Time to set the TPI...two questions

[stormsedge]

I've been putting it off, but the ole girl is surging and stuttering with the occasional backfire at 4-5000rpms...time to reset the TPI. Two questions here--1) want to get a fluke meter that will read the very low millivolts for this operation...used my old meter last time and best guessed the needle position, but far from optimum. Pls recommend make/model of meter and where you purchased (USA). 2) Is it worth my effort to procure and install the Harley TPI piece during this tune up? If so, pls pass the US part number. Thank you.

 

2001 Rosso Mandello w/open air box, and PCIIIusb. k--Tampa

[Guest ratchethack]

For setting the TPS, I've been using a Fluke 22-816, which is very accurate, and rounds to the nearest mV. This model has been superceded, and can't remember where I found it (very possibly Sears Automotive), but by feature/function, it's equivalent to the Fluke 115 here:

 

http://www.testequipmentdepot.com/fluke/dmm/115.htm

 

Can't conceive of any reason you'd want to install a Harley TPS (which has a slightly different output curve) unless your Magneti Marelli TPS has gone South.

 

Hope this helps.

 

EDIT: I back-probe the top and bottom pins on the TPS through the rubber cover on the TPS connector with semi-permanently mounted bell wire with insulated connectors on them, zip-tied back to the connector and left on for instant checking. You can check the health of the TPS by connecting the DVM and taking the TPS through its full rotation with the throttle. Any continuity fault will be obvious on the display. If needed, the TPS can be removed for cleaning. The wiper and contacts are accessed through open slots in the bottom of the TPS. A few shots of contact cleaner (NOT WD-40!) followed with a blast of compressed air to dry it out will do nicely.

[luhbo]

..... If needed, the TPS can be removed for cleaning. The wiper and contacts are accessed through open slots in the bottom of the TPS. A few shots of contact cleaner (NOT WD-40!) followed with a blast of compressed air to dry it out will do nicely.

 

Don't listen to the above. Ratchet is talking bullshit again. They're closed, they're not designed to get opened and they're not designed to get cleaned.

 

Hubert

 

And of course something a bit cheaper than Fluke will do the job as well.

[Guest ratchethack]

Don't listen to the above. Ratchet is talking bullshit again. They're closed, they're not designed to get opened and they're not designed to get cleaned.

 

Hubert

 

And of course something a bit cheaper than Fluke will do the job as well.

Um, excuse me, Hubert. But you are mistaken (again). I'm not the only one here to have cleaned the TPS with contact cleaner through the openings on the bottom (there are 2 openings for cleaning access, IIRC), based on posts here for many years, as you will find with a search.

 

Here's one:

 

Yesterday I took the TPS off and found there is access to get contact cleaner in. Of course that means there is access for nastiness to get in as well.

 

To refresh your memory, Hubert, you've raised your objections to this before, about 3 years ago, and I answered them then:

 

Hubert, we discovered previously that although we have the same model Guzzi, you got different fork springs than I got from Mandello. I suspect this may not be the only difference between US-issue and Euro-issue Guzzis. I don't know what your TPS looks like, but if yours is "sealed", mine is most definitely not the same.

 

The bottom of my TPS is OPEN -- that is, when held upside down, you can look into the open "drum" area of the TPS through two openings in the bottom of the plastic housing and see the contacts on the flex strip.

 

For ref., on top of the TPS appears: Magneti Marelli PF3C/00 3239BE

[raz]

Mine too is complely sealed. No way to clean it and no reason to. I'd be a little worried if it had open slots.

[Guest ratchethack]

Mine too is complely sealed. No way to clean it and no reason to. I'd be a little worried if it had open slots.

