170i ECU reset issue?

Discussion of the Genuine Buddy, Hooligan, Black Jack and other topics, both scooter related and not

Moderator: Modern Buddy Staff

Post Reply
GregsBuddy
Member
Posts: 509
Joined: Sun Jan 11, 2015 9:36 pm
Location: North SF Bay

170i ECU reset issue?

Post by GregsBuddy »

Hello,
At 15,000 miles my 2013-built scoot' has shown its first problem. I was riding in a high headwind, pushing the scoot' to about 90% of its capacity, when the engine warning, red, light came on. As I slowed down to check out what might be wrong, the engine died. After looking the scoot' over for about 10 minutes, I was able to restart it with some throttle opening, as apposed to the normal start with no throttle.
When I got home and the engine was cool, it started normally but didn't idle properly. I researched ECU reset and following the instructions as follows:

1. Unplug battery wait a few minutes then reconnect.

2. Hold the throttle wide open and turn the key to the on position (do not start the motor).

3. After the fuel pump and idle motor are heard and stop cycling and engine light goes out release the throttle.

4. Turn the key off - reset preformed.

5. Start engine as usual and hope it runs good.

It started and I took it for a test ride, upon which it died while stopping and would not restart.

I performed the reset again and now it won't start.

Question:

Does it sometime require several resets to have a "real" reset; should I do another reset?
Can a failing spark plug cap create these running conditions?
If this doesn't work, what next?

NOTES: I removed the plug and it looks good (Iridium and about 3,000 Miles old). Valves adjusted about 2,500 miles ago.

Thanks for thoughts, suggestions, and questions!
'09 Yamaha TMAX Large sport scoot.
User avatar
Dooglas
Moderator
Posts: 4368
Joined: Sun Jul 08, 2007 2:17 am
Location: Oregon City, OR

Post by Dooglas »

Spark and fuel. Check to see if you are actually getting a spark. Then check to see that fuel is going thru the injector.
User avatar
Stanza
Member
Posts: 575
Joined: Mon Jan 29, 2018 8:34 pm
Location: Chicago

Post by Stanza »

That reset is not going to help with a stalling issue, it's a TPS (throttle position sensor) reset. It just calibrates the ECU so it knows what's full throttle vs idle. If you changed the battery, or disconnected it, and then DIDN'T do that calibration, it would idle very poorly and be prone to stalling at idle, but it would still rev and run down the road.

Fuel and spark check, seconded. Can you hear the fuel pump spinning up when you turn the key to the on position?
GregsBuddy
Member
Posts: 509
Joined: Sun Jan 11, 2015 9:36 pm
Location: North SF Bay

Post by GregsBuddy »

Fuel pump running. I'll check spark easily enough. How to check for fuel? Just note a wet plug?
'09 Yamaha TMAX Large sport scoot.
User avatar
Stanza
Member
Posts: 575
Joined: Mon Jan 29, 2018 8:34 pm
Location: Chicago

Post by Stanza »

Exactly. Wet plug, or if you are feeling particularly brave, you could unbolt the fuel injector from the intake tube to see if it's spraying when you try to crank the bike. Be careful if you go that route, obviously, as fuel will be misting into the air.
GregsBuddy
Member
Posts: 509
Joined: Sun Jan 11, 2015 9:36 pm
Location: North SF Bay

Post by GregsBuddy »

Tested fuel injector out in open and yup fuel flowing.
Tested spark and removed, and reinstalled plug cap. Working.
Checked valve clearance. No problem.
The last time I had a similar problem with a Honda CH80, the exhaust valve seat had come loose in the head. It acted exactly like this problem. The compression was good when that problem occurred. Hmmm.
I'll check the compression next.
'09 Yamaha TMAX Large sport scoot.
User avatar
Stanza
Member
Posts: 575
Joined: Mon Jan 29, 2018 8:34 pm
Location: Chicago

Post by Stanza »

Compression should be anywhere from 150-180 with this engine, depending on how the rings are feeling. You have spark, and fuel, so that should be the only thing missing from the equation. I say should, because if the ignition coil is acting up, you may be getting inconsistent spark, which would also prevent it from settling into an idle. With the lights dim, get a spray bottle and lightly mist the ignition coil (underneath the rear passenger right side foot rest) to see if it's arcing.
GregsBuddy
Member
Posts: 509
Joined: Sun Jan 11, 2015 9:36 pm
Location: North SF Bay

