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Discussion Starter #1
Sorry for yet Another thread.
I just feel this deserves its own attention as from what I've read so far, affects Many different things & can be a finicky lil booger!!!

& because I'm not going to spend over $100 on a replacement part without some more inquiring from you guys :hail

So the sensor affects pretty much Everything that I am having problems with.

My timing is 100% spot on & the valve clearances.
Throttle Bodies are synced & TPS is set.
Coils are Good.
Plugs are Good.
Battery & charging system is Good.
& so on & so on....

The front cylinder Keeps misfiring.
Although it has lessened, its still there.
Its backfiring on & off the throttle.

Thats pretty much as short & sweet as I can explain the symptoms without taking this into yet Another troubleshooting thread! (not the purpose of it)


Since everything Else that Would cause those problems first are eliminated as being the problem.

All that is left to be the cause is the Crankshaft Position Sensor.
The Ohm reading on it came back OK but the side cover is off & I cant start the bike right now to test it fully.

Sensor basically sends info to the ECU & then branches out to the other parts (coils, etc etc)


So, does it sound like the sensor is going?
Even if all readings come back OK, all fingers point to that now.
Since im pretty sure I already covered all of the other bases.

Just need some Good intel on it before I pull the trigger & buy a new stator & sensor.

Still need to check the wiring at the end connection first tho (didnt have time yesterday)
 

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I've seen 3 faulty sensors

all tested fine.

substitution is the only real confirmation.
 

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Heard an interesting snippet of info relating to crank shaft sensors recently. The trigger for the sensor is just a magnet. Because it sits in front of the sump plug magnet in the oil flow it tends to pick up any stray metallic particles. The particles then produce spurious signals which can mess up the triggering. The particles sticking to the magnet alter the effective gap and the field strength so the signal gets noisy. Clean everything up and the problem goes away.
 

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Discussion Starter #5
Heard an interesting snippet of info relating to crank shaft sensors recently. The trigger for the sensor is just a magnet. Because it sits in front of the sump plug magnet in the oil flow it tends to pick up any stray metallic particles. The particles then produce spurious signals which can mess up the triggering. The particles sticking to the magnet alter the effective gap and the field strength so the signal gets noisy. Clean everything up and the problem goes away.
It was clean when I removed it.
But I do plan to reinstall the side cover, so I can start the bike & check it fully with my multimeter.
So I will clean Everything on the inside Really good first.

Have my attention on the sensor now, because if its causing a problem.
Then all the problems I am having will be a direct result of it.
Of course, if it was fully shot, the bike wouldnt even start & there would be a code.

Which reminds me.
Is it safe to ride the bike in Dealer mode?
In hopes a code will be given at the time of the misfiring & backfiring (backfiring on & off the throttle, so its not just a possible exhaust leak)
 

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faulty crankshaft sensor showed up as missing on and above idle
no apparent reason
erratic codes showed coil errors with no actual coil faults
never found any particles to confuse signals present
 

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....
But I do plan to reinstall the side cover, so I can start the bike & check it fully with my multimeter.
So I will clean Everything on the inside Really good first.
....
As the manual says, you will need a peak detector for your meter, or the meter will need to have a feature that allows it to capture and hold the max readings. Otherwise, it will display voltage values that make no sense, and they will not correlate with the spec in the manual. The crankshaft trigger pulse is too fast for typical multimeters.


Which reminds me.
Is it safe to ride the bike in Dealer mode?
In hopes a code will be given at the time of the misfiring & backfiring (backfiring on & off the throttle, so its not just a possible exhaust leak)
Yes, it is safe to ride it in dealer mode. It is merely a diagnostic feature. It does not change the way the FI system operates.

However, if it were going to throw a crankshaft sensor code, it would have done it by now. I'm not trying to bust your bubble Tombstones, but chances are very good that going through with this exercise will only lead to yet another disappointment.

IMO, you have gone to great lengths to find the stumbling/surging issue with your TL, and I admire your determination and willingness to tackle the 'unknown.' Still, given the various things you have addressed (and some even corrected) and yet the stumble remains, I think it is time to consider employing a reputable shop that has the tools and know-how to diagnose fuel injection problems. I know you are strapped for $$, but if you want to keep this TL, there is a point where your time and frustration are worth something. Also, I gather from your posts that you just don't have the work space or tools that are needed to diagnose the problem at hand.

