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CRF250L Engine Control Details and Tech thread

Fuel & Air EFI Programmers Electrical Engine Fuel & Air Honda CRF250L

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82 replies to this topic
  • MentalGuru
8,854 posts
Location: Wisconsin
Garage View Garage

Posted January 30, 2013 - 01:55 PM


Well here goes....

The injection system on the CRFL is designed using automotive type technology. It is a basic open/closed loop speed density system.


Excellent information about the system and diagnostics are available at RamZ's incredible site :thumbsup: http://www.rickramsey.net/CRF250L.htm


Let me try to explain how the system operates so everyone can hopefully understand. Posted Image

Here's an abbreviation table taken directly from the Helm service manual, thanks to "Bob80". :thumbsup:

I'm used to using automotive abbreviations from when I was a tech so I added those to the list. Posted Image So keep that in mind...


MAP = Manifold Absolute Pressure Sensor(can also read barometric pressure)

TPS or TP sensor = throttle position sensor

CTS = Coolant Temperature Sensor

O2 = Oxygen Sensor

IAC = Idle Air Control valve/stepper motor

CKP = Crankshaft Position Sensor

IAT sensor = Intake Air Temperature sensor

EVAP = Evaporative Emmission system

AI/02 = Air Injection Oxygen system valve/sensor

PAIR = Pulse Secondary Air Injection

ECM/PCM = Engine/Powertrain Control Module

EEPROM = Electrically Erasable Programmable Read Only Memory

MIL = Malfunction Indicator Lamp

DLC = Data Link Connector

DTC = Diagnostic Trouble Code

SCS service connector = Service Check Short connector

VS sensor or VSS = Vehicle Speed sensor

A/F ratio = Air Fuel ratio

PGM-FI =Programmed Fuel Injection.

OBD is On Board Diagnostics. There are different versions like OBDI or OBDII.

Open loop is when the engine is running on base programing.

Closed loop is when the engine is monitoring the sensors and adjusting as needed to maintain the "desired" air/fuel ratio to achieve complete combustion.

Adaptive memory is the computers ability to adapt to and remember what is needed to achieve the desired air/fuel ratio in closed loop mode. It has the ability to add or subtract fuel as needed. There are two types of adaptive memory, long term and short term. Long term memory is stored memory about what was needed and short term memory is what is needed at that moment. The computer uses short term memory to establish it's long term memory.

The MAP sensor is used to read Barometric pressure at key on. This would be how the PCM checks altitude. It monitors engine vacuum which it used to determine engine load by comparing it to the TPS reading. It can also sense alititude change at WOT if programed to...

The TPS sensor tells the computor what position the throttle is in. It's as simple as that.

The CTS is just as simple, it monitors the coolant temperature for the PCM.

The O2 sensor monitors the oxygen level(air/fuel ratio) in the exhaust so the computer can adjust as need when in closed loop mode.

The CKP sensor identifies the crankshaft position, RPM and can be used to sense when the engine fires (or even misfires).

The ECT sensor provide the engine coolant temperature.

The IAC is a air bypass valve that is used to control the engine speed at idle. The throttle body allows a predetermined amount of air past the throttle blade and the IAC controls the extra air flow needed to reach the correct idle speed and prevent stalling. I'll add more details about this later since stalling it is a problem.

The IAT monitors the air temperature going into the engine. Cold air is denser and has more oxygen in it. It is used in combination with the other sensor values to help determine the correct air/fuel ratio.

The lack of the cam sensor and 1 wire narrow band O2 sensor shows me it is basically an early type automotive system. It uses a EEPROM controller.

EEPROM is electronically erasable programable read only memory type controller. This means can be reprogramed/flash programed.


This system doesn't do too much OBD so it is easier to trick it as needed. This also makes diagnoising and testing easier for the average backyard tech. Posted Image


The IAC is a stepper motor that allows extra air into the engine to control the idle speed. The throttle closes sightly further which decrease emissions on decel. When the RPM drops low enough the IAC takes over to control the idle speed. There is a minimum air flow specification that the throttle stop screw is adjustment determines. It is preset by the factory and painted so tampering can be determined(more about this later ). :smirk:

2013 models have different emission standards they need to meet. That is why the stock muffler contains a catalytic converter for example.

