Running Rich? Oil filler cap removed = runs better

[jjs1234]

Back from the dead with a new problem. :musicboohoo:  After riding my K this past summer, I've decided to return to a problem that I've been having.


As some of you might know, I created a thread on this about a year ago, but did not have any of the new information that I now have. Also, completely rebuilt the K about a 18mo. ago and haven't been able to ride it much...



I noticed a symptom of my K (85' K100) possibly running rich. That is:


**when the oil-cap is removed, the K runs a whole-lot better.**


My guess is that its running rich. Searches on this topic reveal that on a working K bike, if you remove the oil-fill cap, it should run rough.


Possible causes:
- Fuel reg. is leaking extra fuel into intake via hose
- AFS (MAF) is in need of a tune/adjustment
- Valve adjustment?


Symptoms: ??
- Throttle works up to 75%. After 75% or WOT, the K does not do anything. In-fact, it looses a bit of acceleration- slight lurching?
- Spark plugs foul too often
- Low gas mileage ~30?
- Black spray comes out of exhaust pipe during start-up. (SEE PICTURE OR ATTACHED)


*Does the K run rich on immediate start-up (while button is pressed), or does it run rich until it warms up?*


During start-up I'll have the "throttle-advance" on 1st notch. Then about 3-5 minutes later, the RPM's suddenly jump up (1000-2000?), and then the throttle is returned to normal.


Also, earlier this week, I was testing to see if the cooling fan would come on (200f?), so I had the K running in my driveway. It got to about 150F and then shut-off. I had to WOT the throttle to even get it to start and it ran really-rough. I rode the K and it was apparent that only 3 pistons were firing.


I dont know if any/all of the problems listed are related or not. Help would be greatly appreciated! :2thumbup:

[Martin]

Had similar symptoms on mine, it was caused by a collapsed fuel return line where it goes into the tank. One of the other signs was when the idle was set a 1000 Rpm and you pressed the green stater button the engine died to the point of stopping. Pressing the green button at 1000 rpm richens up the mixture. The correct response is for the engine revs to remain the same or slightly increase. If the engine revs increase more than a slight rise it is running lean if it dies it is running rich.
Regards Martin.

[Inge K.]

Also check the temp sensor, you can measure the resistance at contact #10 in the FI ECU multiconnector.
Counting from the rear (also open slots) 1 - 13, other multimeter pin to #13 (ground connection).
You should measure ~2.5K ohm at 20^oC, if it's higher you gonna get a richer mix.

[jjs1234]

Also check the temp sensor, you can measure the resistance at contact #10 in the FI ECU multiconnector.
Counting from the rear (also open slots) 1 - 13, other multimeter pin to #13 (ground connection).
You should measure ~2.5K ohm at 20^oC, if it's higher you gonna get a richer mix.

It's approx 70f and the ohms read 2.75k. 20c is 68f

[jjs1234]

Had similar symptoms on mine, it was caused by a collapsed fuel return line where it goes into the tank. One of the other signs was when the idle was set a 1000 Rpm and you pressed the green stater button the engine died to the point of stopping. Pressing the green button at 1000 rpm richens up the mixture. The correct response is for the engine revs to remain the same or slightly increase. If the engine revs increase more than a slight rise it is running lean if it dies it is running rich.
Regards Martin.

It dies.


Also, the fuel reg hose is not leeching fuel into the combustion chamber.


3 out of the 4 cylinders were firing.


Fuel hose is not collapsed either.

[Martin]

Can you check the pressure at the fuel rail? If you pull the vacuum line that goes to the FPR is there evidence of fuel leaking out of the hose. The misfiring cylinder could be the result of it running rich.
Regards Martin.

[jjs1234]

Can you check the pressure at the fuel rail? If you pull the vacuum line that goes to the FPR is there evidence of fuel leaking out of the hose. The misfiring cylinder could be the result of it running rich.
Regards Martin.

No it does not appear to be leaking. No evidence that it it ever had.


When you say you want me to check the pressure, do you mean with a gauge?

[Martin]

Yes it should be 35 Psi at idle. I normally put the gauge in the line at the fuel rail, the line that goes back to the FPR. A "T" fitting with suitable fittings is required.
Regards Martin.

