TheSamba.com :: View topic - Idle Control Module issue (high idle) & cheap fix

Sun May 15, 2005 6:20 pm

Well, one problem down, about a thousand more to go...

My van's now running, but idles very fast - not sure how fast...I wish VW had given me a tach in the dash instead of a huge freaking clock. I turned the idle screw all the way in, and no change. I'm thinking either a big vacuum leak or a stuck/dirty throttle; I can rev the engine up with the pedal, but it doesn't drop back any lower than the original fast idle. The idle stabilizer valve shows continuity, but I guess it could be the controller. I haven't tried unplugging it and starting yet. Any quick ideas?

Sun May 15, 2005 7:10 pm

Turn the idle down by the screw embedded in the Throttle Body, or, is the idle compensator history??? Working????

Can you bring the idle down by putting it in gear, forcing the engine down to an idle? Does it stay down at an idle or go back up?

Idle compensator could be not working, is it a 1.9 or a 2.1 or air cooled?
Some of the water boxers have a green box to the left of the engine with two connections. That also could be defective, you can unplug and put the plugs together to bypass it for testing purposes

my guess is the idle compensator

Sun May 15, 2005 8:16 pm

I had intermitant fast idle problems on my 86/2.1L. engine kept reving at 2000 rpm. I chased wires, swapped out control units, checked for vacuum leaks, adj settings checked idle switches and nothing was wrong. Yet it would just idle away at 2000 rpm. I got sick of looking at the scales of rust on the intake runners the other day and started scraping them lightly and bingo rust holes in the base of the intake tubes where they meet the intake flange for the head. I was not detecting a leak through any of the usual spots when I searched for vacuum leaks but they were there. I just siliconed over the pin holes until I find a clean intake. This must be common back east. The syncro is from Pa, now living in Co.

Sun May 15, 2005 8:36 pm

Thanks for the replies...it's a 2.1. I tried adjusting the idle w/ the screw in the throttle body - still high even turned all the way in (which should normally kill the engine, right?). I haven't tried putting it in gear yet...if it does drop, what does that tell me?

Sun May 15, 2005 8:43 pm

idle compensator is not working, that silver tube looking doo dad is gone, maybe the temp sensor is also going bad or flakey

if tormorow the van dies and dies from too low an idle, check the sensors and the idle compensator...

Throttle body could be gunky, from stuff carbon and all, maybe someday take the boot off and clean the T/B out really good...

Tue May 17, 2005 7:52 am

So, after a bit of a detour involving the throttle body switch (it needed adjustment, but sort of broke in the process...), it looks like the problem is the idle stabilizer. I fired the engine up, and it raced high as usual - unplugged the idle stab. valve...voila! She purrs like a kitten! (Well, it's a Vanagon, but you get the idea). So this tells me it's most likely not a gunked-up and stuck valve, but the electrical signal it's getting from the control module. Agree?

The interesting thing is that it looks like I'm not the first one to play around with the idle stabilizer on this van...there is a section cut out of the plastic panel on the right for easy acess to the module. The original plug is still there attached to the body, but looks like it hasn't been used in a while; there is another harness sitting loose in that area with the module plugged in. I wouldn't be surprised if some water got in while it was sitting there. I'm going to pull the module apart and see if anything is fried - got some good tips after poring through the archives on vanagon.com....

Tue May 17, 2005 9:09 am

Update: there's definitely a fried transistor in there. Same as this post I found on the vanagon.com list; I'm going to try to find a replacement...

/////////////

Vanagonauts,

Recently I related the story of my 87 Syncro suddenly developing a +4,400 RPM
idle. I traced this to the Idle Control Module located forward of the
right/rear taillight. The dealer said list was $208. I called several
wreckers and was quoted from $80 to $20 for this item. I bought the $20 one
and it arrived yesterday.

