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RawUmber
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Joined: June 23, 2019
Posts: 303
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 Posted: Wed May 11, 2022 9:47 am Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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| I think the spec is ~0Ω, but 1.4Ω is likely OK. |
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tanhis
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Joined: July 23, 2005
Posts: 658
Location: Rauma Finland
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| Posted: Tue May 10, 2022 11:47 am Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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I need to borrow a better multimeter that has Farad measurement as a option. But at least the capasitors were not short circuit. And the coating is pain in the ass when doing measurements like this.
As I got my hands dirty I also checked the function of the trottle idle switch it worked but it has 1.4 ohm resistance when closed. What do you think will this cause an issue.
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-58 Typ2 ambulance
-62 Typ 34
-65 Typ 34
-73 411 variant all metal custom
-69 typ 2, 9 seater
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RawUmber
Samba Member
Joined: June 23, 2019
Posts: 303
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| Posted: Tue May 10, 2022 7:20 am Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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| tanhis wrote: |
| Would it be wise to replace the capasitors on the same go as at least one looks a bit chubby. |
My guess is the chubbiness is an illusion of the conformal coating, but can't say for sure. If the bottom terminals of the capacitors are not shorted to each other (ie, ~0Ω), I wouldn't bother replacing them at this point, but it's your call. Obviously, if your Idle Stabilization system doesn't work, something is at fault, but I would start by replacing the known bad components and work up from there. |
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tanhis
Samba Member
Joined: July 23, 2005
Posts: 658
Location: Rauma Finland
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| Posted: Tue May 10, 2022 6:30 am Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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| RawUmber wrote: |
| That burnt looking transistor drives the Idle Stabilization Valve. From the looks, it's a good plan to replace it. So how did it get that way? One possibility is a bad valve. You might do some tests on it. Disconnected, the valve's terminals usually measure somewhere between 4-8Ω. If it measures OK, you can momentarily connect the terminals to a little 9V battery and it should click open. If the valve was shorted (eg, 0Ω) or the internal actuator stuck, the transistor would get hot trying to operate it, eventually failing. That said, the transistor can go bad for other reasons. |
I had to order the transistor. As local electric store did not have it on stock.
And I did measure the burnt looking resitor and it was good.
And next I will check the function of the valve.
Btw as I am going to take my welder and related tools out. Would it be wise to replace the capasitors on the same go as at least one looks a bit chubby.
_________________
-58 Typ2 ambulance
-62 Typ 34
-65 Typ 34
-73 411 variant all metal custom
-69 typ 2, 9 seater
-89 vanagon camper conversion matkaaja
-08 3.0tdi phaeton |
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RawUmber
Samba Member
Joined: June 23, 2019
Posts: 303
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| Posted: Tue May 10, 2022 6:21 am Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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That burnt looking transistor drives the Idle Stabilization Valve. From the looks, it's a good plan to replace it. So how did it get that way? One possibility is a bad valve. You might do some tests on it. Disconnected, the valve's terminals usually measure somewhere between 4-8Ω [edit: Bosch says ~10Ω, YMMV]. If it measures OK, you can momentarily connect the terminals to a little 9V battery and it should click open. If the valve was shorted (eg, 0Ω) or the internal actuator stuck, the transistor would get hot trying to operate it, eventually failing. That said, the transistor can go bad for other reasons.
Last edited by RawUmber on Tue May 10, 2022 9:06 am; edited 1 time in total |
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tanhis
Samba Member
Joined: July 23, 2005
Posts: 658
Location: Rauma Finland
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| Posted: Tue May 10, 2022 5:46 am Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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| RawUmber wrote: |
| I see. That's a 56Ω resistor, and it's most likely OK. After manufacture of the unit, they coated the whole board in a conformal coating to protect it from moisture. When the resistor gets hot, it tends to discolor the coating like that. You can put an ohm meter on both terminals of the resistor... should see 56, give or take a few % (within 10% is spec). If it tests good, it's unlikely to be your problem. |
Thanks. I will measure it but I am going to get spares an will buy that as well . And my main problem can be seen here.
