K100 2V run issues

[andyldean]

Help Please [/size],[/color]
[/size]I currently own 2 K100's a 2v and a 4v.Recently decided to strip the head off the 2v to change the stem seals and give the engine a good clean strip and paint while I was at it.To cut a long story short I managed to get a replacement engine with only 65k on it for $100 so decided that would be the easier job.I rebuilt the bike up and tried to fire it up. The bike did run but very rough and with a distinct misfire.As the wiring loom had been seriously hacked over the years I decided this could be a source of issues so changed that for a replacement in good condition.Still no change misfire and rough running.Timed the Hall sensor unit with a drop clock and led box all goodremoved fuel rail and checked injectors( all spray well)so started to change and check all the following:Fuel side : Injectors (changed) , pressure regulator (changed) fuel tank and fuel pump (changed).Ignition side: plugs (changed), HT leads (changed),coils (checked resistance etc), Hall sensor (checked)Electrical side: battery (checked), Alternator (changed) earth connections ( checked) still the bike will not run well and on occasion will not run at all. fuel is def getting into the cylinders as after a while it will run out of the headers. def getting a spark as it will run on occasion but miss fire.Really at a sticky point now just don't seem to be getting anywhere with this.Determination is the name of the game but any pointers would be very helpful and much appreciated.Thanks in advance[/color]

[^Adrninistrator]

Longest sentence ever.  I have an eye on you.

[The Mighty Gryphon]

I suspect you have the leads for plugs 2 & 3 crossed.   You won't be the first to do that.   Double check the numbers on the wires. 

[Scott_]

Only $100 for a complete engine with 65K, what's wrong with it....   have you done a compression check. Something doesn't sound right.

[andyldean]

Compression is good and equal on all cylinders.
The engine had no covers oil pump etc and the 2v engines are not as valuable as the 4v due to the market in heads.
BMW shop in Brisbane has loads of spares and is very reasonable with prices.

[Martin]

Check the temperature sender and it's connection. A bad sender or connection can cause over fueling.
Regards Martin.
K100 Temp Sensor Values.jpg (38.1 kB . 768x464 - viewed 678 times)

[andyldean]

Ok so I have spent a few more hours on the bike now and completed the following:[/size]Stripped the throttle bodies off the bike checked and cleaned everything and replaced.New plugsNew coilschecked earth terminalsI restarted the bike and it fired straight away but ran very lumpy, and died on throttle.I checked all four exhaust pipes and they were all hot which confirms it feels like a rough running not so much one cylinder down.A suggestion from the shop I bought the engine from was to turn the timing plate slightly to see if it would smooth out, i tried this and it did run a little more smoothly and was able to run at 1000rpm without stalling but still not smoothly. The time plate slots now are a mile out of position so I am not convinced its right.Ok so my next line of thought was valve timing?The rest are observations, not sure if its right or wrong but if I give you the full diagnosis hopefully one of you guys may spot something to work with.I decided to pull the rocker cover and timing cover to check the valve timing.all plugs were dry but black.On pulling the rocker cover the oil (synthetic) appeared dirtier and thinner than I expected. (all engine internals have been cleaned) and maybe a slight sniff of fuel.timing cover off and next job is to check the valve timing, but at first look it appeared ok.I have a rebuilt head and headgasket on the bench so not sure if I should throw that on.Although cylinders check out well on compression.any thought???[/color]

[Martin]

Black plugs indicate running rich, check the temp sensor connection. A bad connection or sensor will cause hard starting and uneven rough running.
Regards Martin.

[andyldean]

Hi,
yes i have checked the temp sensor and even have another one I have put in its place.
I am going to check it again in the morning and then I can be sure.


Is there any way to bypass this sensor?

[^Adrninistrator]

Two longest sentences ever.  I have both eyes on you.

[Martin]

You can substitute the sensor with a variable resistor or possibly a resistor of the correct value in the normal temperature range.. However even if the sensor is good a bad connection will still give problems. I've had it happen twice and managed to get home, and with a bit of a wriggle on the connection it came good. After the second time I bit the bullet and cleaned the connection properly (Deoxit) and smeared dielectric grease around the connector. I believe the grease stops the ingress of water and road crud which leads to oxidization and bad connection. I cleaned all my bricks electrical connection except one, which was hard to get to and it was the only one I've ever had a problem with in twenty years of ownership.
Regards Martin.

[andyldean]

Thanks I am going to try that first thing in the morning.

