Hi everybody,

My Cbr wont spark. I brought it to a shop but they are having trouble finding out what the cause is.
They gues it has a broken ecu.

the strange thing is that it will spark (and start) ocasionally. Therefore, i doubt it will be the ecu.

Does anybody has some suggestions on what we should check before we send the ecu out for repair? They charge €350 for the repair only so i hope there are cheaper options to check first.

Thanks in advance.
I wish you all a great weekend!

cheers,

Leeroy

 

Use better garage. Find exact problem with measuring and looking at numbers, NOT GUESSING! Sounds like safety interloc issue.

Measure your sidestand/clutch switch wires at ECU connector. Should be connected to chassis ground with sidestand up.

Same with neutral switch wire at ECU connector, connected to ground when in neutral.

If switches aren't signaling to ECU properly, it'll think there's unsafe condition and will kill spark. Such as when you put sidestand down when in gear, it kill spark and stops engine.

Doesn't matter one bit if switches themselves are working, ECU has to see them. So wiring and plugs in between may be duff. That's why you want to measure at ECU connector itself.

 

Hi Dannoxyz,

Thanks for the reply!
They will measure at the ECU connector today.
They found out the ECU gives error code 7 and 8 (See pics attached).

But now something weird happened.
First they observed that there was no spark, but it did pump gas out of the injectors.
Now they observed the exact opposite.
It seems very strange to me that this problem is changing its symptoms.
Does this point towards the ECU?

 

TPS and ECT sensors most likely 100% hunky dory, wonky wiring and connectors will do that. Before testing them according to manual (along with safety switch status at ECU connector) , best unplug all connectors and verify terminals inside aren't loose, corroded or broken. Then clean them with electronics contact cleaner. Then re-connect.


https://www.amazon.nl/CAIG-LABS-DN5S.../dp/B06XP32299

 

Hi,

You are probably correct.
We send the ECU out for a check up.
It seems to be fine.
Also now they disconnected the connectors and reconnected them again, it just runs..
But we still did not pin point the problem.
So it will probably die when I try do ride it again.

Probably have to check all the connectors now...
Gonna be very time consuming.

Also still have fault code 7 and 8.

 

You've got major wiring harness issues. ECU is now receiving proper safety interloc status from clutch, sidestand and neutral switches, so it's firing spark.

But you probably have no power to injectors. Measure voltage coming out of fuel-pump relay and verify that voltage makes it to all branches downstream: fuel pump, injectors, exhaust air injection solenoid, ignition coils, O2-sensot, purge control valve and ECU.



Error fault code 7 & 8 as already noted, are for TPS and ECT. Test and measure according to manual's procedures: Vcc reference voltage line, ground wire, output signal wire and output voltage signal itself.

Your symptoms are changing because of duff harness. Corroded or broken wires and terminals inside connectors. When you wiggle harness, it changes which broken wires disconnects or reconnects. Unless you are Superman and can see electrons moving inside wires, there's absolutely zero way any human can just look at wires and determine their ability to conduct electricity. Luckily we have instruments that can.



Find better garage that knows how to use meter to troubleshoot harness. All parts are fine, it's wiring issue.

 

Hi all,

I have been working a lot on the CBR with no result.

Symptoms:
Does Crank
Does Prime
Does have 12V on the sparkplug coils
Does have 12V on the ECU
ECU does have ground
HISS light turns off like it is supposed to after turning on the ignition.

DOES NOT SPARK

Thus far I changed the following parts.
I have the possibility to lend them from another CBR929RR for the time being, in effort to pinpoint the problem.

• Engine stop switch
• HISS Antenna
• Tip over Sensor
• Crankshaft Sensor
• Camshaft Sensor
• Wire three (exluding parts within red circle on drawing attached, including relays: engine stop relay, fuel cut relay, etc).I changed out the wiring three to make sure the ECU gets input. That way I could exclude a broken wire as a cause of the problem.

I measured the kickstand sensor with the ground (beep) function and it does seem to function. (Should the bike be able to crank if this is not functioning properly?).
My ECU has been tested by an external specialist and deemed: functioning properly.
I have exchanged my ECU and key with another CBR and that one fires right up.

At this moment I only have two things left to check in mind.

