ICV with megasquirt

RichieB5 · 05-08-2006, 07:56 PM

I am a new user of megasquirt and originally set it up with a stepper IACV until I realized it was way too difficult to tune. I then unplugged it and found the car ran great once warm without any idle control.

I then realized idle control is handy at startup. I hooked the original ICV back in to the stock connector and the car starts up great and idles at about 1400, goes up to about 2000rpm, and then never seems to go back down.

Now my question is have I got it plugged in to the wrong connector or is the ICV circuit based on the CIS assembly? Do I have to wire the ICV to megasquirt to run correctly?

Thanks to all that respond!

Jon Clay · 05-09-2006, 03:50 AM

try taking it off and blowing through the side port to see if air will flow. It shouldn't.

I'm running no ISV and just have the idle set to 1200 (warmed-up). when cold it'll do around 950. I have no AC, so this works pretty well, although I have no experience with REALLY cold starts down here in NC.

Good Luck

birdmanmt · 05-09-2006, 05:24 AM

RichieB5 · 05-09-2006, 05:28 AM

Interesting. Never thought there would have been a problem as idle was never an issue when I ran with CIS, even in the dead of winter.

SteveAngry · 05-09-2006, 06:57 AM

I deleted my ISV because I went with the KH EM. It's set up a bit different in the back where the ISV is attached...

Cold idle is 300-400 so I backed the idle screw out until it would idle 800 at cold start/900-950 at warm idle.

This worked fine but because I backed the idle screw out so far I ended up blowing two of them out.

So today I plan on hooking back up my ISV.

Your problem sounds like it's either a bad/dirty ISV, bad ISV control unit or maybe bad ISV temp sensor?

Steve

RichieB5 · 05-09-2006, 10:46 AM

Hmmm

Where is the ISV temp sensor? I read that the way to test the ISV is to jump it with a 12v source and see if it opens.

I assume it is open as it does raise the idle while its plugged in, but it never drops the idle unless I unplug it. If I plug it back in, it won't go back up until the engine is restarted. This bit of info should be key to figuring out what is wrong (for someone who knows!)

Thanks

Black-Wolf · 05-09-2006, 01:34 PM

almost sounds like its wired backwards? opening more when warm rather than closing a bit?

RichieB5 · 05-09-2006, 01:43 PM

I almost think I may have the wrong connector on it (if that's even possible). would anyone be able to confirm what the wire colors should be for the isv connector?

SteveAngry · 05-10-2006, 05:27 PM

There are two temp sensors...

One on top of the coolant flange and one under the power steering pump attached to the head. One is for the ECU and one is for the ISV.

Normally the one on top of the coolant flange is the ISV temp sensor.

Steve
Michigan

TonyOldSchool · 05-10-2006, 08:14 PM

wheel and half of the "relays" are missing. One belongs to the light (dome) etc which I had to remove since the lights would not turn off.

05-09-2006, 03:50 AM	#2
Jon Clay Junior Member Garage is empty, add now Join Date: Feb 2003 Posts: 615	its sounds like your isv may be shot try taking it off and blowing through the side port to see if air will flow. It shouldn't. I'm running no ISV and just have the idle set to 1200 (warmed-up). when cold it'll do around 950. I have no AC, so this works pretty well, although I have no experience with REALLY cold starts down here in NC. Good Luck __________________ <a href="http://filebox.vt.edu/users/jdubyk/Audi/Index.html"> </a> ______________________ AIM SCREEN NAME: j0n clay (that's a zero in j0n)

05-09-2006, 05:24 AM	#3
birdmanmt Junior Member Garage is empty, add now Join Date: Feb 2003 Posts: 1,795	or the ISV controller.... __________________ Jeff R. 87 5kTQ DD, too many goodies to list! 88 80 DD the wife's DD www.034motorsport.com

05-09-2006, 05:28 AM	#4
RichieB5 Audiworld Junior Member Garage is empty, add now Join Date: Jun 2005 Posts: 261	Re: its sounds like your isv may be shot Interesting. Never thought there would have been a problem as idle was never an issue when I ran with CIS, even in the dead of winter. __________________ Richie ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯ '01 B5 A4 (new) '90 200TQ w/EFI+K24@15psi (old)

05-09-2006, 06:57 AM	#5
SteveAngry AudiWorld Super User Garage is empty, add now Join Date: Apr 2000 Posts: 7,277	Same problem here... I deleted my ISV because I went with the KH EM. It's set up a bit different in the back where the ISV is attached... Cold idle is 300-400 so I backed the idle screw out until it would idle 800 at cold start/900-950 at warm idle. This worked fine but because I backed the idle screw out so far I ended up blowing two of them out. So today I plan on hooking back up my ISV. Your problem sounds like it's either a bad/dirty ISV, bad ISV control unit or maybe bad ISV temp sensor? Steve __________________ 1998 A6q 1986 5ktq: Megasquirt EFI and a lot of other mods your car probably doesn't have...

05-09-2006, 10:46 AM	#6
RichieB5 Audiworld Junior Member Garage is empty, add now Join Date: Jun 2005 Posts: 261	KEY INFO Hmmm Where is the ISV temp sensor? I read that the way to test the ISV is to jump it with a 12v source and see if it opens. I assume it is open as it does raise the idle while its plugged in, but it never drops the idle unless I unplug it. If I plug it back in, it won't go back up until the engine is restarted. This bit of info should be key to figuring out what is wrong (for someone who knows!) Thanks __________________ Richie ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯ '01 B5 A4 (new) '90 200TQ w/EFI+K24@15psi (old)

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05-09-2006, 01:34 PM	#7
Black-Wolf Junior Member Garage is empty, add now Join Date: Mar 2004 Posts: 1,444	Re: ICV with megasquirt almost sounds like its wired backwards? opening more when warm rather than closing a bit? __________________ Charlotte, MI 2002 A6 2.7T 6speed Sport RS4 Clutch 1994 UrS4 Black/Ecru Lots o'Mods (for sale)

05-09-2006, 01:43 PM	#8
RichieB5 Audiworld Junior Member Garage is empty, add now Join Date: Jun 2005 Posts: 261	Re: ICV with megasquirt I almost think I may have the wrong connector on it (if that's even possible). would anyone be able to confirm what the wire colors should be for the isv connector? __________________ Richie ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ ¯¯¯¯¯¯ '01 B5 A4 (new) '90 200TQ w/EFI+K24@15psi (old)

05-10-2006, 05:27 PM	#9
SteveAngry AudiWorld Super User Garage is empty, add now Join Date: Apr 2000 Posts: 7,277	Re: KEY INFO There are two temp sensors... One on top of the coolant flange and one under the power steering pump attached to the head. One is for the ECU and one is for the ISV. Normally the one on top of the coolant flange is the ISV temp sensor. Steve Michigan __________________ 1998 A6q 1986 5ktq: Megasquirt EFI and a lot of other mods your car probably doesn't have...

05-10-2006, 08:14 PM	#10
TonyOldSchool AudiWorld Member Garage is empty, add now Join Date: Aug 2003 Location: Brooklawn, NJ Posts: 519	Where is the controller? I looked under the dash next to the steering... wheel and half of the "relays" are missing. One belongs to the light (dome) etc which I had to remove since the lights would not turn off.

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