In open loop it monitors the TPS, MAP, CKS, IAT and the ECT sensors mainly. It uses these values to determine what base programing cells in the computer to use.

In closed loop it monitors the O2 sensor also, using it to provide the information the computer needs to achieve the desired air fuel/ratio results. The adjustments to fuel control are done by the short term and long term adaptive memory. The long term adaptive memory monitors the trends and adjustments the short term memory makes and then adjusts it's values so the short term memory value stays near the center of its adjustment range. The long term memory stores its memory so it's ready for the next time it goes into closed loop operation. The short and long term memory has the ability to add or remove the amount fuel the engine sees by adjusting fuel injector pulse width as needed.

I think closed loop operation has been increased for 2013. It probably handles hot idle and 0% to about 50% throttle openings. It won't go into closed loop until the O2 sensor reaches the proper temperature. There are some other perimeters involved also.

Cold operation and 50%+ throttle operation is probably done in open loop on base programing.

The computer has multiple memory cells it uses for closed and open loop operation. These cells store the base programing for open loop and the adjusted base programing for closed loop operation. There is also a limp in mode if a sensor the open loop needs to monitor fails. Sometimes limp in mode equals tennis shoe mode because of a lost crank sensor signal or a meltdown of some type.

Tennis shoe mode means your walking home. :)

Limp in mode means it will get you to home, but thats about it. Extended riding in limp-in mode could cause damage to the catalytic convertor in the stock muffler. :naughty:

Posted Image

Edited by TNTsXR, February 06, 2013 - 09:44 AM.


  • jlmiller

    TT Member

66 posts
Location: Iowa
Garage View Garage

Posted January 30, 2013 - 06:15 PM


Keep it coming...the big question is will the engine spend enough time in closed loop to adjust to after market exhaust.

  • SpudRider

    TT Silver Member

932 posts
Location: Idaho

Posted January 30, 2013 - 06:53 PM


Thanks for starting the new thread over here at Thumpertalk. :)

Spud :)

  • MentalGuru
8,854 posts
Location: Wisconsin
Garage View Garage

Posted January 31, 2013 - 01:59 AM


Keep it coming...the big question is will the engine spend enough time in closed loop to adjust to after market exhaust.



The closed loop memory cells update pretty quickly and there should be enough adaptive memory to add the extra fuel that is needed. :D


My concern would be about when the computer is in open loop. It is running on it base fuel curve which will probably be quite lean now. :shocked:


I would reccomend a fuel controller is added. They work well even on a stock bike. :smirk:


:cheers:

Edited by TNTsXLR, February 01, 2013 - 03:57 AM.


  • MentalGuru
8,854 posts
Location: Wisconsin
Garage View Garage

Posted January 31, 2013 - 03:30 AM


Note/Disclamer: Some of the following posts may dicuss modifications that are for offroad or closed competion use only. ;)

.
Remember like Sergent Schultz always said... "I know nothing, I see nothing, and I say nothing!" :lol:


:cheers:

Edited by TNTsXR, February 03, 2013 - 02:02 PM.


  • MentalGuru
8,854 posts
Location: Wisconsin
Garage View Garage

Posted January 31, 2013 - 10:09 AM


Are you questioning what happens where the EJK everyone is using adds fuel? One would assume the Honda controller knows nothing about the extra fuel being added by EJK....but...and this is my question....if we assume in closed loop control on A/F ratio (O2 sensor), and we have an EJK functioning and we are tricking the injector to give more fuel, the Honda controller, if it has appropriate range of authority, MIGHT command less fuel, EFFECTIVELY taking away the fuel the EJK is adding....or said differently, what's the possibility that the EJK is totally ineffective in closed loop operation?


In closed loop mode it can pull or add fuel as the controller sees fit. This isn't an issue because the A/F ratio it wants is 14.7 to 1 just like you would want. This is what will help maintain your fuel economy yet still perform as desired.

