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Guest Message by DevFuse
 

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Custom built fast idle valve


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21 replies to this topic

#1 Speedbuggy

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Posted 05 June 2012 - 09:11 PM

ON my buggy (http://www.ultimates...ad.php?t=113679 ) that's running a turbo charge EJ25D, controlled by an EMS Stinger ECU, I don't currently have any sort of idle control, which means when the engine is cold it tends to stall when you let off the gas until it warms up a bit. I want to add an ICV, but my ECU won't support one.

what I want to do is get something like this:
http://www.ebay.com/...#ht_2389wt_1163

And plumb a line from the outlet of my intercooler, through the solenoid and into my intake manifold upstream of the throttle body. Then all I'd need to do is flip a switch and the idle should jump up....

Theoretically. This valve has an 1/8" inch orifice, so I'm not sure how much that's going to boost my idle. I'd like it to idle at around 1200 rpm when the switch is engaged.

So, first, is there any merit to this idea at all? Second, does anyone have any idea how much of an idle increase I'd get with basically an 1/8th" leak in my intake manifold?

Edited by Speedbuggy, 05 June 2012 - 09:24 PM.


#2 nipper

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Posted 05 June 2012 - 09:26 PM

Some background on what you want to do

http://www.megamanual.com/ms2/IAC.htm

not sure if that will help.

#3 Speedbuggy

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Posted 05 June 2012 - 09:42 PM

Thanks.. I've read all up on that.. The megasquirt WILL support an idle control valve, but my ECU wont.. Well, it WILL support a PWM valve, but I haven't been able to find a way to get a PWM valve into the intake path. I have a block for using a stepper valve, but my ECU won't control a stepper valve.

#4 nipper

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Posted 05 June 2012 - 09:50 PM

Since this is not a ton of money here, may be only one way to find out

#5 Fairtax4me

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Posted 05 June 2012 - 11:08 PM

I wonder if you could do a timer / temperature controlled setup?
Also, part of the cold idle programming is injecting more fuel, so you'll want a way to enrich the mixture slightly when the idle valve is open.

#6 Speedbuggy

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Posted 05 June 2012 - 11:46 PM

I wonder if you could do a timer / temperature controlled setup?
Also, part of the cold idle programming is injecting more fuel, so you'll want a way to enrich the mixture slightly when the idle valve is open.


The ECU will take care of that. Once it sees the manifold pressure change it will increase the fuel to compensate.

I've been trying to figure out a way to do a time or temperature based solution but haven't been able to come up with anything yet

#7 Speedbuggy

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Posted 05 June 2012 - 11:47 PM

Since this is not a ton of money here, may be only one way to find out


I'm more worried about having to tap the intercooler and intake manifold.

#8 nipper

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Posted 06 June 2012 - 12:02 AM

SIlly question, was this a custom intake manifold so it just wasnt used ?

#9 Speedbuggy

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Posted 06 June 2012 - 07:34 AM

SIlly question, was this a custom intake manifold so it just wasnt used ?


Yes it's custom. I believe the original Idle Control valve plugs into the throttle body right? I'm not even sure what the throttle body I have is from, but a Subaru tuner told me it's not a stock Subaru body.

#10 nipper

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Posted 06 June 2012 - 08:59 AM

hrmmm.

I slept on this over night and I think there may be a simplier more elegant solution.

A throttle kicker solenoid. An IACV can be blocked off on performance applications with no issues. A throttle kicker does the same thing as an IACV for your purposes but without plumbing. It just kicks the throttle open a hair to compensate for load. Many feedback carbs had this. My Justy has one.

#11 Fairtax4me

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Posted 06 June 2012 - 01:09 PM

Hey! I just had that same Idea! :-p

Ford used some for years that were run off of the EECIV engine control system that would actually compensate for changes in idle speed and throttle position. Of course the ECU was controlling all of it, but it was a variable solenoid. You might be able to use a simple controller like an Arduino that could read throttle position temperature and engine speed and drive the solenoid based on inputs from the sensors already on the engine. You could even use it to control an idle air control valve. :-p

#12 Speedbuggy

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Posted 07 June 2012 - 10:25 PM

Any links for a throttle kicker? Sounds like an intriguing idea.

#13 nipper

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Posted 07 June 2012 - 10:45 PM

ALl it is is just a solenoid that pushes against a tab on the throttle plate. Almost any car with a carb has one. They can also be called a high idle solenoid. Some are vac operated, some electrical.

http://books.google....olenoid&f=false


http://www.auto-part...-es4026235.html

They go by various names, high idle solenoid, throttle kicker, idle stop, AC solenoid.... Cheap american unit overbuilt may work well from a junkyard.

#14 nncoolg

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Posted 08 June 2012 - 02:18 AM

Why dont you use a standard EA82 Cold Idle valve from a 1987+ (hi-rise intake)XT?