Meanwhile I was pursuing repairing the bad module. Inside the module I
discovered two components that were suspect. The first one, a voltage
stabilizer transistor was definitely fried. I found (from my 88 Vanagon
module) a company logo: SGS in tall narrow letters pushed up against
eachother & other numbers were BD 438 and 9 741. I found that an ECG or NTE
185 was a replacement component for it. The other component was a rectifier
diode that had some signs of being overheated but was not overtly fried as
the other component had been. The diode had the numbers GP15G-7001 and GI
8641. I thingk the GI is for General Instruments. Well, found that it
could be replaced with an NTE 125 or ECG 125.

Yesterday, I installed the two new components and the bottom line is that
after poping the module back in, my van idles normally again! :)

Cost?
NTE185: $2.25
NTE125: $.88

Total: $3.13 + tax

Compared to dealer list, I saved about $205. - that's 98.5% less!! :) :)
:)
So now I've gone from needing a new module to having a spare for future use.
:)

Jim Davis
87 GL Syncro
88 GL Wolfsburg

Wed May 18, 2005 8:06 am

Well, I fixed it! Soldered in a new transistor and diode, and plugged it in...normal idle. $3.78 fix for a $200 part!

Tue Jul 30, 2013 5:50 am

shenan-agon wrote: Well, I fixed it! Soldered in a new transistor and diode, and plugged it in...normal idle. $3.78 fix for a $200 part!

I love a good DIY fix for a stupidly expensive part. Kudos to you Shenanagon!

Wed Oct 23, 2013 12:27 pm

how did you know which diode to replace?is it the one right infront of nte185

Mon Oct 28, 2013 7:53 pm

can any one tell me where the nte125 diode goes...is it the one behind bd348?
pics anyone...nte 125 in the mail

Wed Oct 30, 2013 6:51 pm

any recommendations where to order those parts online?
Thanks

Wed Oct 30, 2013 6:52 pm

i got mine on flea bay...
i still dont know wich nte125 to replace

Mon Sep 04, 2017 6:44 am

minsk wrote: i got mine on flea bay...
i still dont know wich nte125 to replace

Were you able to ever figure this out?

Have a high idle on my 86 2.1 on startup. At first thought an air leak, bo issues. Then tracked it to ICV ( unplugged ICV wire and noemal idle, also unplug ICU and normal idle ).

When turning on ignition ICV opens then closes, no humming. Any thoughts?

Mon Sep 04, 2017 6:58 am

You might find this thread helpful.....

https://www.thesamba.com/vw/forum/viewtopic.php?t=353187

Dave

Mon Sep 04, 2017 10:13 am

besides replacing or rebuilding the idle control module and after that if there's little result.. you could do this

in the back of the idle control valve (ICV) there's a small allen screw to adjust the idle...

Sun Jul 29, 2018 1:25 pm

Locations of NTB185 and NTB125 (before and after).

Tue Nov 20, 2018 9:00 pm

Goodie wrote: Locations of NTB185 and NTB125 (before and after).

Any idea what resistor is in the foreground of the bottom image? The big grey out of focused one.

Tue Nov 20, 2018 9:24 pm

Found this other pic in Goodie's gallery:

Resistor in question seems to be marked "66R 10%"...whatever that means... :wink:

- Dave

Tue Nov 20, 2018 9:42 pm

dhaavers wrote: Found this other pic in Goodie's gallery:

Resistor in question seems to be marked "66R 10%"...whatever that means... :wink:

- Dave

Thanks for that picture! It shows everything much better. I know so little about circuit boards. I believe its 56r printed on there.

I already soldered the NTE185 into my idle control module, but this 56r 10% has a small burnt spot on the side of it. I bought this( https://canada.newark.com/ohmite/oy560ke/resistor-ceramic-56-ohm-2w-10/dp/64K5435?st=56r%2010% ) to replace it but I'm not sure if it's the right replacement for that resistor. Dont want to solder it in and mess up more things in this module.