I'm all for 'doing it yourself,' but for the sake of your sanity and your family's well being, a qualified tech could be well worth his wages. I'm not saying go to a dealer, but ask around and search the web, and you'll find an independent mechanic or a race shop who knows what they are doing. I know Pennsylvania is full of motor heads. My bother-in-law lives in Bangor, PA, and while he does much of his own wrenching, he has had plenty of interaction with the local speed shops while maintaining his many Ducatis and Kawasakis through the years. If you would like, I could get some names and references from him for you.

I only suggest this option, because the tone of your posts paints a stressed-out image in my mind. That's not what working on your bike is all about. It is suppose to be enjoyable. However, if you are happy with the progress you are making, then 'keep on trucking!' Hopefully, you'll have breakthrough soon.
 

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Discussion Starter #8
Yeah I am stressed out on the bike. Haha
Ya I will do some searching, already know I can't go to the big dealers, they will just rip me off, has happened before.....

Well, when I got the bike, it was fine.
I did two things.
Timing and valve clearances are perfect.

The first thing I did I totally forgot about.
Which was taking the stator cover off.
So I'll look through the manual more and see if I did anything wrong.
Like when I reinstalled those cogs.
Not sure if the timing needs to be at a certain point, or something else.

Also going to clean everything up and inspect the connections first.

If that doesn't help, then I'll start making calls.
 

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Discussion Starter #9
Okay, sorry but im going a little off topic for a minute.

On topic tho.
Just checked the wiring & connectors for the stator & sensor.
All is fine there.

& while I had the rear side fairing off, noticed something odd.
I always thought it was a hose for the battery drain ( two of my bikes had them )
This time I seen the other side of the hose.

Looked the part up & I cant seem to find it on the diagram.
Hell, I cant even see it mounted in pics of the same area in the Manual!

Its plugged in, didnt follow the wire Yet as I came in to look it up & post.

The hose was simply tucked into the battery tray & not hooked up to anything.



 

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Discussion Starter #11
Well, nothing to really update as far as progress goes.
Been too hot, busy working, & by the time I get home im just Exhausted!
I also simply took a break from the bike, physically & mentally! hahaha

Did clean up the stator area & sensor.
Got the cover back on without any leaks, but still misfired.

Few things to cover though.

The rear exhaust connector shouldnt be causing the misfiring. (just the backfiring)
As the front cylinder is misfiring, not the rear.

& one more thing I did when I first got the bike that I forgot about.
I also replaced the spark plugs.
With the same ones that were in there but I tossed the old ones or mixed them up with others in my tool box.
So, Friday I will be picking up some NGK Iridiums for just $7.09 a pop from advance auto that has two stores nearby with them in stock.

Also grabbing some carb cleaner & doing a Better cleaning of the throttle bodies.

Before I take the TB's off though.
Im doing another compression test.

As if there is no change from better new plugs & a Thorough TB cleaning.
I'm going to go out on a limb & say its a front valve problem.

Few reasons for this thought.
The valve clearances were tight as HELL when I first checked them.
& its when the issue started.

The other.
When I had the head off, i cleaned the living Hell out of the bottom of the valves, & left some WD40 soak overnight in the top areas.

After that is when the bucking Greatly decreased & went from acting up between 3 & 4K to 2 & 3K RPMs.

I've done a TON of valve work on my GS500, on multiple heads & multiple engines ( bought one engine with a bent valve, the 2nd engine I didnt seal the header pipe enough & it bent one in that)

So removing, installing, & lapping valves is no trouble at all.
Since its backfiring into the throttle bodies still, im going to assume that is from the Intake valves?

Removing the valves & having them, the springs, & the seats inspected will cost me very little.
Another reason it might be a valve problem.
Since the shop did it for free (leak down test)
He might have just half assed it & didnt properly detect Where the leak was.
I've already watched a ton of videos on leak down testing too.
So he might have not listened & looked in the proper areas to detect Whats leaking.

& as far as paying a shop to diagnose it.
I've run out of time to spare that much $$$ at once.
Its now Two months & Two weeks away from the Twins C section schedule date.

Honestly, I just needed time away from it.
 

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Do NOT lap valves. the valves have worn with a curve on them and a matching curve on the seat.

when you lap them you make the curve deeper.

when the engine gets hot the curves don't seal on each other cos the valve is bigger than the seat.

So take the heads to an auto engine reconditioner with tools for late model japanese cars and get then cut and face properly.

they will not need to be lapped after that

the flat surfaces still seal when the valve expands.
 

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Discussion Starter #13
I dont plan to lap the Current valves.
There was no indication of leaking when I had the head off.

If the new Iridiums & Thorough TB cleaning doesnt help.