Post by GregsBuddy »

Thanks for the info, Stanza.
I have the pet carrier out and can check the coil.
The spark is bright blue.
The engine hasn't started since it quit on the ride that I had to return in the truck bed.
The most it will do now is fire several times and then quit with some throttle. I've been keeping the newish Yuasa battery charged with an external charger so I can continue testing.
'09 Yamaha TMAX Large sport scoot.
GregsBuddy
Member
Posts: 509
Joined: Sun Jan 11, 2015 9:36 pm
Location: North SF Bay

Post by GregsBuddy »

110 PSI increasing to 130 PSI with WD40 added for second test.
Something major...
'09 Yamaha TMAX Large sport scoot.
User avatar
Stanza
Member
Posts: 575
Joined: Mon Jan 29, 2018 8:34 pm
Location: Chicago

Post by Stanza »

Eep, that's not good. That means either you have a valve seal problem, or the rings are letting go. Neither is a good scenario. Sounds like you're going to have to take the top end off and see what's going on in there.
GregsBuddy
Member
Posts: 509
Joined: Sun Jan 11, 2015 9:36 pm
Location: North SF Bay

Post by GregsBuddy »

Yes, prepping now.
Fun, from my perspective. I hope the damage is limited and not too expensive.
'09 Yamaha TMAX Large sport scoot.
GregsBuddy
Member
Posts: 509
Joined: Sun Jan 11, 2015 9:36 pm
Location: North SF Bay

Post by GregsBuddy »

Cracked piston.
Will remove later today.
'09 Yamaha TMAX Large sport scoot.
User avatar
Stanza
Member
Posts: 575
Joined: Mon Jan 29, 2018 8:34 pm
Location: Chicago

Post by Stanza »

Holy smokes. Any pictures? Also how'd it crack in the first place, I wonder. Check the intake manifold tube where it joins the head, look for a crack in the plastic spacer or a broken o-ring that might have let it run too lean.
GregsBuddy
Member
Posts: 509
Joined: Sun Jan 11, 2015 9:36 pm
Location: North SF Bay

Post by GregsBuddy »

The piston is also slightly caved in in the center and the second and oil control ring are pinched in their ring lands. The part between the top ring and piston top on the intake side, where there's a gap, is turned up. The cylinder has not aluminum transfer, while the piston is scuffed on the intake and exhaust sides.
Ordered parts including cylinder (might as well start with new mating surfaces).
I'm told that this is not entirely uncommon for the 170i. If a rider pushes too hard on the throttle without high RPM's to provide cooling, the piston MIGHT overheat and fail like this. This is not what will happen to many engines, only those that have been pushed a little too much with low RPM's.
The head and bottom end look great and no more work is required.
I'm not any less a Buddy fan with this problem. With 14,700 miles, this is the first non-scheduled work on the scoot'.
I DO, however, think the oil cooler is not enough for POTENTIAL riding conditions that some riders WILL experience.
'09 Yamaha TMAX Large sport scoot.
User avatar
Dooglas
Moderator
Posts: 4368
Joined: Sun Jul 08, 2007 2:17 am
Location: Oregon City, OR

Post by Dooglas »

GregsBuddy wrote:I DO, however, think the oil cooler is not enough for POTENTIAL riding conditions that some riders WILL experience.
Well, there is no doubt that the factory concluded that the 170i engine required an oil cooler, unlike the 125 engine.
GregsBuddy
Member
Posts: 509
Joined: Sun Jan 11, 2015 9:36 pm
Location: North SF Bay

Post by GregsBuddy »

I've measured the temperature of the heat exchanger and oil in/out and it's not producing much cooling. The surface area of the exchanger is pretty small and the mass is high, therefore responds slowly to changing oil temperatures.
'09 Yamaha TMAX Large sport scoot.
User avatar
Stanza
Member
Posts: 575
Joined: Mon Jan 29, 2018 8:34 pm
Location: Chicago

Post by Stanza »

Did you measure it with airflow? Static cooling might not be much, but it's probably better with airflow. That being said, I wonder if you could mount an aftermarket oil cooler that's more of a radiator style rather than a big aluminum block.
scootERIK
Member
Posts: 714
Joined: Thu Jul 12, 2012 3:40 am
Location: Lake Geneva, WI

Post by scootERIK »

That sucks.

