Mongo

This may be a question for Shark Tuners and John Speake. This is more food for thought than anything else when it comes to understanding LH Jetronic.

Several months ago with help from Bill Ball I got my car running back to normal again due to a dodgy connection in my MAF wiring harness and a Loose LH ground under the passenger side fuel pressure regulator. While dedicating months to diagnosis, I picked up an ROW non-cat coding plug with potentiometer to see if eliminating the O2 sensor solved the issue. That was unsuccessful as it was a bigger problem as stated earlier.

Sitting here looking at Sharktuner threads and my WSM CD on lunch, I have a question on what the difference is between a US Coded LH and an ROW coded LH.

Obviously, cracking open the passenger carpet reveals a visible difference with the potentiometer and 3-plug connector attached to the LH/EZK mounting plate. On a more deeper level comes my question of the differences in fuel maps on these cars.

If I remember correctly, the US idle/cruise map is directly related to the O2 sensor, adjusting mixtures to stoichiometry. With the ROW car it's different; the Potentiometer (adjusted manually with a screwdriver) controls how rich/lean the car runs at idle and cruise.

Then comes the 'go-pedal.' WOT the map changes, correct? On the WOT map, what is the difference in fueling between the US and ROW car? The readings on the oxygen sensor are irrelevant at WOT at the flick of the WOT switch on the TPS. How much more rich is the ROW compared to the US at wide open throttle? Can the Sharktuner show these figures?

I think I have added enough paragraphs now.

John Speake

The basic answer to your question is that there is no real difference in the fuel maps between US and ROW cars. There are seperate cat and non-cat fuel maps, for idle/cruise and WOT but very little difference between them IIRC. The cat or non cat maps are selected by the 8 pin coding plug, as you mention.

I can check tommorrow when I'm back in the office...