'07 FXDB won't start when engine hot
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Intermediate
Joined: Apr 2018
Posts: 27
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From: Vancouver, BC
'07 FXDB won't start when engine hot
Hey guys, this has happened twice now and i'm a little concerned.
about a month ago the following scenario occurred:
Rode about an hour and a half. External temps were not high- 17-22 celsius. Got to a stop, powered down bike. It sat for 5 minutes or so, tried to start it again, engine turns over gets a bit of life then dies. Engine will not start again. Nearly wore out the battery trying (plenty of turning over but sounds like no fuel). Let it sit for a few hours, tried again, bike runs. Rode it home, had trouble with idle (bike would die), but by the time i got home the problem disappeared.
Figured it was a fuel pressure problem. Replaced fuel filter, fuel sock, fuel regulator, and the hoses inside the tank.
Did a poker run yesterday. On the way to the first stop there was lots of idle or slow speed movement (big group). Shut down bike, let sit for 5 minutes, went to start it up- same problem as before. FP3 didn't show problem codes, but showed engine temp at about 115 deg celsius. Opened gas cap to relieve negative pressure, no luck. Let it sit for 15 minutes or so*, fired it up, worked, no further issues. Checked temp later at a stop and it said 145 celsius, but bike started up fine.
Any idea or thoughts what it could be?
Specs: 07 FXDB, SE plug wires, fresh plugs (less than 1 year old), fresh oil (less than 1500km), fresh fuel (94 octane), fresh fuel filter and sock, cleaned inside tank.
Largely stock engine except FP3 and VH Competition Series pipe w/ quiet baffle insert.
*while i waited i also reflashed ECM with FP3 using the same map but with mild decel pop fix, as i had just found that feature and wanted it enabled. Not sure if the ECM flash resolved the problem, or the 15 minute wait did.
about a month ago the following scenario occurred:
Rode about an hour and a half. External temps were not high- 17-22 celsius. Got to a stop, powered down bike. It sat for 5 minutes or so, tried to start it again, engine turns over gets a bit of life then dies. Engine will not start again. Nearly wore out the battery trying (plenty of turning over but sounds like no fuel). Let it sit for a few hours, tried again, bike runs. Rode it home, had trouble with idle (bike would die), but by the time i got home the problem disappeared.
Figured it was a fuel pressure problem. Replaced fuel filter, fuel sock, fuel regulator, and the hoses inside the tank.
Did a poker run yesterday. On the way to the first stop there was lots of idle or slow speed movement (big group). Shut down bike, let sit for 5 minutes, went to start it up- same problem as before. FP3 didn't show problem codes, but showed engine temp at about 115 deg celsius. Opened gas cap to relieve negative pressure, no luck. Let it sit for 15 minutes or so*, fired it up, worked, no further issues. Checked temp later at a stop and it said 145 celsius, but bike started up fine.
Any idea or thoughts what it could be?
Specs: 07 FXDB, SE plug wires, fresh plugs (less than 1 year old), fresh oil (less than 1500km), fresh fuel (94 octane), fresh fuel filter and sock, cleaned inside tank.
Largely stock engine except FP3 and VH Competition Series pipe w/ quiet baffle insert.
*while i waited i also reflashed ECM with FP3 using the same map but with mild decel pop fix, as i had just found that feature and wanted it enabled. Not sure if the ECM flash resolved the problem, or the 15 minute wait did.
Last edited by FXDBij; May 27, 2019 at 12:55 PM.
Road Warrior
Joined: Mar 2014
Posts: 1,623
Likes: 698
From: nowhere
It very well could be the CPS starting to go bad. Usually, when they go bad you're dead in the water. Pull it and see if it has any "fuzz" on it. If it does, obviously clean it and reinstall.
Or it could be the IAC or ETS. Next time it doesn't want to start, pull the AC and feel if the IAC stepper motor is working properly. If it isn't, I would replace the ETS.
It could also be the TPS. It's easy enough to check. It's a rheostat, (resistance changes as it rotates) Put a meter on it and see if the resistance increases/decreases as you turn it.
My WG just did this and it turned out to be an intermittent open wire to the ETS. Hot starts were a crap shoot, sometimes ok, other times I had to let it cool down to start. Drove me about 1/2 batshit trying to find it. I was almost ready to (shudder) take it to a dealer! Let the stoning begin.
Or it could be the IAC or ETS. Next time it doesn't want to start, pull the AC and feel if the IAC stepper motor is working properly. If it isn't, I would replace the ETS.
It could also be the TPS. It's easy enough to check. It's a rheostat, (resistance changes as it rotates) Put a meter on it and see if the resistance increases/decreases as you turn it.
