JH600 stalling

**cz81** · 03-29-2012, 05:52 AM

I wonder whether this is similar to the problem I experienced with my factory-new JH600: During those first days of riding the new motorcycle around Chongqing, occasionally, after an hour or so of riding, when I would take a short break to take photos or buy something from a road-side stall, after sitting for a few minutes, the motor just wouldn't catch, even after 10-15 seconds, just turn and turn and turn, even though everything was obviously still warm. I'd have to retry multiple times and turn the key to completely off and on repeatedly and this was cause for some momentary concern.

Will try learn to listen for the fuel-pump spinning up sound, if there's any way it helps in the investigation to look at the wiring etc. of the JH600-A version - the motorcycle is in Shanghai now.

**998S** · 03-29-2012, 06:20 AM

Causes for this problem are actually pretty limited:
1 - lack of fuel (too lean) - fuel pump not working / blocked lines / blocked fuel filter / injection blocked / electric signal to the injection
2 - lack of air (too rich) - air filter / throttle valve incorrect
3 - no spark / bad spark - electric / timing / wrong temperature sparkplug

Most of the No. 1 can be pretty much ruled out, as the engine should run bad in other conditions. Lets presume the broken fuel pump relay was an incidental case.
No. 2 can be ruled out for same reasons.

My thoughts are therefore going right now to a signal error (to or from the ECU).
The injection does not get a signal to open (no fuel injected), due to an ECU mishap.
Or the spark does not get a signal to fire at all, or due to timing mishap, fires way too early or way too late.

Should be interesting to pull the spark plug after a long start-motor run (without the engine firing up).
If the sparkplug is wet (fuel), the injections signal should be ok, and then it is the spark.
If the sparkplug is dry, it might be injection related.

Above is a bit rough, but a start for diagnosing the problem.

**milton** · 03-29-2012, 06:31 AM

Originally Posted by cz81

I wonder whether this is similar to the problem I experienced with my factory-new JH600.

Doesn't appear to be the case. "Our" problems (mine, Motokai, Victor) are all related to cold engine start. Once after getting started and warm, it never acts up until after it gets cold again.

**MotoKai** · 03-29-2012, 06:40 AM

So here's how I netted out:

Had a call with LZD, the Shanghai Jialing Quarterback who helps a lot of us out on a myriad of JH600 issues. (Note: LZD is not a Jialing employee). He reported that the bike runs, but this doesn't mean it's fixed. In order to fix a broken bike you need to know what the problem is. He said that they weren't able to discover/isolate what caused my bike to 1. Difficulty Starting 2. Loss of Power 3. Cut-outs

- Mechanic Fan worked his way thru the wiring off the fuel pump relay to suss out why/where the fault was.
- He confirmed that the fuel pump is working fine.
- The bike now starts/runs, but issue remains a mystery.

I'll go pick it up after work today and have a test ride. I will hopefully know more when I speak to the mechanic, but for now it seems that without solving the problem, there's no confidence that these symptoms will not come back.

To be continued.....

[By the way, I've officially hijacked Milton's thread!]

**milton** · 03-29-2012, 09:32 AM

Originally Posted by MotoKai

[By the way, I've officially hijacked Milton's thread!]

I am more than happy to let you "hijack" my thread as long as I stay trouble free.
My Jialing now runs perfectly. Even the cold start problem has gone away. When it's cold, I let my thumb press the start button a bit longer than before, and make sure it fires "properly" before letting go of it. That seems to have made the difference. Obviously there is a distinct possibility that the problem may come back after the voodoo fades.

**MotoKai** · 03-29-2012, 03:23 PM

Originally Posted by MotoKai

I'll go pick it up after work today and have a test ride. I will hopefully know more when I speak to the mechanic, but for now it seems that without solving the problem, there's no confidence that these symptoms will not come back.

To be continued.....

Arrived at the repair shop after work and took the bike out for a spin. But before taking off, repairman Xiao Fan reminded me what LZD said - it runs now, but they haven't yet found the cause of the "cut-out". Well, she started right up on the first click of the starter with a roar, and without needing to thumb it 3-4 times. A good sign I thought. Turned it off and started it back up again just to check. No problem.

