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

931 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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Yeah my exhaust has always been on the very rich side... I think even a pre-cat thingie would help burn excess fuel, but I think it probably meant there was a problem.

I guess the question is, is there a benefit to installing an EZL module if I have the opportunity? You have the vacuum port for better ignition mapping and a higher energy coil and distributor. The only issue I see is the ring gear and trans housing would need adjusting/swapping, and that mightn't be worthwhile.

I've put together a thread with all the EZL modules I've come across that might hopefully help.
I've just gotten access to a complete Gen II engine management system for a 500, and I'm not sure what the benefits would be if I went to the expense of retrofitting it. Would it just be a slight improvement in power and economy? It has the proper 4-piece headers, EZL, distributor, Fuel distributor with EHA, loom, sensors, ecu etc as well - but I have to remove them.

Anyone have any recommendations? I have all the diagrams, would it be worthwhile? Or should I just proceed with the old 500 engine standard setup already on the engine?
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