High Idle On E320 - PeachParts Mercedes-Benz Forum

300EVIL · #1 05-11-2002, 11:49 PM

I would like to start off by thanking everyone who has helped me with all the problems that have suddenly overcome my 94 E320.
Thanks!
Now i just have two more things to fix. I replaced the fuel pressure regulator and the car now starts up fine and there is no more check engine light. The problem is high idle, about 1400 rpm and no kickdown under 40 mph. I have tried adjusting the bowden cable and the throttle cable with no success. This one is really stumping me. Should i adjust the idle screw? the problem started after i cleaned the throttle body with sea foam. Any help is welcome.
Thanks!
Adam

stevebfl · #2 05-12-2002, 11:02 AM

Well, first I would suggest seeing if there are any codes in CC/ISC (I am presuming that you don't have EA) (electronic accelerator, cruise control, idle speed control).

With a scanner I would like to see how far the throttle is opening and I sure would be sure of those linkages. The throttle assy goes to a fixed openning under some "limp home" conditions (limp home is a term for the default "basic" condition the system is designed to use when it can't trust itself).

I am pretty sure that the codes can be gotten by the impulse method, seems like pin 14 but thats from memory, definitely verify.

Arthur Dalton · #3 05-12-2002, 11:13 AM

Pin 14 will get to it.
E320-124 chassis do have AE/CC/ISC module.

I have the codes , if needed.....

300EVIL · #4 05-12-2002, 11:56 AM

Okay, so what do i do, Do i need to jump pin 14 to retrieve any codes or do i need to have it hooked to a scanner for further diagnosis?
Thanks,
Adam

BTW: Im not sure what you mean by electronic accelerator. It does have a mechanical linkage to the throttle body. Does this change things od does the "electronic accelerator" have a different function?

stevebfl · #5 05-12-2002, 12:03 PM

A scanner would be nice (bg). That car will have actual values and maybe some activation available through a scanner.

But, As I replied I think it can be checked for fault codes by the impulse counting method. There have been many posts on making impulse testers. If you have a scope or voltmeter it can be done using the technique I describe in the DIY article "Evaluating engine controls".

300EVIL · #6 05-12-2002, 12:19 PM

Steve,
I have been checking the codes with that switch/LED box next to my battery. so far i have had all of them dissappear. Are these the same codes you are talking about or are they different codes?
Thanks for your Help!
Adam

stevebfl · #7 05-12-2002, 12:27 PM

Did you read the article?

The push button arrangement was constructed to facilitate reading the DM (diagnostic module - a totally US device installed to track US mandated emissions failures). You ONLY can read the DM with this technique.

Your car should have the 16 pin diagnostic socket and if you look in the holes, everyone that has a metal connector represents a system that can be evaluated by a simialr technique. Only problem is one must set up the light ones self for each system. One must also know what each system represents and eventually have a code list for the read out.

300EVIL · #8 05-12-2002, 12:40 PM

Steve,
Oh okay, I have read the article before but i must have not understood that part. I will go back and read the article and then test pin 14 for fault codes.
Thanks again!

engatwork · #9 05-12-2002, 08:03 PM

Make the tester and as Steve says - test every hole that has the metal connector down in it then come back with the reading on each hole.

300EVIL · #10 05-12-2002, 08:49 PM

After i ground a pin for 3 seconds, what do i hook the test light to? pin and ground?

Arthur Dalton · #11 05-12-2002, 10:23 PM

Here is the tool you can make to get to the other codes.
It shows what pins to plug into your diagnostic socket. [ pin #14 for your AE/CC/ISC module]
This is just a copy of the circuit Benz uses to get to the emmissions module with there built-in led, so the code retrival procedure is the same as the built-in one , except you can now move to the different modules....

http://members.aol.com/ajdalton7/e320led.jpg

300EVIL · #12 05-12-2002, 10:28 PM

Arthur,
Thanks for the schematic! I'll put one togather tonight if i can find myself a good momentary pushbutton.
Thanks Again!
Adam

Arthur Dalton · #13 05-12-2002, 10:41 PM

If you can't find a momentary one, a regular on/off will work just to get you your codes . You will just have to switch it on/off for the required 2-3 secs.

A clear plastic film can makes a good chassis/container for the tool. You can run the leads out a hole in the bottom and mount the sw. in the cover. Can still see the led through the clear plastic and it keeps everything contained nicely.....
Have also used a plastic test tube and even a small plastic flashlight case with the led behind the lens.....
Spend a little time on making it a permanent tool , as you will use it many times....

300EVIL · #14 05-12-2002, 10:54 PM

I have an assortment of project boxes and and LED's from Radio shack. I plan on making it a premanent tool. Definately worthy of the tool box!

Arthur Dalton · #15 05-12-2002, 10:59 PM

I have made several for some friends and a few members. We have found that it is best to keep the leads SHORT [ 4-5"s] so
it can be thrown back into the Tool Boxy without the wrapping up leads hassle,,,
Good Luck .
If you need the codes , get back to one of us...