Rev-limiter uk TT auto

Recently acquired 2 owner 45k uk supra '94. 1st owner complety de-cat with cone filter 2nd owner 69yrs old 2k a year last 7 yrs. looked after like a baby. So i've just fully serviced car before giving it a good thrash.

Last night came on to dual carriage and gave it the gun. Past a car with over drive off. Concertrating on road head. When heard a click warning light + engine symbol came on, felt loss of power, ie. engine cut out. All in the same breath clicked in overdrive. Lights symbol go out engine resumes. Carry on journey, was it the reve-limiter cutting in + because no other gear to go to. Cut out as safe guard. But because in that spilt sec put in overdrive. engine reconnected. am i right or has any one got any ideas? also manual switch. When selected does this act as sport mode ie. making gear changes hold in for longer?

Also in service just done had throttle bodies cleaned and set up as I had problems coming up to juctions to quick revs would come right down. More often than not would stall. But still comes down now but seems ok. On my 3.0 n/a car revs would drop to 1k split sec drop again to 8.5 rpm should this be the same on the uk TT, any sugestions? Will put some photos on soon, as totally oringnal apart from exhust and filter don't know wether to put back to oringnal or leave. can only be descibed as new.

Could be fuel cut. If the boost goes over 1.0bar, which it will with a full decat, it will hit fuel cut.

Has it had an FCD fitted?

Don't know worth checking only had the car 6 wks, just getting to grips with it. But as it is virutually standard this shouldn't happen surley.

Have a look in the passenger footwell, under the plastic cover and see if you can see something that has been added.

Also might be worth getting a boost gauge fitted so you can see whats going on with your boost pressure

If it has had a decat mate it will hit fuel cut, especially in this cold weather.

If it has had a decat mate it will hit fuel cut, especially in this cold weather.

nope

without a boost controller it wouldn't come close to fuel cut.

What if I put 2nd cat back into exhust system would this eleviate fuel cut in this cold weather? so what are my options? with out getting silly would like to keep car oringnal as pos.

It's UKSpec mate, so the wastegate is well-proportioned to the engine.

Unlike JSpecs, decats do not affect boost.

You really need to have the car checked with a boost gauge attatched.

If it really hits 1 bar then you have to check for a boost controller, or dodgy pipes around the actuator.

Fail to mention its got a dump valve fitted. Would this have any bearing on it? or i'am complety up the wrong tree.

nothing at all.

although along with the decats and the cone filter (more "go faster" mods) it does indicate that someone *might* have fitted a boost controller as well - it's worth checking.

if a boost controller has been fitted are these prone to go wrong[ if one fitted it would have been done between 94-99 cant see the elderly chap doing anything like that] and can it be taken out and left out?sorry if i sound a bit vague, i'll drive it. lookafter it,but as for this hi-tec stuff it's a little bit above me so be patient ;hence why i'd keep it standerd easy then for everyone

Could be a bleed valve! My UK spec hit fuel cut when i decat. However i have a 4" exhaust on it! Best thing to do IMHO opinion is get rid of the dump valve and put the airfilter back to std. And stuff a bootgauge in. This will answer all your questions!

I've got a stock UK airbox for sale in a couple of weeks dude, check for a bleed valve though

it's got a hks silent hi-power exhaust from de-cat back,the anoying thing when left in overdrive it perform ok ;made new m3 look slow ,it the not knowing when or where or if it will happen again [only thing did'nt get done in service was petrol filter got to go back as they got wrong type

this does sound like fuel cut to me

I know of a couple of uk cars that when decated did actually hit fuel cut

on a cold run

It obviously needs looking at, but I think you need to get a boost guage

fitted to see what boost you are running

manual switch. When selected does this act as sport mode ie. making gear changes hold in for longer?

when you select manual mode the car will not change gear automaticaly you have to change gear your self

Also in service just done had throttle bodies cleaned and set up as I had problems coming up to juctions to quick revs would come right down. More often than not would stall.

some dump valves don,t work well on the auto supra

read this threadhttp://www.mkivsupra.net/vbb/showthread.php?t=59154&highlight=Bov

when you say fuel cut on cold run?are you saying that this won't happen if climate is warmer

what I mean is if the the conditions are right

cold day /atmospheric pressure then this could happen

fuel cut happens not just when you hit a specific boost pressure it has to be at that pressure for a period of time i.e 1 bar ish for 1 second ish

boost over time

It's closer to three seconds over 1 bar, and it's unlikely to reach this without a boost controller the way you've described it.

I'd investigate further as to what else they might have 'improved'.

It's not a big deal for the car to hit fuel cut --- wear'n'tear accelerates fast beyond that point though.

Also the 'dump valve' and the 'performance' filter are more 'show' at the expense of 'go'.

I'd stick to the standard items.

The decats are fine, as long as you have a spare rear cat for MOT time.

hi john, what boost should a uk acheive with disconnected wastegate but both cats in(remember my overboosting when cats removed)just wondering as i had no fuel cut with cats in even thought wastegate was not opening. 2 cats must give enougth restriction on there own.everything running fine just like to know how much stress my turbos may have had in the 1000 miles wastegate not functioning

mmm! think ive just answered my own question. less than one bar as no fuel cut

hi john, what boost should a uk acheive with disconnected wastegate but both cats in(remember my overboosting when cats removed)just wondering as i had no fuel cut with cats in even thought wastegate was not opening. 2 cats must give enougth restriction on there own.everything running fine just like to know how much stress my turbos may have had in the 1000 miles wastegate not functioning

 

 

 

mmm! think ive just answered my own question. less than one bar as no fuel cut

With decat and wastegate disconnected (i.e. back of the actuator being at atmospheric pressure) a UKSpec will easily see over 22psi during these cold spell. 24 perhaps.

But if you haven't hit boost cut (and there is no Fuel Cut Defender installed!) then either your wastegate was not totally disconnected or the actuator spring has gone very soft.

Can't say with cats in place because it is unwise to run such high boost with the cats in place. They'd probably melt.

In one of posts it said maybe faulty pipes around actuator (is this what i would called throttle bodies, if so i've just had bodies off and cleaned and re-set up by toyota, is this pos they have been set up wrong).

Also is it pos that with de-cat fuel mixture would change ie. ecu would alter engine running maybe then causing rev-limiter to cut in earlier, causing engine to shut down as a safe guard and re start when safe as this happens with bmw's. Also if it is fuel cut would this show as a fault on memory on car.

I don't think you can do much troubleshooting without a boost gauge - not worth speculating for things that can be measured.

Same with the air/fuel mixture, that can be checked later on the wideband of a RR.

Try eliminating one factor at a time.