Check for vacuum leaks .Even split hoses will cause problems .

checked the fuel pressure yesterday. It was pretty steady around 82psi and held it idling and revving just fine. The lower port was around 79psi. From memory i believe those numbers are normal? I drove it on a 2 hour round trip today and it did fine other than occasional power loss under 2-3k rpm and a misfire when you first start it. Often i find a delay in acceleration when driving spirited though.

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99' ML320
03' C32 AMG
89' 190e

Drew,

The lower port pressure (differential pressure) should be 5.8psi (.4 bar) lower that your system pressure. Importantly, the differential pressure is measures with the EHA unplugged.

Sounds like your differential pressure is off.

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1993 2.6 Sportline 5 speed
1992 2.3 Canadian delivery

All indications is that you are running lean.

Here is the factory fuel pressure testing doc.

Attached Files

07.3-1603.pdf (299.4 KB, 107 views)

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1993 2.6 Sportline 5 speed
1992 2.3 Canadian delivery

I checked the fuel pressure again with the EHA unplugged and it was around a .3 bar difference. I pulled the eha and turned it half a turn and put it back on. I haven't put many miles on it since but it feels much better than it did. A lot more responsive thats for sure. Time will tell if that "fixed" my problem or if its just covering up another issue? The idle seems to surge a little bit but its just barely noticeable at times.

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99' ML320
03' C32 AMG
89' 190e

Big difference between .3 and .4 differential pressure. ( Assuming you set it at .4. Could you CONFIRM the differential pressure now that is running better?)

From a cold start, does it rev @ ~1100 rpm for 28 seconds then settle in at ~800 rpm.

If it were me, I would go and set the mixture using the X11 port now.

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1993 2.6 Sportline 5 speed
1992 2.3 Canadian delivery