Starting Problem

[LTRracer4]

Ive posted about this before, but ive tried some more stuff and i am still having the same problems. Bolt came loose on my oil filter cover, lost oil, the bike locked up. I replaced the cylinder and piston, everything was looked over, valves checked etc. The bike will turn over all day but never start. Tore it down to check timing again and again, its right. Still wont start. Simon plugged it into BUDDS at Ballance and it came up clean, TPS and everything is on. He said to try a new injector. I did this, and once again turn over but not start. the bike will pop start and run great, but it doesnt like to idle when its hot. when the bike is hot the electric start will fire it up, but it usually takes several tries. also if we hook it up to a jumper and have it turn over really fast it will start. Im at a loss, anyone have any ideas? My harness is BCS cut.

[TNT]

Sounds like an ECM to me, not registering failt codes not working properly be my guess.

[LTRracer4]

Should i get it re-programmed or look into buying a new one? I still have stock sparkplug cables. Recently when i pulled the cable off the inner plug it left a metal casing on the plug, when i put the wire back on it seamed to go back in right, and the bike still ran fine when pull started. Could this also be a reason for it not starting? Today i went out and it was the first time ive tried to start it in weeks. It fired up in about 2 seconds, ran for 45 seconds or so and as soon as i let it idle it died, then it wouldnt start again.

[X400EX]

I think you should replace your spark plug cables. The same thing happened to me (broken cable after remove). I've installed the NGK racing cable kit, runs great!

[LTRracer4]

Did your bike have problems starting? My bike runs great when its running it just wont start.

[X400EX]

I did not try after I broke my cable with the same cable, I replaced both right away...

[TNT]

If your cables or spark were bad you be throwing ECM codes and you said Simon seen none on BUDs, you would not run good after a kick start that’s why I am leaning to your ECM as the prob…Even if it were an intermittent wire, etc, a fault code should register there are over 50 of them. You can try and flash by BUDs, take the whole bike then test it for codes and the ECM, or if you can borrow one a different ECM plug it in see if it solves the probs.


Prior to that try testing your neutral and clutch switches by starting in neutral or with the clutch pulled in any gear. Since it runs good after a kick the ignition system, coils, wires, and sparks are probably fine it’s in your starting system or EFI. I’m thinking you may have a bad Idle Air Control Valve (IACV), it lets bypass air around the TB when the butterfly valve is closed. If it is bad, no idle air no start but there may enough compressed air for a hot start if the decompression has not cycled, and it can be bypassed by a kick start but won’t idle if faulty. A coolant sensor (CTS) is also possible since you say it fires up when hot not cold, but if it were bad it affect all RPM's run rich probably see dark smoke out the exhaust. I've seen a blown or leaky head gasket cause a bike to act weird like this before w/a coolant code, but you said you just replaced the top end. Again, if either were bad you'd think you see a code but it does seem to make sense one could be bad. If you can borrow one of them try replacing it too.

Sounds like you got multiple problems, starting and idling and they are two different systems only thing in common to cause this behavior is the IACV, CTS, and ECM I can think of.

I’d get the NGK’s anyway

[TNT]

Forgot to mention a quick indication your ECM is not working properly is fuel pump does not come on within 5 seconds of run/start switch. Providing the pump and relay is working which it sounds like it is.

You can try and clean the IACV bypass channel may be clogged causing a stuck piston just don't try and move the piston by hand since the drive screw breaks easily, dry w/air....you can do resistance test on but best to check by R&R. Clean your TB too.

Check your coolant sensor terminals, cut or shorted wires, etc...

[LTRracer4]

fuel pump comes on like it should, most recently we have tried new spark plug cables, a leak down test and just another good general look over. Its still doing the same thing. Im getting extremely fed up. How complicated can it be?

[TNT]

Originally posted by LTRracer4
fuel pump comes on like it should, most recently we have tried new spark plug cables, a leak down test and just another good general look over. Its still doing the same thing. Im getting extremely fed up. How complicated can it be?

Is weird! Fact that the jumper starts it fine points to maybe the battery, bad cell, low CCA's....I heard of bad cells making cars start then not run when hot and visa-versa....dunno! :confused:

I'm calling it the ECM or something electrical, I'd go back to BUDs now w/and check the battery by load test.

Once the bike starts you say it runs fine, so it's in the starting system, fuse, battery, solenoid, starter, neultral/clutch switch, ignition switch, off-on switch, ECM.....not cables, plugs, rings that work fine when it's running.

Fuel pump low pressure regulator or the low fuel probe maybe seen it cause start probs like this, and you replaced all your relays lately they can make weird things happen I've seen. You need to do a fuel and oil pressure test not sure BUDs picks them up. You get hung up on start if it were decompression but you did not describe that. Check your low oil pressure/regulator too.

I feel your pain, I’ve had a bad morning working on my 5th wheel…jack would not work after hours of troubleshooting found out to be a bad cell in my battery. Before that electric brakes driving me nuts! When it comes to problems what can go wrong will go wrong....just keep plugging away until you find it!

Good luck!