crf 450 2014 won't idle + hesitation at 1/3 throttle

munch
Posts
48
Joined
5/4/2014
Location
GB
BACK STORY:
I purchased the bike as "only runs with high idle out".
I removed the throttle body, cleaned injector, TPS was set at .47 I reset to .48 (tried .50, .55) still wouldn't idle, at this point it was running the same as when I purchased it.

I was told to try a TPS setting of 0.62, I did so and finally the bike would idle however at this point it ran quite badly, I guess it was from over fueling? It would pop and just not run well at all.

Once I had it idling I then battled the bad running, I did A LOT of messing about before realising the poor running was because of the 0.62 TPS setting.

I have currently gone through:
Replaced complete throttle body (inc all sensors + injector)
Replaced fuel pump
Cleaned all earth points
Changed spark plug
Cleaned the wiring harness inc all plugs
Checked ECT sensor

Current:
TPS set to 0.5.
Bike will idle for 15 seconds when cold (I guess bike is in enrichment mode?)
Once warm it will NOT idle, if it ever does idle it's for 1 second maximum just enough to grab the throttle
When on the stand and revved it will rev out from 0 - 100 absolutely fine
When riding if you are aggressive for example riding in straight lines going from 0% - 100% throttle and not cruising. Once you try to hold the throttle or higher the rpms at a much slower rate you will get a very aggressive juddering / hesitation feeling around 1/3 throttle, once it passes it (aggressively turn throttle) then it's fine.

I am hoping I just need to play with the TPS a lot more and get it to where it needs to be however others opinions are always appreciated. I can get access to a 2013 ECU and coil if people suspect that could be the problem however it runs flawless at high RPM which is usually where the coil breaks down?

Oh also the bike has full yoshi twin pipe, does this mean the TPS should be set a little higher or do you only touch mapping when running an after market pipe? Thanks!
1
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Paul_Pitzonka
Posts
693
Joined
5/1/2018
Location
Grand Terrace, CA US
2/28/2019 5:03pm Edited Date/Time 2/28/2019 5:09pm
Just a guess have you taken a look at the Air Charge Temp sensor? Also as stated in your previous post the last crf I did the TPS ended up being set to .52... I have found the .58-.62 to be a great baseline but doesn’t always hold true... A faulty air charge temp sensor could make the bike run rich and also explain some of your fuel wash I believe...
1
speed_racer
Posts
353
Joined
7/29/2016
Location
Aiea, HI US
2/28/2019 5:58pm
Sure sound like a dirty fuel pump screen. Was the screen dirty?
kb228
Posts
6154
Joined
1/31/2018
Location
Mansfield, OH US
3/1/2019 3:53am
Air temp sensor and a coolant temp sensor can be a problem. A faulty ecu can cause issues too. Seems like you already replaced the common suspects. But you want your tps voltage at .6-.62. Thats the best setting period. It sounds like your mapping is super rich. Popping is excess fuel going out your exhaust valves and igniting.
dirtmike86
Posts
1212
Joined
10/28/2015
Location
Grand Terrace, CA US
3/1/2019 5:41am
Have you checked compression or done a leak down? Had a kx450f that did the same thing. Hairline crack parallel with wrist pin on the piston.

The Shop

5/21/2019 11:31am
munch wrote:
[b]BACK STORY:[/b] I purchased the bike as "only runs with high idle out". I removed the throttle body, cleaned injector, TPS was set at .47 I...
BACK STORY:
I purchased the bike as "only runs with high idle out".
I removed the throttle body, cleaned injector, TPS was set at .47 I reset to .48 (tried .50, .55) still wouldn't idle, at this point it was running the same as when I purchased it.

I was told to try a TPS setting of 0.62, I did so and finally the bike would idle however at this point it ran quite badly, I guess it was from over fueling? It would pop and just not run well at all.

Once I had it idling I then battled the bad running, I did A LOT of messing about before realising the poor running was because of the 0.62 TPS setting.

