2002 955i Tiger in need of advice

[metalguru]

I can see your thinking here BB, what threw me from blaming the IACV totally was the rather clean port but only on one inlet.

AT, when replacing the TPS make sure you replace the screws as they are soft. The TB gasket will have to be replaced as the TPS will not clear the frame. As these engines run so lean a tiny leak can make them run quite rough but when things are warm and the clearances close then so can the leak, have had similar before, but Girlies can be individual likewise the faults.

[Bixxer Bob]

Ah, you have the advantage MG, I've got photos turned off on my phone due to crappy one G reception here in darkest Kent.

[Arkansas Traveler]

Okay folks, problem solved!  I only replaced the stepper motor and it fixed it.  I still don't know why the diagnostics didn't turn up a fault with the old stepper.  Anyway, it is fixed now. 

MG- I don't know the cause of that clean port, possibly still have a leaking throttle body gasket.  I sprayed it down with TB cleaner though while it was idling and again with the throttle lock on at a higher RPM and didn't notice any change in RPM or other sign of a leak.  I'm about 4,000 miles out for a valve clearance check so I'll hold off until then to replace the seal.  Another possibility is that the IACV seal to the airbox was not very tight.  I could see light on the inside of the airbox when shining a flashlight on the IACV from outside the box.  I doubt it could create an air current draw up into that stack and down that single port.  I sealed it up so I'll find out next time I change the filter.

Thanks again to everyone for all of the input.  I really appreciate it.

[Arkansas Traveler]

Well, I didn't fix it.  It ran fine for two days after the stepper motor swap and then day three following a 400 mile ride, it started the whole no idle when cold routine again. 

Yesterday I replaced the throttle body gasket as MG recommended and checked the compression which was good.  I got it running long enough to warm up and balance the throttle bodies.  After putting it all back together it would start fine but it was still warmed up from the TB balance.  This morning, same old issue, no idle when cold and now it is weak to idle when warm, around 800-900 RPM. 

I'm guessing it is the TPS but I'm not getting an error code for it.  I reset the TPS with TuneECU several times.  I am getting a voltage of between .61-.69 from it.  Can it be bad without a fault being recorded by the ECU?  My book doesn't give any pinpoint values for checking the sensor, just continuity checks to the ECU.

Thanks again for any input. 

[Bixxer Bob]

AT, if it's ok when warm but not when cold you need to be looking at a temp sensor. The ECU takes values from the engine (water) temp, the intake air temp and intake air pressure- as well as the throttle position - to work out  a) how much oxygen is available in the air and so by referencing the correct part of the fuel map, b) how long to open the injectors to allow fuel into the TBs.  If the engine or air temp sensor is reading warm when the engine is cold you won't be getting enough fuel going in (think cold carb engine with no choke).

Read the sensor voltage in TuneECU for clues.

If not a sensor, and bearing in mind a 400 mile run screwed it up again, look at what changed in your trims.  The ECU for some reason may have trimmed a value out of range.

For what it's worth, mine was running sweet when I went out this morning  having just done a TB balance, 100 miles later it's back to normal, and not in a good way.

[metalguru]

I'm guessing it is the TPS but I'm not getting an error code for it.  I reset the TPS with TuneECU several times.  I am getting a voltage of between .61-.69 from it.  Can it be bad without a fault being recorded by the ECU?  My book doesn't give any pinpoint values for checking the sensor, just continuity checks to the ECU.

If the variation is more than .66 then the tps is at fault.

Strange it is giving cold start problems, Check out the warm up map and what is your LTFT set at and the IFT.

[Arkansas Traveler]

MG- LTFT 4.1 and IFT 0.0

I attached some screenshots from TuneECU.  I got the program after this issue developed, so I don't have a healthy baseline for comparison.  Does anything look abnormal? The first image is of a cold engine and the last is after it's warmed up.

I also just received a book with resistance values for the coolant and IAT sensors.  Both of them were slightly less than their listed tolerances.  I'll be ordering them today with a TPS.

[metalguru]

1st pic is a good clue to the TPS being at fault, it is showing .69 when it should be less, unless throttle was open at the time of the shot. It is good practice when making any adjustments to reset TPS, start engine and without touching the throttle (best done warm in this case) untill the Throttle value stabilises from 0.0 TPS reset to running value. (can vary).

[Arkansas Traveler]

I ordered a TPS, coolant temp sensor, and an IAT. The movers surprised me with an early packing of my household goods of which the Tiger belongs for shipping to Germany. I'll carry the parts with me and swap them all out when I get the bike over there.

Thanks again folks.

[Arkansas Traveler]

**Update**

Valve clearances were the culprit.  I replaced the TPS, Coolant Temp Sensor, Intake Air Temp Sensor, Stepper Motor, and Throttle Body Gasket, none of them changed a thing.  So checking the valve clearances found several slightly out of tolerance.  Compression checked good when warm, just a little weak when cold.  I had a shop do the 12,000 mile service and I am willing to bet they didn't check my valve clearances then.  Anyhow, runs great and I just got it plated in Germany.  Lets ride, Dutch!

[Dutch]

I replaced the TPS, Coolant Temp Sensor, Intake Air Temp Sensor, Stepper Motor, and Throttle Body Gasket

Guess you have some spare parts for sale then

Lets ride, Dutch!

Daytrip "around Ruhrstausee" sounds great to me. I'll contact you via pb soon. Looking forward to meet you in person

Greetz, Dutch

[Arkansas Traveler]

Yeah, I have all of the sensors in the spares bin. Somehow I lost the stepper in the move though. Let me know if you need one.

Looking forward to the ride.