When i drove i got a tiny amount of compressor stall which, along with the slight spooling, makes me wonder if its a wastegate issue. I can only assume its either something silly or something big lol, don't think its an in-between issue.

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Well I'm assuming it's still on stock turbos in which case your wastegate does nothing until 4000rpm or so and only works on the second turbo anyway, so I doubt it's that.

 

If you are making slight boost and everything sounds smooth and there is no oil smoke then I'd say you haven't lunched the first turbo unless it's committed suicide in a clean manner. The exhaust noise should be slightly louder if this were the case as the exhaust wheel would be missing.

 

Aside from reiterating "check all your intercooler pipes", have a look here:

http://www.mkivsupra.net/vbb/showthread.php?t=35926

 

Especially at problem #4.

 

Being a MAP based fuelling system it'll run fine even with the hose off the throttle body so that can't tell you anything really.

 

-Ian

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Firstly thanks for the replies, its a bit worrying as you can probably understand.

 

For clarification my car is a Facelift Jspec on stock twins with shitty HKS intake and Greddy (unknown row) intercooler & Hardpipes.

 

Ok i took it out for a run and managed a max of just under 0.5 bar. I'm guessing thats not good? I think i saw that around 5k-5.5k revs.

 

When i got the car back i had a look at all the pipes and i can't see anything wrong but i wasn't sure where to focus as there are a lot of hidden bits.

 

The boost during driving is as follows...

 

Idle = -500

idle to 2.5k = -700

2.5k to 4k = 0

4k - 5k = 0.1/0.2

5k onwards = 0.5

 

I didn't like pushing the car too hard so i only took it to around 5.5k rpm in 3rd. I took it to 6k in 2nd and much the same happened.

 

All my mates work during the week but hopefully i'll get one of them round and go out for a spin so that i can record my boost gauge and rev's while driving, that way i have something to show you guys.

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I never seen this as I was on holiday, for the sake of saving you a few quid in diagnostics get the front bumper off or jack the car up and check every angle of the route between first turbo compressor and the intercooler, if its banjo clamps I'd even undo them and push them in to double check

 

Once you have done that blank off the BOV or refit the stock one if you have it, is it a genuine HKS?

 

Compressor stall should be negligable at stock boost

 

Go around and check no vac hoses have come loose, any t pieces for boost controllers(if you have one) then take it for a short blast

 

What noise is coming from the turbos under boost? Does the 2nd turbo even come online?

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I never seen this as I was on holiday, for the sake of saving you a few quid in diagnostics get the front bumper off or jack the car up and check every angle of the route between first turbo compressor and the intercooler, if its banjo clamps I'd even undo them and push them in to double check

 

Once you have done that blank off the BOV or refit the stock one if you have it, is it a genuine HKS?

 

Compressor stall should be negligable at stock boost

 

Go around and check no vac hoses have come loose, any t pieces for boost controllers(if you have one) then take it for a short blast

 

What noise is coming from the turbos under boost? Does the 2nd turbo even come online?

 

I plan on going over as much of it as i can over the weekend (properly) and if i can't find anything i'll have to take it to the garage.

 

The Dump valve is genuine but i did take it out and block it off to see if that made a difference. I'm not sure if the 2nd turbo is coming online, i think it is as i get 0.5 bar at 5k revs but not below so i can't be sure.

 

As for noise it spools up very very quietly, nowhere near as much spool as i would normally get. I can hear it around 2.5k but its very feint.

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I think i have ruled out the IC pipes. I took off my air filter and managed to stall the car by covering the hole. I'm guessing that would mean that there is no leak in the IC piping as it would at least hiss a little bit. The system did try to pull pressure through the dump valve but very little.

 

I had a good look around the IACV actuator and VSV but there were no splits or pipes off, they were actually quite supple. The only pipes i couldn't check properly were the ones that go round the back of the engine, i couldn't see them properly but i had a feel around though and they seem fine.

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