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PostPosted: Thu May 01, 2014 2:45 pm 
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If you have fitted a larger exhaust and a decat then it can occur, although its less common on the ST185 I believe.

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PostPosted: Thu May 01, 2014 9:42 pm 
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Right guys, I've had a chance to do some checking.

<It may be worth starting it, then switching off and checking for a code 12 before it's had a chance for one of it's spurious engine lights. It may just be possible the 12 isn't generated by the spurious engine light while driving>

Chris, I cleared the ECU, started the car, stopped it (the light hadn't come on), then checked for Error codes. There were no codes stored. This would indicate that the codes are generated whilst I'm driving along rather than at start-up.
Thanks for the ECU diagrams, one thought I had was for me to swap out the rest of the capacitors, as a leaky capacitor could be slow to charge which might explain why the problem gets better the longer the engine has been running, as the capacitor gradually charges up and works properly.

Diceman, I've also switched off the boost controller and measured the boost using the Greddy's digital readout. On full boost it reads 1.05bar. That's higher than the 0.7bar I would expect. However the T-VSV is disconnected so shouldn't it be 0.5bar?

It could mean the gauge overestimates by 0.35 or 0.55 bar, this would explain why I never get a fuel cut and why the car doesn't feel awesomely fast. I have to admit the car felt quite gutless (when warm) with the Boost controller off.

I should check the value with another meter.
I was wondering if there a way to tell if it's creep? Should the boost rise to 4,500rpm and then fall off between 4,500rpm & 7,000 rpm and if it doesn't fall off that's creep?


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PostPosted: Thu May 01, 2014 10:47 pm 
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Boost creep means that the actuator gets you to 0.5 bar (ish) by 3500rpm and boost slowly rises as RPM increases.

With TVSV disconnected yes it should be about 0.5-0.6 bar.

gauges are normally pretty accurate, I can't even think of a way it could have been plumbed in wrong to measure how it is.

The reason I have suggested looking at the boost is that the ECU would retard timing if it detected detonation (which is likely to occur at 1.25 bar or so) which will make the car sluggish and missing power.

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PostPosted: Fri May 02, 2014 8:02 am 
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Air/Boost leak when cold is my guess as it warms up things expand and probably seals enough to not cause same lack of power. Would also explain the not mutch get up and go when warm as 1.2bar should feel way more than stock.


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PostPosted: Fri May 02, 2014 9:10 am 
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You mentioned that the TVSV was disconnected. Is the air pipe from the actuator blocked?

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PostPosted: Fri May 02, 2014 9:38 am 
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Hi Sirius,

the vacuum pipe that fed the TVSV has been blocked. I've heard from one source it should be open and several others it should be blocked. I can easily change it if required.

With the boost controller disabled I've had a chance to have a good look at the boost profile, (actually had some clear road). Boost peaked at 1.09bar at about 5,000rpm then fell back to 0.7bar by 6,800rpm, so it looks like we can eliminate boost creep. (Dosen't explain why the reading is nearly double what's expected).

For the record the car has been de-cated, I believe the rest of the exhaust is the original fitted to the car in Japan.

An air/boost leak does look to be a promising lead. I’m trying to source all the hoses for the car air/water + a length of vacuum and I’m going to replace the whole lot, as I’ve already had a few minor failures in air and vacuum lines and there could easily be another tucked away in a corner I can’t see.

Are there any hose kit/manufacturers that anyone would recommend?

Thanks for the support.


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PostPosted: Fri May 02, 2014 1:38 pm 
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The feed to the TVSV being open or closed is not important. What is critical is that the 2nd port on the actuator, the one that feeds the TVSV is blocked. Otherwise the system is open to atmosphere and you will get large amounts of boost.

In terms of hoses - the OEM stuff is hard to beat. I have recently gone back to the OEM kit from the silicon stuff.

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PostPosted: Fri May 02, 2014 2:43 pm 
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Hi Sirius,

just to confirm by OEM you mean 'Original Equipment Manufacturer' eg. Whoever makes it for Toyota, as opposed to the company OEM Autoparts?

When I had a Mk2 16v Golf I could get OEM parts (exactly the same part VW sold) much cheaper from 'German & Swedish', than from VW. Are you aware of a cheaper alternative for us, than the local Toyota dealer?

