Help with ECM
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Novice
Joined: Jul 2015
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From: Near Springfield MO
Help with ECM
Have a 99 ultra with the MM EFI...cutting out at steady throttle position with occasional check engine light coming on, but doesn't stay on. Took bike to dealer for diagnostic scan, they said throwing code for TPS...but no guarantees that was problem. Ordered and tackled install of new TPS myself...using manual and info I was able to find on setting TPS and idle from multi-meter readings...SO>>> got all ready to adjust sensor, and couldn't get anywhere near the recommended voltage...then started back tracking and checked the 5v reference voltage to TPS...I am ONLY getting .67volts!!!! I also pulled barometric pressure sensor and checked reference voltage there...all are reading .67volts instead of 5v. I am not an electronics guy, just have a smattering of knowledge about it. So can someone please help me diagnose this problem? Do I have a bad ECM? (I am going to check voltage right at ecm and make sure it is not a wiring or connection issue...just haven't had time yet to do so...also am trickle charging battery and thought I would double check ECM ground...already checked battery connections, fuses etc.) Can someone tell me if I am overlooking something or not doing something correctly? Is there any way to test the ECM? Ideas???
Thanks in advance!!!]
Chucky
Thanks in advance!!!]
Chucky
Stellar HDF Member
Joined: Jan 2009
Posts: 2,578
Likes: 463
From: On a Lake, not far from the Gulf
First thing is to make sure that your battery is good. Have it load tested at the autoparts store.
Second, do you have a fuel tuner on the bike? If you do, remove it from the line, and test the readings again. If they test within spec then the tuner is bad.
Second, do you have a fuel tuner on the bike? If you do, remove it from the line, and test the readings again. If they test within spec then the tuner is bad.
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Novice
Joined: Jul 2015
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From: Near Springfield MO
Thanks!
No tuner...still stock. I haven't load tested battery, but have not noticed any "bad battery" issues as far as starting or anything...
I have placed a trickle charger on it for now...it has been charging for a couple of days. I plan to work on it again tomorrow night. I will check 5v ref line at ecm. Will post findings soon...
No tuner...still stock. I haven't load tested battery, but have not noticed any "bad battery" issues as far as starting or anything...
I have placed a trickle charger on it for now...it has been charging for a couple of days. I plan to work on it again tomorrow night. I will check 5v ref line at ecm. Will post findings soon...
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Novice
Joined: Jul 2015
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From: Near Springfield MO
Could someone please verify my findings on the ecm before I drop 600 on a part I may not need?? After 3 days on trickle charger, battery showing 12.91v...I pulled ecm for access to Amp connector on top...first pulled away from ecm and did continuity probe terminal 14, r/wh stripe, which is the 5v reference signal to 4 sensors...good continuity and therefor I believe no issue with wiring between ecm and sensors. Next,reattached connector less cover, and while grounding ecm case, powered up bike and tested voltage at same terminal. I am getting same voltage I originally found while trying to adjust TPS... .681v So I assume I should be getting a full 5v here, or at least very close...not less than 1v? Is this pretty much conclusive that the ecm is bad or am I missing something??
Thanks again everyone!
Thanks again everyone!
Cruiser
Joined: Aug 2016
Posts: 247
Likes: 59
From: California
Yes, if the 5v reference line is not very close to 5v at the ecm connector, then that would definitely indicate a bad ECM.
Just for thoroughness, have you checked that you are getting 12v at the ECM? We have had cases of low 5v power, but we weren't getting 12v in. Just a last second diag check before spending the $$
Just for thoroughness, have you checked that you are getting 12v at the ECM? We have had cases of low 5v power, but we weren't getting 12v in. Just a last second diag check before spending the $$
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Novice
Joined: Jul 2015
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From: Near Springfield MO
Was just checking that very thing!!! I am not 100% sure of relay wiring...but if I interpret correctly, it should be the pink wire terminal 35? If so, I am NOT getting 12v at the ecm. I just located the ecm relay behind the battery, but not sure how to remove it for terminal access for checking? I am getting 12+ volts after the 5amp fuse...so POSSIBLY a ecm power relay??
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I have a few of those ECMs in perfect working condition - they were take offs in the day. If you go the ECM route, let me know if you're interested. However, it does seen that if you are uncertain about your measurements, you might want to completely verify all this with a qualified shop before replacing expensive parts.
Last edited by Ed Ramberger; Sep 3, 2016 at 02:49 PM.
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Thread Starter
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Novice
Joined: Jul 2015
Posts: 22
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From: Near Springfield MO
Ok!! Got it fixed!! Thanks to all that replied...ended up checking voltage into ecm, as Crotonrz suggested, and sure enough, wasn't getting correct voltage. Tracked it down to a faulty ecm relay!!! Was able to finally set new TPS sensor and adjust hot/cold idle! Bike is running great! Now on to a couple other projects for the bike!!! Hope to eventually switch over to a tuner and closed loop conversion! But that's down the road!
Ride safe!
Ride safe!
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