Guys,
Im thinking this is probably an ecu/tuning problem but i thought I may throw a few possibilities out there and see what i get back....
I have a worked pinto motor and head with lumpy cam. Im running EFI on a microtech fuel only ecu. The injectors are 205cc (admittedly a bit too big for this purpose but bought that size so to turbo it one day) Still running points distributor due to issues with Petronix Ignition. I dont run an ECV valvle but run a straight dump from the sump into the atmosphere (dont tell the greenys)
 
Whats happening is the car will run great when its cold and will idle at 700-800rpm but once it warms up and has been driven around, the idle wont go below 1500rpm.
Ive thought of a few things it could be:
Vacuum leaks (which may explain why it doesn't idle high when its cold because the cold fuel map is richening up the mix, hence leveling out the air leak) Maybe the lack of PCV valve?brake booster?
Worn Distributor advancing timing
*head scratch*
Can anyone offer me up any suggestions apart from ECU tuning?
 
Thankyou,
Kieran
 

Do you run an idle stepper motor?

Check your valve clearances,
 
Woz

Hi Spigot, no stepper motor on the car
 
Cheers Woz, i shall check that out also. You thinking they are too close, hence heating up, expanding and leaving the valves open for too long?

An idle control valve will help with cold start amongst many other things. If you have a vac leak. Spray carby cleaner around the suspect areas with the car idling.

How are adjusting the idle speed?

Ionix

Hi Spigot, no stepper motor on the car

Cheers Woz, i shall check that out also. You thinking they are too close, hence heating up, expanding and leaving the valves open for too long?

 
Have seen it before, so worth a look.  I have had a few customers cars come to me with that problem, and more often than not the valve clearances have closed up.  Resetting them fixes the problem straight away, so if they haven't been done for a while could be the problem.
 
Cheers
Woz

Im just adjusting idle speed in combination with the cold start fuel map/idle screw and the fuel maps.
Is this not a way to do it? Bearing in mind i run a fuel only computer?

Thanks Woz,
I shall have a look at it that , I adjusted it not long ago when i got the cam reground, but its always worth looking at all the options!
 
Thanks,
Kieran

You have way too many questions on stuff that should be checked straight away.
 
IMO throw that microtech in the bin if you want to turbo the engine, 205cc injectors are puny for boosted applications.  As a comparison 2.6L Magnas used 24lbs injectors. 
 
All initial tuning should be done when the engine is at operating temps and THEN you use your trims/modifiers for everything else.  Please tell me you are using a wideband AFR meter to tune the microtech with.
 
16 deg should be your initial timing with it maxed out at 36 deg at about 3500-400 rpm.  Slap a timing light on it, if the reading goes all over the place the dissy is flogged, easy.
 
 

I will eventually go away from the Micro tech, but that's down the track when money permits so i can have allot more tuning options.
 
Going turbo is still a pipe dream so well see. So you reckon a 205cc injector wouldn't be too big then for a na even? Just thought it may have been.
 
Yeah, using a lamba sensor etc so thats all good. sits consistently at about 14.7 through the whole rev range and when under load etc.
 
Cheers for your help woz and spigot, ill let you guys know how it goes.