View Single Post
dave9400 dave9400 is offline
Registered User
Join Date: Sep 2018
Posts: 1
Dyno results show lean

I have an 89 325i with a newly rebuilt engine. There are two issues. One is that Idle is a bit high - 1000+ rpm. I've been able to lower it slightly after a smoke test showed a small hose leak, but I'm out of ideas now. I think I have them all plugged up.

Second issue is that the engine runs lean at WOT. AFR during a dyno run last Friday was between 14:1 and 15:1 for most of the rpm curve. good news is it makes good power - 160 HP and 160 ftlbs as measured on a mustang dynomometer which i'm told is conservative. I may even have to de-tune it a bit for spec series racing.

First question is - should I be worried about this? I can live with a high idle on a racecar and engine makes plenty of power as long as it's not a reliability issue. Second question - any idea what could be the cause?

I've tested resistance of the temp sensors, and according to Bentley they are in spec.
Old 09-03-2018, 05:24 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)