TheSamba.com Forums
 
  View original topic: Sudden idle raise up to 4000RPM
spillane Sun Oct 25, 2020 3:57 pm

Hi all, driving my 1987 2.3L WBX gowesty

On 750th mile of a road trip and experienced the following:

Driving on the hghwy wanted to reduce gear and shift lanes, pulled the foot out of the gas pedal and pushed the clutch Rpm is 4000, got out of the hgwy stopped the vehicle opened the engine compartment everything looks normal, throttle body etc.

Started the engine again started at normal RPM 900

Drove some more on the hghwy and the same thing, at this point I started thinking about idle stabilization computer or the valve.

Pulled to the side again this time did not kill the engine RPM peaking around 4000 first thing I did unplugged the cable goes to the ISCV and voila RPM dropped down to 900.

Want to fact check with you all this: I cleaned the ISCV about a month ago, and the fact that when I disconnected the cable idle dropped to normal makes me think that the Valve is faulty??

So what this leads me now is it is most likely the Idle computer is faulty, I am here to see what do you guys think in terms of options to move on from here, I am not thinking about ordering parts or waiting, have some tools with me. right now in Joshua Tree, CA

Options that I am leaning on

1 - Keep the ISCV disconnected until I go back home which is probably 12-20 days away and deal with it later. The
weather will get colder and I am aware that cold idle without the ISC might be hard.
2 - Somehow diagnose and repair the computer. Read some posts about this already here but not exactly sure yet.
3 - ??


Thanks

zoti Sun Oct 25, 2020 4:15 pm

It sounds like the idle control unit is
Faulty.

I would pull it out and take a look.

DanHoug Sun Oct 25, 2020 4:15 pm

ayup. it's just not a problem to keep the electrical connector to the idle valve disconnected. MAYBE you'll have to keep your foot on the throttle for a minute or two after startup but i live in essentially arctic winter temps and have my entire idle stabilization system disconnected. it's just fine.

spillane Sun Oct 25, 2020 4:34 pm




Doesn’t look great haha

RawUmber Sun Oct 25, 2020 6:08 pm

Good thinking on removing the valve cable to diagnose.

If an Idle Stabilizer Control Unit makes a properly adjusted engine rev more than ~1200RPM, I think it should be removed. Its base design target is ~880RPM, but it will bump it up a bit depending on parameters (AC, power steering switch, cold engine, etc). 4000 is way out of spec/defective.

It's hard to tell by the pictures, but something on there appears to have gotten a little warm.

spillane Sun Oct 25, 2020 8:28 pm

RawUmber wrote: Good thinking on removing the valve cable to diagnose.

If an Idle Stabilizer Control Unit makes a properly adjusted engine rev more than ~1200RPM, I think it should be removed. Its base design target is ~880RPM, but it will bump it up a bit depending on parameters (AC, power steering switch, cold engine, etc). 4000 is way out of spec/defective.

It's hard to tell by the pictures, but something on there appears to have gotten a little warm.

Yes, I will need the ICU repaired because I will need the AC during the hot months.

The question in my head is, Is there a reason why ICU is pushed to its limits and got fried all of a sudden because although parts look very fried they were probably not in a much better shape 2 days before this happened.



Here are some better photos


spillane Sun Oct 25, 2020 8:42 pm

DanHoug wrote: ayup. it's just not a problem to keep the electrical connector to the idle valve disconnected. MAYBE you'll have to keep your foot on the throttle for a minute or two after startup but I live in essentially arctic winter temps and have my entire idle stabilization system disconnected. it's just fine.

Great! tho for A/C I will need an idle stabilizer I think, this summer I forgot to plug the cable on the ISCV after engine cleanup, and the Engine stalled and gave me a headache during traffic, really not fun.

bobhill8 Mon Oct 26, 2020 6:03 am

Question for DanHoug, if you don't mind me jumping in. Do you simply disconnect the ICV connector, or have you unplugged the ICM as well? Thanks.



Powered by phpBB © 2001, 2005 phpBB Group