_________________
-58 Typ2 ambulance
-62 Typ 34
-65 Typ 34
-73 411 variant all metal custom
-69 typ 2, 9 seater
-89 vanagon camper conversion matkaaja
-08 3.0tdi phaeton |
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RawUmber
Samba Member
Joined: June 23, 2019
Posts: 303
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| Posted: Tue May 10, 2022 5:39 am Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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| I see. That's a 56Ω resistor, and it's most likely OK. After manufacture of the unit, they coated the whole board in a conformal coating to protect it from moisture. When the resistor gets hot, it tends to discolor the coating like that. You can put an ohm meter on both terminals of the resistor... should see 56, give or take a few % (within 10% is spec). If it tests good, it's unlikely to be your problem. |
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tanhis
Samba Member
Joined: July 23, 2005
Posts: 658
Location: Rauma Finland
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| Posted: Tue May 10, 2022 5:20 am Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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| RawUmber wrote: |
| tanhis wrote: |
| 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. |
If the control unit is a 251907393A (you have a '739' in there), the phillips driver in your photo is pointing to a diode. If you like NTE, their sub for it is NTE125. Unlike resistors, the polarity/orientation of diodes and transistors is critical. You can use Goodie's photo as a reference:
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For some reason the quote shows randomly two different images.
This it the burnt resitor that I am talking about.
_________________
-58 Typ2 ambulance
-62 Typ 34
-65 Typ 34
-73 411 variant all metal custom
-69 typ 2, 9 seater
-89 vanagon camper conversion matkaaja
-08 3.0tdi phaeton |
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RawUmber
Samba Member
Joined: June 23, 2019
Posts: 303
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| Posted: Tue May 10, 2022 5:07 am Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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| tanhis wrote: |
| 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. |
If the control unit is a 251907393A (you have a '739' in there), the phillips driver in your photo is pointing to a diode. If you like NTE, their sub for it is NTE125. Unlike resistors, the polarity/orientation of diodes and transistors is critical. You can use Goodie's photo as a reference:
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tanhis
Samba Member
Joined: July 23, 2005
Posts: 658
Location: Rauma Finland
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| Posted: Mon May 09, 2022 10:22 pm Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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| OldBlueSyncro wrote: |
| dhaavers wrote: |
Found this other pic in Goodie's gallery:
Resistor in question seems to be marked "66R 10%"...whatever that means... 
- 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.
_________________
-58 Typ2 ambulance
-62 Typ 34
-65 Typ 34
-73 411 variant all metal custom
-69 typ 2, 9 seater
-89 vanagon camper conversion matkaaja
-08 3.0tdi phaeton |
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[email protected]
Samba Member
Joined: April 13, 2020
Posts: 6
Location: South Africa
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| Posted: Sun Mar 06, 2022 5:02 am Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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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. |
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Vwtechal
Samba Member
Joined: January 30, 2014
Posts: 1
Location: Texas
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| Posted: Sun Aug 15, 2021 10:13 am Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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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. |
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VicVan
Samba Member
Joined: July 01, 2015
Posts: 1936
Location: Vancouver Island, BC
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| Posted: Thu May 13, 2021 12:14 pm Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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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 
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bobhill8 
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Joined: June 09, 2017
Posts: 781
Location: MA
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| Posted: Thu May 13, 2021 3:49 am Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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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.
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[email protected]
Samba Member
Joined: April 13, 2020
Posts: 6
Location: South Africa
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| Posted: Tue May 11, 2021 12:54 pm Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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| Its a bit of a pain that I cant load them as PDF's |
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dhaavers
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Joined: March 19, 2010
Posts: 8376
Location: NE MN (tinyurl.com/dhaaverslocation)
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| Posted: Thu Nov 12, 2020 9:32 am Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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Those ^^^ are working for me...very nice!
Hearty thanks to Roger & Bob!
- Dave
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"The WonderVan"
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bobhill8
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Posts: 781
Location: MA
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Jake de Villiers
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bobhill8
Samba Member
Joined: June 09, 2017
Posts: 781
Location: MA
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| Posted: Thu Nov 12, 2020 8:14 am Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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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.
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1986 Westy
1971 Squareback
Last edited by bobhill8 on Thu Nov 12, 2020 9:59 am; edited 1 time in total |
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bobhill8
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Posts: 781
Location: MA
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| Posted: Thu Nov 12, 2020 5:08 am Post subject: Re: Idle Control Module issue (high idle) & cheap fix |
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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.
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1986 Westy
1971 Squareback |
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