Triumphrat

pete2 · 05-02-2009, 11:06 AM

Okay. I've had terrible fuel consumption, I thought it was part because of my rather short gearing. But I also noticed the bike was running rather rich. And every now and then it would foul a plug when starting. So today I stated investigating.

All the plugs were black as... well a very black thing. Some of them also had a bit of deposit on them -> replaced. When removing the fuel tank, I noticed the "white" fuel line, whichever it is (in or out), was a bit on the moist side. Then I thought I had occasionally sensed a bit of fuel smell, but as it came and went, didn't pay attention to it. I thought to myself "oh well, that's where it comes from." The ICAV to airbox hose was cracked, but luckily I had a suitable hose -> replaced. The ICAV itself was a bit on the dirty side, so I cleaned it. Seemed to work alright, however. Then I fitted everything back and fired it up.

Still a lot of rich mixture smoke in the exhaust. After that I noticed a drip of fuel under the bike. "Oh well, that's probably just from removing the tank." Oh poo, there's another! The white connector was leaking, and not by a small amount! Then I emptied the tank and removed both the female connectors. These I will have to replace with metal bits next week, I think. Also the O-rings on the male connectors were a bit knackered.

There still was the problem with the bike running rich. I played with a voltmeter a bit and saw that there's always voltage from the TPS no matter how I adjust it. This puzzled me a bit. I got this killer OBD2 reader & datalogger tool, which I plugged in. TPS showed 42% open with the throttle closed. Man, no wonder it's been feeling like it's running rich & fouls plugs on startup! I then adjusted the TPS to minimum, but still it shows 7% open... The worse thing is that it only goes to 68% when throttle fully open.

Now the next step after I get new fittings for the fuel pump is to get the lambda attachment part welded to the exhaust and hope I can compensate the TPS not giving out proper signal with the Power Commander...

Which also raised another question... I know I could go and check this out myself, but I'm really not too keen into working with the bike (I'd actually rather go fit the leaking connectors back and go for a ride until it cathes fire), but does the PC TPS lead give out any current?

BombFactory · 05-02-2009, 03:14 PM

The throttle position sensor isn't going to, nor does it need to read 0% at closed or 100% at full-open. A typical full-throttle is going to read around 70%.

pete2 · 05-02-2009, 04:02 PM

What? Really? How come? Doesn't make sense to me...

BombFactory · 05-02-2009, 06:01 PM

The percentage of throttle shaft movement is calculated starting at the closed position reading of the TPS's range, which does not have to be 0% in terms of electrical current readings. The computer is programmed to take the closed throttle position (set in the computer to zero by the factory diagnostic tool or TuneBoy) and make calculations for all throttle angles based off that point. The TPS does not need to be set at a perfect 0% on a multimeter (if this is even possible), so long as the ECM is told that the position is the zero point from which it is to make calculations.

The problem with trying to set the TPS at closed position using a multimeter is that unless you set the TPS on the engine at the exact same, properly set resistance for that exact same ECM, the computer's idea of 0% throttle position will be off. To reiterate, you cannot simply change the TPS's position on the engine, you must also reset the computer's old reading for zero TP to the new TPS position.

Will · 05-02-2009, 07:11 PM

It's one reason why TuneEdit is such a great too.. You can reset the TPS electronically without taking anything apart.

pete2 · 05-03-2009, 04:28 AM

Quote:

Originally Posted by BombFactory

you cannot simply change the TPS's position on the engine, you must also reset the computer's old reading for zero TP to the new TPS position.

Crap. Oh well, I'll fix it with PC3

BombFactory · 05-03-2009, 02:02 PM

Quote:

Originally Posted by pete2

Crap. Oh well, I'll fix it with PC3

I didn't think PC3 had that capability?

DEcosse · 05-03-2009, 03:48 PM

Quote:

Originally Posted by pete2

Crap. Oh well, I'll fix it with PC3

Quote:

Originally Posted by BombFactory

I didn't think PC3 had that capability?

PC3 will only zero for its own map - it will NOT reset the position for the ECM map.

pete2 · 05-05-2009, 06:26 AM

Quote:

Originally Posted by DEcosse

PC3 will only zero for its own map - it will NOT reset the position for the ECM map.

Yes I know. But it can alter the F/I map to compensate.

More about the TPS reading, as I got it from the ECU and not from TPS, I feel it strange to believe it's not reading the throttle position set by ECU. Afterall, I just set the analyzer to show the throttle position from the ECU, not TPS signal. And it showed percentage.

BombFactory · 05-05-2009, 12:42 PM

Quote:

Originally Posted by pete2

Yes I know. But it can alter the F/I map to compensate.

More about the TPS reading, as I got it from the ECU and not from TPS, I feel it strange to believe it's not reading the throttle position set by ECU. Afterall, I just set the analyzer to show the throttle position from the ECU, not TPS signal. And it showed percentage.

Yes, and you said the ECM thinks the TP is at 42% when it is physically at 0%. What the ECM thinks doesn't change the fact that the sensor's old position of 0% TP is no longer the same.

The air/fuel ration of the ECM map will not compensate for an ECM that has the wrong reading for closed throttle position; it will simply apply whatever a/f ration it reads for whatever TP the ECM believes it is at. If the ECM thinks that when the TBs are actually closed that they are 10% open, it will supply the engine with the a/f ration in the map for a TP of 10% when the TBs are in fact closed, it will not correct that.

Your analyzer tool is reading the ECM's TP, but that TP is calculation 'zeroed' off the old position of the TPS. Because you have been moving the TPS around, the actually closed TP is not what the ECM thinks. Unless it is 'zeroed' off what the new TPS is set to, it will be off.

An analogy that comes to mind is that of an adjustable calibration vernier dial caliper.

For an accurate reading, the slide bar of the caliper must be set to zero (i.e. the jaws are fully closed), and you then rotate the numerical scale readout by hand so that the needle reads zero. This would be like zeroing the ECM TP (scale) to the TPS position (jaws). What is happening in your case is that the old TPS position was fully closed and the ECM TP was set to zero. So it was calibrated, jaws at zero, scale at zero. Now, by moving the TPS position, you have essentially placed an object, say a 1/2” diameter bolt head, between the caliper jaws and wish to make this point ‘zero,’ but you did not zero out the scale. So even though the jaws are placed where you want zero to be, the scale will always read 0.5”. Until the scale is zeroed to that 0.5” at the jaws, the caliper is no calibrated.