Engine shut off while downshifting

[Jay In Milpitas]

The used to be another RX3 web group I followed, I think a guy named Andy (cat herder?) posted that he started having stalling problems and found the ignition switch assembly had some dust inside. Seems the dust fluffered the contactulators and wouldn't let the pixies go to the wires they wanted to dance in.

I seem to recall he used a couple shots of electrical contact cleaner/lube. I think he also covered the holes in the switch body. He never reported another repeat of the stalling up until the web site vanished.

[2LZ]

Mine only does it rarely, usually just after it's been fired. I'll have to check this out! Thanks for the heads-up. I hate it when my pixies can't properly dance!

[pepperami]

Another one who`s bike stalls.

I`ve changed my riding style when I`m on my RX3.
I find mine will stall sometimes when rolling off the throttle after a hard blast at higher revs.
So now as I come down the revs/gears, I blip the throttle once or twice.

Not a cure but at least I don`t end up at the side of the road trying to start it again
I wonder if these bikes are running to lean and the fuel injection/electronic wizardry cant cope at times???

[2LZ]

Originally Posted by pepperami

Another one who`s bike stalls.

I`ve changed my riding style when I`m on my RX3.
I find mine will stall sometimes when rolling off the throttle after a hard blast at higher revs.
So now as I come down the revs/gears, I blip the throttle once or twice.

Not a cure but at least I don`t end up at the side of the road trying to start it again
I wonder if these bikes are running to lean and the fuel injection/electronic wizardry cant cope at times???

I can't say it's a real problem with mine. It's very rare. maybe it's my riding style. I do blip the throttle when downshifting. I bet out of the 10 months I've owned the RX3, it's only done it maybe twice, three time possibly? It was also only when it wasn't warmed up completely to operating temp. Within the first five minutes or so of run time. I'm not considering it a major issue, just a minor nuisance....but it would be nice to find out why.

[pepperami]

Originally Posted by 2LZ

I can't say it's a real problem with mine. it's only done it maybe twice, three time possibly? It was also only when it wasn't warmed up completely to operating temp. Within the first five minutes or so of run time. I'm not considering it a major issue, just a minor nuisance....but it would be nice to find out why.

Over here it`s -3 degrees in the morning and around +6 or 7 degrees during the day at the moment here in sunny East Anglia in the UK.
Hmm? could it be more of a problem here because the bike cant warm up properly? whaddya think?

[katflap]

Originally Posted by pepperami

Another one who`s bike stalls.

I`ve changed my riding style when I`m on my RX3.
I find mine will stall sometimes when rolling off the throttle after a hard blast at higher revs.
So now as I come down the revs/gears, I blip the throttle once or twice.

Not a cure but at least I don`t end up at the side of the road trying to start it again
I wonder if these bikes are running to lean and the fuel injection/electronic wizardry cant cope at times???

it is a standard response from the ECU, when certain criteria are met, to cut the injector pulse to zero, thus injecting no fuel.
Completely closing the throttle when travelling at speed will cause this to happen.

Some of the reason for this is to encourage "good" Emissions and fuel economy.

To bring the ECU out of this state, and start injecting fuel ,again, certain criteria has to be met.

2 of these are :-

The RPM dropping below a pre determined figure

The throttle being open more than a pre determined amount


by blipping the throttle you are bringing it out of this "cut-off circuit" thus re introducing fuel into the engine, helping to prevent it from stalling.


Amongst other things, having to do this indicates to me an under developed ECU "maps"

The Delphi mt05 ECU has not been specifically designed for the RX3 but is supplied to motorcycle manufacturers with a basic default "map" setup.
It is then down to the motorcycle manufacturers to develop and change the ECU mapping to suit the motorcycle it is been fitted to.

Getting the correct ECU response to a particular engine at any given time, is a very difficult thing to get right and takes time.

Though I think Zongshen may of spent a lot of time in the workshop doing this, I dont think they spent enough time monitoring the bike in "real life" situations.

As we are unlikely to get ECU "map" updates, we are stuck with trying to work around these glitches.

Some time ago I replaced my thermostat with a higher temperature one. I had a different reason for doing this but have found it had the added benefit of the bike not stalling when coming to a stop and other situations when it would stall inexplicably.

Perhaps a hotter engine is better able to cope with this type of ECU "glitch" and not stall.

DISCAIMER: just my opinion

[2LZ]

Originally Posted by katflap

it is a standard response from the ECU, when certain criteria are met, to cut the injector pulse to zero, thus injecting no fuel.
Completely closing the throttle when travelling at speed will cause this to happen.

