Hard start after oil change, now only idles?

[stuarto49]

I have a 2012 ST with about 25K miles, purchased a few months ago. Have other bikes and many years of maint experience including extensive farkling. This bike has always started on first try, tho not with great enthusiasm. Battery likely original but not sure.

Just changed the oil and filter (and rear drive). Tried to start to warm up and check level, top up, etc. Would not start at all. Tried WOT and crank to clear out. No avail.
Suggested that I check the plugs - not a 10 min job - and they looked OK, not wet or fouled, but replaced anyway. Continued trying to start with no success. Decided to replace battery. As also suggested on this forum, I pulled the FI fuse and cranked. It actually started and ran for a few seconds. Replaced fuse, no luck starting.

Finally, I remembered that I had just filled the fuel tank less than 2 miles before arriving home. Thought maybe I got some bad gas or water? So I added half can of SeaFoam. After some coaxing the engine started, with the CE light on. And idled, but would take NO throttle. So I dumped in the rest of the SeaFoam, and now it will start pretty much every time, but will ONLY IDLE. Will not take any throttle. Doesn't even change sound with any throttle. Both cyl;s firing (checked with IR thermo).

Next step is to lift the tank and check that the air temp sensor is fully plugged in. What else could possibly be wrong after having just changed the oil???

Was planning to ride this ST to JAX next week for Iron Butt dinner party. Hmmm, might just need to take my FJR.

Thanks, Stuart in Richmond, VA Iron Butt #11000.

 

[Thrasherg]

Its sounds like you did get bad gas, if I was you, rather than dumping large amounts of additive to the gas, I would drain the tank and refill with good new gas. If your gas is bad, no amount of additive is going to get it running right and the additives cost more than just dumping the old tank of gas and just refilling it!!.

Gary

 

[Dogdaze]

Just a suggestion, but when you changed the oil, did you by chance kinked or trapped the breather tubes that run down to the bash plate? This will starve the fuel, enough gets through to run, but nothing more.

 

[WJBertrand]

Is the CE light still on? Should be able to pull a malfunction code if so.

 

[stuarto49]

Yes, CE light still on, plan to check that code(s) before anything else.

Which code(s) would indicate 'bad load of gas'?

 

[WJBertrand]

Probably no code for that, you'd have some kind of related code and work back. Have you inspected all the wiring (and hoses) around where you were working? No need to disturb any of them for a regular oil and filter change, were you doing anything else to the bike while changing the oil?

 

[SkunkWorks]

The likelihood of getting a "Bad load of gas" or even water in the gas at any modern filling station is nearly ZERO..............
They all have fuel/water separator filters on the pump hardware, and it has been reduced to a non-issue.
These bikes are "Throttle-by-wire". Having no change in engine sound when you give it any amount of throttle indicates you have a break in the electricals between the sensor side, and the throttle-motor side.
I would check all the plugs and wiring on or around the throttle-body assembly.

 

[EricV]

I'm with DogDaze, sounds like it's got a starvation issue. The two lines that run from under the tank may have been fine when you did the oil change, but you had the tank up/off for the spark plugs, so I'd be looking there first, as well as the breather line under the airbox, though that really shouldn't cause much of an issue, aside from dirty air getting into the box.

Did you un-plug any part of the harness when you changed the plugs? IIRC, there are two plugs in that area that can be swapped, one is efi and I've forgotten what the other is.

 

[whisperquiet]

Check this thread out....lots of problems with the throttle position sensor on the 12-13 bikes. My 2012 was real bad.
Just a suggestion.

https://www.yamahasupertenere.com/index.php?threads/jumpy-throttle-fixed.12376/#post-319560

Plus, I (among other owners) use the YTZ14BS battery as a replacement for the YTZ12BS OEM as the bike starts
much better.

 

[Juan]

You changed the oil. It's a Gen 1 bike. Did you hear any unusual metal clanking whist cranking the engine? CCT problem???

 

[stuarto49]

OK - lifted tank, one of the hoses had a slight kink but that is straightened by gently pulling both hoses down while tank is lowered back down. Rechecked all connectors - all looked to be seated OK. Looked especially at the connector under the airbox (air temp sensor?) as I had disconnected this one when I removed the airbox.

Went into DIAG mode and scrolled thru - all values seemed OK according to downloaded chart. Went in again and rechecked DO14 and 15 - Accel position, and both went from about 17 to about 101 (+/-) as I rolled the throttle open. So those signals are getting thru OK to the ECU. DO1 TPS reads 18, DO5 and DO6 both read in the mid 40's, as is temp in my garage.

Finally, restarted the engine. Starts right up and idles, although a little bumpy, but will NOT take any throttle. So it just sits there idling with the CE light glowing.

Appreciate all comments. Stuart

 

[Scoop47501]

Have you had the recall on the throttle wiring done yet ?
Mine went to crap all at once without warning.
Long shot I know but,,

 

[stutrump]

I dont think I can help sorry but you mention at some point that you did WOT.
Might be worth undoing the throttle cable housing (on the handlebar) and checking the cable is still seated properly??

 

[SkunkWorks]

Which Fault-Code(s) are you getting?

 

[Don in Lodi]

Umm, you didn't accidentally grab the diesel nozzle did you... You prolly wouldn't have got home from the station tho.

 

[stuarto49]

Diagnostic readings: When key on - CE light illuminates, stays on after starting

DO1 - Throttle Pos = 18 D61 - Malfunction history code display =
DO3 - Intake Air Pr = 101 D62 - To erase history - Stop switch OFF to ON
DO4 - Air Intake Tmp= 48 (cold in garage)
DO6 - Coolant Tmp = 48 " " "
DO7 - Rear Whl Sensor = 0
DO9 - Fuel Sys Voltage = 0 ***** should be 12 Fuel Pump Relay ??? Why -0- ??
D13 - Throttle Pos Snsr = 18 (fully closed 7-23)
D14 - Accel Pos snsr 1 = 17 - 101 as throttle is opened
D15 - Accel Pos snsr 2 = same as above
D20 - Side Stand = OK
D30 - 34 Ign Coils = 00 All OK
D36 & 37 Injectors = 00 Both OK
D50 - Fuel Sys Voltage = Check 5 X ?? (What does this mean?) CE light will illuminate ?

Tank was NOT filled with Diesel - I went and checked the station island where I filled it. Diesel NOT on this island

After Diag recheck I switched the kill switch back on and heard the fuel pump. Bike then started up easily but will not take any throttle. CE light
ON all the time before starting, and while idling.
Really don't know what to check next.

 

[SkunkWorks]

Malfunction history code display = ?

There is no stored fault codes?

 

[WJBertrand]

Fuses all good?

 

[SkunkWorks]

There should be a separate fuse for the Electronic Throttle Valve.
On the 2014-up it's a 7.5 amp fuse.

As WJBertrand said, check them (especially that one) to make sure it isn't blown.

 

[stuarto49]

FIXED ! Bad fuse, and I'm the electrical wizard! Electrical Throttle Valve fuse - 7.5 A. Thought I checked it, but obviously not. Certainly logical, if the bike runs but the throttle does nothing.

Thanks everyone for suggestions! I learned about the diagnostic system, very useful.