Running on 2

[Patman1200]

Hi all

I am new to this forum and an looking for help with my 2001 955i (one of the initial production 955i's for the press launch)

My 2001 955i suddenly started running on 2 cylinders yesterday after I managed to stall it at some lights when a moron in a car cut me up.
I immediately re-started her and all seemed OK.
After 5 minutes I stopped at another set of lights and this is where I thought something was up. It was down on power and running rough. When I stopped at work I could hear it was running on 2 cylinders.
After work I rode her home carefully and once or twice full power would cut in for about 10 miles but the last 20 miles it was 2 cylinders only.

Now for the diags I have managed.
There are no engine lights or fault codes from the ECU/M.
I have traced it to cylinder 3 not running.
I have swapped coil from 2 to 3 and the fault stays with 3.
I have replaced the spark plug with a good old one, still number 3 dead.
I'm sure there is fuel going to number 3 as the plug was wet and there is a smell of fuel from the exhaust, though there may be not enough fuel.

Is it possible that the ECM/U got screwed by the stall and very quick restart?
Is there a way to reset the ECM back to factory/last code in case it has just got confused?

Another update.
Easy-start sprayed into the inlet didn't make a difference.
All spark plugs have a nice fat spark external to the cylinders.
The injectors are all getting a nice square wave from the ECU.

So either there is a lack of compression in cylinder 3 or the spark plug isn't firing under compression (I have swapped plugs from the working cylinders)

Latest diags.
Cylinder 1 = 200psi
Cylinder 2 = 200psi
Cylinder 3 = 195psi <- not firing.
All look good to me though.

Now trying to get TuneECU to work, but with no fault codes being presented, I am at a loss.

Thank god my other bike is a Bandit 1200 with no electronics to get in the way.

So, anyone got any further ideas?

[Bixxer Bob]

Not sure if TuneECU does this so might be talking out of my ass but in Tuneboy you can look at the dwell on all three pots so see that the ECU is firing even if the coil isn't.  Also you can look at the injector pulse to see that all three are the same (ish).

What's got me scratching my head is if it was a wiring fault the ECU would throw up a code.  It all points to the coil stick being duff but you've swapped them so it can't be that, oh hang on, just read again, you've got spark to all three so that explains all of that.

Check for an air leak on the IACV pipes to number three (in fact, any air leak to number three).  Failing that, maybe you have an injector fault? I know you said the plug's wet, but if it's sticking you could be getting too much fuel.  

these things are hard to suss from afar....

[Patman1200]

Thanks for the replky Bob.

I cannot find any air leaks and I have disconnected and reconnected the IACV pipes to all 3 cylinders while running. 1&2 make the engine die as expected but disconnecting 3 doesn't.

I have swapped injectors between 2 & 3 and the fault is still with 3.

Does the timing depend on the timing marks on the crankshaft for all 3 cylinders? i.e. the ECU is detecting cylinders 1 and 2 timing marks, but not 3 thus misses out sparking up 3? But this doen't make sense as I am getting coil 3 firing external to the cylinder. Hint, to check this undo the bolts holding down the coil and lift the coil pack off the cam cover by a few mm's and you will see a nice spark to confirm.

Sorry for rambling but until I get the new OBD lead that should work with TuneECU I am out of diag ideas  :lol:

[Bixxer Bob]

If taking the pipe off 3 doesn't work try putting your thumb over the throttle body housing spigot that it goes on to (clutching at straws now but you have to eliminate each item completely).

Given you have fuel and spark, it's looking ever more like valve clearance.  Your compression is only down a little but it might be a sign.  I don't have any experience of valve clearance problem because I keep on top of mine, but over the years I've been a member here many others have rough running related to the valves closing up especially when warm.

I can't say what signal your crank sensor provides - on the 955i the sensor is on the other side and only triggers once per revolution.  Evil Betty has some experience of crank sensors on your model, but again, you've got spark (and presumably in the right place at the right time) so it's not likely to be that.  The only time I've ever come across a plug firing in open air and not in the cylinder under compression was many years ago when I had a 125 Suzuki trail bike.  The Haynes manual recommended the wrong plug and it wouldn't start (I bought it as a non-runner) even though it had spark in air and fuel.  By lucky chance the NGK rep was in my dealer when I was sounding him for ideas.  The rep didn't think the grade of plug looked right, rang his tech engineer and came back with a different grade.  On fitting it fired first kick.  The cylinder head had two plugs for one pot and it would only run on the recommended plug when it was good and hot.  I've never understood plugs since  :roll:

Doesn't help you much though,,, sorry

[Patman1200]

I think you are right about the valve clearance, it's the only thing that the ECU cannot detect, and I know by just disconnecting them while the engine is running I can create fault codes on the coil and injector.

Cam cover off next methinks!
Poooooo

[Bixxer Bob]

The valve cover gasket is fairly robust treated sensibly and is re-usable (assuming it's the same as the 955 of course) so you should be good to go.  Let's know how you get on

[Patman1200]

Another easy test I am going to do first is spray all the gasket areas for an air leak. You never know....

[Bixxer Bob]

You just reminded me, the injector body (to head) gasket is a known problem on all Triumphs that use this engine.   It's an easy fix and cheap too (about £7) just watch for the usual, don't drop any gasket crap into the intakes etc and the torx screws are quite soft so be careful not to round one out.  SS allen bolts are a good swap. I did a post in the "how to" section on it a while back.  Here it is if you need it:

http://tigertriple.com/forum/index.php/msg,44959 (http://tigertriple.com/forum/index.php/msg,44959)

[Patman1200]

Latest update.

I sprayed the entire trottle body area with WD40 to see if any air leaks might get temporarily blocked and help the cylinder fire and no joy.

I took the Idle control valve pipe off throttle 3 and I get good suction from the throttle. Am I supposed to get anything from the valve itself?

I finally got around to attaching my laptop with TuneECU and the cheap USB OBD diags lead from fleabay and I got lots of good data. Sadly the ECU believes everything is hunky dory so still no joy.

Once I recover from my Enduro race fun I will start stripping the cam cover off to look at the valve clearances.

[Bixxer Bob]

I took the Idle control valve pipe off throttle 3 and I get good suction from the throttle. Am I supposed to get anything from the valve itself?

No, the valve lets the throttle body draw air from the airbox.  It's controlled by an internal stepper motor that opens or closes the valve to the extent decided by the ECU.

I've decided that if your valve clearances are ok then it must be pixies stealing your spark ....

[Patman1200]

The kids have stolen all the Pixies, so it must be Gremlins!  :D

[NKL]

Did you compression test it with the throttle open, if not you get a false reading if its an inlet valve at fault because the closed throttle stops the air coming out the cylinder

[Patman1200]

Yup throttle to the stop

[NKL]

In that case I have no idea

[Patman1200]

Finally I have an answer. Air leak in the throttle body to head gasket.
I felt a very slight puff of air around the bottom of the gasket so I slapped some exhaust gun gum around it and although the bike still sounds rough the exhaust from cylinder 3 is now getting hot and I am getting the usual popping on the over run.
Time to order a new gasket  :lol: