[lrmzx636]

I was ridin my 03 636 today, 10500 miles on her... and she started skipping and burning fuel. My immediate guess was fouled plug. Original plugs on the bike. I just threw on a GPR Titanium exhaust pipe. Well got it home, about 20 miles... picked up new plugs, swapped em... still ran like ass. Tried pullin em 1 at a time to check validity of each plug install. On the last one the bike appeared to have no power to crank. Tried push start, nothing. Took all plugs out and hit the start switch, shot gas straight up in the air out of the cylinder with the fouled plug. Put em back in and cranked up... gas comin outta somewhere! So i strip the fairings... and see its coming from the exhaust midpipe. Pull the exhaust off.. crank it up... shoots a good 3 foot spray of gas out of the exhaust.... its pumpin out gas like a sumbitch. FI light is now coming on and staying on.

1. Is it from ridin on fouled plug? Flooded cylinder is still trying to free itself of the gas?
2. Do I need to reset the PCM? Pumping too much gas to the motor flooding.

What are your thoughts?

 

[Greenvetter]

You may have an ECU problem. First thing I would do is pull the codes out of the ECU. If it's setting the light it's storing something. See where that takes you.

Do you have spark at each plug?

Next I would get a meter on your inject connectors and see if they are pulsing voltage when you crank it. You should see a quick on off voltage.

If it's pulsing voltage you may have a bad injector.

If you have no spark and no pulsing at the injectors it may be your position sensor which should set a code.

Good luck.

 

[lrmzx636]

Ok, the code was thrown due to the air box connector not being plugged in. I plugged that sucker up and the FI light went off. I pulled the #4 plug and let it turn over until the excess gas was out. Tested each coil pack for spark, positive on all cylinders. Put the plug in the bitch and cranked right up and ran fine... for a lil bit.... then started pouring gas out again. What now could be the problem?

Injector? Staying open, or clogged, flooding the cylinder, fouling the plug?

 

[lrmzx636]

So I have run every test I know how to do on the bike. I tried the oil in the cylinder to burn off the gas in it. ran it without gas. Ran it without plugs. The bike cranks and runs but dumps a serious amount of gas on the ground straight out of the header. What is the problem! I am getting fire to all 4 plugs.

 

[Q-Ball]

Does the bike have a Power Commander? If so, disconnect it from the bike (injectors, power harness, everything) and try again for testing purposes. Would be nice to know if it's a PC3 or PC3 USB, some of the PC3's (non USB) were supposed to have had some recalls or something so it would be a good data point.

Good luck,
Q

 

[lrmzx636]

No power commander. Anyone deal with a fuel pressure regulator?Could be the culprit

 

[spitz04]

I believe the regulator is in the tank near the pump and if it was anything to do with that it would affect all cylinder equally..

If your spraying raw fuel out of a cylinder there is something wrong with the injector(hanging open mechaincally) or its being commanded on by the ecu for whatever reason, or some wierd wiring short circuit between the injector and ecu. To test what problem it does have i would disconnect the culprit injector and cycle the key on and off a few times to build fuel pressure, then remove that cylinder spark plug and see if raw fuel comes out like before.. If so, the injector is mechanically sticking open (cant be electrical because you disconnected that before hand). Make SURE you disconnect the coil too because you want no spark near misting fuel. You also could simply disconnect the one injector too and use a noid light (just a 12v bulb) across the two terminals of the injector harness and start the engine to see the pulsing from the ecu, it will be a simple pulse every time the piston comes up to tdc on the compression stroke, if its really erratic or stays on all the time, then you have electrical problems.


ps- after you solve the problem do an oil change right away.

 

[lrmzx636]

That sounds like a very good explanation to the problem. If it is sticking open what is the easiest way to unstick it? If its an ECU issue I will have to get it reprogrammed. My buddy says he can access the ECU through his gauge cluster on his R6. Is this possible on the 636?

 

[lrmzx636]

So I should leave plugs and coil packs and plugs in all cylinders... unplug the suspect fuel injector. Turn ignition key on and off several times to engage fuel pump - build pressure. I assume I need the tank on and hooked up for this to work... then turn off the ignition, pull the plug out and hit the ignition again to start it up and see if gas shoots out?

 

[lrmzx636]

Ok, update. I swapped the fuel rails with my other ninja. Did not help the situation. Checked all hoses, wires, harnesses, etc. All seems to be in order. Still pumping out gas. What are the possibilities of a bent valve? Valve stuck open allowing fuel to just pump into the exhaust. Is this possible or is it just strictly FI related. I didnt swap the ECU yet. Is there a connector I can pick up to run diagnostics on my laptop?

 

[Greenvetter]

I'm going to assume when you swapped the fuel rail you swapped the injectors too? To get that much gas out of the header, if you did swap the injectors, you got something going on electrically. I have never seen any engine do what you are describing.

Next time you getting running, even for a few seconds feel the header and see if they are all around the same temperature. That will tell you if you have a problem with one cylinder.

I doubt you have a bent/stuck valve, etc. A compression test will tell you that answer.

