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 Post subject: Fuel cut mystery
PostPosted: Fri Sep 05, 2014 9:21 pm 
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Group N
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Joined: Wed May 02, 2012 9:49 am
Posts: 188
Location: Fife
Car Model: ST205
Since fitting the new clutch the car has been driving well, and the kevlar plate has bedded in meaning I've been having fun in the car once more... Until today.
I was out and about, decided to overtake another car, and at full chat I hit fuel cut and nearly ended up with "OMOM" embossed on my forehead.
After this slightly embarrassing near death experience, I tried WOT a few times more and sure enough the boost was reading 1.4 and triggering fuel cut. Code 34. Over boost.
I turned off the ebc and it still happens. Argh.
I don't get it... The night before I was out doing a bit of "testing" on the open road and all was fine. I actually felt the car was pulling better than ever.
So what are the likely culprits? Sticking wastegate? VAC lines? I noticed a slight split in the intake hose from the airbox to tubby... Maybe this? It drives fine until you floor it.
:(

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 Post subject: Re: Fuel cut mystery
PostPosted: Sat Sep 06, 2014 9:38 am 
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Joined: Sat Sep 02, 2006 3:13 pm
Posts: 3679
Location: Bournemouth
Car Model: None
What turbo & what exhaust ?

What boost does it normally reach with no ebc ?

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 Post subject: Re: Fuel cut mystery
PostPosted: Sat Sep 06, 2014 10:57 am 
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Joined: Wed Jul 13, 2005 12:06 am
Posts: 4743
Location: Perth, Western Australia
Car Model: ST205
1.4bar :shock: your engine won't stay in one piece very long at that level. The car would have felt like a rocket-ship (very addictive :twisted: ). If you switch off your EBC then the actuator boost should be 0.9bar. If not then the wastegate is possibly jammed shut. This has happened to me after a track day when the spindle overheated and 'galled' thus sticking the wastegate. In my case it stuck partly open. Easy enough to check but to be sure remove the downpipe to examine the wastegate in more detail.

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1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp


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 Post subject: Re: Fuel cut mystery
PostPosted: Sun Sep 07, 2014 12:25 am 
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Group N
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Joined: Wed May 02, 2012 9:49 am
Posts: 188
Location: Fife
Car Model: ST205
Hi. It's a stock tubby and normally limited to 0.9 by the ebc, and about 0.7 when it's off. Something has changed since the other night and the boost just keeps rising when accelerating. I've only let it trigger fuel cut a few times while diagnosing, so hopefully no damage.
Looks like I'll need to take things apart to see what's what. This is uncharted territory for me so... I'll be back!

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 Post subject: Re: Fuel cut mystery
PostPosted: Sun Sep 07, 2014 10:59 am 
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Joined: Wed Jul 13, 2005 12:06 am
Posts: 4743
Location: Perth, Western Australia
Car Model: ST205
Hmm, sounds like there's nothing wrong with your EBC config so it points to something mechanical. Just wondering if it's worth checking the actuator with the old bicycle pump test? If you search on here I'm sure you'll find references on how to do this. Easier to do this with the actuator off the car. Just a bit of a pain having to dismantle stuff. Let us know how you get on. Good luck!

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Don
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1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp


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 Post subject: Re: Fuel cut mystery
PostPosted: Sun Sep 07, 2014 11:38 am 
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Group N
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Joined: Wed May 02, 2012 9:49 am
Posts: 188
Location: Fife
Car Model: ST205
Thanks for the help. Really appreciated.
Are the wastegate and actuator fixable parts, or are we talking replacement with new or refurb bits?
Just need time to work on it now!

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 Post subject: Re: Fuel cut mystery
PostPosted: Sun Sep 07, 2014 1:12 pm 
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Location: Perth, Western Australia
Car Model: ST205
Wastegate is fixable but IMO you really need the help of experienced turbo reconditioners to make sure the job is done right. The actuator would either be an exchange unit or new. The aftermarket ones normally are of the bolt-on variety and have a threaded end which allows more mechanical adjustment. With the OEM type small washers are the only way to change (slightly) the length of the arm. Actuators can be rated at different boost levels. I had a 1bar actuator on my 300+bhp 3S-GTE.

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Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp


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 Post subject: Re: Fuel cut mystery
PostPosted: Mon Sep 08, 2014 2:34 pm 
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Joined: Wed May 02, 2012 9:49 am
Posts: 188
Location: Fife
Car Model: ST205
OK, have had a closer look at the Actuator pipework, and I discovered that the bolt which was put in about 6 years back to block the TVSV hose has disappeared (and the rubber hose is pretty split)!

Am I correct in saying that this is likely to cause my problem?

Either way, I'm going to get some replacement hose etc. and block these off in a more effective manner!

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 Post subject: Re: Fuel cut mystery
PostPosted: Mon Sep 08, 2014 5:36 pm 
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Joined: Sun Aug 25, 2013 2:54 pm
Posts: 120
Car Model: None
I once had an issue with my ebc solenoid sticking shut and this cause constant overboost and the boost rises fast as he'll. try and run it on actuator pressure without the solenoid in place. As you say though it could be tvsv


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 Post subject: Re: Fuel cut mystery
PostPosted: Mon Sep 08, 2014 10:32 pm 
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Joined: Sat Sep 02, 2006 3:13 pm
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Location: Bournemouth
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The Lorro wrote:
OK, have had a closer look at the Actuator pipework, and I discovered that the bolt which was put in about 6 years back to block the TVSV hose has disappeared (and the rubber hose is pretty split)!

Am I correct in saying that this is likely to cause my problem?

Either way, I'm going to get some replacement hose etc. and block these off in a more effective manner!


Yes. If that is open there is no way of building up pressure in the actuator to open the wastegate.

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 Post subject: Re: Fuel cut mystery
PostPosted: Mon Sep 08, 2014 10:45 pm 
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Group N
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Joined: Wed May 02, 2012 9:49 am
Posts: 188
Location: Fife
Car Model: ST205
Yup. Problem solved.

Thanks to everyone for their input.

Now I just have to set up my ebc again, having *bleep* around with the settings when it first threw a wobbly.

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 Post subject: Re: Fuel cut mystery
PostPosted: Mon Sep 08, 2014 11:44 pm 
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Joined: Wed Jul 13, 2005 12:06 am
Posts: 4743
Location: Perth, Western Australia
Car Model: ST205
That's very odd, if your EBC was plumbed in to the actuator and the feed from the turbo compressor was also plumbed into the EBC then the actuator should have worked fine. The original line from the VSV to the actuator being open shouldn't have made any difference although its good practice to block it off with a small bolt to stop the ingress of water and debris. If, on the other hand, you'd disconnected the EBC plumbing and not reconnected both the lines from the turbo compressor to the actuator and the VSV to the actuator then as Chris says the actuator won't function and the wastegate will stay closed.

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Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp


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