Idle surges until ICV hose is pinched?

Speedster990 · Post by **Speedster990** » Dec 10, 2013 7:35 PM

So I have an 86 528e that has an idle issue. As soon as the car warms up it starts surging as shown in the video. Then, when I pinch the air hose that goes to the ICV the idle stabilizes, but iis still a bit high.

edit: The ICV was actually replaced with a "like new" one purchased & installed by a questionable mechanic haha. But, it had this same idle issue before it was replaced if that helps.)

Idle surges unless ICV hose is pinched
(sorry for dark video, I was in a hurry!)
(also sorry for the odd video quality, I was screwing around with Youtube's video stabilizer)

waynet1 · Post by **waynet1** » Dec 10, 2013 7:48 PM

Here's a hint;

http://www.mye28.com/viewtopic.php?t=122226

Speedster990 · Post by **Speedster990** » Dec 10, 2013 7:54 PM

gotcha. I saw the Maytag thread, but maybe there is a chance someone knows a way around buying another one?

waynet1 · Post by **waynet1** » Dec 10, 2013 8:01 PM

Speedster990 · Post by **Speedster990** » Dec 10, 2013 9:20 PM

I just cleaned and tested the valve. It opens and closes as it should and it's clean. Could it be something with the cold start valve? (And as I already told you I don't wan't to drop $100 untill it is necessary.)

waynet1 · Post by **waynet1** » Dec 10, 2013 9:32 PM

Speedster990 wrote:I just cleaned and tested the valve. It opens and closes as it should and it's clean. Could it be something with the cold start valve? (And as I already told you I don't wan't to drop $100 untill it is necessary.)

Have you tested any thing else yet?

Tested the O2 sensor electrically? Unplug it to see if idle stabilizes?
Swap in a known good ICM?
Check everywhere for any vacuum leaks?

Speedster990 · Post by **Speedster990** » Dec 10, 2013 9:42 PM

Just a minute ago I used a battery to close the icv while the car was running. While the icv is closed it idles great. As soon as I remove the battery, the icv opens and the idle goes crazy as expected, and when I put the connector back on the icv it idles a lot better but it still surges like crazy. So I guess my question now is what controls the voltage to the icv? And what could be some other areas to check.

waynet1 · Post by **waynet1** » Dec 10, 2013 9:46 PM

This is how I just sat in my chair for the last couple of minutes;

Speedster990 · Post by **Speedster990** » Dec 10, 2013 9:48 PM

What would you have me do then kind sir?

Kyle in NO · Post by **Kyle in NO** » Dec 10, 2013 9:51 PM

Sounds like your throttle plate and tps are mal-adjusted.

Speedster990 · Post by **Speedster990** » Dec 10, 2013 10:13 PM

Thanks Kyle, I will for sure check the position sensor and plate.

Here is some background info on what happened to this car:

-It was running perfect in 2010

-Sat in a garage undriven for 2 years

-When we pulled it out it idled horribly even from a cold start (we put fresh gas in it as well)

-Late 2012 we had a guy check for vacuum leaks and he claims that he replaced the ICV with a used one and the manifold gasket.

-After that it idles great when it is cold, but as soon as it gets to operating temperature it idles crazy as shown in the video above

-As of today I noticed that when the air hose to the ICV is pinched it idles perfectly normal.

-I just cleaned the ICV and checked that it was operating freely (it looks like it is when voltage is applied but I could be wrong)

-Still does the same thing.

-Also, it is completely fine while driving

freetoride · Post by **freetoride** » Dec 10, 2013 11:24 PM

Flipper · Post by **Flipper** » Dec 11, 2013 7:31 AM

I would bet your TPS is not adjusted correctly. Your ICV is probably fine, it's just not getting any feedback to control your idle.

tn535i · Post by **tn535i** » Dec 11, 2013 9:01 AM

The ICV on an eta can let in a lot of air and that's why pinching the hose helps. Yes first make sure the TPS closes and brings the idle input from 5v to 0v. The click doesn't insure anything you need to know the voltage to ecm drops to 0. If it does then you need to check the current through the ICV. If it is no where near about 450-500 mA I don't think adjusting the screw will help and you probably have a bad ICM. Even if the TPS is out there should be current similar to this at the ICV. The earlier ones (I also had an 86) suffer from bad solder joints and will then never regulate properly.

demetk · Post by **demetk** » Dec 11, 2013 11:07 AM

If you want to stabilize your idle with your existing valve, add a manual valve before the ICV and adjust the idle to about 900 rpm. Do the adjustment with the ICV disconnected. Then reconnect it and it should work, maybe. On mine it worked great but you may have worst problems.

