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Engine misfires at low speeds

From earlier in this thread when looking for an intake leak, I ended up using carb cleaner since it seemed to work well. I first tried propane and as a test, tried puffing it into my intake so to know what it would do, but didn't do anything to engine speed/sound (I gave it a pretty good sniff - shouldn't it have reacted in some way??). When I did the same thing with the carb cleaner it nearly stalled the motor, so used that, but did not find any leaks. Also, the dealer later changed out my intake seals since they thought that might be the problem too.

I will try pulling the other wires on the DFO and retesting.
 
I'm new to the game so excuse me but I have to ask, What are some of these intials stand for like TPS, DFO, etc..? I am having some of the same issues with my 02 RK and I want to learn more about keepin' her runnin' my self, like my Chevys..
 
Arthur10 said:
I'm new to the game so excuse me but I have to ask, What are some of these intials stand for like TPS, DFO, etc..? I am having some of the same issues with my 02 RK and I want to learn more about keepin' her runnin' my self, like my Chevys..
Click to expand...

TPS= throttle position sensor, DFO= Digital fuel optimizer Have a look in the self help section or use the search engine with KEY words, you will find tons of info:s You need to excuse yourself for wanting to learn, that is why we are all here to share and have a good time:D
 
Amish Hawg said:
I'm going to stick my neck out here. And this is a stretch.

I went through a somewhat similar problem on my 03 RKC. However, I did have the holes in the fuel line. I changed the lines, filter, plugs, sensors even the fuel pump. Same problem afterward, high idle sometimes, acted like it was missing, sputtered at low to mid speed....on the higher speeds, I think I was ok. ( could have been mental )

I bit the bullet, took her in. It took them two days to find it and only after I went in to tell them what I did previously. I told them i changed out the TPS sensor ( and showed them). When i pulled the TPS sensor, a small shaft came out. Well, that shaft wasnt supposed to come out. It was my Intake Body Shaft. It was cracked in half and the TPS sensor was holding it in place making it almost invisble to the eye.

Its the shaft holding the "butterfly" in your intake. Thats what was snapped in half. Put a new one in........better ever since. $300 at the shop, parts and all.

just a shot in the dark....good luck

you live, you learn
Click to expand...

My 2001 Heritage Softail with Delphi EFI appears to have the EXACT same problem that you had. It sputters intermittently, only when warm. It runs perfect when starting from cold until it warms up. Also, I am getting really bad gas mileage. People riding behind me can smell gas. I've checked EVERYTHING and it is all within spec. See below. I have changed the TPS, spark plugs, MAP sensor and intake manifold gaskets and still the same problem. Also, when stopped at a light, my RPM starts to increase for no reason. I checked the TPS shaft and it is fine. I am really at a loss to figure out this problem.


I’ve read posts that suggest that it could be the fuel pressure regulator sticking but, wouldn’t it stick when the bike is cold as well?


Checked:
crankcase position sensor
spark plug wires
coil
engine temperature sensor
cleaned vacuum lines

Replaced:Fuel filter and check valve
spark plugs
map sensor
throttle position sensor
intake manifold gasket


Thanks.
 
kruzzin5 said:
My 2001 Heritage Softail with Delphi EFI appears to have the EXACT same problem that you had. It sputters intermittently, only when warm. It runs perfect when starting from cold until it warms up. Also, I am getting really bad gas mileage. People riding behind me can smell gas. I've checked EVERYTHING and it is all within spec. See below. I have changed the TPS, spark plugs, MAP sensor and intake manifold gaskets and still the same problem. Also, when stopped at a light, my RPM starts to increase for no reason. I checked the TPS shaft and it is fine. I am really at a loss to figure out this problem.


I’ve read posts that suggest that it could be the fuel pressure regulator sticking but, wouldn’t it stick when the bike is cold as well?


Checked:
crankcase position sensor
spark plug wires
coil
engine temperature sensor
cleaned vacuum lines

Replaced:Fuel filter and check valve
spark plugs
map sensor
throttle position sensor
intake manifold gasket


Thanks.
Click to expand...
Take a closer look at the butterfly shaft, if it is broken it is staying part way closed common problem easy fix
Look here, you cannot see it but in the throat with a light you will see if the shaft is broken



HD01FXST010.gif
 
Jack Klarich said:
Take a closer look at the butterfly shaft, if it is broken it is staying part way closed common problem easy fix
Look here, you cannot see it but in the throat with a light you will see if the shaft is broken



HD01FXST010.gif
Click to expand...

How will I know if the shaft is broken? Which item number is the TPS shaft?
Thanks for the quick reply!!
 
Jack Klarich said:
http://www.ebay.com/bhp/harley-throttle-body
Start here, I dunno u can buy the parts or
http://www.boardtrackerharleyonline.com/
Here for free shipping and NO tax on NEW HD parts
8

27603-01 THROTTLE BODY ASSEMBLY, W/ IDLE SCREW 1 230.99 203.49
This is retail, Bordtracker I think will beat this price
Click to expand...


I just checked TPS shaft and it is good. throttle rotates fine and the shaft/butterfly is not broken. Any other thoughts on what the problem could be?

Thank you.
 
The engine vibrates alot more when idling. Vibration will reveal a fuel injector wire that is broken inside the insulation. When warmed up, the insulation is more flexible, making the problem worse. A wiggle test or, better yet, a good wiring check with a meter & wiggling could reveal a problem like that. Injector wiring is notorious for doing that.

Enjoy,
Rich P
 
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