Then I plan to remove the front head & ALL of the valves.
Take the valves, springs, & head to the shop to have them inspected with the proper tools that I do not have.
Unless I notice something wrong before hand.

Like a Very slight bend in one of the valves, or a valve spring being shorter then the others when placed next to eachother.

Only thing I dont know how to inspect or have any tools to, is the valve seat & guide.

I only said what I know how to do when it comes to valves.
Incase I would need to replace one of the valves.

Honestly, I doubt bothering the TB's or new better plugs will change things.

All the problems are up front & the PO wheeling Poorly caused the problems up front.
The fork seals being blown, leak down test showing leaking in the front chamber, & the misfiring staying in the front cylinder.
So if all fingers point there, then thats where I should of been thoroughly inspecting from the start.
I've just been working too much (have to), stressed out, & bombarded with every problem in the book over the past 3 years! (financial, legal, family death & health problems, my mother losing the family home because of finances, etc!)


Reading up on valves & problems.
I read they need to be "Precise", any difference will cause problems.

Also for a future reminder for myself.
Going to take a magnifying lens to everything, including the head.
Could always be a hairline crack in something.
 

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Discussion Starter #14
Throttle bodies off AGAIN! haha
Going to remove all the hoses & soak them in some slightly soapy hot water & pretty much clean every single thing i possibly can.
If I dont find anything gummed up, ruling the TBs off the list.

Spark plugs still look perfectly fine.
But, they are NGK 9's, not 8's that I read are recommended for the S (9s for the R)
But I doubt it would cause these issues.

Still getting Iridium 8's tho.

another problem with the TB's.
Everytime I would sync them, the fluid in the meter was never ever smooth.
I could still get them synced really good but it was quite a chore.
One little tiny touch of the screw & it would change the sync level of the fluid Quite a bit.
Should have made a video of it one of those times.....

They were synced as best as I can the last time I did them.
But when I took the TBs off & held them up towards the sun.
I could clearly tell, one was showing more light around the butterfly flaps then the other.

& its not me or my cheapo sync tool.
I had them 100% spot on at idle a few times when the shop rechecked them.
Only part I didnt have 100%, was at higher RPM's, but he said they were close as hell!

Which leads me to an even more indication of a valve problem.

I dont care either way.
That front cylinder head is coming off & im removing the valves & having everything checked.

& it appears I dont need a new exhaust connector clamp :D
Ya its a little crusty but not faulty.
The Bolt was fuxxed tho!
ended up snapping on me

Also need to snag new lower connecting pipe bolts.
The one stripped to hell but Luckily I was able to get it out..... in Twice the time it would have taken me to drop the exhaust without issues!
 

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Throttle bodies off AGAIN! haha
Going to remove all the hoses & soak them in some slightly soapy hot water & pretty much clean every single thing i possibly can.
If I dont find anything gummed up, ruling the TBs off the list.

.....
Beware. Some of the vacuum lines have tiny plastic jets inserted into them to control the air flow. Be sure water does not get trapped in a section between the jets. It may just add to your problems.

This is not a TLS image, but it illustrates the typical locations of the vacuum jets.

 

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its an R image with S gauges!
 

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Discussion Starter #17
Thank you Six for the reminder.
Just seen those jets in the parts diagram on bikebandit, when I was looking up how much all new hoses would be.
 

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Discussion Starter #19
Well, just got done with the TB cleaning.

Prior to that, snagged the new Iridium plugs, new bolts for the exhaust connection underneath (one stripped) & one for the rear header clamp.
Rear header clamp gasket is otw.

TB's themselves were not that dirty, but I scrubbed them good.
The vacuum hoses were quite dirty tho.
Lots of black inside the T connector.
Soaked them in hot water for a bit, then shot a lil cleaner through them all, rinsed them good and soaking them some more.

Going to hold off on touching the front cyl head until the rear header clamp arrives, get it back together & see how it runs.

Doubtful it will be any different, but still a chance & im not wasting time taking the head off if I dont have to.
 

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Discussion Starter #20
checked to see if the new bolts were good for the exhaust clamp......
damned threads are shot.

Just ordered two clamps Six suggested (proper size)

Two questions now.
What size & type of hose for the vacuum lines on the throttle bodies?
(if they are cheap, why not just replace them)

& what size fuel hose for the one under the tank? (Not the clip on one or the overflow hose)

Hate working 9 to 10 hrs a day Mon thru Sat...
Could have gotten ALL of this at a local cycle & atv salvage yard! (they dont just deal with used)
 
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