Honda CBR 600RR Forum banner

1 - 20 of 79 Posts

·
Registered
Joined
·
34 Posts
Discussion Starter #1
Hey all,

So I own a 08 CBR600RR with about 87k miles on her. Long story short the upper fuel rail is not firing. I figured this out by opening the air intake and holding my hand under the injectors and looking inside the airbox for fuel when revving the engine. The engine RPM jumps around at 3k-5k, around 10k, and wont redline (being that it isn't getting the fuel it needs) alongside when I engine brake I can see that it flutters when dropping through the 3k-5k area. I'm sure these RPM issues are due to not having the proper fuel.

My troubleshooting so far is:
-Checked Battery (Pretty much new from shelf)
-Replaced Fuel Pump (due to mileage it didn't bother me)
-Attempted different ECU (No change)
-Pulled off fuel rail and checked for clogs (None)
-Pulled line and checked for fuel push from pump by holding a bottle to the line, the line sprays a fountain of fuel (forgot to put it back on and turned key...almost got a face full)
-Jumped BAS
-Replaced Spark Plugs (didn't need it but decided since I was there mind as well)

It seems that the fuel rail is not getting the Electrical Signal to fire/spray. Judging from the wire schematics its a direct signal from the ECU. A mechanic is saying I should replace the TPS but I don't know how this is connected since it's a straight shot from ECU signal...Also from what I've read on the forum people have suggested the Voltage Regulator/Rectifier but as stated im not sure how it's connected to the system.

Does the TPS/Voltage Reg/Rec give the signal to the ECU to fire the upper rail?

Thanks for your time and the read. I'll be checking periodically for posts and help. At this point I'm not sure what else to try besides the already above stuff.
 

·
Registered
Joined
·
382 Posts
Here's some thoughts - may or may not be correct.

Looking at the diagram, have you considered testing continuity on the BL/W pin from the engine stop relay to each BL/W pin on the fuel injectors? If you get continuity, maybe check for 12v on each BL/W pin on the fuel injectors. If you notice, there is a splice from the BL/W wire from the engine stop relay to the fuel injectors.
 

·
Registered
Joined
·
34 Posts
Discussion Starter #3
Here's some thoughts - may or may not be correct.

Looking at the diagram, have you considered testing continuity on the BL/W pin from the engine stop relay to each BL/W pin on the fuel injectors? If you get continuity, maybe check for 12v on each BL/W pin on the fuel injectors. If you notice, there is a splice from the BL/W wire from the engine stop relay to the fuel injectors.
You do have a point, the only signal that would stop all injectors is that engine stop relay, I don't know why I didn't look at that before. I'll swing by Autozone, get a quick multi and check those wires. I guess I have been looking at it too long and needed fresh eyes.
 

·
Registered
Joined
·
382 Posts
You do have a point, the only signal that would stop all injectors is that engine stop relay, I don't know why I didn't look at that before. I'll swing by Autozone, get a quick multi and check those wires. I guess I have been looking at it too long and needed fresh eyes.
I don't know man, but if the wire was broken at the first splice, none of your injectors would fire, but maybe the splices to the injectors for your upper rail are broken, or corroded plugs, whatever... Easy enough to check until wibbly stops by and tells you exactly what is wrong :grin2:
 

·
Registered
Joined
·
34 Posts
Discussion Starter #6 (Edited)
***UPDATE***

I checked the wires from the Injectors to the Engine Stop Relay. The wires checked good with <0.1 ohms. I even went further back and checked the wires from the engine stop to the battery and BAS. Everything seemed to give me the same result. I did blow the FI fuse somehow which seemed strange but I have plenty of spares.

From what I read and videos I've seen, it seems like the Secondary injectors fire at 4.4k/10% Throttle rotation and or above 7.5k RPM. I could be wrong but these were the numbers I came to when searching endless amounts of forums. They just don't fire at all.

I would say take it around the block and or see for yourself. If I had a GoPro I would video the bike during a standard ride but when the bike doesn't want to get up and go on the freeway (it was not moving past 5k RPM and seemed to be clogged until I went WOT till it cleared up) and or dumping RPM's in a tight right hand turn I'm to the point where I don't want to ride until I get it fixed.
 

·
BOTY 2014 Winner
Joined
·
4,903 Posts
just checked the manual, seems different years have different operating methods. 4400 and 10 degrees should be pretty simple to simulate on the stand. (have you tried in gear? could be a neutral thing)


have you checked the condition of the pins within the secondary rail connectors?
 

·
Registered
Joined
·
34 Posts
Discussion Starter #9
You absolutely positive you have good gas in the bike? Do you have a power commander installed? When did the issue first occur? What maintenance did you do prior to the issue occurring?
I've pushed sea foam through the tank and positive I have good gas, even have it at 93 octane due to Florida area. I do not have a PC installed. The issue start mainly these past 6 months. It was intermittent the first few so I thought it was just a fluke or water in the tank. I ran a Fuel Injector Cleaner through it and it seemed to help buff it out before but now it's always there. I can ride the bike slowly and it wont stutter but when I go to punch it the RPM's fluctuate and the bike bucks.

