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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Steveo277 on January 05, 2023, 09:17:39 AM

Title: K75 Running on 2 at idle and 3 when above 1500
Post by: Steveo277 on January 05, 2023, 09:17:39 AM
Hey all,

So I have my K running after 5 years of rebuild and it runs beautifully above 1500 but at idle she only runs on 2.

It has new coils, plugs, changed both ICU's, new injectors, fuel lines. It runs at 36 psi fuel pressure.

It has me stumped.
Title: Re: K75 Running on 2 at idle and 3 when above 1500
Post by: Steveo277 on January 05, 2023, 09:19:51 AM
Forgot to add a picture of my bike.
Title: Re: K75 Running on 2 at idle and 3 when above 1500
Post by: Laitch on January 05, 2023, 11:32:38 AM
Do a noid test on #2 injector electrical connection to determine if that's the source of the intermittent problem. If the light isn't flashing at idle but flashes at higher revs, there's a wiring connection problem to that injector. This video explains the procedure. As mentioned in the video, noid kits possible can be gotten at major auto parts stores but you only need the light for Bosch injectors.https://www.youtube.com/watch?v=5MmR-wXddVw (https://www.youtube.com/watch?v=5MmR-wXddVw)
Title: Re: K75 Running on 2 at idle and 3 when above 1500
Post by: KCinSB on January 05, 2023, 11:12:46 PM
Since I’ve never seen a Noid tester, or know what a Noid is, I started to ask how you know its only running on #2 at idle,……. But reading again, I think you mean it is only running on 2 of the 3 cylinders correct?
Title: Re: K75 Running on 2 at idle and 3 when above 1500
Post by: Chaos on January 06, 2023, 01:34:44 AM
Compression test?
Title: Re: K75 Running on 2 at idle and 3 when above 1500
Post by: Martin on January 06, 2023, 03:00:38 AM
From a cold start the header pipe of the non-firing cylinder will be colder to touch as it warms up. You can also use a laser temperature gun which is a worthwhile addition to any tool kit.
Regards Martin.
Title: Re: K75 Running on 2 at idle and 3 when above 1500
Post by: frankenduck on January 06, 2023, 04:21:41 AM
If you've replaced all of that stuff and swapped th ICU and L-Jetronic then the next link in the chain is the FI wiring harness - 61111459978. Do you have a spare one of those to try?