I wonder if the 170 would benefit from running lighter weight rollers to let the engine rev a little more while accelerating?
GregsBuddy
Member
Posts: 509
Joined: Sun Jan 11, 2015 9:36 pm
Location: North SF Bay

Post by GregsBuddy »

I'm in the thermal business. The temperatures I measured were while running and with no motion.
I think a real heat exchanger designed like a radiator would be great.
Nice lateral thinking regarding using light weights that make the engine spin to a higher RPM and provide better cooling!
'09 Yamaha TMAX Large sport scoot.
GregsBuddy
Member
Posts: 509
Joined: Sun Jan 11, 2015 9:36 pm
Location: North SF Bay

Post by GregsBuddy »

Parts arrived from Scooterwest yesterday.
I only have one question on reassembly; The cam drive chain "tensioner" doesn't appear to have any travel and is locked in position. Is this the way it's supposed to be?
Looking forward to working on the engine soon.
'09 Yamaha TMAX Large sport scoot.
GregsBuddy
Member
Posts: 509
Joined: Sun Jan 11, 2015 9:36 pm
Location: North SF Bay

Post by GregsBuddy »

Started reassembling the engine last night. I damaged the oil control ring when working the piston into the cylinder and have to order a new one. Delay.
'09 Yamaha TMAX Large sport scoot.
User avatar
Stanza
Member
Posts: 575
Joined: Mon Jan 29, 2018 8:34 pm
Location: Chicago

Post by Stanza »

GregsBuddy wrote:Parts arrived from Scooterwest yesterday.
I only have one question on reassembly; The cam drive chain "tensioner" doesn't appear to have any travel and is locked in position. Is this the way it's supposed to be?
Looking forward to working on the engine soon.
Chain tensioner is a spring loaded plunger with a locking pawl. In order to release it, you need to remove the 10mm bolt from the tensioner, push the pawl in manually to release the teeth, and install into the head with the plunger all the way retracted. Once you have installed the two mounting bolts (m6, 8mm head), you install the spring loaded 10mm bolt, which will tension the plunger against the chain.
GregsBuddy
Member
Posts: 509
Joined: Sun Jan 11, 2015 9:36 pm
Location: North SF Bay

Post by GregsBuddy »

Thank you, Stanza. I removed the Philips head screw on the outside and didn't see a means of further dismantling. I'll check it out again!
'09 Yamaha TMAX Large sport scoot.
GregsBuddy
Member
Posts: 509
Joined: Sun Jan 11, 2015 9:36 pm
Location: North SF Bay

Post by GregsBuddy »

Engine back together and in scoot' where it promptly started with its new piston/rings/wrist pin/gaskets/air filter/oil filter/ sparking plug/oil.
Now to finish the many panels and details and take it for a ride. Fuel injection is so great. If the connectors are correct, the fuel pump starts and the engine fires like new.
'09 Yamaha TMAX Large sport scoot.
User avatar
Stanza
Member
Posts: 575
Joined: Mon Jan 29, 2018 8:34 pm
Location: Chicago

Post by Stanza »

Excellent! Congrats on a successful top end rebuild. Glad it went according to plan.
GregsBuddy
Member
Posts: 509
Joined: Sun Jan 11, 2015 9:36 pm
Location: North SF Bay

Post by GregsBuddy »

Oh, and the cylinder is new.
The cylinder that came out of the engine was slightly out of round. The removed piston would slide in the cylinder when it was oriented in its normal manner but not when 90 degrees from normal.
'09 Yamaha TMAX Large sport scoot.
GregsBuddy
Member
Posts: 509
Joined: Sun Jan 11, 2015 9:36 pm
Location: North SF Bay

Post by GregsBuddy »

With ~100 miles of break-in and several thermal cycles, the compression is 210 PSI as measured with a motorcycle compression tester, not an automotive tester. The service manual indicates 11 kg/cm^2 = 156 PSI. Either manual is wrong, or, what?
The scoot' runs great and I'm breaking it in according to the manual for new scooter,s since the thing that breaks in the most is the piston/rings/cylinder during break in.
One thing I've noticed is a missing "loose metal part" sound the scoot used to make at neutral throttle (not accelerating or decelerating). Maybe that sound was the top ring bouncing in the damaged ring land.
'09 Yamaha TMAX Large sport scoot.
Post Reply