Some of the reason for this is to encourage "good" Emissions and fuel economy.

To bring the ECU out of this state, and start injecting fuel ,again, certain criteria has to be met.

2 of these are :-

The RPM dropping below a pre determined figure

The throttle being open more than a pre determined amount


by blipping the throttle you are bringing it out of this "cut-off circuit" thus re introducing fuel into the engine, helping to prevent it from stalling.


Amongst other things, having to do this indicates to me an under developed ECU "maps"

The Delphi mt05 ECU has not been specifically designed for the RX3 but is supplied to motorcycle manufacturers with a basic default "map" setup.
It is then down to the motorcycle manufacturers to develop and change the ECU mapping to suit the motorcycle it is been fitted to.

Getting the correct ECU response to a particular engine at any given time, is a very difficult thing to get right and takes time.

Though I think Zongshen may of spent a lot of time in the workshop doing this, I dont think they spent enough time monitoring the bike in "real life" situations.

As we are unlikely to get ECU "map" updates, we are stuck with trying to work around these glitches.

Some time ago I replaced my thermostat with a higher temperature one. I had a different reason for doing this but have found it had the added benefit of the bike not stalling when coming to a stop and other situations when it would stall inexplicably.

Perhaps a hotter engine is better able to cope with this type of ECU "glitch" and not stall.

DISCAIMER: just my opinion

All good stuff katflap and probably right on, especially when it comes to the "canned mapping" from Delphi.

Question though, since this is a closed loop system after it reaches operating temp, (open loop or choke mode should run on a set mapping), wouldn't then the O2 sensor (along with MAP, etc..) take over and adjust the injector pulse width, as needed, to attempt to reach it's optimum 14.7 to 1 or as close as possible?.....or I wonder if by EPA standards, as you suggest, don't allow that anymore and run them lean, even in closed loop?...which really makes no sense because usually a lean condition creates more HC's. I've never figured that one out. I know way back when I was a CA smog tech, anytime we saw high HC's, they had an air leak somewhere.

It would be interesting if someone could get a sniff at full operating temp at both idle and cruise rpms.

[Sullybiker]

Someone should start collecting some data on this, particularly ambient temperature, that kind of thing.

ECU updates are a common thing, but there's some logistical problems involved, as you can either present the bike to a dealer, or (and I suspect this would be more likely) mail the ECU somewhere to get the firmware flashed.

This problem isn't unheard of on EFI bikes, my own Ninja had a rep for it (I mentioned it up thread) but mine was not affected. I think the cure was a more aggressive idle fuel map.

Interestingly, though I've not ridden an RX3, a common remark is that the bike has excellent fuelling, by no means common on EFI bikes. It would suggest Zong has done a fair bit of work in this area.

[katflap]

Originally Posted by 2LZ

All good stuff katflap and probably right on, especially when it comes to the "canned mapping" from Delphi.

Question though, since this is a closed loop system after it reaches operating temp, (open loop or choke mode should run on a set mapping), wouldn't then the O2 sensor (along with MAP, etc..) take over and adjust the injector pulse width, as needed, to attempt to reach it's optimum 14.7 to 1 or as close as possible?.....or I wonder if by EPA standards, as you suggest, don't allow that anymore and run them lean, even in closed loop?...which really makes no sense because usually a lean condition creates more HC's. I've never figured that one out. I know way back when I was a CA smog tech, anytime we saw high HC's, they had an air leak somewhere.

It would be interesting if someone could get a sniff at full operating temp at both idle and cruise rpms.

Until the engine reaches a pre defined operating temperature and the 02 sensor is up to a working temp your bike is in open loop.

In open loop it uses all the other sensors to reference against the map tables in order to try and maintain a 14.6:1 air/ fuel ratio when idling, gentle acceleration or cruising.

Without the O2 sensor in use it has no way of checking that this has been achieved.

Once the engine temp is around 25 degs C and the O2 sensor is up to temp your bike enters in to closed loop.

In closed loop the O2 sensor is been used as well. Now the bike can monitor the emissions and now knows if the air fuel ratio is correct and will make small adjustments many times a second to maintain 14.6:1 A/F .

Your bike will only remain in "true" closed loop when idling, gentle acceleration and cruising.

At any other time a different fuel/air ratio is required. There are a number of "overrides" that can come in to play when this occurs to give a richer or leaner mixture.