Have you done the voltage test at the injector wires yet?

If you are really bold you can try this but it might be a bit insane so if you do it, do it outside your garage with someone standing next to you with a CO2 fire extinguisher. Pull the fuel rail and keep in connected electrically and to the fuel pump. Get a shitload of rags and put them in front of the injectors or put a small soda bottle over the ends of each one. Turn the key on let the fuel pump cycle and see if any of the injectors are spraying or leaking. If the answer is no. Then try to start the bike the injectors should cycle one at a time while cranking. I would do the voltage test before I go to this extreme.

 

[lrmzx636]

Yes, when I swapped the rails the injectors went with em. I havent done the voltage check on the injector wires yet, going to try and get that done today. I donnt know if I am going to be as bold as to run the bike with the injectors in my hand yet . But it makes sense to try eventually, lol. Since my roomate got burned up in a house fire working on an F4i 2 months ago he isnt so keen on playin with gasoline anymore. LOL.

 

[lrmzx636]

bump

 

[spitz04]

Wow, you are running yourself around in circles.. You have to know how the system works before you go diving into it like you already have. The injector works like this, two wires, one power, one ground. The ecu simply grounds the injector for a set amount of time (milliseconds!) to open the valve in the injector and allow the pressureized fuel into the intake or in some right into the cylinder. Power should be at each injector when the ignition is on at one terminal. If your seeing liquid fuel like you are saying then for whatever reason it is WAY too much fuel. If I were you, and this is just my opinion.. I'd tell you to take it to a reputable dealer before you end up burning down your garage and your bike.

ps- wires can short within the harness where you may not see it.


What I explained is just disconnecting the one injector electrically and starting the engine, the engine will run rough as there is only 3 cylinders creating power.. The reason for this is to see if fuel is leaking past the injector or if the injector is being opened too often for a reason.. Since you swapped injectors chances are very unlikely its the injector itself.. Your focus should be on the wiring harness or the ecu.. Make sure you look at the harness closely, a shorted ground wire for that injector would be causing a problem like this, in effect grounding and bypassing any ecu control. If the harness is ok i would be suspect to the ecu..

 

[lrmzx636]

If indeed it is the ECU what is the next step? Can it be repaired or must it be replaced?

 

[Greenvetter]

Your going to have to replace it if you verify the problem is in the ECU. Do the voltage test at the injector and you will have your answer. When you are doing this make sure to test each injector for pulsing voltage. I wouldn't try or change anything else until you do this test.

 

[greenracer]

Spitz is on the money with his troubleshooting.I hope this guy does the above mentioned tests before buying an ecu,they arent cheap.

 

[spitz04]

You cant simply do a "voltage" test at the injector because............ The control for the injector is to ground it. Voltage should be applied to the injectors when the ignition is on. The ecu is for the most part, a big ground controller, rarely does it "power" anything up.

The reason I bring up the harness may be rubbed through somewhere and contacting ground is because it will cause this problem and it wont cause circuit overload simply because its on the grounding side of the circuit.. Instead of the ecu grounding the circuit and opening the injector a bare ground lead for that injector could be rubbing on the block or something and grounding it whenever and dumping way too much fuel in, which is the case here.. It could be a faulty ecu too, but like said the only real way to verify that instance is to rule out everything else first Or replace it and hope for the best.. Your best bet is to double check that harness because its only a few feet long!



A good test to do would be to gain access to the injectors and still be able to run the bike. A noid light ( a cheap 12v light made to stick into the injector connector) would be ideal, but a rigged up test light would work too. Anyway, i would run the bike with the test light hooked up to your problem injector( the vehicles harness of course) and just observe what the flash pattern is, at idle it should be consistent and when your rev the bike it should pulse faster and faster relative to engine rpm. Then i would try this same thing on another injector connector and note any differences?

 

[greenracer]

He could also test the ground wire on that injector(one side being 12v & the other being controlled ground)Testing the ground circuit could be as simple as using a test light from the ground wire on injector harness to 12 source. With bike running, if solid light then ground problem. (Or use multimeter)If that shows problem, use meter to do resistance test from injector harness(unplugged) to the same wire on the ecu(unplugged). If wire is good reading will be near zero, if bad will get above that. If reading is higher means wire is pinched/rubbed through.Be sure you have the correct wire end to end.

 

[spitz04]

"Testing the ground circuit could be as simple as using a test light from the ground wire on injector harness to 12 source."

Yes thats basically the noid light setup, assuming you know you have a power source at the injector connector to begin with.

The only thing wrong with ohming out a wire like this is it may be intermittent, and it may not even show up as a problem for the meter... Although the wire may be touching ground somewhere the little 9v battery in most meters doesnt push enough amperage to make a voltage drop across semi-bare wires.. A true voltage drop test would be best but in this case a pulsed on off signal doesnt help. If you want to use an ohm meter you could go from one end of the ground side wire (ecu or injector) and hook one lead there and then put the other lead on a good ground and wiggle the harness around and see if you get a closed circuit somewhere(wire is shorting somewhere to ground), that would work.