Cannot control RPM during ER Self-Test low RPM check

[kowalczyk86]

89 Mustang 5.0

Check engine light has been coming on/off for the past month or so. It only seems to come on when I accelerate, and then immediately turns off. At that it doesn't ALWAYS come on when I accelerate, just sometimes.

My buddy ran KOEO test (not sure why he didn't do a test with ER), and we got codes 13 (Cannot control RPM during ER Self-Test low RPM check/ECA could not lower idle speed. Suspect Idle Bypass valve problems. KE15), and code 67 (Neutral safety circuit failure {A/C was not on}). I read online to not worry too much about the code 67 (btw my car is a 5 speed)...? Now that I think of it, the clutch was in 1st, so that may be why it pulled a code 67..

Car runs top notch from what I can tell. 15k miles and only mod is BBK cold air intake. I am thinking maybe this has something to do with it or else the MAF sensor?? I took the sensor off and cleaned it as best I could (there is a little bit of white residue, but not much).

I am just wondering if someone can guide me in the right direction. I want to get this fixed, and I would like to do it myself if at all possible. If I do have to end up taking it to a mechanic, I want to know exactly what the problem is so that I don't get ripped off.

I have a complete exhaust kit coming soon, but I do not even want to think about that until I fix this problem..

Cold idol is around 900 RPM - it is right around there, maybe a little higher when it is warm.

Any help is appreciated.

Shawn

 

[LarsD]

I have that code right now too, found it while trying to chase down a few other problems. You might need to clean or replace the IAC valve.

 

[kowalczyk86]

Thanks. I will check it out. If that fails do you have any other ideas? Is this valve easy to get to?

 

[Haus]

Thanks. I will check it out. If that fails do you have any other ideas? Is this valve easy to get to?

yes...its connected to the Throttle Body

 

[HISSIN50]

If you fix 12 and 67, you should be able to retrieve KOER codes.

 

[kowalczyk86]

LarsD,

Not sure if this helps also, but check it out.. I cannot understand a lot of what is being said:

How to Tune and Modify Ford Fuel ... - Google Books

Pg. 74...

I am going to try to disconnect the IAC connection tonight when I get home. If the RPMs drop when I disconnect, does that mean the IAC is the root problem? I understand that vac leaks might be next - but I want to try this first. Not a mechanic by any means so I am learning as I go..

Shawn

P.S. - One thing I noticed... My Dad and I installed a BBK cold air intake in May, and 9k miles later, the filter (under the fender) is not dirty one bit.. I am wondering if the whole thing is even setup right and if this could be causing a problem? The light just started coming on a month or so ago, so it has been on with no problems...

 

[jrichker]

Code 13 Key on Engine running - Idle Speed Control motor or Air Bypass not controlling idle properly (generally idle too high)

If your idle is above 725 RPM, the computer will set this code. Normal idle speed is 650-725 RPM. Higher than that may mean that you have a vacuum leak or someone has mechanically set the idle speed by use of the idle speed screw. This effectively disables to computer’s ability to control idle speed.

Code 67 - clutch not depressed (5 speed) or car not in neutral or park (auto) or A/C in On position when codes where dumped. Possible neutral safety switch or wiring problem. This code may prevent you from running the Key On Engine On tests. You can generally ignore this code, since it has no effect on engine performance.

The computer wants to make sure the A/C is off due to the added load on the engine for the engine running tests. It also checks to see that the transmission is in Neutral or the clutch depressed (T5, T56, Tremec 3550 & TKO). This prevents the diagnostics from being run when the car is driven. Key On Engine Running test mode takes the throttle control away from the driver for several tests. This could prove hazardous if the computer was jumpered into test mode and then driven.

The NSS code 67 can be bypassed for testing. You will need to temporarily ground computer pin 30 to the chassis. Computer pin 30 uses a Lt blue/yellow wire. Remove the passenger side kick panel and then remove the plastic cover from the computer wiring connector. Use a safety pin to probe the connector from the rear and jumper the safety pin to the ground near the computer



See the "Surging Idle Checklist” for help with all your idle/stall problems. Everything you need to find and fix idle problems is in there.

The first two posts contain all the updates to the fixes. At last count there were 24 possible causes and fixes for surging idle/stall problems. I continue to update it as more people post fixes or ask questions.

 

[kowalczyk86]

First of all, thank you all TREMENDOUSLY for guiding me along. I really appreciate it..

I took off the IAC - looked pretty clean - I wiped it out as best as I could - I even took it apart to clean in there as well. I looked for problems with vac lines. There is nothing apparent to me.

I unplugged battery, and and going to drive it for a bit and see if I get a light. Most likely it will come on. The IAC is 21 yrs old. Should i just replace it? Any other ideas?

I was trying to pay very close attention to the idling. It idles pretty nice for the most part. I do notice that sometimes from a stop when I put it in first and let the clutch out it wants to give out sometimes, where in the past it would put me to a nice roll...

Shawn

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[jrichker]

While those are excellent pictures, the main concern with the hard plastic vacuum lines is that they tend to crack in the bends and that connection points. You will need to do a touchy-feelly examination of them.

 

[kowalczyk86]

Going to take a multimeter to iac this weekend when I have time
Not surebwhat else to do.. running out of ideas. Car is idling at 800 so not sure why the lights coming on. Adjust the throttle???

 

[LarsD]

Good pics. I just got rid of my code 12 by replacing the IAC:

http://www.stangnet.com/mustang-for...terrible-could-use-some-help.html#post8340009

 

[kowalczyk86]

And a 12 is pretty much the same as a 13 so maybe I will do the same.. was your iac dirty? Mine wasn't too bad.

 

[LarsD]

And a 12 is pretty much the same as a 13 so maybe I will do the same.. was your iac dirty? Mine wasn't too bad.

Well, it was pretty nasty. However, the bad one measured 10 ohms, and the new one did also. My indicators that it is fixed is the car seems to idle better (hard to detect since it is running rough), and the code went away.

 

[kowalczyk86]

You will all get a laugh at this (or tell me how stupid I am)..

I bought a new IAC from Autozone (Duralast). JUNK. My car idled up and down between 550-700 or so. I took it back.

I put on my old IAC and this is what happened when I tightened it.

So I just now bought a Motercraft, so I guess I will see what happens when I put it on. This blows. Maybe everything will be fixed in the end. I sure hope.

 

[LarsD]

Autozone electronics are pretty trashy, it wouldn't surprise me if you got a bad one out of the box. Went a little hulk on your old one there eh?