Hi folks,

I know this topic has been discussed many times in many forums but I need some clarification from an actual F4i owner/tech

Some background:

2001 CBR600 F4i
13,000 kms
Stock Standard
Full service history
Australian Delivered Vehicle

I'm the second owner of this bike and the original owner was a 50+ year old that was very meticulous with it. A few weeks after getting the bike, I noticed the bike was blowing a little black smoke and exhaust popping on overrun (standard muffler, like I say... Completely standard bike). A little later, the bike refused to start.

First thoughts were over fuelling so I did my Internet research and read up about the ever troublesome fuel pressure regulator. I have since bought a brand new genuine one from Honda, along with "o" ring, installed it and put in a fresh set of plugs to go along with it as the originals were obviously fouled up from the excess fuel.

Bike now starts.... BUT.... When I turn the bike on I can hear the fuel pump prime but it keeps running (priming). Is this normal? It has done this since i bought the bike so
I don know any different. I ask as I'm used to fuel pumps priming and getting up to pressure in the fuel rail, then stopping, awaiting the actual start of the engine. Is this totally normal or is there a further problem like a faulty pressure cut switch etc?

Can anyone confirm that knows for sure in regard to the f4i.

Thanks.
Regards
Stuart.

 

the fuel pump should prime for something like 4 seconds and then stop when you turn the key to the on position with the kill switch on run.

 

Thanks for the reply.

Well, I can say for certain mine isn't doing that. It runs continuously. Any suggestions to where the fault may be?

 

i think there is a fuel pump relay. make sure that is working properly, and also make sure someone didnt straight wire your fuel pump to run in such a manner.

 

Ok, not having a win yet.

Checked the "Fuel Cut Relay" and the "Engine Cut Relay" to ensure correct functioning of the internal switching by applying 12v to the appropriate terminals and checking for correct continuity with a multimeter. Bank angle sensor also checked and in working order.

Fuel pump is wired as from the factory and has not been tampered with. There is a red and yellow wire with a crimp on yellow ring terminal connected to the 12+ terminal of the battery. It looked a bit "after market" so I followed it up to the side of the fuse block where it has a 20A fuse, changes colour to red/white and then goes on to the engine cut relay. I double checked the F4i service manual wiring diagram and verified the wire is indeed factory. Just looked weird in with all the other wiring as it looked like an afterthought. So it would appear the wiring has not been tampered with in any way on the bike.

I jumped the FI diagnostic plug just to see if there were any codes in memory and there were none. Another dead end.

So!.......where to next? Leak in the system perhaps? No visible signs of fuel anywhere. I wouldn't have thought it could be a stuck injector because I would expect it run poorly and rough. What actually triggers the pump to stop priming? Is there a pressure sensor somewhere in the fuel system? Could it be a faulty ECU? Clutching at straws now....

I read on "fireblades.org" a post (relating to a similar problem to mine) mentioning the fuel vacuum hose. Not sure what I should be checking in relation to this to determine if it is working correctly or not. I know its the line coming off the side of the Pressure Reg. What is it supposed to do exactly?

Im just trying to troubleshoot the best I can before admitting defeat and taking the bike to a shop. Ive never had much luck with mechanics and it always seems to me that the ones I've dealt with start by replacing the expensive bits first. "sorry sir, you need a new fuel pump, injectors, blah blah..... oh sorry... turned out to be a 20 cent "o ring".

Ok, complaining over.

Any further suggestions appreciated. If I cant get it sorted in a week or two I'll book it in.

Cheers.

 

Check your vacuum hose that goes to your fuel pressure regulator. I could just have a pin hole leak that doesnt allow the regulator to work properly. I could be off, but hey, its a quick and easy fix

 

Man, all I have tried to read about this following checking grounds, checking cont. checking voltage, all of it leads back to the ECM. The ECM controls the operations of the relays, of the pump. Unfortunately there is not much you can do to repair it.

Can you get your hands on another ECM by chance to see if that sorts your problem?

Check for ground circuit. Underneath your seat on the left side there is a bolt right into the frame. Make sure its free of corrosion and tight.

From everything else, the problems were intermittent at best. Short here, bad ground there. You can try swapping relays and see if that helps.

Otherwise man, look for an ECM that you can use to test if one is readily avial, (a friends bike).

But if its not bothering performance at all a lot of people seem to think its not a problem. That pump is powered regardless when the bike is running anyway. There is obviously something a miss from normal operation but the "a miss" isnt really hurting anything logically thinking about it. I mean unless you sit there with just the key in on position and not starting it, otherwise Id say check as you can.