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Honda CRF250L - Tuning EJK
June 12, 2014 version

 Introduction 

 Modifications 

 Big Bore 

 Maintenance 

 Tuning EJK 

 Tuning AFR+ 

 Head-to-Head 

Rick's Home Page

Click pictures to supersize.

Fuel injection controller

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I bought the EJK (Electronic Jet Kit). The initial installation is on my CRF250L which has been modified as described on my modifications page.  Initially, I had no engine, intake, or exhaust mods, so my results were relevant to most readers who have stock CRFLs. Over time, I modified the intake, exhaust, and engine (big bore kit), so results apply as indicated.

        In May 2014, I installed the Dobeck AFR+ kit - see Honda CRF250L - Tuning AFR+

The EJK is manufactured by Dobeck Performance.
  EJK - Electronic Jet Kit  Look in OFF-ROAD, DualSport.

You might be able to install the EJK without removing the fuel tank, if you had small hands and can work on electrical connectors without being able to see them. I can't, so I took the easy way out and raised the fuel tank to allow unimpeded view and access. See Removing the fuel tank for hints on raising the fuel tank.

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<--- Looking down on the top of the injector connector, the gray plastic piece in the middle with two wires entering at the top.

The conector top removed. --->

Click to supersize.

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<--- The EJK connectors now connected in-line. The EJK harness is wrapped with gray tape to keep all the wires together and away from the engine or being pinched under the fuel tank when it is installed.

A view of the harness routing. --->

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I did not mount the ground wire on the battery negative terminal. Instead, I mounted it on the grounding point on the right side of the frame, near the radiator overflow tank. You can see all the green ground wires mounted under the bolt head. One more fits fine.
BTW, do this first, before starting to work on the connectors, as the instructions note.

The EJK signal wires and ground wire are shown wrapped with gray tape, running along the steering head/frame up to the instrument panel.

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I decided I wanted to see the EJK lights while riding and to be able to adjust the settings while on a ride (NOT actually while moving), so I made a mount for the EJK so it sits next to the instrument panel, easily reached and readable.

I spent some time reading up on the EJK. There are six numbers you can change that determine where in the power band and to what extent jetting changes are made. These are well-explained in the paperwork that comes with the EJK and on their web site. The numbers that are preset in the EJK are 3 3 6 5 4 4.5 which I verified before the first ride.

The EJK is designed to add fuel to the Honda ECU-calculated injector pulse, never to reduce fuel. The EJK depends on the Honda ECU to calculate pulse width based on elevation, temperature, and several other factors. The presumption is that Honda has jetted lean for EPA regulations and to get more power, you have to add more fuel. If you open up the airbox and/or add a free-flowing exhaust, you'll also need more fuel.

On the initial 51 mile check-ride, I noticed that the CRFL now pulls like my WR250R in the mid range and top end. It was like riding a different bike! The low end is also stronger, but not as much as the WRR. I am really impressed with the EJK. I anticipate that I'll be making a few changes to the base numbers and have high hopes that the low end will come around. AND, there's still the header and muffler coming soon to add even more performance.
 

Update: I rode my CRFL for about a month with the EJK and stock exhaust and the bike performed very well. I did not change any of the EJK numbers.

In mid-November 2012, I installed the FMF Q4 muffler and MegaBomb header. I made no adjustments to the EJK numbers and the engine ran fine, producing more power with very crisp response. The low end cleaned up nicely and the CRFL pulls great from the bottom now. Unfortunately, the FMF muffler is too loud for my use, and I have reverted to the stock muffler. I will soon be installing a 283cc big bore kit and will report on the EJK performance as I do further testing.
 

Fuel injection controller - $225, free shipping.  EJK - Electronic Jet Kit  Look in OFF-ROAD, DualSport.
Also click the "VIEW DISCOUNTS" button on the home page.


 

 

Mileage

The tables show miles ridden and gas used to give MPG. Time and MPH are shown sometimes. Gearing, FI settings, and mods which directly affect engine performance and thus MPG are also shown.

This table is for the stock 250cc engine, plus mods as noted.

