No voltage at TPS

[dale-j]

Hey all.

 

I'm following dlaing's TPS adjustment and sync sticky, trying to chase a running problem where despite several PC3 map changes the bike is still heavily rich (10.0:1 -11.5:1 AFR) at light throttle. Better at larger throttle openings after resetting PC3 closed and full throttle values, but that indicates there has been some TPS signal drift to my mind, as the values saved in the PC3 showed that at closed throttle, the PC3 was reading the signal as 13-15% opened (this might explain the detonation at 3K if the ECU advance curve was 13-15% ahead)....

 

probing my tps connector using wires and paper clips inserted, I'm getting no discernable voltage with a multimeter.

soldering extensions and pigtails on as the suggested alternative, I'm getting no discernable voltage with a multimeter.

changing to my backup meter, I'm getting no discernable voltage with a multimeter.

Borrowing my father-in-law's older analog meter, I'm getting no discernable voltage with a multimeter.

Borrowing my brother-in law's newer and more sensitive digital meter, I'm getting no discernable voltage with a multimeter.

 

Do I have four bad meters (yes, batteries are fresh in at least three of the four), or am I doing something wrong? Probing the two outside wires but have tried the middle against both outside wires as well; still no love.

 

The bike still runs (if the throttle rod is reconnected)... makes good power too but is sooty black (exhaust and plugs), rich, detonates at part throttle 3K and delivers poor fuel economy compared with my brother in law's V11 Sport.

 

Any suggestions? TPS is coded PF3C/00, bears the guzzi eagle, and looks stock.

 

Steve

[Kiwi_Roy]

You should have 5 Volts DC across the TPS.

If you unplug it you can test the resistance as shown.

Roy

ECU Test Points.pdf

[mznyc]

Same thing happened to me when I went to adjust my TPS a while ago .just didn't have good contact with the TPS from the probes .dont remember how I got readings,believe I just fiddled with the probes till I got it.

[fotoguzzi]

try probing the same color wires but at the cpu box, they can be easier to get to, might have to turn the box over to see the plug.

[dale-j]

Thanks Guys. I have fiddled some more and still nothing, but thankfully I happen to be a short distance from Roy and he has offered to assist. Will update when I know what the culprit was.

 

S

[Tom M]

I found that small safety pins worked well for taking readings at the TPS. No need to pierce the wires, just slide them down into the connector until they stop.

[Kiwi_Roy]

I'm pleased to report we were able to sort out Steve's immaculate LeMans, what a beauty

 

We found the TPS set very high, about 300 mV but it looked as though it had never been tampered with

yellow paint in the fixing screws.

Steve has fitted a mixture indicator which came back into line once the throttle bodies were all lined up

as per Dlaing method on the FAQ

 

She ticks over like a Swiss watch.

 

The bike is in good hands with her new owner, obviously very fussy about having things just so.

[Lucky Phil]

I'm pleased to report we were able to sort out Steve's immaculate LeMans, what a beauty

 

She ticks over like a Swiss watch.

Thats great Roy but no point posting this without details so we can learn something.

Ciao

[dale-j]

Roy is being diplomatic, that's all....

 

The problem was first and foremost an assortment of junk multimeters of which only one was accurate, coupled with an extreme case of operator ineptitude and one bad crimp connection with no current.

 

Once sorted, and the voltage reduced to correct levels, the low throttle richness is gone and wow is the bike smooth... it was not off by a lot, but the sync really made the idle nice and the throttle response crisp.

 

Thanks again to Roy who is a brilliant mind with this stuff, I'm glad different people are good at different things because I'm lost with this stuff.

 

Steve

[dale-j]

By the way, the map that I am running is Map 4 from the PC3 map thread (somewhere) here in the fileshare section (thanks to Gord at Valley Motorsports for the assistance with this), that is intended for later crossover pipe equipped bikes running the FbF Crossover, FbF airbox lid eliminator, MG Ti cans etc.

My bike is similar but not the same - I have the modified airbox lid per the thread (sorry, can't find it at the moment) that Greg Field, Doc and a few others contributed to (three 25mm /1 inch holes in specific locations, plus the removal of the rubber and expansion of the intake bells). I have what appear to be either Mistral or MG (Lafranconi) Ti Cans and a Stucchi crossover. Fresh UFI air filter (and oil filter, and 20w50 Redline synthetic, fresh Motul Transoil in tranny and fresh Redline Heavy Shockproof in the final drive).

Valves were just adjusted to the world specs per Jaap's great write up, fresh NGK plugs, and as noted we followed dlaing's instructions on the TPS per the FAQ, which were clear enough (after Roy's assistance in clearing up my issues with the readings) even for a first timer.

I have an Innovate Motorsports MTX-L Air Fuel Ratio gauge installed, so I have instant info on the mixture.

SO, the richness at idle and part throttle is fixed. Beautifully so, and so is (it appears, after two long rides yesterday and no fuel light on yet) that my fuel mileage issue is fixed as well. Light throttle openings are now 13:1 to 13.5:1 give or take, depending on rpm and actual throttle position. BUT there is still detonation at larger throttle openings between 2000 and 2500, just for a short blip.

Checking the PC3 map, map 04 has -12 and -13% fuel cut at those rpm, so I dialed about half of this back in. I was not sure whether the lean reading I got (14.5-15.0:1 AFR) was a result of the detonation, or whether a lean condition was causing the detonation. Lo, and behold... reducing the fuel cut at those rpm and the detonation is much reduced as well.

Map 04, on my bike, is pretty rough. On the bike at different rpms even WOT, you can see the needle swing wildly. Same thing when rolling on the throttle. Looking at the map itself in the PC software it is easy to see why, there are wild +\- swings all over the map as well, which apparently not the best approach.

I'll be tweaking the map some more to smooth it out, and will report - but for now the good news is she runs well and is both safe and generally much improved as well.