M103 mods to improve economy/fuel efficiency - Page 2 - PeachParts Mercedes-Benz Forum

MAG58 · #16 01-13-2013, 04:22 AM

I cant answer to CIS as it's not my forte, but yes, to my knowledge we're both running cats. Mine are aftermarket however.

RBYCC · #17 01-13-2013, 07:52 AM

Quote:

Originally Posted by Ozarkdude

Bob, may I assume you guys are running cats?

I've read the O2 goes open loop at WOT, and was sure I read the CIS went rich at WOT too, but havnt confirmed. Anyone know?

Just to be clear, mines an 89, if it makes any difference.

My car is a 1988 300CE that I purchased new in May of 1988.
A TurboTechnics UK twin turbo kit was installed in early 2007 at 65K miles.
The kit uses additional injectors that are fired by a stand alone system.

The CIS-E remains stock and to factory spec settings including the narrow band O2 sensor. At idle 140 PPM HC and 0.02 % CO which indicates that it is as it should be.

As far as cats, I have a true 2.5" dual exhaust with each pipe having a Magnaflow hi flow spun metal cat (Random Technology knockoff ) installed.

The design of the K-Jet III is to always maintain stoichmetric via the O2 sensor except at idle and WOT.

The closed loop system, if all settings are correct, tends to assure maximum fuel economy and low emissions.

Try disconnecting your WOT switch which then will keep the system in closed loop, preventing WOT enrichment and see if you get any pinging...

You don't want to disconnect the idle switch.

Of course always consider the basics for max economy such as eliminate vacuum leaks, assure the O2 sensor and other components are within spec, clean air filter, and tuned to factory spec and of course the human element of having a very, very light foot !!!

Ed A.

P.S.

You may or may not have an air temp sensor in the inlet to the air filter housing...if you do, check if it is functioning. Also check the engine water temp sensor as these effect the ignition maps which can be slightly fooled but not changed.

Ozarkdude · #18 01-13-2013, 04:33 PM

[QUOTE=RBYCC;3082813]

The design of the K-Jet III is to always maintain stoichmetric via the O2 sensor except at idle and WOT.[QUOTE]

My understanding is the O2/Lamda is an add on control to the CIS, that the O2 was only used to keep the mixture under tighter control than the system could do on its own, to meet US emissions standards.

But I dont intend to delete it.

My question was simply if the basic system increased mixture at WOT, but I think it just answered itself, that in fact it must.

RBYCC · #19 01-14-2013, 07:20 AM

Quote:

Originally Posted by Ozarkdude

Quote:

Originally Posted by RBYCC

The design of the K-Jet III is to always maintain stoichmetric via the O2 sensor except at idle and WOT.

My understanding is the O2/Lamda is an add on control to the CIS, that the O2 was only used to keep the mixture under tighter control than the system could do on its own, to meet US emissions standards.

But I dont intend to delete it.

My question was simply if the basic system increased mixture at WOT, but I think it just answered itself, that in fact it must.

You ask a question but don't like the answer you get...

Why are you now commenting on the earlier CIS-Lambda / K-Jetronic-Lambda when your car has CIS-E / KE-Jetronic

Good luck in winning the Mobil Economy run....

Ozarkdude · #20 01-14-2013, 04:48 PM

Quote:

Originally Posted by RBYCC

You ask a question but don't like the answer you get..

Where did that come from? I simply asked if the CIS enriched at WOT on its own without O2, and never got the answer. That the O2 signal is disregarded at WOT would by inference indicate the CIS is doing it on it internally, and answers the question on its own, would it not?

JayRash · #21 01-14-2013, 05:49 PM

yes cis goes to open loop at wot and any time ur on the throttle and rpm above 4000 or so. fit a wide band and ull see it. if u depress the throttle and engange the kickdown switch further enrichment takes place.

RBYCC · #22 01-14-2013, 09:50 PM

Quote:

Originally Posted by Ozarkdude

Where did that come from? I simply asked if the CIS enriched at WOT on its own without O2, and never got the answer. That the O2 signal is disregarded at WOT would by inference indicate the CIS is doing it on it internally, and answers the question on its own, would it not?