Date
 
Miles
 
Gas
 
MPG
 
Time
 
MPH
 
Front
/rear
FI
settings
Exhaust
 
Where
 
9/14/12 81.2 1.22 67     13/42 - Stock Herring, Ark Hills
9/16/12 62.5 1.00 63 2:54 21.5 13/42 - Stock Bonanza
10/7/12 82.2 1.19 69     13/42 - Stock Mt Taylor, Longs Gul
10/20/12 86.8 1.31 66 3:19 26.2 13/43 - Stock Summitville, Aspen Ridge
10/21/12 51.4 .78 66 1:43 29.9 13/43 EJK def Stock Herring
11/1/12 83.3 1.68 50 3:40 22.7 13/43 EJK def Stock Longs Gul, North Fork
11/16/12 54.9 1.00 55 2:03 26.8 13/43 EJK def FMFQ4/MB Ute Tr, Longs Gul
1/22/13 72.3 1.56 46 3:31 20.6 13/43 EJK def NoCat, 2Tips FR173, Ute Tr, Gulches, Garden Park

EJK def = EJK default 3 3 6 5 4 4.5

 

This table is for the modified 283cc engine, plus mods as noted.

Note: The EJK is still installed with the original numbers that were in it when I installed it. These numbers were supposed to work with the 283 kit and the stock muffler. My muffler has been de-catted, so it runs just a little freer than the stock muffler. I'll be attentive to the need for adjusting the EJK and report changes here and on the Big Bore page. So far, the EJK 'jetting' seems spot on.

Date
 
Miles
 
Gas
 
MPG
 
Time
 
MPH
 
Front
/rear
FI
settings
Exhaust
 
Where
 
3/7/13 58.9 .94 63 2:01 29.2 13/43 EJK def NoCat River Rd
3/14/13 104.7 1.64 64 3:54 26.8 13/43 EJK def NoCat River Rd, Coaldale
4/2/13 60.3 .95 63 2:01 29.9 13/43 EJK def NoCat Ute Tr, Turret, S Site
5/20/13 79.3 1.48 54 3:33 22.3 13/43 EJK def NoCat, BB tip SLV east
6/9/13 87.2 1.32 66 3:13 27.1 13/43 EJK def NoCat, BB tip Sargents
7/9/13 86.4 1.27 68 2:47 31.0 13/43 EJK def NoCat, BB tip Herring, FR182

EJK def = EJK default 3 3 6 5 4 4.5

 

Performance Parts

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Look what showed up on my front porch today (Mon, 10/22/2012).

FMF Q4 muffler - about $360  Best Dual Sport Bikes.
FMF MegaBomb header with free ceramic coating - about $275  Best Dual Sport Bikes.
See also: CRF250L Stage I performance kit - FMF Q4 muffler and Mega Bomb header, FI programmer, front sprocket.

 

PGM-FI

This reference section will always be at the end of the Tuning page.

Information is presented here from Chapter 4 of the Honda CRF250L Service Manual which shows information about the PGM-FI system (Programmed Fuel Injection).
Chapter 4 Sections include:
PGM-FI System Location, Diagram, and Troubleshooting
DTC Index and Troubleshooting
Sensor Unit Power Line Inspection
MIL Circuit Troubleshooting
Sensor Unit
ECT, O2, and Bank Angle sensors
ECM

Chapter 4 describes how to read out and clear DTCs and how to reset the TP sensor. I show some selected information from the chapter to give you an idea of how to troubleshoot, but you should refer to the Service Manual for a complete discussion.

Other information I show here is taken from the "Fuel Injection System for Small Engines" write-up on the "Technology Close-up" web page where Honda describes PGM-FI as an emerging technology and standard for fuel injection on small-displacement engines (up to 250cc).

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I am also using information found in the "PGM-FI Pinout Box Troubleshooting Manual" which discusses some of the same information found in Chapter 4 of the CRF250L Service Manual.

Here is an important list of abbreviations that is used throughout the literature I am referencing.

CKP sensor
DLC
DTC
ECM
ECT sensor
EEPROM
EVAP
IACV
IAT sensor
MAP sensor
MIL
O2 sensor
PAIR
PGM-FI
SCS connector
TP sensor
VS sensor
Crankshaft Position sensor
Data Link Connector
Diagnostic Trouble Code
Engine Control Module
Engine Coolant Temperature sensor
Electrically Erasable Programmable Read Only Memory
Evaporative Emission
Idle Air Control Valve
Intake Air Temperature sensor
Manifold Absolute Pressure sensor
Malfunction Indicator Lamp (found on speedometer display)
Oxygen sensor
Pulse Secondary Air Injection
Programmed Fuel Injection
Service Check Short connector
Throttle Position sensor
Vehicle Speed sensor

 

SELF-DIAGNOSIS SYSTEM

The PGM-FI system is equipped with a self-diagnostic system. When any abnormality occurs in the system, the ECM turns on the MIL and stores a DTC in its erasable memory.

