Since I was all a panic in the last thread and I have made some updates since, I'm starting a clean thread for my problem. I'm on the verge on scrapping the HGT and buying a very boring Hyundai i20 from my parents, but I want to give the car one more chance. Basically, the car stalls at idle until the engine is thoroughly warmed. From there, it performs faultlessly.

The problem was originally at intermediate temperatures, but seems to have spread to when the engine is cold too. I found the coolant temperature sensor to be slightly out of calibration, so this was replaced, but the issue is still there :bang: I disconnected the MAF to see if that improved things, but it didn't.

Now since I have an electronic throttle, presumably I don't have an Idle Control Valve, is that correct? It's almost as if the engine isn't holding its idle high enough during the warm-up phase. Interestingly, when I try to actuate the motorised throttle through MES, the procedure fails. Now I know that the throttle works, because it responds to the accelerator pedal, but is it possible that it is not responding to the additional inputs required of the ECU during warm up? Unfortunately, I don't know enough about the Hitachi MPI system to know what parameters and actuations it controls during warm-up.

I don't know if it helps, but the fault came on suddenly during very hot weather, it wasn't a gradual deterioration. Engine temperature was fine though (CTS was over-reading, so it would have been cooler than indicated by ~10%).

Cheers,

Mick

Has to be some sort of idle air control on it, I'd have though, either on the throttle body or the air box. A simple air bleed.

As Dave Walker is fond of saying "Tou can't get air down a wire".

Looks like post 2001 HGTs did without an ICV according to this post. I assume it must control the idle speed using the motorised throttle. I think it's worth the cost of a bottle of carburettor cleaner to investigate.

just take the hundy you know you want to
dont forget to have a set of pearls made up though and have a blue rinse
some vaseline might be handy too at service time for when you go in

I did intend to get myself a diesel Bravo next. However, the folks have owned this car from new so I know its complete history, and the price is right. Whilst my HGT came with 'Full Service History', it's clear that it was mistreated somehow because of the high oil usage, so if I can avoid such risks, that's for the best. However, I will be back to Fiat eventually, because I have promised to sell the i20 back to my little brother once he's passed his test.

As for the HGT, I got myself some throttle body cleaner and gave the throttle body and MAF some attention. The body didn't look dirty, so, as I expected, it made no improvement. I also used some electrical contact cleaner on the throttle body plug to ensure good connectivity there, and dumped some injector cleaner in to improve the spray pattern. The only thing left is to start replacing components (throttle body, ECU etc...) until it works, but that will get really expensive really quickly, so I prefer to get rid.

On the plus side, I've got REALLY good at controlling both accelerator and brake pedals with the one foot. Useful skill when I'm heel 'n' toeing on the track in the upcoming MNR Vortx.

hi
i see you are going to do 70 miles a day in it so i retract my statement
you do need a diesel

s and b said:

hi
i see you are going to do 70 miles a day in it so i retract my statement
you do need a diesel

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Managed it fine in my 55 BHP mk1 Punto but yes, I quite fancy the lazy driving style of riding the torque when it comes to the motorway.

Have just solved exact same problem with 2004 Punto 1.2 Active Sport. Was an incorrectly functioning air bypass valve (driven by the idle control stepper motor) supplying less air than required for cold starting. You can tell this is the problem if you run the engine from cold with the air filter housing removed. If the air bypass valve is working correctly, you will hear a hiss of air being sucked into the small chamber at the front of the air intake opening. The sound reduces in magnitude as the engine warms up and the valve progressively closes. If you don't hear this then the valve is stuck closed or the valve port is blocked with debris.

Firstly, ensure there is a very good earth connection to the front of the throttle body. Clean off any corrosion and dirty from the mating faces of the connector and throttle body and ensure it is bolted down correctly. I also coated the surfaces with petroleum jelly.

If this doesn't solve the problem, remove the throttle body and spray WD40 onto the air bypass valve, clean it's surfaces and the airflow port, then refit it ensuring all the electrical connectors and the earth are properly refitted.

If this doesn't work then you'll need a replacement throttle body.

fidoctor said:

If this doesn't work then you'll need a replacement throttle body.

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That would have been my next move, albeit replacing the throttle body due to faulty stepper motor on the main throttle butterfly because it's fly by wire and doesn't have an idle bypass valve. However, since it was drinking oil, had an intermittent airbag fault, the rear catalytic converter fell apart and I needed a diesel for my type of driving now, it got scrapped.