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Re: Bosch LSU 4.9 sensors dropping like flies

Posted: Wed Feb 01, 2017 6:19 pm
by dr_jones
No - I wasn't capturing it at the time - will include it in the ongoing troubleshooting exercise.

-Ed.

Re: Bosch LSU 4.9 sensors dropping like flies

Posted: Fri Feb 03, 2017 4:19 pm
by dr_jones
Attached is the log (inc duty cycle) of the observed heater voltages with varying output d/c's withthe engine stopped

Full description and notes are in the comments. There seems to be some unexpected behavior (?) on LSUFeedback_U03 at one point and the duty cycle on the output seems to do the inverse of what I'd expected - I imagine there is a reason for that that I'm not aware of.

Next stop - switching to Lambda #2 and seeing if the behaviour is the same.

Re: Bosch LSU 4.9 sensors dropping like flies

Posted: Thu Feb 23, 2017 9:47 am
by TimH
Someone linked to this article on FB, regarding premature LSU failures. Thought it might be of interest.

Re: Bosch LSU 4.9 sensors dropping like flies

Posted: Tue Mar 28, 2017 2:05 pm
by dr_jones
Thanks Tim - that's useful - it pretty much consolidates all the various points made several different sources onto one place!

Re: Bosch LSU 4.9 sensors dropping like flies

Posted: Wed Mar 14, 2018 5:34 pm
by Ryan.g
Gents,

We have done further updates to the Bosch CJ125 Controller based on some new Bosch infomation. If you are using the LSU4.9 on a S6Plus Ecu purchased before 02/18 then please email support@Syvecs.com and will get an update file out to you which flashes via USB for the updates.

Support@Syvecs.com

Re: Bosch LSU 4.9 sensors dropping like flies

Posted: Wed Apr 03, 2019 1:10 pm
by rac
Ed,

How has this ended for you?
Looks like I've done this twice now, first time on an ADV and just now on 2x 4.9's. I wasn’t logging all the Lambda info because I thought I’d moved past this issue but the only thing I can think of that relates my first failure with my second is that I had the ignition on for a period of time prior to starting the car because I needed accessory power for whatever reason. so that makes me suspect that something is up with the heating strategy when the car is not running that is the beginning of the sequence of events. unfortunately not logged. after failure, the sensors behaves like yours did (this time I had two installed side by side), and they respond exactly the same give or take a small time lag - goes leaner and leaner until I go open loop then they rapidly go ultra-lean. It doesn't appear reasonable for me to think a wire continuity issue or the like would affect two separate sensors identically at the same time but I will check it out all the same.

I've got quite a few things to check before drawing any conclusions but was interested if there was a positive conclusion to this thread from your experience.

thanks,
R.

Re: Bosch LSU 4.9 sensors dropping like flies

Posted: Sat Apr 13, 2019 6:12 am
by rac
I spoke to soon, I lost three injectors and prematurely blamed these guys. oops.