I have currently gone through:
Replaced complete throttle body (inc all sensors + injector)
Replaced fuel pump
Cleaned all earth points
Changed spark plug
Cleaned the wiring harness inc all plugs
Checked ECT sensor

Current:
TPS set to 0.5.
Bike will idle for 15 seconds when cold (I guess bike is in enrichment mode?)
Once warm it will NOT idle, if it ever does idle it's for 1 second maximum just enough to grab the throttle
When on the stand and revved it will rev out from 0 - 100 absolutely fine
When riding if you are aggressive for example riding in straight lines going from 0% - 100% throttle and not cruising. Once you try to hold the throttle or higher the rpms at a much slower rate you will get a very aggressive juddering / hesitation feeling around 1/3 throttle, once it passes it (aggressively turn throttle) then it's fine.

I am hoping I just need to play with the TPS a lot more and get it to where it needs to be however others opinions are always appreciated. I can get access to a 2013 ECU and coil if people suspect that could be the problem however it runs flawless at high RPM which is usually where the coil breaks down?

Oh also the bike has full yoshi twin pipe, does this mean the TPS should be set a little higher or do you only touch mapping when running an after market pipe? Thanks!
Hi munch, did you ever find out what was wrong with your 2013 Ktm 450 sxf by bypassing the relay I got the same problem and it’s doing me in big time


Many thanks
Steve
munch
Posts
48
Joined
5/4/2014
Location
GB
5/21/2019 11:46am
munch wrote:
[b]BACK STORY:[/b] I purchased the bike as "only runs with high idle out". I removed the throttle body, cleaned injector, TPS was set at .47 I...
BACK STORY:
I purchased the bike as "only runs with high idle out".
I removed the throttle body, cleaned injector, TPS was set at .47 I reset to .48 (tried .50, .55) still wouldn't idle, at this point it was running the same as when I purchased it.

I was told to try a TPS setting of 0.62, I did so and finally the bike would idle however at this point it ran quite badly, I guess it was from over fueling? It would pop and just not run well at all.

Once I had it idling I then battled the bad running, I did A LOT of messing about before realising the poor running was because of the 0.62 TPS setting.

I have currently gone through:
Replaced complete throttle body (inc all sensors + injector)
Replaced fuel pump
Cleaned all earth points
Changed spark plug
Cleaned the wiring harness inc all plugs
Checked ECT sensor

Current:
TPS set to 0.5.
Bike will idle for 15 seconds when cold (I guess bike is in enrichment mode?)
Once warm it will NOT idle, if it ever does idle it's for 1 second maximum just enough to grab the throttle
When on the stand and revved it will rev out from 0 - 100 absolutely fine
When riding if you are aggressive for example riding in straight lines going from 0% - 100% throttle and not cruising. Once you try to hold the throttle or higher the rpms at a much slower rate you will get a very aggressive juddering / hesitation feeling around 1/3 throttle, once it passes it (aggressively turn throttle) then it's fine.

I am hoping I just need to play with the TPS a lot more and get it to where it needs to be however others opinions are always appreciated. I can get access to a 2013 ECU and coil if people suspect that could be the problem however it runs flawless at high RPM which is usually where the coil breaks down?

Oh also the bike has full yoshi twin pipe, does this mean the TPS should be set a little higher or do you only touch mapping when running an after market pipe? Thanks!
Hi munch, did you ever find out what was wrong with your 2013 Ktm 450 sxf by bypassing the relay I got the same problem and...
Hi munch, did you ever find out what was wrong with your 2013 Ktm 450 sxf by bypassing the relay I got the same problem and it’s doing me in big time


Many thanks
Steve
Hi Steve, I don't remember all of the gritty details but I know the solution was replacing the regulator and the CDI. I purchased the regulator first thinking it would be that however it didn't fix it and the issue continued so I purchased a CDI but putting the new CDI on didn't fix it either! What I discovered is I had to fit the new CDI and regulator at the same time for the issue to be fixed. I'm wondering if the regulator ends up fried by the bad CDI and that's why I needed both.

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