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

Wed Nov 21, 2018 8:13 am

While in there, those electrolytic capacitors should be changed.

Wed Nov 21, 2018 8:23 am

My idle control unit on my Digijet was causing intermittent starting issues.

I talked to a professor at school and he thinks I could get away with maybe just eliminating the burnt caps and just running wires as the values of those resistors are unknown.

Regardless, Van Cafe sold me one (last year) for $30. Van has never gave me any issues since.

Wed Nov 21, 2018 9:57 am

drumbum68 wrote: While in there, those electrolytic capacitors should be changed.

Which ones are those?

Sat Jul 06, 2019 11:19 am

Took my control unit apart and the NTE 185 transistor was fried. Contacted a local guy who works on circuit boards and he's able to repair it for me. He tested the rest of the unit was fine.

Hope to have it back next week and get the IAC valve back in the loop.

Thanks again Samba people!

Brian

Tue Sep 17, 2019 2:20 pm

Does anybody can get the Idle Control Unit electronic sketch for my Vanagon GL 1987?
y

Mon Apr 13, 2020 12:49 pm

I just repaired my ICU from an 86 2.1l
I had 2 Faults:
1) 2000 RPM idle
2) Rough Idling
No burned components
After reverse-engineering the unit, I had a set of schematic diagrams.
With a scope confirmed that the Solenoid Valve was outputting a PWM waveform.
It was just erratic in idle and 2000 rpm.
Twisting the boards whilst idling I was able to exhibit these symptoms.
On the mainboard I re-soldered all the main large components joints. (Connectors, Large Diodes, Large Resistors, Electrolytic Capacitors)
After this, the 2000 rpm issue was gone, but the erratic idle remained. Twisting the 2nd board was able to simulate this fault. Turned out to be the 0.01uF cap inline with the ignition signal. This is a large component, and the joints were dry, Resolderd all caps on this board, and the fault was gone.

I cant find out how to load files on this site, so if someone wants a copy, just mesage me.

Tue Apr 14, 2020 7:53 am

[email protected] wrote: I cant find out how to load files on this site, so if someone wants a copy, just mesage me.

The only means I know of loading any "files" here is as photos. If you could save the diagrams as a JPG image, they could be loaded to the image gallery. Kludgey, but lacking anything better...

Jim Davis

Wed Nov 11, 2020 8:09 pm

[email protected] wrote: I just repaired my ICU from an 86 2.1l
I had 2 Faults:
1) 2000 RPM idle
2) Rough Idling
No burned components
After reverse-engineering the unit, I had a set of schematic diagrams.
With a scope confirmed that the Solenoid Valve was outputting a PWM waveform.
It was just erratic in idle and 2000 rpm.
Twisting the boards whilst idling I was able to exhibit these symptoms.
On the mainboard I re-soldered all the main large components joints. (Connectors, Large Diodes, Large Resistors, Electrolytic Capacitors)
After this, the 2000 rpm issue was gone, but the erratic idle remained. Twisting the 2nd board was able to simulate this fault. Turned out to be the 0.01uF cap inline with the ignition signal. This is a large component, and the joints were dry, Resolderd all caps on this board, and the fault was gone.

I cant find out how to load files on this site, so if someone wants a copy, just mesage me.

I’m interested in the file. Sending you a PM

Wed Nov 11, 2020 8:19 pm

@ Roger...Can you share a link to Dropbox, or PDF saved in your Google drive, or...???

- Dave

Thu Nov 12, 2020 5:08 am

Hey folks, Roger sent me the files a while ago and I told him I would post them for him. Haven't done it yet, but will get them up here today when I get to work - yes, I actually go to work a couple of days a week, at least for now.

Thu Nov 12, 2020 8:14 am

OK, testing to see if these links will work. Could someone click on them and see if you have access to the schematics?
EDIT: The links did not work. Public links are a few posts below.

