JH600 stalling

[Lao Jia Hou]

UPDATE - my bike has gone in & should, by now, be in pieces. Hopefully, I'll have something to report by 11/11/11, an auspicious day!

Thanks Motokai & Eric. This is very helpful.

I have used injector cleaner once or twice, but not for at least 6 months. Hence, there might be some gumming up. I also noticed that the Beijing Service Center has a fancy-shmancy new injector cleaning machine, so perhaps it knows something us owners do not.

By the way, when I went to deliver my JH600 a few days ago, its battery was down (from lack of use) ... but it had just barely enough juice to start it. And the stalls were worse than ever - at least every 20 or 30 seconds. After riding around my parking lot, and having no less than a dozen stalls, I swapped the battery with my fully-charged "B" and my "A" returned to its more-normal acute stalling, allowing me to ride the bike over to the Service Center.

[998S]

How are the electric connectors on these bikes?
If I remember my old Chinese made SUV, all stainless steel parts started to corrode, because the stainless steel was not so much stainless steel after all .....
We are in a very humid environment in China, and corrosion is a big problem, let alone some high pressure washing or whatever.
I know of Ducati's who loose 2Volt over 1 meter from the battery to the gauges, mostly by corroded connectors.

You might want to have a look at that while the bike is apart, and spray them all with special electric connector spray, or even better, the special dielectric grease.
Special towards the black box and related components.

E.

[euphonius]

How are the electric connectors on these bikes?
If I remember my old Chinese made SUV, all stainless steel parts started to corrode, because the stainless steel was not so much stainless steel after all .....
We are in a very humid environment in China, and corrosion is a big problem, let alone some high pressure washing or whatever.
I know of Ducati's who loose 2Volt over 1 meter from the battery to the gauges, mostly by corroded connectors.

You might want to have a look at that while the bike is apart, and spray them all with special electric connector spray, or even better, the special dielectric grease.
Special towards the black box and related components.

E.

A couple of weeks ago Milton posted about this subject, noting a thread in a Chinese forum in which a JH600 owner found that a key electrical spring connection between the ECU and wiring harness had become corroded. Once he soldered the connections his stalling problems were resolved.

Wonder if anyone else has tinkered with those connections?

cheers

[Barry]

UPDATE - my bike has gone in & should, by now, be in pieces. Hopefully, I'll have something to report by 11/11/11, an auspicious day!

I saw that black piece of shit sitting at the dealer this morning. Front side looked striped: dashboard, headlight, side panels of the tank were off.

Had a small oil leak from the oil filter cover, had to replace the rubber ring on it. And had a new rear tire put on.

[Lao Jia Hou]

How are the electric connectors on these bikes?

You might want to have a look at that while the bike is apart, and spray them all with special electric connector spray, or even better, the special dielectric grease.
Special towards the black box and related components.

About a year ago, when I first started noticing the stall issue, Franki (a JH600 owner from HK) was up in Beijing, and he recommended the same thing.

I subsequently went through the bike with CRC contact cleaner & dieletric grease (boy, that was hard to find in China ... and when I found it, I bought out the vendor!). It seemed to have only a slight benefit. However, anything & everything related to preventative maintenance is always a good idea.

I saw that black piece of shit sitting at the dealer this morning. Front side looked striped: dashboard, headlight, side panels of the tank were off.

Had a small oil leak from the oil filter cover, had to replace the rubber ring on it. And had a new rear tire put on.

I hope it was YOUR bike that was getting the o-ring and tire replacement? Replacing a rear tire to fix "the stall" ???? Well, who knows what people think sometimes.

[milton]

A couple of weeks ago Milton posted about this subject, noting a thread in a Chinese forum in which a JH600 owner found that a key electrical spring connection between the ECU and wiring harness had become corroded. Once he soldered the connections his stalling problems were resolved.

Wonder if anyone else has tinkered with those connections?

cheers

1. Compression pressure low; faulty decompression valve
2. Vacuum leak in intake manifold
3. Spark plug wire worn or faulty
4. Fuel pump pressure low, due to worn/faulty part
5. Fuel jet worn/faulty/dirty
6. Idle speed actuator worn/faulty
7. Throttle position sensor worn/faulty
8. Manifold absolute pressure sensor worn/faulty
9. Coolant temperature sensor worn/faulty
10. Bad wire contacts, spark plug, etc.
11. Bad fuel, bad fuel filter, junks in the fuel line

This is a list of possible symptoms and causes for JH600 engine stalling, complied by a Jialing owner (Xiao Zhang in Shanghai) based on materials gleaned from the Chinese Jialing manuals and translated by me. As we can see, there are a large number of possible (official too) causes to the problem and there is no single point of failure that can be identified as the sole culprit. However, with this list and what Eric has suggested about the fuel mixture being too lean, I have gradually formed my opinion about this tough problem. I believe that the lean fuel mixture compresses the “margin of error” for all the components involved and makes the ECU highly unreliable. In other word, the ECU is not robust enough and has very low tolerance to any aberrations coming from any of those sensors, leads, contacts, fuel lines, etc. Boosting the fuel mixture numbers on the right part of the “map” could be the silver bullet.