[jjs1234]

Yes it should be 35 Psi at idle. I normally put the gauge in the line at the fuel rail, the line that goes back to the FPR. A "T" fitting with suitable fittings is required.
Regards Martin.

Can one of these be purchased at an automotive store? Or is it specialized?

[Martin]

I just cobbled mine up from bits and pieces in the shed . The gauge I think was salvaged off a compressor regulator, it goes up to 160 Psi but 80Psi should do.
Regards Martin.

FPR Test Gauge 1.jpg (56.35 kB . 768x576 - viewed 606 times)
FPR Test Gauge 2.jpg (57.34 kB . 768x576 - viewed 525 times)
 

[jjs1234]

I just cobbled mine up from bits and pieces in the shed . The gauge I think was salvaged off a compressor regulator, it goes up to 160 Psi but 80Psi should do.
Regards Martin.

I went ahead and did the fuel pressure test. I tested it right before the fuel pump. It was 30 PSI. What is next? To troubleshoot?

[Laitch]

What is next? To troubleshoot?

Focus on determining why one cylinder isn't firing. Is its spark plug's wire connection loose or damaged at the plug or at the coil? Is the spark plug loose in its socket? Is there something bridging the spark plug's electrode? Is the spark plug getting a firing signal from the Ignition Control Unit?

[jjs1234]

Focus on determining why one cylinder isn't firing. Is its spark plug's wire connection loose or damaged at the plug or at the coil? Is the spark plug loose in its socket? Is there something bridging the spark plug's electrode? Is the spark plug getting a firing signal from the Ignition Control Unit?

It's likely fouled due to little oxygen or too much fuel.

[Laitch]

It's likely fouled due to little oxygen or too much fuel.

That is one of the conditions to determine.

[jjs1234]

That is one of the conditions to determine.

I think it's the MAF. Should that be the next step? Or should I pull the plugs? One was white-ish color. Only pulled one to check compression but had the wrong fitting.

[The Mighty Gryphon]

Whitish is LEAN.  You want to know what all the cylinders are doing.  You are wasting your time troubleshooting without knowing all the symptoms.  Plug readings are a valuable window into what is happening in the cylinders.  Be careful not to mix them up when you pull them.

[Scott_]

OP, you mentioned that you rebuilt the motor 18mo ago.... silly questions, and I have to ask so we can eliminate them.

What did you put in it for plugs.
Do they have the correct type top(cap) for the cables you are using, some plugs do not come with the top, only a threaded stud for the top to be installed on.

How old are your spark plug wires, are they original or aftermarket.

[jjs1234]

OP, you mentioned that you rebuilt the motor 18mo ago.... silly questions, and I have to ask so we can eliminate them.

What did you put in it for plugs.
Do they have the correct type top(cap) for the cables you are using, some plugs do not come with the top, only a threaded stud for the top to be installed on.

How old are your spark plug wires, are they original or aftermarket.

Original spark plug wires. Spark plug NGK D8EA.

Whitish is LEAN.  You want to know what all the cylinders are doing.  You are wasting your time troubleshooting without knowing all the symptoms.  Plug readings are a valuable window into what is happening in the cylinders.  Be careful not to mix them up when you pull them.

Sorry, I think I was wrong. Bad lighting. See pics.

Focus on determining why one cylinder isn't firing. Is its spark plug's wire connection loose or damaged at the plug or at the coil? Is the spark plug loose in its socket? Is there something bridging the spark plug's electrode? Is the spark plug getting a firing signal from the Ignition Control Unit?

It's oily and smells like gasoline. #3 counting from front. Gaps are .027-.03.

I just cobbled mine up from bits and pieces in the shed . The gauge I think was salvaged off a compressor regulator, it goes up to 160 Psi but 80Psi should do.
Regards Martin.

FPR Test Gauge 1.jpg (56.35 kB . 768x576 - viewed 606 times)
FPR Test Gauge 2.jpg (57.34 kB . 768x576 - viewed 525 times)

Was 30psi.

Hope everyone can see the pics!

