Harley Davidson Forums banner

1 - 5 of 5 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter #1
I have a 96 Ultra classic with fuel injection. I have been having a problem for some time nowand it is driving me nuts.
Whem I start the bke from cold she fires up with out any problems. However, if I stop at a petroil station for example and kill the engine for a few minutes, when I restart her she idles OK for about 30 secounds and then the revs climb up to either 3k or 4k and will not die down until I bog the engine down with the clutch or hit the kill switch. When I have
hit the kill switch she will not restart for 10mins or so until she cools down. On the rare occusion that she does start stright away she run very rough in deed.
I have replaced the idle and throttle cables but no joy.

Any help please.....

Many thanks

Phil
 

·
Registered
Joined
·
40,786 Posts
Do you have any sort of aftermarket fuel management device installed?
 

·
STAND AND FIGHT!
Joined
·
13,504 Posts
That's one that I'll bet is going to be very difficult for a DIY'er to fix, (Do-It-Yourself) and I'm a pretty hard core DIY'er.

I think my first suspicion would be something related to heat soak.
Some component that stays in it's proper mode, gets too hot and malfunctions when a fully warmed up bike sits w/no air flow for a few minutes.

An electronic control unit of that vintage has relatively fewer inputs than the newest ones, no O2 sensors for instance.

I'd get the manual, figure out if and where there is a throttle position sensor, and an RPM sensor, and where they are.

To support the heat soak idea, test whether after a good cold start, if you let the bike warm up just a little, but not to full temp, turn the engine off and let it sit for just a minute and see if the symptom comes back. If it does not, but letting it warm up thoroughly does cause the problem, that might point to other simple tests.

Maybe if you're lucky, you could even use some kind of cooling air flow, like a vacuum cleaner on blower mode, choose one component or another, like the throttle position sensor, and after letting the engine warm up thoroughly, so you know the problem is likely to come back, and them apply the cooling air to the TPS to be sure that it is not getting hot while sitting still and soaking up engine heat, turn the bike off and see if that causes the problem. If that does not change the symptom, repeat the test with the cooling air on the RPM sensor.

Last and most expensive, duplicate the test on the electronic control unit itself. Maybe you'll get lucky and be able to tell which of the components is causing the problem by this simple method.
 

·
Just passing thru
Joined
·
6,636 Posts
May be a bad sensor. Are there any trouble codes? I'm not sure if they are displayed on your bike or not. One that comes to mind is the inlet air temp sensor.
 
1 - 5 of 5 Posts
Top