628 CSI ‘81 choked too rich vacume ?

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Haagen
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Joined: Sat Mar 25, 2023 5:12 pm
Location: Denmark

628 CSI ‘81 choked too rich vacume ?

Post by Haagen »

Hi specialists. I am new to this group.
My ‘81 628 CSI 190k km has been inactive for 2 years
Now engine makes trouble. After changing all below; engine started, and got choked after 10 min. And will not star. What can you advice ?
Following is changed;
- all fuel hoses changed
- new fuel pump, filter and fuel
- cleaned/ replaced injectors
- oscilloscope test of ECU looks good
- new air flow sensor
- new throttle sensor
Spark OK,
Fuel pressure Ok.

Any advice is really appreciated🙂
Thanks a lot 🙏
Last edited by Haagen on Wed Mar 29, 2023 2:15 pm, edited 1 time in total.
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hornhospital
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Re: 628 CSI ‘81 choked too rich vacuum?

Post by hornhospital »

Welcome to the group!

Does the engine have the three basics: fuel pressure, injector pulses and spark? Any one missing equals a no start/no run.
Ken Kanne
'84 633CSi "Sylvia"; '85 635CSi "Katja";'85 325e "Hazel Ann"; '95 M3 "Ashlyn"
Haagen
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Joined: Sat Mar 25, 2023 5:12 pm
Location: Denmark

Re: 628 CSI ‘81 choked too rich vacume ?

Post by Haagen »

Thank you Ken,
Yes, all 3 basics OK.
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Ralph in Socal
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Re: 628 CSI ‘81 choked too rich vacume ?

Post by Ralph in Socal »

Check Coolant Temperature Sensor input to ecu. The sensor provides a resistance value that increases as temperature increases. Control system defaults to rich condition if there's a sensor input issue

Was fuel tank inspected for rust? Common issue that slowly cuts off fuel supply. Fuel Pressure is important along with volume. You should get at least 1 liter per minute out of the pressure regulator return line

When you say "choked up" do you mean running rich where you can smell hydrocarbons at the exhaust?

Ralph
There is a very fine line between "Hobby" and Mental Illness.

85 635csi Zinno Auto
84 528i Euro
83 635 Euro Arktik
81 528i Kastanien 5-speed
88 528e Bronzit (Granpa Car)
86 535i Auto (For Sale)
81 633 csi (retired)
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