:cheers:

Edited by TNTsXLR, February 01, 2013 - 03:59 AM.


  • Ed@Ford@home

    TT Newbie

17 posts
Location: Michigan

Posted January 31, 2013 - 11:13 AM


In closed loop mode it can pull or add fuel as the controller sees fit. This isn't an issue because the A/F ratio it wants is 14.7 to 1 just like you would want. This is what will help maintain your fuel economy yet still perform as desired.

Full throttle is the area that would concern me.


Personally, I would think 14.7, although chemically correct, might be too lean even for closed loop...being a tad richer, like 14.3 might be better...especially considering there is so much ethanol gasoine around that would make chemically correct A/F something less than 14.7

  • MentalGuru
8,854 posts
Location: Wisconsin
Garage View Garage

Posted January 31, 2013 - 11:35 AM


Personally, I would think 14.7, although chemically correct, might be too lean even for closed loop...being a tad richer, like 14.3 might be better...especially considering there is so much ethanol gasoline around that would make chemically correct A/F something less than 14.7


The computer is programed for complete combustion and maximum volumetric efficiency in most memory cells.. If ethanol gasoline is used the O2 sensor reading would show the leaner condition. The computer can compensate for this in closed loop mode with the adaptive memory to reach it's desired O2 sensor reading.

The O2 sensor reads exhaust gasses to check for complete combustion. The computer uses this information to adjust the fuel output to achieve the desired O2 sensor reading.

I used 14.7 to 1 as an known example. When ethanol gasoline is used the actual A/F ratio will vary.

:cheers:

  • Ed@Ford@home

    TT Newbie

17 posts
Location: Michigan

Posted January 31, 2013 - 06:26 PM


The computer is programed for complete combustion and maximum volumetric efficiency in most memory cells.. If ethanol gasoline is used the O2 sensor reading would show the leaner condition. The computer can compensate for this in closed loop mode with the adaptive memory to reach it's desired O2 sensor reading.

The O2 sensor reads exhaust gasses to check for complete combustion. The computer uses this information to adjust the fuel output to achieve the desired O2 sensor reading.

I used 14.7 to 1 as an known example. When ethanol gasoline is used the actual A/F ratio will vary.

:cheers:


Everyone is entitled to opinions about mudslinging....well if it bothers people, just don't read what "mudslinger" says....EASY PEASY..issue done....I'm interested in EFI issues.

I just keep coming back to this closed loop/open loop thing. Just got reminded of the following...Best Dirt Bikes has suggested unplugging the O2 sensor. Obviously they were one of the first to put an EJK on the CRF, and make decent power...yeah yeah, there were folks that said they were "making up" dyno runs...so what...people bought their stuff, and the CRF ran well, better power, and happy customers. This still makes me think they HAD to force the engine into open loop by unplugging O2....then used EJK to add fuel ACROSS THE BOARD..everywhere..and make more power. Now...the thing that could make me a liar is this...throttle position goes beyond say 50%...ECU says open loop....ECU does not override closed loop fuel....bike makes more power....so i'm guessing there are multiple ways to get into "open loop/EJK operation" areas....maybe I'm thinking out loud...whatever

  • MentalGuru
8,854 posts
Location: Wisconsin
Garage View Garage

Posted January 31, 2013 - 07:45 PM


EJK Jet Kit, FMF controller and JD jetting controller Operating Principles Tuning and Adjustments

EJK = Electronic Jet Kit. (They give a great military discount if you served)

JD Jetting is the same controller.

The FMF controller is the same also. It is used withe Best Dual Sport bike's Stage 1 kit.

FC = Fuel controller

These are an aftermarket fuel controllers ("a magic wands" in a way :) )


Excellent information about installation tuning and diagnostics is available at RamZ's incredible site :thumbsup: http://www.rickramsey.net/CRF250L.htm


Here's are some links so you know what products is being discussing. http://www.electroni...tnumber=9110028 http://www.jdjetting...167&cat=&page=1

This tuning link from EKG that will help understand it's operation and this post. http://www.electroni....com/tuning.asp

Here is a link from JD Jetting that may also help. http://jdjetting.com/html/faq.htm#demo

Lets not forget a link to BDSB's site http://bestdualsport...3-honda-crf250l


The EJK's version 3 allows stock settings to be used and/or to add fuel as needed only.