I didn't know that a lean mixture gives high HC's , that doesn't make sense to me but I have no knowledge about this

here is a graph of my RX3 showing a zero injector pulse when the throttle position hits zero

And the next graph is of my engine temp before I changed the thermostat. the temp only peeks at the end because I came to a stop and let it idle. (temp in degs C )

[kumatae]

So I emailed Gerry regarding this stalling issue and received a not so encouraging email. He stated that I should be fueling high octane 91 fuel from a name brand station (i've been using costco) even though owner's manual states 87 octane or higher. He also says fuel filter needs to be replaced every 10,000 miles but again, there is no statement in the owner's manual that says it ever needs replacing. He made it sound like I was a negligent owner and not doing my due diligence as if I was supposed to know it all. Whatevers, I'll do a valve clearance and see what happens.

[2LZ]

Originally Posted by kumatae

So I emailed Gerry regarding this stalling issue and received a not so encouraging email. He stated that I should be fueling high octane 91 fuel from a name brand station (i've been using costco) even though owner's manual states 87 octane or higher. He also says fuel filter needs to be replaced every 10,000 miles but again, there is no statement in the owner's manual that says it ever needs replacing. He made it sound like I was a negligent owner and not doing my due diligence as if I was supposed to know it all. Whatevers, I'll do a valve clearance and see what happens.

Usually the stalling issue starts far earlier than 10,000 miles. I've basically attributed it to the system being in open loop because it usually only happens in the first 10 minutes of riding.
I'd be curious to see if the guys changing to hotter stats have any stalling issues. Maybe the bike doesn't run quite hot enough to keep it in closed loop all the time?....or right on the border??

[pyoungbl]

2LZ, mine does not stall. I'm running the higher temp thermostat and Iridium plug. I'm running 87 octane. Personally, I cannot understand how higher octane figures into this problem (or carbon build-up either). The name brand idea sounds interesting until you see that the same truck is delivering to COSTCO and EXXON. The additive package might be a bit different but not by much. Furthermore, lots of studies have shown that buying higher octane fuel is a waste of money unless the engine needs it due to higher compression or turbo. Gerry has years of experience so I'm not about to call BS, just that I do not understand the reasoning.

Peter Y.

[2LZ]

Originally Posted by pyoungbl

2LZ, mine does not stall. I'm running the higher temp thermostat and Iridium plug. I'm running 87 octane. Personally, I cannot understand how higher octane figures into this problem (or carbon build-up either). The name brand idea sounds interesting until you see that the same truck is delivering to COSTCO and EXXON. The additive package might be a bit different but not by much. Furthermore, lots of studies have shown that buying higher octane fuel is a waste of money unless the engine needs it due to higher compression or turbo. Gerry has years of experience so I'm not about to call BS, just that I do not understand the reasoning.

Peter Y.

I'm wondering if this whole stalling thing could be because of the cooler stat? Thanks for the heads up. It'l be good to hear from other "hotter stat" guys also.

I'm with you on the octane, basically. It's just out of years of habit more than anything that I run my bikes and yard tools on premium.

Other than the hot rods and high strung 2 strokes I've run in my younger years, I've noticed zero difference in running the different fuels in modern vehicles. I will say this for absolute positive though. Both my Jeep Patriot and our Challenger do run better and have more spunk with mid grade. It's definitely noticeable. It jumps both almost 2 mpg also. The Challenger actually recommends mid grade. though The Patriot recommends regular.....but even my car pool partner (nice gal, knows nothing about cars and has an identical Patriot) said after I filled with mid grade, "What did you do to your Jeep? I don't have to push on the pedal as far as mine to get going." If she noticed a difference, that let me know I wasn't dreaming.

[katflap]

Originally Posted by 2LZ

I'm wondering if this whole stalling thing could be because of the cooler stat? Thanks for the heads up. It'l be good to hear from other "hotter stat" guys also.

Yep, I think so too.

Since fitting the hotter stat, stalling issues that I had in the past have all but gone. Only occasionally will it now stall when the engine is still quite cold or has just dropped down from its fast idle after initially starting the engine.

Before, with the cool stat, I noticed that if just cruising the coolant temp could drop well below 52c but still show 2 bars on the temp gauge. The engine would often stall pulling up to the same junction on my commute to work

The "bar" temp Gauge gives a temperature range at best. Its close to useless.

I don't think the engine management system works well at these low temps and is much better once a decent temp is reached and maintained

[jbfla]

To add some info:

My Rx3 experienced stalling only on the first day I rode it.

It hasn't stalled since (8,000 miles).

Don't think the thermostat is the problem.

I did install the 90C thermostat, but did so in order to possibly burn off excessive crankcase gases.

FYI: The thermostat on my water cooled Triumph Bonneville is 88C (190F).

jb