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Benefits of later CIS-E / Jetronic management (EZL) etc on non-cat cars

930 Views 3 Replies 2 Participants Last post by  harlz
Just wondering what advantages the incremental upgrades in the engine management system did if the car doesn't have cats. I'm wiring in electronic idle control, so this is what has started me wondering. I've also given MegaSquirt a go, but wanting to know more about the upgrades that happened from Mercedes over the years.

I have a euro 500 that I'm putting into a euro '85 380, my car doesn't have cats and I've been looking through all the various electrical diagrams over the model years. I'm wondering if the first and second generation 500 engine is mechanically identical, with just different management systems.

If it's the same, then would there be an advantage in using the EZL computer to provide the ignition timing and also use an EHA fuel distributor with an 02 sensor to tune the engine? Would this be compatible with my engine?

I've got a few odds and ends from different cars, an air metering box from a 420 (is this compatible with a 500?), a fuel distributor from a 380 & 500.

The additional things seem to be full throttle electronic detection with a 3 wire position sensor, the altitude adjustment sensor, and some later models have the expensive and hard to find knock detection computers, which may not be ideal to use.

Any recommendations? At the moment I'm just going to try installing the engine with only electronic idle control, and no jetronic computers - just as it was before. Is there any advantages in going with the later setups?
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My US Spec 1988 SEC has not Cats (since I removed them).
I tweaked with CIS-E extensively to get it all dialed in and seems to be happy.
It doesn't have any idea the cat is gone except for some potentially different back-pressure.

In retrospect I would replace the CAT with a modern hi-flow device as the CAT-less exhaust doesn't smell nearly as good. Or more accurately, the CAT equipped cars smell better.

I also welded my EGR thing shut, but I don't think that impacts much.
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