The EJK's new version 3.5, FMF controller(from what I found) and the JD fuel controller allows stock settings to be used and/or add or subtract fuel as needed also. This will increase the tuning abilitys as more modifications are done.


Many owners have this product in use now but aren't sure how it functions, should be set, tuned and adjusted.

Both can be used in both open and closed loop modes or just open loop mode.


The best way to run the FC IMO would be with the O2 sensor plugged in for operation in open and closed loop modes.


Here are some basics I have figured out I believe... :rolleyes:

It changes the injector pulse width to make the fuel curve richer or leaner if needed.


Lets look at open loop operation first.

The suggested way to keep it in open loop by Best Dual Sport Bikes to leave the O2 sensor disconnected. This should work fine.

Setting when it switches on at idle or above idle is an area I'm not sure of. Idle would be where i would start the setting at and the ending point will be when it switches to the second stage of the FC.
It will probably need some fuel added (but don't get carried away since it should be set so closed loop operation works correctly if you use it). This will need to be set for about 14.6 to 1 A/F ratio unless you have ethanol gasoline then a richer A/F ratio may be needed.

At about 50% throttle to about 80% throttle the FC should switch to its 2nd adjustment range. This 2nd stage engagement should be tuned to switch on about when the engine controller goes in open loop mode normally. It should be tuned to add fuel at this point to reach about a 13 to 1 A/F ratio. The FC is tuned to add extra fuel to the base fuel curve in this range.

At 80% to WOT the FC goes into it's 3rd adjustment range. You will be adding fuel adding extra fuel again to the base fuel curve This is where the engine needs its richest at about a 12 to 1 A/F ratio. Since the base program changes for engine temp, altitude and other parameters these adjustments will rarely need to be changed after they are fine tuned for your bike.

The open load setting may vary slightly at high altitudes or when it is very cold or hot out so you might have a few settings you like...


The FC's 1st stage can be set-up for operation in both open loop and closed loop modes also.

Why you ask? The bike idles and runs nice on th road and gets great fuel economy stock right. You want more power thou. You can achieve them both by doing it, thats why....

First you would adjust it just like described for open loop mode. The key is to set the open loop mode to about a 14 to 1 A/F ratio. Plug the O2 sensor back in and you should be done.
The engine controller will make adjustments to reach it's desired O2 sensor just like when it was stock, except it's reading slightly rich insteady of lean. The computers adaptive memory can and will adjust it as needed. It doesn't know if you opened up the air box, put a pipe on it and the fuel controller. It just knows the O2 sensor needs to read correctly and makes the adjustments.

If you set the first stage too rich the computer might set an O2 sensor rich code because it has to adjust too much. This is why you want to have the mixture set quite close in open loop mode.

You might want to unplug the O2 sensor for offroad use and plug it back for on road use possibly also. Remember it's your bike do what ever is best for you.


EJK's new version 3.5 allows stock settings to be used and/or add or subtract fuel as needed also. Just like the FMF controller and JD Jetting FC unit.Posted Image

These systems is ideal because once you have increased the air flow and fuel flow need for your built engine the injector can be swapped to a larger one or the fuel pressure increased. Posted Image

This will bring the adjustments back to correct range so the base program with the FC will work correctly for built engine. :D

You know what I mean. :smirk: Something like a 280cc big bore with a ported head, bored throttle body and a full stainless exhaust system putting out 30 hp with ease... :crazy:


This was just a quick fuel controller tuning guide. You will need fine tune your bike some due to your modifications, climate and/or altitude.


The best way to tune and adjust this system is with a wide band O2 sensor to accurately see and adjust the A/F ratio. Some units can data log also. Hand held ones are available if you want to adjust other bikes or cars also.


