2000+ Revs From Cold Starts, Rises With Clutch

[Ryban83]

Hi all, any advice on this would be greatly appreciated!!

I recently bought a Gen 7 140 Celica which needed a new engine. The engine i bought was coded E1Z-T72R which i believe is from an Avensis. Everything runs great apart from the revs when i start the engine...

From cold the revs jump straight to 2000-2300rpm and stay there for about 10 minutes of which it will then sit at a comfortable 700-800rpm at idle. During this 10 minutes i notice that every time i press the clutch the revs jump by a few hundred. When the revs do start to drop it still flickers up to around 2000, its like the ECU is telling the engine to do so, It looks like im constantly challenging people to race at red lights :P

Once the idle revs sit at 700-800, if i turn the engine off and then back on the revs shoot straight back up to 2000-2300 and then still take a few minutes to calm back down. Ive tested this a few times just sitting still. My ST202 idled high (2000) from cold but quickly came down and wouldn't shoot back up if turned off and on again.

Ive read that Toyota programme the ECU to rev high from cold as to warm the engine up quickly thus not releasing so many pollutants which im all for but all this high revving is having a frustrating impact on fuel consumption. I've also been reading that cleaning/replacing the Idle Air Control valve can fix this but i havent tried this yet.

Maybe this isnt an issue and im just paranoid but if not i would really appreciate some guidance! :)

[Phil01]

First of all I would check the engine coolant thermostat,, as to me it appears it could be faulty and not opening at the correct temperature, engine running to cool, even tho the dash gauge may show it is at correct temp. I had this once on a Camry and the idle rpm was too high for ages and ages, the only time it would drop to the correct idle rpm was when I was in traffic and the under bonnet temp rose, hence the reason why when you turn it off and back on again the revs rise again as the engine coolant temp sensor has read that the coolant is still low and instructing the ecu to raise the revs to compensate, you might even find that the MPG will improve once new T/stat is fitted as it will warm the engine quicker and thus shortening the warm up injection cycle.

Other item I would check for the issue of the revs rising when you open the throttle maybe the throttle plate damper needs backing off as it could be set to high.

I do not think that cleaning the throttle body will cure your problem, this is only applicable in the reverse order, that is you have a very low cold start rpm.

[Ryban83]

Morning Phil01 - Just wanted to say thanks for the reply. I'm speaking to a mechanic today based on your reply as he wasn't sure what the problem was when he first checked. Ill repost when I find out more.

Thanks again!

[Ryban83]

Just incase it sparks other thoughts, i drove into work today and revs are worse. After a 15 minute drive, then at stationary the revs go from 1000 to 2000 constantly like im pressing the pedal as soon as it gets back down to 1000. A friend at work said it could be the timing belt?

Ill speak to a mechanic later taking the advice above but any other thoughts again would be appreciated! Thanks