[Scott_]

Unless the timing chain was removed at some point in time, and then installed wrong, it should be set correctly. The timing chain shouldn't jump, and if it did, it would throw off your compression tests. Probably not a lot, but I suspect an electrical related issue.

Does your 2v bike have an air flow meter? is the flapper binding.
Have you checked your TPS switch.

[andyldean]

Hi,


yes checked the TPS and the Airflow both check out ok.


I know the valve timing is  along shot but the engine was sat around in a repair shop for some years so it is a possibility.


Not sure how it would show on compression check it could be wrong on the crank?

[Scott_]

Basically if the valves opening/closing are out of time from what is intended, you would run the risk of hitting a valve with the piston top at worst case, or compression in general being lower than normal, at best case of incorrect valve timing.

I haven't looked at the wiring diagrams in depth, but double check that the low voltage leads to the coils are on the correct coil. I suspect they are probably correct as it runs somewhat, albeit not good, but it does run.

[Laitch]

checked the TPS and the Airflow both check out ok.

Have you rechecked the temperature sensor values as you intended, and checked its connections and wiring? Yours is a story that's been repeated from time to time—many parts replaced without a change of results. If the fuel pressure to the injectors is correct, options are narrowing.

Consider returning to the K100 troubleshooting guide and performing the diagnostic tests described in it for the fuel injection control unit and the ignition control unit. I've been involved in threads where a defect in one of those units was the underlying cause of the engine performance you have described. After finding non-conforming data, substituting a unit that is known to be working is usually the last step.

On the other hand,  "Oh! I just found a disconnected/misconnected wire. Everything works now" isn't an unusual outcome either. :giggles

[andyldean]

[/size]Ok so I tested and cleaned all the temp sendor contacts checked resistance at the sendor and at the computer. temp was approx 25 deg C so guessing this is ok.[/color]

[andyldean]

Checked valve timing and retimed the hall sensor all ok there as well.[/size]checked the pressure at the fuel line 30psi and stable so assume thats ok.then decided to try and balance the carbs.This is when i discovered something interesting, when i remove the rubber bung to attach the vacuum gauge teh bike starts to run a little better.when i attach the vacuum gauge its runs shit again.so i remove all the rubber bungs and it runs even better.no way i can balance carbs as everytime i attach gauge the bike starts to die.only one vacuum point looked like it would alter with winding screw and vac gauge attached.what is going on here ?eventually stalled the bike and now it will not restart I assume its flooded.[/color]

[Laitch]

. . . when i remove the rubber bung to attach the vacuum gauge teh bike starts to run a little better.what is going on here ?

The mixture is getting leaner with the addition of air. That would improve idle in an over-fueled engine up to a certain point then the computer inputs don't align and it stalls.

[andyldean]

ok so are we looking at a sensor issue then?
I have just pulled the airflow meter and tested the airflow and air temp side and that reads right.
I checked the temp sendor and that looked good as well.


I iwll check all pin values at the ecu tomorrow to double check that as well.

[rbm]

Have you checked the state of the MAF?  And I'm talking about the electrical operation of the internal wiper as well as the mechanical operation of the door mechanism.  There could be problems with the resistor array that incorrectly informs the ECU about  current air temperature and mass.  The centre pivot wiper is known to act up in that unit.

[andyldean]

Ok so I checked all the pin readings at the ecu and everything looked ok.

checked the airflow sensor and all ok there again checked at the ecu and all good.
Still the bike ran very rough and flooded after running for a few minutes.
I got another temp sender and wired it out of the bike and left it dangling in boiling water.[/size][/font][/color]
started the bike and it all ran well checked at the ecu plug and readings the same as the old sensor.
To cut a long story short it was a dicky plug on the temp sensor.
soldered up the break in the wire and she runs like a new one :-)

[Martin]

 :2thumbup:

[Laitch]

Help Please . . .

Ok so I have spent a few more hour . . .

Compression is good and equal on all cylinders. . . .

Hi,
yes i have checked the temp sensor . . .

Thanks I am going to try that first thing in the morning.

Hi . . .

Ok so I tested and cleaned all the temp sendor contacts checked resistance at the sendor and at the compute.

Checked valve timing and retimed the hall sensor all ok there as well. . . .

I checked the temp sendor and that looked good as well.

To cut a long story short it was a dicky plug on the temp sensor.
soldered up the break in the wire and she runs like a new one

I think it's too late to cut the story short, andy.  :giggles
Congratulations!