My WG just did this and it turned out to be an intermittent open wire to the ETS. Hot starts were a crap shoot, sometimes ok, other times I had to let it cool down to start. Drove me about 1/2 batshit trying to find it. I was almost ready to (shudder) take it to a dealer! Let the stoning begin.
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,922
Likes: 8,027
From: poway
It very well could be the CPS starting to go bad. Usually, when they go bad you're dead in the water. Pull it and see if it has any "fuzz" on it. If it does, obviously clean it and reinstall.
Or it could be the IAC or ETS. Next time it doesn't want to start, pull the AC and feel if the IAC stepper motor is working properly. If it isn't, I would replace the ETS.
It could also be the TPS. It's easy enough to check. It's a rheostat, (resistance changes as it rotates) Put a meter on it and see if the resistance increases/decreases as you turn it.
My WG just did this and it turned out to be an intermittent open wire to the ETS. Hot starts were a crap shoot, sometimes ok, other times I had to let it cool down to start. Drove me about 1/2 batshit trying to find it. I was almost ready to (shudder) take it to a dealer! Let the stoning begin.
Or it could be the IAC or ETS. Next time it doesn't want to start, pull the AC and feel if the IAC stepper motor is working properly. If it isn't, I would replace the ETS.
It could also be the TPS. It's easy enough to check. It's a rheostat, (resistance changes as it rotates) Put a meter on it and see if the resistance increases/decreases as you turn it.
My WG just did this and it turned out to be an intermittent open wire to the ETS. Hot starts were a crap shoot, sometimes ok, other times I had to let it cool down to start. Drove me about 1/2 batshit trying to find it. I was almost ready to (shudder) take it to a dealer! Let the stoning begin.
Engine temp sensor and wiring issues are a good suggestion. If the connection is open, the ECU will think the motor is really cold and flood it out.
Thread Starter
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Intermediate
Joined: Apr 2018
Posts: 27
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From: Vancouver, BC
Thank you for the thorough suggestion list, gonna check all these as time, tools, and skill allow (in that order).
Last edited by FXDBij; May 28, 2019 at 10:25 AM.
Road Warrior
Joined: Mar 2014
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From: nowhere
I assume this is in the service manual? i can probably figure this out. Will do when i get home, i am guessing it doesn't require the engine to be in 'problem state' to be checked.
Yes
Ok i'm getting Engine Temp Sensor (thanks Max Headflow), but what's IAC and AC? I'm new to mechanics BUT i have a service manual and a handle on google to try **** out.
IAC is the Idle air control motor. It is located @ 12 o'clock directly behind the air cleaner (AC) It controls idle speed by moving a plunger in the Throttle Body (TB). Basically it is a variable idle jet in carb terms. Put your finger in the throttle body about an inch and you will feel a hole. If it is working you will feel and hear the plunger move when you turn the ignition on.
And TPS... what's that?
Throttle Position Sensor It tells the ECM how for the throttle is open. It is at 9 o'clock and is attached to the same shaft as the butterfly
Last one.. what's an intermittent open wire?
Basically a broken wire the sometimes makes contact and other time it doesn't, A good example of this would be a loose positive battery cable. Hit the start button 5 times and nothing happens. Hit it the 6th time and the bike starts. The cable is then welded(due to arcing) to the battery and will start the bike until it vibrates off again and leaves you going WTF? If it's inside the insulation, it is a real bitch to find.
Thank you for the thorough suggestion list, gonna check all these as time, tools, and skill allow (in that order).
Yes
Ok i'm getting Engine Temp Sensor (thanks Max Headflow), but what's IAC and AC? I'm new to mechanics BUT i have a service manual and a handle on google to try **** out.
IAC is the Idle air control motor. It is located @ 12 o'clock directly behind the air cleaner (AC) It controls idle speed by moving a plunger in the Throttle Body (TB). Basically it is a variable idle jet in carb terms. Put your finger in the throttle body about an inch and you will feel a hole. If it is working you will feel and hear the plunger move when you turn the ignition on.
And TPS... what's that?
Throttle Position Sensor It tells the ECM how for the throttle is open. It is at 9 o'clock and is attached to the same shaft as the butterfly
Last one.. what's an intermittent open wire?
Basically a broken wire the sometimes makes contact and other time it doesn't, A good example of this would be a loose positive battery cable. Hit the start button 5 times and nothing happens. Hit it the 6th time and the bike starts. The cable is then welded(due to arcing) to the battery and will start the bike until it vibrates off again and leaves you going WTF? If it's inside the insulation, it is a real bitch to find.
Thank you for the thorough suggestion list, gonna check all these as time, tools, and skill allow (in that order).
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,922
Likes: 8,027
From: poway
I think you mean IAC.
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Road Warrior
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