Insanity & The Supra ECU!

I have never come across a car with a more unhinged idle control than the Supra! i swear it has more moods than a premenstrual woman! mine seems to have a different setting for every day of the week, just when i have gotten kind of used to it, it will surprises me with a new one:blink: it now seems to have a slight miss after a high speed run, but on starting it this morning, its back to a "cough" normal idle, for a change.

Just taking a wild stab here but could it possibly be a faulty O2 sensor ?

Or

Maybe the IAC needs a clean.

As I said, just taking a wild stab.

Thanks Joe but the lambder is fine, and the IAC valve was checked and cleaned not long ago, i swear mine has a multi personalty disorder:blink:

You're not the only one Dick, mine does too.. Some mornings it idles high, some low and occasionally it idles just right!

Must be the Hastings air

Glad to hear mine is not on it's own but it is in for a service tomorrow.

Cleaning ISCV is not normally succesfull

I remember from my Ford dealership days, you used to get the Granadas and Seirras randomly revving on their own from 600 - 5000rpm great if it was a Auto!!

Cleaning was only a short term cure it was usually back within a week, they all work on the same priciple in all makes Vauxhalls suffer the same,

Only answer to really cure it is fit a new valve, no doubt £££££££ from Toyota

small vacuum leak?

small vacuum leak?

small vacuum leak?

Agreed but that would be poss give high idle all the time or even stalling,

But definatley worth checking all your vac pipes for sure, especially if you have a Vac gauge fitted

Also check your intake pipes if you still have the standard Toyota rubber one, where it has the ribbed section they can split in between the ribs,Although TBH you'd probably have no idle or stalling as soon as you took your foot off the accelarator.

 

Only answer to really cure it is fit a new valve, no doubt £££££££ from Toyota

Only £470+vat

Ours is the same, one day its running fine. the next day its revving at 2000rpm on idle. and some mornings it has a verry slight missfire but runs perfectly fine. i think it might be because it is on choke? Any things i can do to stop this little missfire, or when it idles high?

Although I have no experience with the 2JZ or any other turbo engine for that matter I do have a lot of experience with a multitude (sp?) of cars. One thing I can tell you is that it sounds like you have an air leak somewhere, believe me an air leak does not always present the same problems for day to day. From experince the car will run fine one day and rubbish the next. Things I have had problems with and would check are, any breather pipes, all vacuum pipes, inlet pipes and one that always gets over looked check the fuel pipes inlet and return. On cars that are getting on a bit the fuel pipes tend to perish round the ends and small cracks can allow air to be sucked in. Also check you exhaust system for leaks, this can cause weird problems as the engine often sucks air back up when you come off throttle and this throws the o2 sensor out. Hope you find the problem.

Well, I fell the need to get involved in this thread because my random idle is strating to bug me. Tonight for example, on cold startup it went straight up to 1500rpm, which is fine, 15 mins later its at 1100 rpm, it then stays that way for the next 20 mins, then all of a sudden, you pull up at a set of lights and the revs drop to the 500-600 mark, but by this time, im virtually outside my house and about to park the car in the garage, surely, it shouldn't take that long to warm up, especially as I was giving it large on the deserted motorway on the way home, I thought maybe a good hard run would clean it out a bit.

Bit bloody cold tonight though! and that is a large lump of metal to heat Mine did something similar. Once she got up to temp she was purring like a kitten though. Normal for my old gal is about 1600rpm when cold until the temp gets to somewhere normal (this makes the auto rather - interesting to drive from cold, a bit like running a/c in summer - idling in traffic, then a/c picks up / revs increase - woah baby, lets not mount the car in front!) then she drops to 600 idle.

I suppose your right, I have noticed it more since its been cold, I've also noticed my gear change has been different lately but I put that down to the cold weather as well, being that the gearbox fluid will be thicker when cold, I changed it two days ago anyway just to be on the safe side