Thu Nov 12, 2020 8:48 am

bobhill8 wrote: OK, testing to see if these links will work. Could someone click on them and see if you have access to the schematics?

https://drive.google.com/file/d/1SXoqJIQqLxQuR-lN4MDz5od8d_024nsT/view?usp=drivesdk

https://drive.google.com/file/d/1Uf9NMt_NyEDv6aCEXafgHdzojProhru_/view?usp=drivesdk Access denied. You need to check the 'Share with everybody' box in Drive.

Thu Nov 12, 2020 9:12 am

https://drive.google.com/file/d/1_phf85X-USw12Q39zog2PxEwQQu3U8UT/view?usp=sharing

https://drive.google.com/file/d/1N2UR4Q8PCaDwS940UHxiQZPu8M4moD05/view?usp=sharing

These should work!

Thu Nov 12, 2020 9:32 am

Those ^^^ are working for me...very nice!

Hearty thanks to Roger & Bob! 8)

- Dave

Tue May 11, 2021 12:54 pm

Its a bit of a pain that I cant load them as PDF's

Thu May 13, 2021 3:49 am

I turned the schematics into jpegs. Not sure if it's more helpful in this format, but it was easy enough:

All the work was done by Roger - I'm just the Amazon driver.

Thu May 13, 2021 12:14 pm

Are you sure you want to share all this intellectual property? I appreciate the sentiment, however some might take advantage of this. You could maybe share it under a creative commons license. https://creativecommons.org/licenses/

Antway, great work. Can't wait for my idle module to go bad so I can buy this 8)

Sun Aug 15, 2021 10:13 am

Thank you for the great information. I noticed in the schematic that you said that the terminal 50 was a mystery as the voltage always stays at 0v. That is because it only receives power to this terminal, and ECM terminal 1, when the engine is cranking. Terminal 50 power comes from the ignition switch when the key is in the "start" position.

[email protected] wrote: I just repaired my ICU from an 86 2.1l
I had 2 Faults:
1) 2000 RPM idle
2) Rough Idling
No burned components
After reverse-engineering the unit, I had a set of schematic diagrams.
With a scope confirmed that the Solenoid Valve was outputting a PWM waveform.
It was just erratic in idle and 2000 rpm.
Twisting the boards whilst idling I was able to exhibit these symptoms.
On the mainboard I re-soldered all the main large components joints. (Connectors, Large Diodes, Large Resistors, Electrolytic Capacitors)
After this, the 2000 rpm issue was gone, but the erratic idle remained. Twisting the 2nd board was able to simulate this fault. Turned out to be the 0.01uF cap inline with the ignition signal. This is a large component, and the joints were dry, Resolderd all caps on this board, and the fault was gone.

I cant find out how to load files on this site, so if someone wants a copy, just mesage me.

Sun Mar 06, 2022 5:02 am

Thanks, not sure why I missed that !!

Vwtechal wrote: Thank you for the great information. I noticed in the schematic that you said that the terminal 50 was a mystery as the voltage always stays at 0v. That is because it only receives power to this terminal, and ECM terminal 1, when the engine is cranking. Terminal 50 power comes from the ignition switch when the key is in the "start" position.

[email protected] wrote: I just repaired my ICU from an 86 2.1l
I had 2 Faults:
1) 2000 RPM idle
2) Rough Idling
No burned components
After reverse-engineering the unit, I had a set of schematic diagrams.
With a scope confirmed that the Solenoid Valve was outputting a PWM waveform.
It was just erratic in idle and 2000 rpm.
Twisting the boards whilst idling I was able to exhibit these symptoms.
On the mainboard I re-soldered all the main large components joints. (Connectors, Large Diodes, Large Resistors, Electrolytic Capacitors)
After this, the 2000 rpm issue was gone, but the erratic idle remained. Twisting the 2nd board was able to simulate this fault. Turned out to be the 0.01uF cap inline with the ignition signal. This is a large component, and the joints were dry, Resolderd all caps on this board, and the fault was gone.

I cant find out how to load files on this site, so if someone wants a copy, just mesage me.

Mon May 09, 2022 10:22 pm

OldBlueSyncro wrote: 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.

Can someone confirm is this the correct resitor as I have the same burnt resitor in my digijet 2.1 DJ 251 907 739 A on top of burt NTE185.