Ionix
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Idles perfect when cold, not when hot.....Pinto with EFI
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
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spigot
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Re:Idles perfect when cold, not when hot.....Pinto with EFI
2011/12/09 17:57:33
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Do you run an idle stepper motor?
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Wozzah
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Re:Idles perfect when cold, not when hot.....Pinto with EFI
2011/12/09 20:29:42
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Check your valve clearances,
Woz
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Ionix
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Re:Idles perfect when cold, not when hot.....Pinto with EFI
2011/12/10 15:55:04
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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?
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spigot
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Re:Idles perfect when cold, not when hot.....Pinto with EFI
2011/12/11 10:41:04
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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?
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Wozzah
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Re:Idles perfect when cold, not when hot.....Pinto with EFI
2011/12/11 12:06:14
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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
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Ionix
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Re:Idles perfect when cold, not when hot.....Pinto with EFI
2011/12/12 14:49:52
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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?
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Ionix
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Re:Idles perfect when cold, not when hot.....Pinto with EFI
2011/12/12 14:51:01
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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
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spigot
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Re:Idles perfect when cold, not when hot.....Pinto with EFI
2011/12/12 18:54:43
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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.
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Ionix
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Re:Idles perfect when cold, not when hot.....Pinto with EFI
2011/12/13 10:13:47
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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.
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spigot
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Re:Idles perfect when cold, not when hot.....Pinto with EFI
2011/12/14 16:04:15
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If you are using a wideband then 14.7 is too lean for under load and most big cammed engines like it slightly richer at idle. Minimum should be 13 under wot.
I am helping a mate to turbo a pinto and for 200fwhp I would not even think of using less than 30lb injectors, that size will do about 240fwhp max. 205cc injectors I believe are about 20lbs and thats no more that 150-160fwhp.
There are now a lot of fairly powerful ecu's for very little money, both 2nd hand and new. Megasquirt II's are apparently pretty good. I know delco hack is another.
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gazz
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Re:Idles perfect when cold, not when hot.....Pinto with EFI
2011/12/16 08:20:12
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Ionix
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Re:Idles perfect when cold, not when hot.....Pinto with EFI
2011/12/16 12:02:01
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After being told that, i checked my part numbers, and not sure how i got 205cc in my head but they are actually 315cc( or there a bouts)...apologies for the confusion there.
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RS 2000
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Re:Idles perfect when cold, not when hot.....Pinto with EFI
2011/12/31 18:35:20
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To utilise what you have there you need a cold start air bypass. commonly used on earlier efi cars, once you have one of these installed. you then need to adjust your idle speed and mixtures etc at normal operating temps and cold air bypass will/should allow for stable idle while cold and warming up providing the air fuel mix and timing are right. an example of a common cold air bypass valve  Or another method(although not prefered) is to use electric solenoid , however this would be operated by the driver via a switch. these are comonly found on toyota engines 1990-2000 as an a/c idle up solenoid. here is an example( this particular one is on/off type solenoid but is adjustable )  Although very very agricultural microtech can be adjusted by those who know what they doing. Cheers
post edited by RS 2000 - 2011/12/31 23:22:55
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Ionix
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Re:Idles perfect when cold, not when hot.....Pinto with EFI
2012/01/02 14:27:08
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Thanks RS2000, appreciate the response. After reading these articles I have gone with peoples suggestions and decided to move away from the computer I've got and ordered a megasuirt II.
With this, I'm hoping to be able to utilise the standard for sierra IAC valve, which they said i would be able too, is this correct ?
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