As far as maintenance I've done the usual Spark Plugs, Oil changes, Chain and Sprocket, Coolant, Air Filter (Also I did clean this while trying to figure out the current problem), Clutch (didn't need it really). I think thats all.

The only mod I installed was a Speedo Healer to fix the speedo due to doing the 1 down 2 up conversion on the sprockets but I don't think that would have an issue on this.

I could just run tank after tank of Seafoam in it and do it that way...not sure if it would hurt the bike at all
 

·
Registered
Joined
·
11,434 Posts
Well there seems to be one more thing you might want to check, fuel pump pressure. Volume and pressure and not the same. Once you reconnect the fuel line your volume can drop if you don't have enough pump pressure to overcome system pressure. If your pressure regulator is bad it'll dump fuel back into the tank and never give your fuel rail enough pressure or volume to function at design.

But I'm still of the opinion that they're actually working. You just may not be able to replicate running conditions in order to actually see them work on the bench.

So when you go back to the original symptoms, it sounds like a fuel pressure problem starving the bike at higher rpm.

Sent from my XT1097 using Tapatalk
 

·
Registered
Joined
·
34 Posts
Discussion Starter #12 (Edited)
I just replaced the pump but i know it's possible to get a bad fuel pump from the factory but usually that's pretty rare.

I did read that someone took out the pressure regulator on there bike and it was the problem but I don't recall seeing one on the fuel pump setup. Did I miss something? I know this is an essential part but if I remove it and run the bike and it fixes my problem then I know what to order.

Is there a way I can test the pressure without purchasing the pressure gauge? As in will a vehicle fuel pressure gauge work?

UPDATE

I checked all the wires going to the TPS and everything checked good. Even checked the ohms of the TPS like the service manual said and it was good, got a small amount (0.1) which the pub said if it shows something you're good.
 

·
Registered
Joined
·
34 Posts
Discussion Starter #13
Rigged up an auto fuel pressure test set and it checked at 50psi, just like the service manual says. I had to remove the factory plug and shoot straight from the hose but if it works it works. So I can rule out the fuel pump and psi...anyone have any other ideas?

I shot the battery during this test and it was at 14 volts so I believe the voltage regulator is working just fine.

It does idle low, maybe at 1200 or so but doesn't bog. I thought it might be a charging issue due to seeing the headlights (I converted them to hid) flicker a bit and stop flickering when I rolled the throttle.
 

·
Registered
Joined
·
34 Posts
Discussion Starter #14 (Edited)
UPDATE
So I got bored and decided to try something on the bike. I shoved some safety wire into the injector connector to see if I got power while it was running. It got 13 volts which seems good to me. So I have good pressure and power...im guessing bad injectors. I was able to order some off eBay because the injector store near me wanted 30 bucks a pop for cleaning...i got a whole rail for 25 used...they maybe be used but I'm sure they are not as used as these with 87k miles...ill post in a day or two when I get them installed. Thanks for all your help on the forum.
 

·
BOTY 2014 Winner
Joined
·
4,903 Posts
just something to consider.


it helps to look at the wiring diagram so you're able to diagnose what SHOULD be there, before you start measuring. your meter is useless if you don't know what you're looking for.



if you probed both terminals on the injector for voltage that would be a different story. but if you just probed the hot wire and put the black lead from your meter to chassis or battery negative, you are fooling yourself.
 

·
Registered
Joined
·
34 Posts
Discussion Starter #18
I've considered your response and verified my work. I do get a little voltage on the lower rail and it increases with throttle (checked the #1 Inj). The upper rail doesn't seem to get the same voltage feedback from the ECU. I've uploaded two videos to youtube to show what the bike does currently with the throttle being held and also trying to increase the throttle. Hopefully this will show what I'm dealing with.

https://youtu.be/aeffolfdRhs
https://youtu.be/mcMuaG9lTy0

I do appreciate your help though Wibbly, even if I do make stupid nugget mistakes in my troubleshooting.
 

·
BOTY 2014 Winner
Joined
·
4,903 Posts
When you set your meter to dc volts it will give you the average voltage. Not the peak voltage.


So if you have 12 volts supplied, and your injectors are open 1/4 of the time, you will have 3vdc.

That's why dc reads zero when you put it on an ac line.


So if your main injectors show some volts across them and your secondaries don't then it's pretty clear the issue is that the ecu doesn't want them on.

Now to figure out why that's the case.
 

·
Registered
Joined
·
11,434 Posts
After watching the videos, your bike is doing almost the exact same thing as mine. The one thing I didn't see that you tried was cleaning the injectors. ??

Your fuel problem is not related to the upper injectors because they don't kick on below 5k. So if the bike stumbles in the lower RPM range then your lower injectors are the only ones in play.

I don't know about yours but my problem came on immediately and hasn't gotten any better. I'm soaking both sets of injectors and praying that solves the problem. If it does I'll be sure to let you know.

Sent from my XT1097 using Tapatalk
 
1 - 20 of 79 Posts
Top