Duxthe1,

I just found this thread, and am VERY intrigued. I have recently been talking to a fellow enthusiast about this very subject; fooling the ECU via a modified 02 sensor output. (However, the intended application is not a CIS or CIS-E car, but instead LH-SFI M119 applications.)

The CIS-E cars have a certain degree of simplicity which is very much in your favor; I believe getting the ECU to “digest” an altered signal is fairly straightforward and WILL work well, as you have discovered. (It would also work for the older CIS systems with a frequency valve instead of an EHA.) I applaud your inventiveness & diligence in developing the methodology. I particularly like the idea of being able to adjust the mix on the fly.

I was not looking at partial load situations, but strictly full load enrichment. I had envisioned a much cruder system: using a resistor to drop the voltage sensed by the ECU, thereby feeding a false lean condition with the modified signal being switched into & out of the circuit via a double pole relay tied into the kickdown switch. Unfortunately, this is where my ignorance of the LH-SFI system comes into play – if they go open-loop at full throttle, then my idea will not work - it would then take an actual re-mapping of the fuel flows burned into the LH unit. (And I do know that the 1992 LH systems DID have WOT enrichment, but probably not “enough” to achieve full power potential in lieu of emissions & catalyst life expectancy)

Also, being an MB tech and therefore being MUCH more knowledgeable than myself, I was wondering if there is any way to adjust the basic lambda settings on an LH car? (and if so, would that only effect idle settings, or would it shift the entire fuel map commensurately? (the only analogy I can think of is when adjusting an old (non-lambda) CIS car with a hex key near the fuel distributor head, OR adjusting the control pressure via modifying the warmup regulator.)

I would LOVE to hear your feedback on this stuff!

Thanks in advance!


P.S. - If you are planning on producing these controllers as kits, you will find a much wider market if you were to include the LH-SFI cars in your target market. Meanwhile, if you need a guinea-pig to test your prototype on an LH-SFI car…

P.P.S. On your friend’s stroked 500SL, was this simply a long-throw (5.6) M117 crank into a M117 engine, or into a M119?

__________________
Current rolling stock:
2001 E55 183,000+ Newest member of the fleet.
2002 E320 83,000 - The "cream-puff"!
1992 500E 217,000+
1995 E300D 412,000+
1998 E300D 155,000+
2001 E320 227,000+
2001 E320 Wagon, 177,000+

Prior MBZ’s:
1952 220 Cab A
1966 300SE
1971 280SE
1973 350SLC (euro)
1980 450SLC
1980 450SLC (#2)
1978 450SLC 5.0
1984 300D ~243,000 & fondly remembered
1993 500E - sorely missed.
1975 VW Scirocco w/ slightly de-tuned Super-Vee engine - Sold after 30+ years.