Now come back to the question asked by E. My latest struggle with my JH600 is as follows (don’t laugh): On last Friday, I brought my bike to Xiao Zhang for a free fix for that “bad contact” problem I posted (from ECU plug to its circuit board). After that, the bike ran “seemingly” better for a short 10 minutes (although made no difference on the stalling) then started to exhibit some hesitation whenever the engine reaches 4000 to 5000 rpm (almost like what I experienced last time with bad fuel). Xiao Zhang happens to have a “spare” manifold pressure sensor handy, so we pull it out and replaced that. Then he thought my spark plug NGK cr7eix is not the correct part and replaced it with his used cr8eix too. After this 2 new components installed, my bike started to give me the worst ever performance with incessant stalls, rough idling and epic backfires. Now it sits in the parking basement waiting for the idle speed actuator, which is not readily available from the Bosch distributor. Those parts are not super expensive and new parts are “usually better” than old parts, which is why I let him, or me rather, to go down this wholesale parts replacement path. If the idle speed actuator does not bring the bike back to life, I’d have him reverse some of the steps and see if any one of the steps is causing my new problems. If that doesn’t work, I am going back to Dr. Cui.

Summary: the tinkering and soldering did not bring my bike any closer to the resolution of the problem. It might have helped, but I just don't know any more.

[998S]

I will send you a PM in 5 min.

E.

[998S]

Then he thought my spark plug NGK cr7eix is not the correct part and replaced it with his used cr8eix too. After this 2 new components installed, my bike started to give me the worst ever performance with incessant stalls, rough idling and epic backfires.

Well, this is in itself an interesting find, especially if he had done the changes one by one......
But presuming the manifold pressure sensor was not faulty, then your rough(er) running is caused by using a "colder")* sparkplug.
Xiao Zhang seems to be right that, under the circumstances of very high gas temperatures, a colder sparkplug might solve it.
However, the fact that it did not work (actually made it worse) confirms, that these hot temperatures are caused by the lean-mixture itself, not by pre-ignition (which can be caused by a too-hot sparkplug).

I think I asked Milton and Motokai if they experienced pre-ignition (engine knocking), specially at accelerating from lower rpm's. I forgot the answer though.
If that does not occur, we can delete at least a part of the possible causes.

Milton, how did the sparkplug you pulled look like? Clean or fouled?

E.

)* The major structural difference affecting the heat rating is the length of the insulator nose. A hot type spark plug has a longer insulator nose. The insulator nose of a hotter spark plug has a longer distance between the firing tip of the insulator, and the point where insulator meets the metal shell. Therefore, the path for the dissipation of heat from the insulator nose to the cylinder head is longer and the firing end stays hotter. The insulator nose of a hotter spark plug also has a greater surface area that is exposed to more of the ignited gases and is easily heated to higher temperatures. A colder spark plug functions in an opposite manner. The heat range must be carefully selected for proper spark plug thermal performance. If the heat range is not optimal, then serious trouble can be the result. The optimal firing end temperature is approximately between 500°C (932°F) and 800°C (1472°F). The two most common causes of spark plug problems are carbon fouling (< 450°C) and overheating (> 800°C).

[Barry]

I hope it was YOUR bike that was getting the o-ring and tire replacement? Replacing a rear tire to fix "the stall" ???? Well, who knows what people think sometimes.

That was my bike indeed, but I'm experimenting with different color socks to see how it affects the stalling! Next I will try how different color underwear will affect it!


To get back on topic again, really noone has upgraded the "spark plug lead" to an aftermarket one yet right? I will probably upgrade mine before next riding season, since the original has a small crack in the rubber. But then again I don't have any serious stalling issues at the moment.

It will probably still take a while before we hear any news from Jialing about LJH's bike, since it wasn't shipped yet yesterday at least!

[Lao Jia Hou]

Most recent information ...

Jialing (CQ) instructed the Beijing Service Center to try a "fix" on my JH600 (without sending the bike to CQ), as follows:

- disconnect the Oxygen sensor;
- test bike for stalling; and,
- if no immediate stalling, return to customer.

The Beijing Service Center has informed us that the bike is "ready for pick up".

It was only after "discussion" that it was determined what Jialing has offered to do to remedy the problem, and how it is "fixed".

My response is very simple, so there is absolutely NO misunderstanding, but also very firm ...

1) Fix the problem properly (i.e., modify the ECU map), OR;
2) Provide the ability for the end user to modify the map (e.g., provide the end user with the appropriate software to modify the map). This can be done by either the Service Centers, or by the end user (who is willing to purchase a licensed copy), or perhaps by both.

If Jialing refuses, I have given instructions to sell both of my Jialings. (at least I have plate values on the bikes).

I will NOT be picking up the bike until there is a proper solution ... if no solution, I'll just sell the damn thing.

I can't be bothered with any more of this nonsense in dealing with Jialing. In fairness, I think the Service Centers are as frustrated as each of us are.

I'll give Jialing another week to come to its "senses" (with or without its sensors). But I really think that Jialing wishes I would just go away.

PS: I have recently heard that, as Euphonius had uncovered earlier, Jialing has not paid Bosch for the licensing of the software that is necessary to remap the ECUs. The Service Centers do not have the capability with the JH600 nor does it believe CQ has, either.