FAIL-SAFE FUNCTION

The PGM-Fl system is provided with a fail-safe function to secure a minimum running capability even when there is trouble in the system. When any abnormality is detected by the self-diagnosis function, running capability is maintained by pre-programed values in the simulated program map. When any abnormality is detected in the fuel injector, the fail-safe function stops the engine to protect it from damage.

MIL Blink Pattern

The DTC can be read from the ECM memory by the MIL blink pattern.

The MIL will blink the current DTC, in case the ECM detects the problem at present, when the ignition switch ON and engine stop switch in the run position or idling. The MIL will stay ON when the engine speed is over 2,100 rpm.

The MIL has two types of blinks, a long blink and a short blink. The long blinking lasts for 1.3 seconds, the short blinking lasts for 0.3 seconds. One long blink is the equivalent of ten short blinks. For example, when two long blinks are followed by five short blinks, the MIL is 25 (two long blinks = 20 blinks, plus five short blinks).

When the ECM stores more than one DTC, the MIL will indicate them by blinking in the order from the lowest number to highest number.

MIL Check

When the ignition switch is turned ON and engine stop switch in the run position the MIL will stay on for a few seconds, then go off. If the MIL does not come on, troubleshoot the MIL circuit.

CURRENT DTC / STORED DTC

The DTC is indicated in two ways according to the failure status.

* In case the ECM detects the problem at present, the MIL will come on and the MIL will start to blink as its DTC when the sidestand is lowered. It is possible to readout the MIL blink pattern as the current DTC.

* In case the ECM does not detect any problem at present but has a problem stored in its memory, the MIL will not light and blink. If it is necessary to retrieve the past problem, readout the stored DTC by following the DTC readout procedure.

 

HDS POCKET TESTER INFORMATION

The HDS pocket tester can read out the DTC, freeze data, current data and other ECM condition.
TOOL: HDS pocket tester TDS3557-0112-01 (U.S.A. only)

How to connect the HDS pocket tester

Turn the ignition switch OFF.

Remove the dummy connector from the DLC.

Connect the HDS pocket tester to the DLC.

Turn the ignition switch ON and engine stop switch in the run position.

Check the DTC and freeze data.

NOTE: Freeze data indicates the engine conditions when the first malfunction was detected.

 

ECM RESET

The HDS pocket tester can reset the ECM data including the DTC, freeze data, and some learning memory.

After the ECM reset, perform the TP sensor reset procedure.

 

DTC READOUT

Start the engine and check the MIL.

NOTE: When the ignition switch is turned ON and engine stop switch in the run position, the MIL will stay on for a few seconds, then go off.
If the MIL stays on or blinks, read the DTC, freeze data, and follow the troubleshooting index.

To read the DTC with the MIL blinking, refer to the following procedure.

Reading DTC with the MIL

Turn the ignition switch OFF.

Remove the dummy connector from the DLC.

Short the DLC terminals using the special tool.
TOOL: SCS service connector 070PZ-ZY30100

Turn the ignition switch ON and engine stop switch in the run position.

Read and note the MIL blinks and refer to the DTC index.

NOTE: If the ECM has any DTC in its memory, the MIL will start blinking.

 

ERASING DTC

Turn the ignition switch OFF.

Remove the dummy connector from the DLC.

Short the DLC terminals using the special tool.
TOOL: SCS service connector 070PZ-ZY30100

Turn the ignition switch ON and engine stop switch in the run position.

Remove the special tool from the DLC.

The MIL will light for approximately 5 seconds. While the MIL lights, short the DLC terminals again with the special tool. The self-diagnostic memory is erased if the MIL goes off and starts blinking.

NOTES:

The DLC must be jumped while the MIL lights. If not, the MIL will not start blinking.

The self-diagnostic memory cannot be erased if the ignition switch is turned OFF before the MIL starts blinking.

 

TP SENSOR RESET PROCEDURE

NOTE: If the sensor unit (fastened to the throttle body) is removed, reset the throttle valve fully closed position as following.

1. Erase the DTC.

2. Turn the ignition switch OFF.

3. Remove the dummy connector.

4. Short the DLC using the special tool.
TOOL: SCS service connector 070PZ-ZY30100

5. Disconnect the ECT sensor 3P connector.
Short the ECT sensor 3P connector terminals of the wire harness side with a jumper wire.
Connection: Yellow/blue - Green/white

6. Turn the ignition switch ON and engine stop switch to the run position then MIL will start blinking.
Disconnect the jumper wire while the MIL blinking (within 10 seconds).

