1.4 VVT-I Idling at 1200 when warm won’t drop to 600 or so

[Richo]

1.4 VVT-I idling at 1200, won’t idle at 600 when warmed up, I’ve checked the MAF sensor it looks clean the cables, I’ve checked for leaks, I’ve checked the cable isn’t opening the throttle at idle. It’s running rich as you can smell petrol from the exhaust, still running very sweet despite but it’s getting less than 20 mpg. I wondered about a Lambda sensor, could that be the issue? If so how many are there I can only see one but I haven’t had a good poke around just a quick look. I’d hazard a guess at 3, could there be 4? If so where are the others. 
 

any advice greatly appreciated, it’s got its MOT in 4 days and no way would that pass emissions and also the brakes have failed (I just bought the car no MOT job) the brake line is only a half an hour fix but it’s this engine that’s got me stumped. 
 

thanks in advance, Cam.

[fordulike]

Possibly coolant temperature sensor faulty or connection loose/corroded.

[Richo]

2 hours ago, fordulike said:

Possibly coolant temperature sensor faulty or connection loose/corroded.

 It’s not running obviously hot like, I take it the coolant temp sensor will start the fan etc well the fan is coming on when it should

[fordulike]

I'm not a car mechanic by profession, so am only guessing on what I think is happening.

I thought, and hope to be corrected, that modern cars adjust their cold start fuel enrichment by monitoring the coolant temperature. If the coolant sensor is not reading properly, then the ECU may think the engine is still cold and overfuel constantly.

Please don't take this as gospel, it is only an uneducated guess.

[fordulike]

9 minutes ago, Richo said:

 It’s not running obviously hot like, I take it the coolant temp sensor will start the fan etc well the fan is coming on when it should

Was writing the same time as you replied. Ok, probably not coolant sensor related 😔

[LukeLuke]

I don't think the car should idle at 600 it would die after about 650

Also did you try run the car with the maf disconnected to see if it makes any difference?

[Richo]

7 hours ago, LukeLuke said:

I don't think the car should idle at 600 it would die after about 650

Also did you try run the car with the maf disconnected to see if it makes any difference?

I have a Toyota avensis with the 2ltr VVT-I and I swapped the MAF into the Corolla and it made no difference I’ve checked for air leaks in the vacuum hoses nothing, and the avensis idles at 600 that’s what the tack says like but certainly has a low rpm at tick over, I gave the steel housing that the idle control goes into a gentle tap with a small hammer and it momentarily improved it so tomorrow I’m going to remove the throttle body completely and clean inside there and check the condition of the parts. 
 

I found thAt the rear wheel hub assembly is different on petrol to diesel and some clown has put a diesel one on and it’s only been making contact with half the disk and half the pads, I was livid because that’s been on more than a year so I reckon a dodgy MOT centre has let that slide 

[furtula]

Could be something simple like the old owner had/bought  another car, and swapped the Battery before selling it, and did not let the car re-learn idle.

I would try the simplest solution 1st, disconnect Battery for 10 minutes, reconnect, let it idle for 10 minutes, take for a drive, and let us know if it fixed it.

[Richo]

1 hour ago, furtula said:

Could be something simple like the old owner had/bought  another car, and swapped the battery before selling it, and did not let the car re-learn idle.

I would try the simplest solution 1st, disconnect battery for 10 minutes, reconnect, let it idle for 10 minutes, take for a drive, and let us know if it fixed it.

It got MOT in 3 days it ran out in dec hence why I got a car that looks and feels so tight to drive for £300, the Battery I shall have a go with that tomorrow the Battery was flat but judging by the terminals I’d say that Battery been on a while, there’s an airbag wArning light on I think it’s because the battery was flat... I hope. 
 

I hate working on new engines, just newer cars in general access it rubbish, expensive parts, hard to fault find. Give me a car from the 60s any day, the best of it was I was going to buy a 1972 mk3 Ford cortina estate for my gardening business 1600 pinto engine I love them. But outbid at last second 😭 so instead I ended up with the Toyota Corolla, great fun to drive like but I can’t get my Honda mower in the back or the strimmer, even with a trailer it’s a squeeze. 
 

but it’ll do me till I can find a 3rd gen avensis tourer 1800 petrol. (I’m 18 hence not being able to insure the 2.2 diesel or even the 2.0 diesel ) because insurers think that even though I’d be driving an avensis estate... not very boy racer ish I’d still drive like a loon and crash. Irony is I can insure a 4.2 jag420g  for less than my Corolla 😭 

 

[Richo]

Well after a fortnight of scratching my head I’ve found the issue, it was a sticking idle control valve I’ve cleaned it and it’s not perfect but much better it’s idling at 600rpm as it should.