I don't know! But what I figure is, the upper chamber of the fuel distributor does not have an adjustment like the lower chamber (EHA), as it relies on a good functioning fuel pump, regulator and accumulator for its pressure while the lower chamber relies on the EHA.

Now... what is good upper chamber pressure and do I just set my lower chamber .4 bar lower to get it within spec.?

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'89 300E - 153k miles - California car - Black/Palomino

YGPM.

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2016 Monsoon Gray Audi Allroad - 21k
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2003 Gray Mercedes ML350 - 122k