Let's here how you are using yours, how its hooked up and what adjustments are working best. Including your mod list will help too.


I started on new post for further discussion at this link. http://www.thumperta...el-controllers/


:cheers:

Note: I am not affiliated in any way with these products.

Edited by TNTsXR, February 06, 2013 - 04:31 PM.


  • Bob80

    TT Bronze Member

259 posts
Location: Other

Posted February 01, 2013 - 10:51 AM


Wow...Great job on all of the above :thumbsup: It really "paints a better picture" for us n00bs, to understand how these systems/controllers work.

It's great info. to read and re-read, and we can post/ask questions as need be..All the neccessary and intresting links are provided also.

Sorry for this "meaningless" post....but it's just my way of "giving credit where credit is due"

Thank you and keep up the great work!!

  • MentalGuru
8,854 posts
Location: Wisconsin
Garage View Garage

Posted February 01, 2013 - 01:07 PM


Stalling issues?? This might help.


Look for the minimum air flow adjuster screw.


New picture needed... I want nothing to do with him


The screw pointed at in the picture is the minimum air flow screw. A baseline of sorts. The IAC valve is what controls the extra airflow need to reach the correct idle speed.

It is set below idle speed to reduce emissions and conserve fuel on decel. As the engine rpm gets close to the idle rpm the IAC adds air as needed.

The reason the adjuster has white paint on it is because adjusting it is an federal emissions violation and may cause grief at the dealer too.

(It looks and flows the same as some partially dried up Testor model paint). ;)

It is set by the factory to allow a specfic amount air flow.

Adjusting the screw slightly should help solve the stalling problem, but the TPS sensor should be adjusted and reset.

Valvoline makes some brake cleaner that will take the paint right off. Just don't get it on any other paint.

Posted Image

On a side note: I was able to remove the factory side panel number plate paint in about one minute with this. It even removes factory engine paint.


If you are having a stall out problem start by cleaning and inspecting the throttle body.

Remove then clean the IAC and the chamber the valve runs in. This is to make sure the valve isn't sticking and to allow more air to flow.
This probably isn't the issue since the bikes have low mileage. You'll have to see how much residue there is to know for sure.

Also clean any residue off of the throttle plate edges and bore. This will increase the airflow when the throttle is fully closed.

I would probe the TPS sensor before making any adjustments so it can be readjusted to that value if needed.


The TPS and IAC valve will need to reset and the computers adaptive memory should be erased.


See RamZ's CRF250L site for details about it and tons of other great info.. http://www.rickramsey.net/CRF250L.htm


Note: Adjusting that screw is concidered a no-no by the feds and some dealers.

I'm not telling thou... :smirk:

:cheers:

Edited by TNTsXR, February 09, 2013 - 02:33 AM.


  • MentalGuru
8,854 posts
Location: Wisconsin
Garage View Garage

Posted February 03, 2013 - 05:01 AM


Here is some information about the sensors, the different codes and what the readings mean. This should help to understand the codes and diagnostic procedures.

The sensors use a 5 volt circuit just like automotive sensor do. The principles of operation are the same also.

A high impedence digital volt/ohm meter should be used when testing is done.

Note: Do not use a analog meter or low impedence meter for testing. System damage may result..

MAP sensor = Manifold Absolute Pressure Sensor

Operating range = .35 to 3.75 volts
Code information = DTC 1 for out of range voltage reading. MAP sensor circuit low voltage = less than 0.195 volts is DTC 1-1. MAP sensor circuit high voltage =more than 3.848 V is DTC 1-2
Limp in mode = Runs OK. Uses 525 mmHg/700 hPa as the MAP sensors default value when a code is set.
Basic Operation = Low vacuum is the high voltage reading. High vacuum is a low voltage reading. Increasing the vacuum should cause the voltage decrease smoothly.