7. After disconnection of the jumper wire, the MIL will start short blinking.
Check if the MIL blinks.
If the MIL begins short blink (0.3 seconds), the TP sensor is reset successfully.
If the MIL remains ON, the TP sensor is not reset, repeat the reset procedure from step 1.

8. Turn the ignition switch OFF.

9. Connect the ECT sensor 3P connector.

10. Install the dummy connector to the DLC.

 

PGM-FI SYMPTOM TROUBLESHOOTING

When the motorcycle has one of these symptoms, check the MIL blinking, refer to the MIL code index, and begin the appropriate troubleshooting procedure. If there are MIL blinking stored in the ECM memory, do the diagnostic procedure for the symptom, in sequence listed below, until you find the cause.

Symptom Diagnosis procedure Also check for
Engine cranks but won't start
No MIL blinking
 
 
 
 
 
 
1. Inspect the IACV.
2. Inspect the fuel supply system.
3. Inspect the ignition system.
 
 
 
 
 
* No fuel to fuel injector
  - Clogged fuel filter
  - Pinched or clogged fuel feed hose
  - Faulty fuel pump
  - Faulty fuel pump circuits
* Intake air leak
* Contaminated/deteriorated fuel
* Faulty fuel injector
Engine cranks but won't start
No fuel pump operation sound
when the turning the ignition ON
 
1. ECM power/ground circuits malfunction.
2. Inspect the fuel supply system.
 
 
* Open circuit in the power input
and/or ground wire of the ECM
* Blown main fuse (30 A)
* Blown FI, IGN fuse (10 A)
Engine stalls, hard to start,
rough idling
 
 
 
 
 
 
1. Inspect the engine idle speed.
2. Inspect the IACV.
3. Inspect the fuel supply system.
4. Inspect the battery charging system.
5. Inspect the ignition system.
 
 
 
* Restricted fuel feed hose
* Contaminated/deteriorated fuel
* Intake air leak
* Faulty MAP sensor
* Restricted fuel tank-to-EVAP
canister hose (USA Type)
* Restricted fuel tank breather hose
(Canada type)
Afterburn when engine braking
is used
1. Inspect the PAIR system.
2. Inspect the ignition system
 
 
Backfiring or misfiring during
acceleration
Inspect the ignition system.
 
 
 
Poor performance (driveability)
and poor fuel economy
 
1. Inspect the fuel supply system.
2. Inspect the air cleaner element.
3. Inspect the ignition system.
* Faulty pressure regulator (fuel pump)
* Faulty fuel injector
* Faulty MAP sensor
Idle speed is below specifications
or fast idle too low
No MIL blinking
1. Inspect the engine idle speed.
2. Inspect the IACV.
3. Inspect the ignition system.
 
 
 
Idle speed is above specifications
or fast idle too high
No MIL blinking
 
1. Inspect the engine idle speed.
2. Inspect the throttle operation and freeplay.
3. Inspect the IACV.
4. Inspect the ignition system.
* Intake air leak
* Engine top-end problem
* Air cleaner element condition
 
MIL never comes ON at all Inspect the MIL circuit.  
MIL stays ON (No DTC set)
 
1. Inspect the DLC circuit.
2. Inspect the MIL circuit.
 
 

 

DTC INDEX

The DTC INDEX shows each Diagnostic Trouble Code, it's corresponding MIL blink rate(), a brief description of the failure, and a symptom/fail safe description.

DTC
(MIL blinks)
Function Failure Symptom/Fail-safe function
1-1 (1) MAP sensor circuit low voltage (less than 0.195 V)
* MAP sensor or its circuit malfunction
Engine operates normally
Pre-program value: 525 mmHg/700 hPa
1-2 (1) MAP sensor circuit high voltage (more than 3.848 V)
* Loose or poor contact of the sensor unit connector
* MAP sensor or its circuit malfunction
Engine operates normally
Pre-program value: 525 mmHg/700 hPa
 
7-1 (7) ECT sensor circuit low voltage (less than 0.078 V)
* ECT sensor or its circuit malfunction
 
