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Hesitation under boost

PostPosted: Sat Jan 17, 2015 10:33 am
by gradg
Hey guys,

Driving home from work yesterday, I was giving the car a bit of a wrap through some corners and all was fine under S#. Having a blast. About an hour later, I am having power issues. Nothing seems to be going to the wheels.

The car drives fine, runs fine, with no obvious sound of a miss fire and no miss when I actually accelerate. No fault codes are showing on torque either.

When I accelerate, the car hits about 3psi and it just can't hold. I was in a rush, so I couldn't look at it as soon as I got home.

My thoughts were immediately an air leak somewhere.VAC was showing around -22 ish, when normally it would sit around -19 or -20 right?

I'm basically going to have all of a couple of hours to try and hunt around for the leak when I get the chance and just thought i'd ask for any other opinions before I go hunting for the wrong thing. I've been around these things a while and this is the only logical thing i could come up with.

Cheers

G

Re: Hesitation under boost

PostPosted: Sat Jan 17, 2015 1:51 pm
by Manaz
Stock TMIC & throttle hose? Throttle hose is known to fail...

Re: Hesitation under boost

PostPosted: Sat Jan 17, 2015 3:12 pm
by HardwareBoB
100% throttle body hose:

Stock hose with prolapsed gasket:
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Gasket:
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New hose and location of hose: ( I used a kobe hose)
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I also recommend using T bolt clamps. I had to trim the hose, you may or may not have to do this on the stock TMIC.

Re: Hesitation under boost

PostPosted: Sun Jan 18, 2015 9:19 am
by Manaz
I have a space AVO throttle hose if you need one - pre-trimmed (it seems they all come a bit longer than is required) to fit.

I used it for maybe 1,000km, until my Process West TMIC went on. AVO want $88 plus shipping - happy to let it go for $50 to your door, including clamps!

Re: Hesitation under boost

PostPosted: Sun Jan 18, 2015 1:34 pm
by KiDo_Tuning
The 4mm BOV vacuum hose on top is common for coming off. If its on, with engine idling pull off the hose off top of BOV and see if it has vacuum

Re: Hesitation under boost

PostPosted: Mon Jan 19, 2015 8:15 am
by gradg
Thanks for the input guys, I'll be having a quick look this afternoon.

I've got a Kobe intake and short fat bit, i'll be checking those straight away, the throttle hose I'm sure isn't stock, as it's got an AVO TMIC, but I'll check that also.

Naturally i'll have a look at vac lines, from memory I think there's a clamp on my BOV line as I thought it came off a little too easy.

Cheers all.

G

Re: Hesitation under boost

PostPosted: Mon Jan 19, 2015 9:34 am
by senator
Check the 2 mounting bolts on the BOV, the aluminium is too soft to hold the thread and leaks occur, best to get a helical insert

Re: Hesitation under boost

PostPosted: Tue Jan 20, 2015 9:54 am
by gradg
I found the culprit this morning. I'm not real happy about it, given what could have happened. I'm considering myself very lucky.

The problem was an aftermarket BOV was installed. The grub screws which hold the base to the BOV unit surely cannot have had threadlock on them (maybe that's my fault for not taking the thing apart before I installed it, who knows?).

2 of the grub screws have come loose and the plate has fallen outward. What I can only hope is that one of the screws and the plate have both rattled free on to the road somewhere, and not down my intake pipe, which is where I found exhibit A.

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The grub screw I found in the intake.

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The bottom of the BOV showing where the two screws fell out.

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BOV from the top showing the leak as a result of the plate no longer sealing it up.

Now to reset faults and give her a bit of a run.

Thanks for the input fellas.

Re: Hesitation under boost

PostPosted: Tue Jan 20, 2015 10:17 am
by HardwareBoB
Wow, not heard about a BOV failure like that - that's scary stuff - If you bought it from a vendor, I would contact them, and in either case I'd probably call whoever made the valve (looks like a GFB?)

This couldn't happen on mine because the BOV port on the hyperflow intercooler is round, but it's pretty scary still.x

Re: Hesitation under boost

PostPosted: Tue Jan 20, 2015 12:20 pm
by gradg
HardwareBoB wrote:Wow, not heard about a BOV failure like that - that's scary stuff - If you bought it from a vendor, I would contact them, and in either case I'd probably call whoever made the valve (looks like a GFB?)

This couldn't happen on mine because the BOV port on the hyperflow intercooler is round, but it's pretty scary still.x


VERY scary. I've since put the stock one back on and she's running fine after a steady drive, with and without S#.

I've contacted the source of the BOV for now to let them know what happened.

X ;) haha

Re: Hesitation under boost

PostPosted: Tue Jan 20, 2015 12:41 pm
by shav
Man you are lucky. *makes mental note of brand*

Re: Hesitation under boost

PostPosted: Tue Jan 20, 2015 8:19 pm
by gen3v8
Some fuktard is at fault to blame. NOT GOOD!

Re: Hesitation under boost

PostPosted: Sat Jan 24, 2015 4:25 pm
by gradg
The possibility of a lot of damage being done aside, the place I purchased the BOV from has been extremely good about the whole situation.

I'll look for something in the future to replace the stock one but I think for now it'll stay!