Speedster990 · Post by **Speedster990** » Dec 11, 2013 7:03 PM

I did check the tps for continuity and it performed to the bently specifications. I also check the connector and it is getting 4.95 volts on all terminals. Next I will have to get a multimeter that measures current because mine can only check for voltage and resistance. Any idea of what an new/working used icm would cost? Also, what kind of manual valve would you suggest?

jc72 · Post by **jc72** » Dec 11, 2013 7:10 PM

Speedster990 wrote:I did check the tps for continuity and it performed to the bently specifications. I also check the connector and it is getting 4.95 volts on all terminals. Next I will have to get a multimeter that measures current because mine can only check for voltage and resistance. Any idea of what an new/working used icm would cost? Also, what kind of manual valve would you suggest?

used ICV's are cheap at the junkyard but you may have to try more than once to get a good one, new they are north of 100$.

A needle valve would be ideal if you add a manual valve. That way you can fine tune it for the flow you want, although I have heard of people drilling a hole in a penny and using that as a restrictor if your really cheap. Just start with a small hole and work your way up until you get the idle you want

Speedster990 · Post by **Speedster990** » Dec 11, 2013 7:26 PM

Ok kewl. I might try the valve for a temporary fix, but I am wondering what an ICM costs rather than and ICV.

demetk · Post by **demetk** » Dec 11, 2013 7:31 PM

Speedster990 wrote:Also, what kind of manual valve would you suggest?

A simple 1/2" plumbing ball valve will work just fine.

Post by **Jeremy** » Dec 11, 2013 8:08 PM

Penny trick FTW.

Looks factory. Works almost as well as the ball valve. Next buyer doesn't know it's there (not that you shouldn't divulge).

Win-win-win.

Post by **tig** » Dec 11, 2013 8:16 PM

Jeremy wrote:Penny trick FTW.

Looks factory. Works almost as well as the ball valve. Next buyer doesn't know it's there (not that you shouldn't divulge).

Win-win-win.

My clamp, the ball valve, and the penny tricks are work-arounds.

In the clamp case, at least for me, the car barely starts when cold, I have to take the clamp off. With a ball valve, this would be easier, but stupid. With a penny?

I want to get to the root cause of the problem and fix it. I have a 'new' ICV inbound and am crossing my fingers it will fix the problem.

I'm now frustrated I didn't know to/think to test the TPS when I had the fraking intake manifold completely off last week.

Speedster990 · Post by **Speedster990** » Dec 11, 2013 8:28 PM

Alright! Thanks for the responses. I would/probably will try the penny trick, but it is 10 F here so I am also worried about the starting. Cek I saw your issue and mine seems to do the same. Let me know if the new icv fixes the issue!

Post by **Jeremy** » Dec 11, 2013 8:33 PM

cek wrote:My clamp, the ball valve, and the penny tricks are work-arounds.

Oh, absolutely. I didn't mean to imply that it was anything other than a kludge. The penny trick just happens to be my favorite/preferred idle kludge. I remember giving mine a little throttle when starting it when it was deathly cold out. After running for a short while it was fine. Mine was an automatic, so two-footing it for the first few minutes was no biggie.

The ball valve is certainly more adjustable.

Speedster990 · Post by **Speedster990** » Dec 11, 2013 8:35 PM

Also, can I get a rough estimate of how big the hole in the penny should be?

Post by **Jeremy** » Dec 11, 2013 8:40 PM

In the "oldie but goodie" category (I remember reading this back in 1996). It might help with your troubleshooting. Kludging is section 5.

http://www.mesaperformance.com/faqs/idle.html

Speedster990 · Post by **Speedster990** » Dec 11, 2013 10:41 PM

Update: Thanks Jeremy, That page was extremely helpful! I tried the penny method and with a 9/64 hole in there it is idling VERY well. So for now it is temporarily fixed! Thanks Y'all!

Post by **tig** » Dec 11, 2013 11:24 PM

Jeremy wrote:In the "oldie but goodie" category (I remember reading this back in 1996). It might help with your troubleshooting. Kludging is section 5.

http://www.mesaperformance.com/faqs/idle.html

Of for the love of God. This should have been in the FAQ or something! If I would have read this two weeks ago life would have been so much better for me. That's a great resource!

I don't have time tonight to actually USE it, but now that I've READ it I'm pumped.

Better late than never, I guess. Thanks Jeremy.

Acid House · Post by **Acid House** » Dec 12, 2013 2:08 AM

This could explain why my eta idles well at altitude but not at sea level. I will try this trick when/if it reverts as I head down to the coast.

MyE28.com

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Idle surges until ICV hose is pinched?

Idle surges until ICV hose is pinched?