Hard start at a low temperature
Pre-program value: 80°C/176°F
Cooling fan turns on
7-2 (7) ECT sensor circuit high voltage (more than 4.922 V)
* Loose or poor contact of the ECT sensor connector
* ECT sensor or its circuit malfunction
Hard start at a low temperature
Pre-program value: 80°C/176°F
Cooling fan turns on
8-1 (8) TP sensor circuit low voltage (less than 0.215 V)
* Loose or poor contact of the sensor unit connector
* TP sensor or its circuit malfunction
Poor engine acceleration
Pre-program value: 0°
 
8-2 (8) TP sensor circuit high voltage (more than 4.922 V)
* TP sensor or its circuit malfunction
Poor engine acceleration
Pre-program value: 0°
9-1 (9) IAT sensor circuit low voltage (less than 0.078 V)
* IAT sensor or its circuit malfunction
Engine operates normally
Pre-program value: 35°C/95°F
9-2 (9) IAT sensor circuit high voltage (more than 4.922 V)
* Loose or poor contact of the sensor unit connector
* IAT sensor or its circuit malfunction
Engine operates normally
Pre-program value: 35°C/95°F
 
11-1 (11) VS sensor malfunction
* Loose or poor contact of the VS sensor connector
* VS sensor or its circuit malfunction
Engine operates normally
 
 
12-1 (12) Fuel injector circuit malfunction
* Loose or poor contact of the fuel injector connector
* Fuel injector or its circuit malfunction
Engine does not start
Fuel injector, fuel pump, and ignition coil shut down
 
21-1 (21) O2 sensor malfunction
* Loose or poor contact of the O2 sensor connector
* O2 sensor or its circuit malfunction
Engine operates normally
 
 
29-1 (29) IACV circuit malfunction
* Loose or poor contact of the IACV connector
* IACV or its circuit malfunction
Engine stalls, hard to start, rough idling
 
 
33-2 (-) ECM EEPROM malfunction Engine operates normally
54-1 (54) Bank angle sensor circuit low voltage (less than 0.35 V)
* Bank angle sensor or its circuit malfunction
 
Engine operates normally
Bank angle sensor does not operate.
The engine keeps running when the vehicle falls.
54-2 (54) Bank angle sensor circuit high voltage (more than 4.5 V)
* Loose or poor contact of the bank angle sensor connector
* Bank angle sensor or its circuit malfunction
Engine operates normally
Bank angle sensor does not operate.
The engine keeps running when the vehicle falls.

 

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<--- DLC - Data Link Connector
Look under the right side radiator shroud. The DLC may be taped to a short section of the wiring harness in this area. Remove the tape. The connector cover is released by pulling the small tab outward then sliding the cover off.

With SCS connecter plugged in. --->

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SCS connector - Service Check Short connector
You can read out and clear the DTCs using an expensive meter ($2400 at HelmInc, $1200 on eBay) or the relatively cheap SCS connector ($20). I went for the SCS connector. It's nothing more than a female connector with a jumper wire installed which allows you to connect two pins in the DLC. You could do this with a short piece of wire, but be careful you don't short out anything else in there; the DLC has four pins inside it. You could also look for the female connector in an electronics supply store and add your own jumper - probably in the $5 range.

 

EXPAND

O2 sensor is used for emissions only
open vs closed loop
WOT
FI controllers
EJK/Dobeck
Bazzaz ZAFM ZFi
DynoJet DFC

DynoJet:
A typical production vehicle uses oxygen sensors that have a very narrow resolution. When you are cruising / idling (closed loop), the vehicle is concerned with maintaining an A/F ratio of 14.7 (stoich). When you put your foot on the floor and go into power enrichment (open loop), the factory sensors do not have enough resolution to tell you an exact A/F ratio. Any system that ties in to the factory oxygen sensors can only tell you if you are richer or leaner than 14.7. The Wide Band Commander, utilizing the Bosch LSU4 wideband sensor, will tell you exactly what A/F ratio you are running.

Oxygen sensor - from Wikipedia
When an internal combustion engine is under high load (e.g. wide open throttle), the output of the oxygen sensor is ignored, and the ECU automatically enriches the mixture to protect the engine, as misfires under load are much more likely to cause damage. This is referred to as an engine running in 'open-loop mode'. Any changes in the sensor output will be ignored in this state. In many cars (with the exception of some turbocharged models), inputs from the air flow meter are also ignored, as they might otherwise lower engine performance due to the mixture being too rich or too lean, and increase the risk of engine damage due to detonation if the mixture is too lean.

Check w/C

 

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