Topic: F4i problem - Please help! CBR forums not helping...

[zanorak]

Does anybody have any experience with the F4i? Mine keeps fouling plugs and will only run for a few minutes. I replaced the FPR, no codes are showing, unplugged the power commander, and voltage across the battery at rest is 13.6, 14.4 charging. I'm out of ideas. The only thing I can think of is that it thinks the temp is 168 degrees ambient? Would this affect the mixture that much? Please help! I got more advice from SOHC forum in a week than I've ever gotten from the CBR forums the whole time I've owned this bike. (all summer fiddling with this thing)

[Gordon]

I'm not familiar with motorcycle efi systems.  Does it have a Mass Airflow Sensor like a car engine?  If it does it sounds like it could be a dirty or bad one. 

[zanorak]

It has a temp/pressure sensor, a cam pulse generator, a water temp sensor, and i think an exhaust gas sensor. No codes show though.
Thanks!

[Danno]

the intake is restricted and the system can't compensate for it did you replace the air filter with a cheap unit? or have you not replaced it at all that is where I would start the efi systems on bikes is actually really simple it does not have the ability to compensate as easily as the one in a car does if something is out of spec it will run crappy I would also recommend getting the manual and looking for the checks for what few sensors you have on the bike also a stuck or sticking thermostat can raise hell with these bikes

[zanorak]

Filter is a K&N - cleaned per the instructions with the filter charger kit. Ran the same without the filter? Maybe less evenly - but about the same time. I'm going to try the thermostat and sensor. It's a #$%* to dig out - have to remove the throttle bodies. :/
Thanks!
Could the thermostat or sensor alone cause this condition?

BTW - this is more responses than I got on the CBR forums in weeks! THanks guys!

[Danno]

the oxygen sensor on the exhaust can if it has one the temp sensor on the water not usually they can just make it run poorly not usualy super rich but how long before they foul a day a week a month? if you have a k&n then no you are not restricted we get  people who sometimes think they are saving money by using cheap parts any way look at the exhaust or o2 sensor if it has one

[phil71]

That bike has a fake 'choke' right? Does it run the same on and off?

[zanorak]

It's never run more than two or three minutes before it just dies. Plugs are really wet. Exhaust is a micron aftermarket - which is probably why it has the power commander. The choke on this thing is what's called a 'wax" unit. As the water heats up it relaxes/liquifies a wax plug which causes the idle to lower. can't be adjusted without some major BS. I haven't touched it... assuming it's ok as the bike idles right at 1500 where it should. It only does it for 3 minutes though. :/
I bet I've fouled the plugs in about 20 minutes of total run time. It's making me crazy - the plugs are super expensive.
It ran fine with the airbox off and no filter - for 3 minutes.
It ran fine with the filter in and airbox sealed - for 3 minutes.

Thanks again for the ideas guys. I hate feeling all alone with a monster project.

When I can (painting the house before fall) I'm going to pull the 02 sensor and the water temp sensor and clean the terminals, use electrolyte on them, reassemble. I'm also going to replace the water sensor while i'm in there. If that doesn't work I'm going to replace the rectifier (because it's cheaper than the computer?) then have the computer tested. I hope it's not the computer. :S

[kpier883]

A few thoughts...

Some CBR600s have a primary and secondary injector per cylinder.  I believe this started in 2007 but don't hold me to it.  I wonder if you have both in your application?  If so, could the power commander be firing both the primary and secondary injectors all the time rather than only when it is supposed to?   

Maybe you could remove the power commander to test without it -  Is it piggy backed onto the normal ecu or did the PO replace the stock ecu with the power commander?

[grcamna2]

It couldn't hurt to get a hold of a very good quality multimeter & the Honda factory service manual & test each component of the fuel injection system.I would determine if any of those sensors are not up to spec(do this in a warm environment like a garage w/ heat) and then I might try disconnecting everything aftermarket & putting it back to stock in the fuel injection system temporarily(remove the power commander,etc. & just run stock) just to see if that will fix your problem...you may have a broken aftermarket part that would be tough to troubleshoot or set up to work together w/ the rest of the system;at least you can see how it runs w/ stock parts:air filter, power commander,etc. ...and then I would check all the connector plugs,etc. ...the simple stuff & just spend "more" time to thoroughly isolate what your problem is. Do you have the Factory service manual ? You may not have to remove the temp.sensor,etc. to test them;just go by the book.

[zanorak]

THanks guys!
I unhooked the PC already. Didn't really affect the running at all. Previously when the intake temp/pressure sensor was bad I could lean down the PC and it would run - then I replaced that sensor and unhooked the PC. I think it might need the PC because of the K&N and the exhaust... not sure. But that would cause a LEAN condition not a rich one! Very strange.
I have the manual - need to do the sensor checks. (yes - takes so long! aaargh!) But it's throwing no codes? Still - at this stage you're right grcamna. I need to do it. I can re-check the wiring harness and look for any grounds as well, and check my ground wires for connection.

This is a 2001 by the way kpier - good thinking though! The PC piggybacks onto the stock ecu by interrupting the wiring harness between the injectors and the ecu.

Looks like I have about 10 hours of additional homework here... :S

AND the RR went out on my cb500 today.

I appreciate the input - keep 'em coming! SOHC ROCKS!

[Danno]

if it was a ground your injectors would not fire test the O2 sensor and the temp sensor as per the manual

[grcamna2]

How's it going with your CBR600F4i,did you find the reason for that extra rich mixture yet ?

[zanorak]

Thanks for the thoughts Grc - I'm parenting right now so no time for bikes... If only my little girl liked motorcycles! I'll probably get some time when she goes back to her mom on Sunday. I'll keep you informed, and maybe post some pics!
I figure if there's a reason to not work on the bikes this is it.

[grcamna2]

I like your thinking !

[zanorak]

Ok everybody - finally came back with the answer.
Over the weekend I decided that if I didn't get the bike running I would take it to the dealer and pay 85 bucks an hour.
Had a friend look at  it and the problem was .... you're gonna love this...

ALL of the tines in the temperature sensor plug were bent THE SAME AMOUNT so they LOOKED like they were ok but they were really all OFF by about a millimeter. I had checked this connector several times (50? I don't know... it was a lot) and I was convinced that it was hooking up. I thought it would be the actual WIRING that ran to the sensor but the issue was actually caused by the tines sliding into the grooves on either side of the actual female receptacle. That's why the resistance would go down when I fooled with the wire and give me a lower reading.

So - to all who helped - thanks! I almost lost my mind but it's fixed and I'm going to ride.