They see 12Vdc at all times from the fuel pump relay. They are not a duty-solenoid or stepper motor type valve, 2 wires, 1+, 1-.

They work with a coil that heats up a bimetal strip and moves a shutter, slowly closing the passage so the rpm's slow as the engine heats up.
They are also adjustable so you will be able to set (within reason)the cold idle speed to how you want.
They look like a one-sided dumbell, just make sure you get a good one, as when they age, they collapse to one side and the shutter moves out of its operating aperture. Old, hard rubber hoses can bend the alloy casing too, jamming the shutter plate.
If you find a source for new ones, please let us know here.

Alternatively, you could use this, which looks like a great solution and I think it suits a PWM valve : General purpose IAC valve

Edited by nncoolg, 08 June 2012 - 02:21 AM.


#15 Speedbuggy

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Posted 08 June 2012 - 08:13 PM

Why dont you use a standard EA82 Cold Idle valve from a 1987+ (hi-rise intake)XT?

They see 12Vdc at all times from the fuel pump relay. They are not a duty-solenoid or stepper motor type valve, 2 wires, 1+, 1-.

They work with a coil that heats up a bimetal strip and moves a shutter, slowly closing the passage so the rpm's slow as the engine heats up.
They are also adjustable so you will be able to set (within reason)the cold idle speed to how you want.
They look like a one-sided dumbell, just make sure you get a good one, as when they age, they collapse to one side and the shutter moves out of its operating aperture. Old, hard rubber hoses can bend the alloy casing too, jamming the shutter plate.
If you find a source for new ones, please let us know here.

Alternatively, you could use this, which looks like a great solution and I think it suits a PWM valve : General purpose IAC valve



Your first solution sounds promising. How is it plumbed in?

Your second suggestion is what i already have. That block is made for a stepper motor, and I haven't been able to find a PWM that will work with it nor a version of it made for a PWM.

#16 nncoolg

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Posted 09 June 2012 - 07:58 PM

Ah OK, I assumed, since that valve had a pintel it was a 'duty solenoid' or 'PWM' type thing - well there you go!

The EA82 one has two 1/4" mounting holes on a flat foot at the bottom, and two hose barbs, 1/2" I think, 1 in 1 out with a 2 pin bosch type EFI plug socket. pretty simple design really, could be mounted anywhere, but engine heat helps them close faster than just the electric coil.

Im sure someone has a picture of one removed...

#17 nncoolg

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Posted 09 June 2012 - 09:28 PM

...actually, I do!

Posted Image

this is the OE valve on 1987+ Subaru XT's, made by Jecs.
Nissans of the same era have a very similar valve, made by Bosch, which MAY work the same!

let us know if you find a supplier of new ones (and if it works in your application of course;))...

#18 Speedbuggy

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Posted 18 June 2012 - 09:47 PM

That looks perfect for my application. Now I just have to find one

#19 Peerson

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Posted 19 June 2012 - 11:44 AM

That is a standard Bosch part. Find any car with Bosch CIS or some with AFC (Datsun 280Z/ZX Toyota pickups with EFI, Opel Manta, pre 83 Volvos and Mercedes the list is very -long-) It is called the air bypass valve. Plumb one end of it after the throttle body, and one end before the throttle body. Supply 12 volts to it and off you go. It uses a small heater and a bi metallic spring to slowly close a shutter so that when cold it will act like the throttle is being held slightly open, and when it closes you return to normal operation. If your ECU happens to control mixture via CTO more than throttle body you should be in the clear. If not a temperature controlled solenoid on the throttle body is your next step (If you have a TPS that controls mixture and no air flow meeter) I can draw you a diagram for one that is vacuum controlled (You can get the throttle kicker from 80's Japanese cars that have AC, that is how they raise the idle when the AC is turned on). Just options.

Example of the valve. If you need to see how they are plumbed I can take a picture of my Peugeot. http://www.ebay.com/...38e469a&vxp=mtr New ones run about 80 bucks.

Edited by Peerson, 19 June 2012 - 11:54 AM.
Adding URL


#20 nncoolg

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Posted 21 June 2012 - 04:42 PM

Its not a Bosch, its JECS as stated in my above post, but yes, the bosch item fitted to other makes appears similar...

#21 Speedbuggy

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Posted 24 June 2012 - 06:54 PM

I'm going to pick up one of those Bosch valves and see how it works. Ill report back when I'm done. Thanks for all the help

BTW would anyone have a rough idea how much that valve might increase my idle while fully open?

Edited by Speedbuggy, 24 June 2012 - 06:57 PM.


#22 nncoolg

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Posted 24 June 2012 - 07:20 PM

I think it will depend a little on what size engine the one you choose is meant for. The factory one on my ea82 cold idles at 1600 and they are adjustable to an extent by the nut on the side. Perhaps one from a Nissan 3L would be a good match, they are easier to adjust slower than faster...Airtex and wells make aftermarket ones too, may be a good option to try...




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