Sent from my HUAWEI MT7-L09 using Tapatalk

[Laitch]

You need to determine why the #3 plug isn't firing. Do the plugs attach firmly to their wires or can the wire caps be wiggled and easily removed from the plugs? If you are trying to convey that the plug gaps measure from 0.024 to 0.027, then they are ok. You should break out your multimeter and run the diagnostic tests found in Vogel's troubleshooting guide for the MAF, fuel injection control unit and ignition control unit. You should check for airflow restriction. The original wires should probably be replaced but you should run the diagnostic tests first.

Did you ever do a throttle body balance on your creation?

[jjs1234]

You need to determine why the #3 plug isn't firing. Do the plugs attach firmly to their wires or can the wire caps be wiggled and easily removed from the plugs? If you are trying to convey that the plug gaps measure from 0.024 to 0.027, then they are ok. You should break out your multimeter and run the diagnostic tests found in Vogel's troubleshooting guide for the MAF, fuel injection control unit and ignition control unit. You should check for airflow restriction. The original wires should probably be replaced but you should run the diagnostic tests first.

Did you ever do a throttle body balance on your creation?

Q: Did you ever do a throttle body balance on your creation?
[/size]A: No I didnt get around to it.
[/size]
One of the cylinders fouls is probably due to me idling it for semi-long periods trying to fix other issues (in this case it was the cooling fan). It has done this before. Cleaning the spark plug fixed the problem + riding it.

I think its not getting enough air due to the fact that I open the oil-fill plug while running and the RPM's increase!

I will start with the MAF. Maybe Ill get lucky and its out of sync.
[/size]

[Laitch]

I will start with the MAF. Maybe Ill get lucky and its out of sync.

You stated #3 plug wasn't firing. Start with determining why #3 isn't firing then if you get it firing, balance the throttle bodies. That would be the time to get around to it.

Messing with the MAF is out of order.

[jjs1234]

You stated #3 plug wasn't firing. Start with determining why #3 isn't firing then if you get it firing, balance the throttle bodies. That would be the time to get around to it.

Messing with the MAF is out of order.

Will do. I was thinking the oily non-firing cylinder was at random, but looking at my previous threads a year ago, it seems its the same one.

[Scott_]

Did I read earlier that you attempted a compression test, but didn't have the correct fittings. So you don't know what the individual compression readings are.
Have you had the injectors replaced/cleaned recently? could be you have an injector on #3 cylinder is leaking and flooding it.

I have my doubts that it is a primary system electrical issue. The coils are paired so if it was a bad spark coil it would also affect cyl #2.

A bad spark plug wire is a possibility--the spark could be leaking out and going to ground elsewhere besides the plug. This can be checked in a dark garage/at night with the bike running, if the leak point is bad enough it could be seen on the outside of the cable, but not very likely.

Just throwing out ideas........

[The Mighty Gryphon]

Four spark plug photos and not one of them shows the terminal...

D8EA plugs do not come with the correct terminal to work with OEM K bike wires.

[jjs1234]

Four spark plug photos and not one of them shows the terminal...

D8EA plugs do not come with the correct terminal to work with OEM K bike wires.

I screwed on the correct terminals from the previous spark plugs.

Did I read earlier that you attempted a compression test, but didn't have the correct fittings. So you don't know what the individual compression readings are.
Have you had the injectors replaced/cleaned recently? could be you have an injector on #3 cylinder is leaking and flooding it.

I have my doubts that it is a primary system electrical issue. The coils are paired so if it was a bad spark coil it would also affect cyl #2.

A bad spark plug wire is a possibility--the spark could be leaking out and going to ground elsewhere besides the plug. This can be checked in a dark garage/at night with the bike running, if the leak point is bad enough it could be seen on the outside of the cable, but not very likely.

Just throwing out ideas........

Injectors are new. They are the 4 hole injectors that other people were using. Still have the originals. Maybe the prob is them? Everyone else was having success not issues...

I've changed the spark plugs 2x and the 3rd cyl is having the same issue.

So today I will:


-Switch spark plug wires
-Clean Spark plugs
-Change back injectors to originals

*Ill see if I can find the correct fittings for a compression test*