The parts from Toyota are sky rocketing now the car is over 20 years old and many parts (especially trim), are no longer available, so any help keeping costs down would be much appreciated. :-)


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PostPosted: Fri May 02, 2014 4:55 pm 
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TCBParts are a great supply for original parts - yes that's what I mean by OEM.

For vacuum line Toyota sell the original stuff by the metre - it wasn't very expensive when I bought some.

I also moved to Celica's from a MK2 16v Golf - great cars :)

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PostPosted: Fri May 02, 2014 11:41 pm 
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Hi
I've checked the second port on the actuator and it's definitely sealed off so that's good.

What I did find whilst rooting around was that the air line, that T's off between the air flow meter and the turbo, has split.
According to page 194 (of 646) of the ST189_90 Workshop manual, it T's again under the intercooler, one branch goes to the air inlet to the cylinder close to the cold start injector and throttle position sensor. I'm not sure quite what it is but it's shown with an input from the ECU, could be a valve that opens in response to an ECU signal. The other branch goes to the Turbo pressure VSV. I'm assuming the T-VSV doesn't matter as it's disconnected anyway, however the other end could be causing me problems?

I'll fix it as soon as I can get the hose, it's pre-shaped so I can't just use some random spare hose.

I have a picture of my 16V next to the Celica, I'll have to find it and scan it in :-)


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PostPosted: Sun May 11, 2014 6:35 pm 
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Hi,
I’ve had a chance to go over the Celica to look at the Cold Running problem and high boost readings I’ve recorded on my Greddy Profec B-spec 2.

Cold Running

I’ve solved the cold running problem, it turned out that when I had a new Dizzy put in, (trying to sort the code 12s) the chap didn’t set the timing correctly. With a warm engine, E1 & TE1 shorted (flashing warning light on dash) the timing was advanced +5°, so was 5° retarded compared to the +10° standard setting. I’ve now set it up to be +12° and the car runs very well when cold.
(I’ve also found that I can adjust the Dizzy with the Intercooler on the RC in place, if this is a problem for others, I could post on how to do this).

High Boost
I’d recently reported getting a peak boost of up to 1.26bar on ‘Hi boost’ and 1.09bar with the Greddy Profec B-spec 2 switched off. I purchased a Stack Turbo Boost Pressure Gauge – (Mechanical
Black Dial Face -1.0 to +2.0 Bar, (thanks Sirius )) and T’d it into the vacuum line to the Greddy. When I checked the values at high boost the Greddy was over reading by 25-30%, which at 1 bar is 0.25-0.3bar!

I think it’s highly unlikely that the Stack gauge is inaccurate as it was unusually high boost readings that prompted me to investigate and the car did not feel 1.26bar fast and with the timing rectified did not feel 1.09 bar fast.

What is interesting, is with the timing at +12°, the boost only rose to 1.09bar, I could not get to the 1.26bar high. Not sure exactly why this is but worth noting.
So I was not in danger of damaging my engine as my high point of 1.26bar would have been 0.96-1.01bar in reality and now at 12° advance my Greddy reading of 1.09 bar is actually 0.9bar.
I’m now going to see if I can get the Greddy, either recalibrated or replaced as it’s less than a year old.

Thanks for everyone’s help, still get the code 12s though!


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PostPosted: Mon May 12, 2014 12:14 pm 
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Retarded timing increases exhaust gas temperature which in turn spools the turbo harder - hence the reduction in peak boost.

The setting should be 10 degrees on the timing. Next time you're driving past some armco or brick wall on your right, wind the window down ans listen for pinking on full throttle over the 3000-5000 RPM range. In theory the knock sensor should retard the timing automatically but I know someone with an RC that does have audible knock if the timing is too advanced.

Glad you've sorted the issues anyway.

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PostPosted: Thu May 29, 2014 9:54 am 
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Boost creep with a stock turbo? Oh yes most definitely, change the exhaust system and remove the cat and the boost creep can rise as at a right rapid rate of knots, the waist gate design of the CT26 is terrible for this.
Just for my pennies worth I find when you have a really annoying problem like this that is difficult to pin point, I find putting the car back to as close as it came out the factory helps and then start from there again, that way you can eliminate previous owners mistakes or incompatibilities, other wise you can spend for ever chasing your tail. Dorris

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PostPosted: Thu May 29, 2014 10:04 am 
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^^ Wise words :)

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