Out onto Honggu Lu into 2nd, 3rd, 4th. The bike just sounded good and felt good. Back to the repair shop and turned the bike off, put the sidestand down. I told Xiao Fan the bike was fine - not sure what he did, but it works. He confessed he's not sure what he did either and warned that the problem could come back. He refused to accept payment for services rendered since he never found "the cause", but I insisted since he spent time working on my bike and should be compensated for that. What he surmised is that there is probably an Intermittent Short with the Fuel Pump Relay, but he can't locate where this bad wiring issue is occurring. He explained that he spoke with the Jialing Factory guys, but the electrical system designer was available. He plans to speak with this guy to better understand how to suss-out the problem and solution.

We agreed that since it's now running I should ride the bike home until he learns more. I got back on the bike, but it wouldn't start this time. The starter turned over...and over and over. Xiao Fan and his assistant ran over with painful looks on their faces. Then after a few more attempts, the bike was silent again (the "cut-out"). When thumbing the starter you don't even here the fuel pump engage with that little electrical humming sound - nothing.After more toying with the bike, listening for the the fuel pump to engage, turning the key on and off, thumbing the starter - it then started once again. WTF?

Xiao Fan continued to tell me that he knows there are 4 places with connection points on the bike where this relay wire runs and it could be any of these places causing the problem. It's going to take the Jialing JH600 Electrical System Designer guy tell him how to best find a fix without having to mess with the entire wiring harness of my JH600.

I agree. And until then, I'm grounded. Just canceled my 7-day first week of April ride!

**cz81** · 03-30-2012, 01:30 AM

Hey, that is starting to sound similar to my "problems re-starting the engine after a ride" problem, minus the "cut-out".

@998S: Thanks for the analysis, the added bonus of this bike is that I get to learn something :-)

I wonder whether the issue could be related to the ECU3 response to temperature sensors, whereby it doesn't supply sufficient fuel to start an engine that is still warm? I realize that I have almost zero experience with motorcycle maintenance at this point, so please forgive if I'm being naive.

Addendum and on to some more wild hypothesizing: I was able to restart the engine after repeated "failed attempt - all off - all on", could this conceivably be a "fail" signal to the ECU to encourage it to revert of some safe parameters?

**998S** · 03-30-2012, 01:57 AM

After reading the entire story, the only thing I might suggest is a bad mass-connection (normally 2 or 3 on the bike, and perhaps one more for the ECU).
Strange things happen if these are corroded / not making proper connection.

If that is not the case, I am at the limit of my armchair-wrenching, and need to see the bike in real.

**MotoKai** · 03-30-2012, 03:00 AM

Well now we know that the earlier symptoms after ecu-swap ("upgrade"), weren't sparkplug or plug wire related, but rather the beginnings of a fuel pump relay problem.

From Buzzle:
* One of the prime symptoms of a faulty bad fuel pump relay is the engine cranking up but not starting. This points towards a problem with the fuel delivery system and it may be that the fuel pump relay that is the culprit.

* Erratic functioning of the engine at the start and delay in starting up can be an indication of a faulty fuel pump relay. That is why, if you consistently notice a delay in engine starting, check the fuel pump relay.

* Once the relay stops functioning, the fuel pump will not switch on and the familiar sound of fuel pump working will not be heard. Ears trained to hear the normal sounds made by the car at start will notice the difference.

So what I experienced was a progression of the fuel-pump relay issue, and possible causes I can surmise are:
* Faulty wiring/loose connection (somewhere along the route)
* Corrosion along the wiring route or at the fuel pump connection
* Bad Ground

So, question is what is the best way for one of the mechanics to source the location and provide a fix?
This doesn't sound very complicated and I hate this "moto limbo" feeling, especially when I have cancelled my ride for next week.
I'd love to have this sorted over the weekend and hit the road. Any suggestions???

**euphonius** · 03-30-2012, 04:20 AM

Originally Posted by MotoKai

...
So what I experienced was a progression of the fuel-pump relay issue, and possible causes I can surmise are:
* Faulty wiring/loose connection (somewhere along the route)
* Corrosion along the wiring route or at the fuel pump connection
* Bad Ground

What about the relay itself? Surely Fan tried to swap it out to rule that out as a cause....

cheers