Here is the symptom. When the car ('89 535i auto) is cold (and I mean COLD, -20C or so), the car starts like a dream. Under warmer conditions, the car cranks for upto five full seconds or more before slowly catching. It then stumbles along for a few more seconds and then evens out and runs normally. Performance when driving seems to be quite normal.
To date, here are the things that have been done or tried:
- Injectors have been pulled out and tested - ok
- Fuel system pressure tested - ok (but with some inconsistancies
- Cracked boot between throttle body and intake replaced
- O2 sensor replaced (it was pretty bad when removed)
- Double dose of injector/fuel system cleaner used
I am losing my patience with this, the only angle I haven't tried yet is the thermo-time switch and related cold start injector. Any other ideas? Any help is appreciated.
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