ECT sensor = Engine Coolant Temp. sensor

Operating range = .08 to 4.9 volts
Code information = DTC code 7 for out of range voltage reading. ECT sensor circuit low voltage = less than 0.078 volts is DTC 7-1. ECT sensor circuit high voltage more then 4.922 V is DTC 7-2.
Limp in mode = Hard starting at a low temperature uses 80°C/176°F as the ECT sensors default value when a code is set. Also turns on the engine cooling fan on.
Basic Operation = ??? is the high voltage reading. ??? is a low voltage reading. (need more information on which way the sensor is biased)

TPS circuit = Throttle Position Sensor or TP sensor

Operating range = .23 to 3.8 volts
Code information = DTC code 8 for out of range voltage reading. TPS sensor circuit low voltage = less than 0.215 volts is DTC 8-1. TPS sensor circuit high voltage more then 4.922 V is DTC 8-2.
Limp in mode = Poor engine acceleration. 0 degrees is the default value when a code is set.
Basic Operation = measures how many degrees the throttle plate is opened. ??? is the high voltage reading. ??? is a low voltage reading. (need more information on which way the sensor is biased)

IAT sensor = Intake Air Temp.sensor

Operating range = .08 to 4.9 volts
Code information = DTC code 9 for out of range voltage reading. IAT sensor circuit low voltage = less than 0.078 volts is DTC 9-1. IAT sensor circuit high voltage more then 4.922 V is DTC 9-2.
Limp in mode = Run OK. 35°C/95°F is the default value when a code is set.
Basic Operation = ??? is the high voltage reading. ??? is a low voltage reading. (need more information on which way the sensor is biased)

VSS or VS sensor = Vehicle Speed sensor

Code information = DTC code 11-1 for VS sensor malfunction.
Limp in mode = Run normal. Speedometer inop.
Basic Operation = Monitor vehicle speed.

Fuel injector circuit

Code information = DTC code 12.1 for Fuel injector circuit malfunction
Limp in mode = Tennis shoe mode. Engine not start.
Basic Operation = Control's fuel injector.

O2 sensor = Oxygen Sensor

Operating range = .0 to 1 volt
Code information = DTC code 21-1
Limp in mode = Runs OK. Operates in open loop mode.
Basic Operation = Once heated by the exhaust it outputs voltage from the sensor about how much 02 present in the exhaust. (used by the ECM for moitoring combustion efficiency)

IACV circuit = Idle Air Control valve/stepper motor

Code information = DTC code 29.1 for IACV or IAC circuit malfunction
Limp in mode = Tennis shoe mode. Engine not start.
Basic Operation = Control's fuel injector.

ECM EEPROM = Engine Control Module Electronically Erasable Programable Read Only Memory

Code information = DTC code 33.2 for ECM EEPROM malfunction
Limp in mode = Runs normally
Basic Operation = Engine controller memory storage component.

BAS = Bank angle sensor

Code information = DTC code 54 for out of range voltage reading. Bank angle sensor circuit low voltage IS less than 0.35 V is DTC 54.1 Bank angle sensor circuit high voltage is more than 4.5 V is DTC 54.2
Limp in mode = Engine operates normally. Bank angle sensor does not operate. The engine keeps running when the vehicle falls.
Basic Operation = It is designed for safety where in if the bike is laid down or in a roll over, the fuel pump is shut down so as not to potentially cause a fire.


Still in progress :smirk:

Some details are still need to fill in the blanks. :prof:

:cheers:

Edited by TNTsXLR, February 03, 2013 - 06:33 AM.


  • MentalGuru
8,854 posts
Location: Wisconsin
Garage View Garage

Posted February 03, 2013 - 08:51 AM


Here's a list of the specialty tools that "Bob80" sent me. :thumbsup:

SCS service connector-
070PZ-ZY30100

Test probe, 2 pack-07ZAJ-RDJA110

HDS pocket tester- TDS3557-0112-01 (USA only) -The HDS pocket tester can readout the DTC, freeze data, current data and other ECM condition.........But, the $$$ is crazy!!


See RamZ tuning page at his site for details about the above tools and there use. :D http://www.rickramsey.net/CRF250L.htm

:cheers:

Edited by TNTsXLR, February 03, 2013 - 08:52 AM.