Seems that here in the US, where Stormsedge is, and where at least SOME (if not all) of the TPS's are OPEN on the bottom (as noted above and many times previously), there's reason to be worried, as I had noted previously:

NOTE: Not to confuse things or get off on a side-track, but this might be a good time to take a peek under the TPS. It lifts straight off with screws out. First time I did this, I found a malignant mass of corrosion in the little "cup" on the TB, where moisture (rain likely, possibly in combo with rinse water from cleaning) had obviously repeatedly collected and cooked off with engine heat. Makes quite a mess, and I wasn't too happy about having this kinda growing mass of corrosion festering in the little "open air sauna" in there , that close to the delicate contacts in the TPS and the throttle butterfly shaft. The TPS has a winding and a wiper contact that are completely OPEN to the space below it, which naturally fills up with wotever drops in there from above. I cleaned out the corrosion, put a couple drops of oil on the throttle butterfly shaft (which had also begun to corrode), let a few drops run down into the "cup" on the TB, and sealed up the open space between the TPS and throttle body with a fillet of silicone sealer. Though corrosion here to the point of freezing throttle shafts is by no means common, it has been reported several times, no doubt in cases of extended riding in inclement weather and/or washing -- any conditions where water is likely to get in there on a repeat basis. The silicone sealer keeps it all out, and flexes enough to allow any TPS adjustment you care to make without interfering. Mine's been happily sealed up that way for at least 3 years now & works like a Champ.

[raz]

For ref., on top of the TPS appears: Magneti Marelli PF3C/00 3239BE

My imprint says PF3C/00 3586AE (hard to read though) whatever that is worth. My bike is a 1997 but there are PO's so I'm not sure if my TPS is that old. I once removed it for checking/cleaning after reading such posts here and I was surprised but reliefed that it is properly sealed.

[Dan M]

Who knows how many different units were sourced over the years by M/M. Most TPSs are sealed units but if you have one that is slotted, cleaning is a good thing. Running off of a 5V reference it doesn't take much dirt to cause glitches in the sweep.

 

My PN is PF3C/00 1221BE

[Skeeve]

Well it's a known fact that Ratch' has an earlier short-frame Guzzi. Maybe the factory made a transition from open-bottom to sealed TPS' at some point?

[docc]

Stormsedge says he has an '01. I bet it's no different from the Y2K. After that, all bets are off ...

[Skeeve]

Stormsedge says he has an '01. I bet it's no different from the Y2K. After that, all bets are off ...

 

Guzzi is known for making substantial changes to models mid-cycle, with little more than a note in the following year's shop manual, from what I understand [Greg's Big Twins book, Guzziology, various sources like v11lm.com, etc. ] Something as minor as converting to a sealed TPS from one m.y. to another I doubt would rate even a note...

[luhbo]

Can anyone produce a pic from a genuine unsealed TPS? A pic of the one in question? Just curious, you know.

 

Hubert

 

Please, no picture out from a shop manual sketch/drawing

[stormsedge]

If mine is unsealed/slotted, I'll take a picture of it. But, I'm not going to get to it for another week...hope it is slotted so I can clean it up. Probably a very good bet that it being mucked up is a part of my problem, since its been outside under a cover for over a year (in the salt air). Good advice from all. Time to get a new digital meter so I can do it right. Keep smiling. k

[docc]

The new digi-meter could be your V11's best friend! Setting the TPS by mV is one thing, but unplug the TPS and check its resistance in Ohms ( set to the little-Ohms setting [milli-ohms?]). As the TPS is opened , the resistance should change gradually, with no 'jumps.' If it jumps abruptly, the TPS is probably done (even if you 'clean' it like I did).

 

Yeah, mine appears "open" and is currently the HD derivative (still Magnetti-Marelli). The original unit was also "open." I've sealed it with silicone, but will try to get a photo up to compare with what Hubert is going to post from Deutschland.

 

EDIT: Well, no good. I tried for a photo, but it doesn't show much. And, it sounds like the point in question is under the TPS which would have to be removed for inspection. I'll pass: mine's been running too good to muck with.

[luhbo]

Here you find the TPS and typical specs.

 

And give me picture of what you guys think is an opened unsealed TPS. You won't find one.

 

Hubert