You got the answer..let me copy it again for you...perhaps you failed to read it...

"The design of the K-Jet III is to always maintain stoichmetric via the O2 sensor except at idle and WOT."

"Try disconnecting your WOT switch which then will keep the system in closed loop, preventing WOT enrichment and see if you get any pinging..."

Finally your car doesn't have CIS !!!!

Hopefully the Bosch manual for the CIS-E / KE-Jetronic which is what you have will help you:

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=9&cad=rja&ved=0CGEQFjAI&url=http%3A%2F%2Fberlinasportivo.com%2FTechnical%2Flancia%2FThema832%2FBosch-KE-Jetronic-OCR.pdf&ei=g171UPnFMs6N0QH9-IHYDw&usg=AFQjCNFKUNnLtr1Qe1P9WZAjtrn5l9ClHw&sig2=JWpihKL8MyiFybQdwjfr-g&bvm=bv.41018144,d.dmQ

Ozarkdude · #23 01-14-2013, 11:20 PM

Quote:

Originally Posted by JayRash

yes cis goes to open loop at wot and any time ur on the throttle and rpm above 4000 or so. fit a wide band and ull see it. if u depress the throttle and engage the kickdown switch further enrichment takes place.

Thanks for confirming that. I finally went out and dug in my books and found my 103 manual, as well as my factory 201 CD which covers the 124/103 on the fuel injection. I've got some re-reading to do.

Ozarkdude · #24 01-14-2013, 11:22 PM

Quote:

Originally Posted by RBYCC

You got the answer..let me copy it again for you...perhaps you failed to read it...

[I]"The design of the K-Jet III is to always maintain stoichmetric via the O2 sensor except at idle and WOT."

I can read just fine. The O2 signal is "disregarded" at WOT. And it IS CIS, short for Continuous Injection System.

RBYCC · #25 01-15-2013, 05:43 AM

Quote:

Originally Posted by Ozarkdude

I can read just fine. The O2 signal is "disregarded" at WOT. And it IS CIS, short for Continuous Injection System.

And if you read "comprehensively" you wouldn't have stated that you didn't get an answer when you did....

Believe what you want but there is a major difference between CIS and CIS-E which you have on your M103....

Good luck troubleshooting your CIS fully mechanical system...
At some point you'll learn what the "E" means...

MagnumPI · #26 01-15-2013, 02:23 PM

Dude should get standalone just to put an end to the smugness, and pomposity. ^ This is the biggest reason not to tune obsolete/inferior fuel injection systems.

RBYCC · #27 01-16-2013, 06:23 AM

Quote:

Originally Posted by MagnumPI

Dude should get standalone just to put an end to the smugness, and pomposity. ^ This is the biggest reason not to tune obsolete/inferior fuel injection systems.

Brilliant comment...not answering the original premise or adding anything of value...

Why not.."Dude should buy a Prius for better mileage"...

The solution isn't always to bastardize a vehicle to attain a goal...

MagnumPI · #28 01-16-2013, 03:57 PM

Quote:

Originally Posted by RBYCC

Brilliant comment...not answering the original premise or adding anything of value...

Why not.."Dude should buy a Prius for better mileage"...

The solution isn't always to bastardize a vehicle to attain a goal...

Your last 3/4/5 posts did?

RBYCC · #29 01-17-2013, 06:45 AM

Quote:

Originally Posted by MagnumPI

Your last 3/4/5 posts did?

I'm not sure who you are or even why you are...perhaps a prepubescent teen who has the the day off?

You tend to post more on this forum on social rather then automotive topics which is a bit bizarre..

Try to add something with value instead of sniping if you fail to understand..

Better yet stick with Twitter as you are less apt to look foolish in 140 characters or less....

MagnumPI · #30 01-17-2013, 02:55 PM

MS3-Pro Standalone ECU only DIYAutoTune.com

They have this now. Pretty slick little unit. Probably more than you'd need. But the lower end kits can be had for less than $400. They also have forums, and customer support that genuinely likes helping you.