  • itrack

    TT Member

27 posts
Location: Texas

Posted February 04, 2013 - 04:14 PM


Stalling issues?? This might help.

Posted Image
Copyright - Lost Rider


The screw is a picture is the minimum air flow screw. A baseline of sorts. The IAC valve is what controls the extra airflow need to reach the correct idle speed.

It is set below idle speed to reduce emissions and conserve fuel on decel. As the engine rpm gets close to the idle rpm the IAC adds air as needed.

The reason the adjuster has white paint on it is because adjusting it is an federal emissions violation and may cause grief at the dealer too.

(It looks and flows the same as some partially dried up Testor model paint). ;)

It is set by the factory to allow a specfic amount air flow.

Adjusting the screw slightly should help solve the stalling problem, but the TPS sensor should be adjusted and reset.

Valvoline makes some brake cleaner that will take the paint right off. Just don't get it on any other paint.

Posted Image

On a side note: I was able to remove the factory side panel number plate paint in about one minute with this. It even removes factory engine paint.


If you are having a stall out problem start by cleaning and inspecting the throttle body.

Remove then clean the IAC and the chamber the valve runs in. This is to make sure the valve isn't sticking and to allow more air to flow.
This probably isn't the issue since the bikes have low mileage. You'll have to see how much residue there is to know for sure.

Also clean any residue off of the throttle plate edges and bore. This will increase the airflow when the throttle is fully closed.

I would probe the TPS sensor before making any adjustments so it can be readjusted to that value if needed.


The TPS and IAC valve will need to reset and the computers adaptive memory should be erased.

See RamZ's CRF250L site for details about it and tons of other great info.. http://www.rickramsey.net/CRF250L.htm


Note: Adjusting that screw is concidered a no-no by the feds and some dealers.

I'm not telling thou... :smirk:

:cheers:

Stalling issues?? This might help.

Posted Image
Copyright - Lost Rider


The screw is a picture is the minimum air flow screw. A baseline of sorts. The IAC valve is what controls the extra airflow need to reach the correct idle speed.

It is set below idle speed to reduce emissions and conserve fuel on decel. As the engine rpm gets close to the idle rpm the IAC adds air as needed.

The reason the adjuster has white paint on it is because adjusting it is an federal emissions violation and may cause grief at the dealer too.

(It looks and flows the same as some partially dried up Testor model paint). ;)

It is set by the factory to allow a specfic amount air flow.

Adjusting the screw slightly should help solve the stalling problem, but the TPS sensor should be adjusted and reset.

Valvoline makes some brake cleaner that will take the paint right off. Just don't get it on any other paint.

Posted Image

On a side note: I was able to remove the factory side panel number plate paint in about one minute with this. It even removes factory engine paint.


If you are having a stall out problem start by cleaning and inspecting the throttle body.

Remove then clean the IAC and the chamber the valve runs in. This is to make sure the valve isn't sticking and to allow more air to flow.
This probably isn't the issue since the bikes have low mileage. You'll have to see how much residue there is to know for sure.

Also clean any residue off of the throttle plate edges and bore. This will increase the airflow when the throttle is fully closed.

I would probe the TPS sensor before making any adjustments so it can be readjusted to that value if needed.


The TPS and IAC valve will need to reset and the computers adaptive memory should be erased.

See RamZ's CRF250L site for details about it and tons of other great info.. http://www.rickramsey.net/CRF250L.htm


Note: Adjusting that screw is concidered a no-no by the feds and some dealers.

I'm not telling thou... :smirk:

:cheers:


Would you loosen or tighten to relieve the stalling? Offroad riding only question :)

  • MentalGuru
8,854 posts
Location: Wisconsin
Garage View Garage

Posted February 04, 2013 - 04:21 PM


Tightening the screw will increase the air flow and raise the base idle speed. Just adjust it slightly and see how it is, it shouldn't take much adjustment.


Since this is for offroad use I would remove the screw and use some brake cleaner to carefully remove the paint on the throttle body. Then clean the paint off of the screw and nut.

This way you can adjust it without the paint getting into the treads on the nut or throttle body.

