K series won’t idle

[22011]

Evening, have got a 2011 SV chassis 7, had a 1400 engine in previous, have rebuilt a 1800 VVC, got parts from Dave Andrews, has got a port and polished head, offset dowels and different exhaust cam. VVC timing and other timing is all on the marks. 
 

wiring has been changed for the vvc engine instead of the 1400 mpi loom so now has vvc oil temp, actuators and cam sensor etc wired in.
 

ecu is a k maps ecu for the 1800, told them what I had done to it so they sent out a ready to go ecu. Problem is She starts half a turn from cold and idles at 1100rpm fine, Revs up ok and idles ok unstick she is warm. Soon as she warms up has a very erratic idle and cuts out. 
 

won't restart without accelerator been pressed. Have tried the 5 pedal reset. Swapped the stepper motor and throttle body from my old engine that's done 14000 miles so know it's not these. 
 

have spoke with k maps it's booked in week on Friday they suggested unplugging lamba sensor and didn't change anything. No obvious vacuum leaks etc. Any ideas what it could be? I'm leading to think it's ECU related.  Moved timing tooth each way and it's noticeably worse so very confident timing is 100%. 
 

just wondering if anyone has had similar problem before I take it to K maps for a plug in?
 

ThanksTom 

[revilla]

Do you have an OBDII scanner that shows live data? If so, worth looking at the sensor values it shows once the engine has warmed to see if any are obviously wrong. Particularly coolant temperature sensor. If that shows -40°C it's a wiring fault, if it shows 140°C it's a short circuit. If it isn't showing something realistic when the engine is hot, the ECU may be overfuelling thinking the engine is still cold.

Check all the other sensors for sensible values too. Things like the inlet air temperature, you're not looking for exact numbers but just make sure they're believable under the current conditions, things would have to be a long way out and implausible to cause what you're seeing.

If you don't have a scanner, check the sensor connections carefully.

[revilla]

Really long shot but I once saw a K Series that started fine and ran perfectly well until it started to get warm, them suddenly it switched to an idle that hunted up and down rhythmically, typical of an air leak. It was quite aggressive, cycling from near stall to about 3000rpm. It turned out to have a crack in the alloy inlet manifold that opened up as it got hot.

[rj]

You can always use brake cleaner to find air leaks.
Spray it around the inlet manifold / hoses. If revs go up, you have a leak.
Don't use it on the exhaust though. Then problem may be solved as the car will be written off in a fire!

[22011]

Thanks for your help everyone, going to have another play this morning, the temp sensor is the one from my old original engine so I'm 99% this is ok, I don't have access to any diagnostic equipment for these only vw/Audi so I'm a bit snookered. 
 

Is the air inlet temp taken from the 4 pin plug/sensor on top of the inlet manifold? Maybe with swapping this with the one from my original 1400 engine as it ran perfect so I know the sensors/senders on that are good. Will double check with some spray to for any obvious inlet manifold leaks. 
 

Regrads Tom 

[PaulRainsford]

Possibly the idle air control valve, if it's stuck closed then it'll struggle to start or idle without help from the throttle being opened - worth a check