1. Peak voltage: I am searching for a peak voltage adaptor. I want to measure the peak voltage at the ignition coils to see if it is ok.
2. Check the timing of the camshaft. I read that if they are not in time, the bike wont spark.

Ps. It is an European bike with HISS. Therefore, I do not have a Zener diode on the ignition key switch, nor do I have a pink wire on there.
It does have a pink wire on the HISS, but I changed this out so this shouldn't be the problem.
The other CBR does start with my HISS antenna.

Does anybody have any ideas on what I could check?
I got my head in my hands because I am losing hope I will be able to figure out the problem.

Any help is much appreciated!

I wish you all a wonderful evening.
Thanks in advance for any help.

Cheers,

Changed everything except the red encircled parts and the rectifier. (Nr. 2)

 

Put ALL original parts back on bike! You may have introduced additional errors into system. Will be chasing problems around in circles because previously good parts may have been replaced with low-quality aftermarket parts. Or wiring may have been damaged in process of desperately swapping parts!

This is useless test and waste of time unless you're troubleshooting 1970s ignition system. Proper testing of inductive ignition-system is with oscilloscope. You will measure battery power fulltime at coils (you've already confirmed this). Then at short 5ms segments, ECU will ground ignition-coil to fire sparks. You will measure zero volts during that time-frame. Still useless test because we already know that ECU is not sending grounding-pulses to fire spark. WHY it's not triggering sparks is more important issue to be discovered through proper testing and measuring! The NUMBERS will tell exactly what's wrong and how to fix it. This is 5-minute fix with multimeter, how much time have you wasted not gathering a single number all this time?





1. Are you still getting error code 7 & 8??? Never provided any numbers from their testing.
2. Were camshafts ever removed to adjust valve-clearance?

Use wiring-diagram and confirm colours of wires going into every sensor. ECT and TPS uses same connectors as some others in that area and can easily get plugged in to improper location during desperate parts swapping. Better to make list before starting. I’ll do 1st one:

TPS= yel/red, grn/org, red/yel
IAT=
MAP=
ECT=
CKP=
CMP=
BAS=
VSS=

Do following measurements.

1. with everything OFF, measure battery power, volts=???
2. key ON, start/stop=RUN, measure battery power, volts=???
3. measure battery power during cranking, volts=???

Following are ONLY things that tells ECU to not fire sparks, even though it does pump-prime. Disconnect ECU from harness-connector:

4. at ECU connector, measure resistance between grn/wht wire and chassis-ground. ohms = ???
5. at ECU connector, measure resistance between grn/red wire and chassis-ground, ohms = ???

These numbers should tell us what's wrong and how to fix it.

 

The other way to check for ignition grounding-pulses from ECU is with solenoid light.

1. Connect to both terminals of each ignition-coil plug, crank engine and it will blink if ECU triggers coil. Probably nothing

Back up one connector to test wiring in between. Unplug ignition sub-harness from main-harness

2. Connect solenoid light to power blk/wht and coil-trigger terminal for each coil at harness connector and crank
#1 = blu/blk
#2 = yel/wht
#3= red/blu
#4 = red/yel

3. Go up harness and test ignition-signal at ECU connector. Back-probe connector with small brad-nails or sewing-needles:

#1 = blu/blk + blk/wht
#2 = yel/wht + blk/wht
#3= red/blu + blk/wht
#4 = red/yel + blk/wht

Most likely you won't get any blinking from solenoid light. Answer's in measuring resistance to chassis-ground at ECU connectors of grn/wht and grn/red wires in previous test.

 

TEST EACH COIL FOR SPARK

1. remove coils from bike and do following on bench

2. what's part# on each coil?

3. measure impedance of each coil, ohms1=???, ohms2=???, ohms3=???, ohms4=???,

4. insert plug into coil

5. using small jumper with alligator clip, connect one terminal to battery +12v terminal

6. connect 2nd jumper to battery -neg terminal and clamp on plug's body

7. connect 3rd jumper to battery -neg terminal

8. quickly tap/release 3rd jumper's free end to coil's other terminal

9. do you see spark jump plug?

10. repeat for each coil



Testing also applies to all new parts! Just because something’s new, doesn’t mean it’s actually good and functional. All parts needed to be tested and verified functional. With lower quality of 3rd-party/aftermarket parts nowadays, many of them are bad right out of box!