Once you have the adjustment set to your liking do the following.

Mark the screws and nuts location so it can be inspected to make sure vibration hasn't caused it to come loose.

Take some Testor model paint and put it in a small container. Let the paint start to thicken, stir it to until the paint is thick and apply it like pictured so you can make sure your adjustment hasn't changed.


I like to use paint on bolts that are problems or ones I want to be able to check visually at a later date.

.
:cheers:

Edited by TNTsXR, February 04, 2013 - 06:38 PM.


  • DirtyBlackIrish

    TT Newbie

15 posts
Location: Washington

Posted February 05, 2013 - 08:49 AM


Hello the camp!

  • Bob80

    TT Bronze Member

259 posts
Location: Other

Posted February 05, 2013 - 08:58 AM


Glad to see ya made er DBI !!!, see ya in a couple hr's when ya get caught up! :thumbsup:

  • MentalGuru
8,854 posts
Location: Wisconsin
Garage View Garage

Posted February 05, 2013 - 08:59 AM


Hello the camp!



I thought you might be dropping in from the darkside. :devil:

Welcome aboard. :thumbsup:


You just found where I'll be at from now on... :smirk:

:cheers:

Edited by TNTsXR, February 15, 2013 - 04:35 AM.


  • Krono

    TT Member

93 posts
Location: Switzerland

Posted February 05, 2013 - 11:20 AM


Tightening the screw will increase the air flow and raise the base idle speed. Just adjust it slightly and see how it is, it shouldn't take much adjustment.


Since this is for offroad use I would remove the screw and use some brake cleaner to carefully remove the paint on the throttle body. Then clean the paint off of the screw and nut.

This way you can adjust it without the paint getting into the treads on the nut or throttle body.

Once you have the adjustment set to your liking do the following.

Mark the screws and nuts location so it can be inspected to make sure vibration hasn't caused it to come loose.

Take some Testor model paint and put it in a small container. Let the paint start to thicken, stir it to until the paint is thick and apply it like pictured so you can make sure your adjustment hasn't changed.


I like to use paint on bolts that are problems or ones I want to be able to check visually at a later date.

.
:cheers:


I did it :thumbsup:

Tried the stop screw setting a few days ago, only a 1/8 of a turn and this appears to have solved my stalling issues
That's the story short.

The long was as follow :
First to give you the background, my bike is equipped w/ FMF Q4 corcked for noise, Megabomb header, EJK, generously drilled air-cover
At this time, PAIR hose was disconneted and tapped, O2 sensor was disconnected too, thus following BDSB suggestions found on their CRFL web-page.
All was ok, despite bad fuel mileage (43mpg). Always running hardcore can explain ...
Also have the 13/42 sprocket combo, but the DRDspeedo makes the odometer reading right.

At 6500km (must be 4000miles) I went into valves setting and oil change, not only because i was bored. Suspected the dealer to not even had a look ito there at 600miles initial service.
That was with reason, because valves play were 0.075mm off everywhere... still best served by itself, doh.

Obviously, the battery was disconnected for about 1 day when I was at this, and this should have led to an ECU reset, which can explain the low idle/stalling issues experienced after.

At first, setted the EJK initial range to 0 in order to lean the mixture, but that didnt worked so well.
Then replugged the PAIR and O2 sensor to have it "as close at stock" i could do. And this worked for the low-idle issue.

But still those stallings when nearly to a stop on engine break. That did occured here and there beforehand to say the truth
Tried then STP fuel additive to cleanfuel circuit and injector, with a little success.

As i was in there ... last chance before an IACV+TP reset ... just broke the white paint giving a 1/8 of a turn to the throttle.
Hopefully the stalling issue issue resolved at this time. 1 week stalling free, and mpg raised noticiably.

All this can be irrelvant to another, since i corcked the muffler, because even if it's advertised as "Q"uiet, it sounded way too loud between buildings in city.

Here's my spark arrestor modified as a dBkiller

Posted Image

L

Edited by Krono, February 05, 2013 - 11:28 AM.






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