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How to read the TPS


red lion
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I"m trying to set the TPS on my 1997 1100 sport. I disconnected the plug to the TPS then inserted fine wires in the female plug, one in the top and one in the middle with the wires sticking out of the plug'. when plugged back in. I then put the + lead of the meter to the top wire and the negative to the middle, but my meter just reads zero. My meter is set on the lowest MV setting. What is the correct way to take this reading?

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You need the voltage supply from the main harness. At the excellent advice of others here, I purchased a Caspers Electronics "TPS breakout harness." Plug one end into the bikes harness, the other into the TPS and the two free leads into your multimeter.

http://www.casperselectronics.com/cart/index.php?route=product/product&search=guzzi+&product_id=853&search=guzzi+

Here's how I decided to terminate the harness. Now it's plug plug plug-n-play.

IMG_3112.JPG

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1 hour ago, red lion said:

I"m trying to set the TPS on my 1997 1100 sport. I disconnected the plug to the TPS then inserted fine wires in the female plug, one in the top and one in the middle with the wires sticking out of the plug'. when plugged back in. I then put the + lead of the meter to the top wire and the negative to the middle, but my meter just reads zero. My meter is set on the lowest MV setting. What is the correct way to take this reading?

From memory the manual for the sport is wrong when identifying the pins. There are 3 wires one constant 5v reference or "power wire" if you like from the ecu. 1 earth wire and 1 output wire back to the ecu to indicate throttle position. You need to measure the voltage between the earth and signal wire output from the tps to the ecu. The PF09 ( Daytona) and PF03 ( Sport) pin positions are different but he manual shows them as the same ( it covers both models). I "think" you need to measure between the middle and lower pins. The centre pin is the earth which is easy to check even with the power off. Once you confirm that then the 5 volt supply wire is easy also because it will be the same voltage no matter what you do with the throttle. The remaining wire must therefore be the signal wire. You know you have it right when you open the throttle and the voltage increases from 0/157mv to around 4.8 volts. If it starts at 5V on goes backwards when you open the throttle then you have the wires crossed.

Ciao   

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Phil is spot on, you'll find some misleading info, not only in the manual, but on my Sporti and HiCam bikes the wiring is different

The best way is to check it as suggested or at least confirm wiring colours.

I "think" on the Sport it's the outside wires, on the HiCam it's one of the outsdie wires and the middle, adjacent to each other.

Loving @po18guy s setup very nice. Being the cheap and lazy sod I am I use a paper clip up the back of the plug to read the voltage

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Now, must devise a fine-threaded rotating thumbwheel for the TPS so that you don't go from .100-50.75 in one little jiggle.

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OK    I got my meter on the right wires on the 1100 sport TPS, Top + bottom negative. My meter read 2300 MV so I tried to adjust it but it would only drop to 1900 MV. So I left it at 2300. I then checked the air bypass screws, the one on the right was 1/2 turn out but the one on the left would not move. I then hooked up the carb mate to check the throttle body balance. It was spot on at idle and at 3000 RPM. The plugs looked like the bike runs rich but it gets about 40 MPG. The bike runs strong but some times  misses at 2800 RPM. It also died at idle once on my last 120 mile ride. It has K&N air pods and PC3. I"m not sure what to do from here. Any thoughts?

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Un-plug the PC3 and see what transpires?

I don't understand those TPS values. Are they that much different from the V11 baseline (157 mV with the throttle plate completely closed = throttle rod unhooked, no idle stop screw contact, no high idle contact, clean plate edges and throttle bore)?

With your (different from the V11) ECU, isn't the CO adjusted manually with a pot on the ECU? But that requires exhaust analysis?

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I made a mistake, the TPS read 230 MV not 2300 MV. And would only drop to 190 MV.I did all that you listed but I did not clean the plate edges and throttle bores. Not sure what to do about left air bypass screw because it wont move so I dont"t know where it"s set.

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While you are cleaning the throttle plate edges and the throttle bore, and throttle shaft - see if you can locate the air bypass hole on the inside of the throttle bore and apply some kind of release agent. A fifty-fifty mix of acetone and automatic transmission fluid is a known contender ("Ed's Red"). Dab a bit up into the air bypass recess from the outside, as well. Let it sit a overnight and maybe apply some heat from a hot air gun. Insert a screwdriver blade into the slot and give it a sharp * RAP * with a little hammer, perhaps even while turning the screwdriver in then out, in then out. Those screws and their channels benefit from a periodic cleaning...

DSCN0522.JPG

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I know nothing of Power Commanders, it always seemed to my mind they were a sticking plaster fix, perhaps not, but I've always been suspicious of them.

Sounds to me like what @docc has already pointed out, the plate needs to completely close. Fouling on the body or throttle plate (sometimes called a butterfly) or the RH throttle stop screw not being backed off, may be causing the odd readings. Lightly opening the plate and allowing it to snap close a few times also helps, (don't go mad). The connecting rod needs to be disconnected too (pointed out as well). Personally I have the RH throttle stop screw completely backed out and only use the LH stop screw when adjusting the system.

The TPS can (will?) move when tightening, snapping the throttle plate closed a few times will help confirm its set up right, you'll get slightly different readings every time you open and close the plate, but as long as it's in spec, I'm happy.

I've seen reports that there can be a difference between the readings when the engine is running. Mine has always been Ok, I guess battery condition might have an affect, but that's just a guess

Setting the TPS is the very first move

This is just how I understand the system, I've been wrong in the past and excuse me if I'm teaching my granny..............

The TPS is an input to the fuel map, it will alter the fuel flow sent to both TBs.

Once its set correctly then you adjust the throttle plates to ensure both bodies are flowing the same amount of air, because no matter what the airflow to each body is, they will still both be getting the same amount of fuel from the ECU. Close the Air bypass screws and adjust to get balance using the linkage connecting rod, I check at 3k RPM.

When that's done adjust the idle via the throttle stop screw (I just use the left one)

Finally adjust the airbypass screw to balance the idle airflow, you might then might have to readjust the idle, but its usually just a one shot. If I've done it right, then air bypass screw adjustment only has a small affect on the idle rpm.

Personally I wouldn't be too bothered about the stuck air bypass screw. Preferable if you can get it move, but not worth damaging the throttle body, as you're achieving good balance at high RPM and idle.

At higher RPM the airbypass screws do little, they are there to balance the airflow to each body at idle, once you have good balance at higher rpm by adjustment of the linkage rod length. They are too small to make a significant impact at higher RPM, besides if it's stuck it's probably completely closed and been screwed home by a shaved ape.

Don't get overly caught up in trying to dial it all in until it's absolutely perfect, you'll go nuts.

IMHO if the bike is idling fine and pulling well, I'm happy with it, during a service or in the Winter I might check it, but that's about all.  I only mess with it when something is amiss, rough running, bad flat spot, persistant stalling etc:

 

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I just cleaned the inside of the throttle bodies and the throttle body plates the best I could with carb cleaner. Then I took another TPS reading, It now reads 180 to 190 MV. before it read 230 to 240 MV. I tried to adjust the TPS, there was room to turn the TPS but by tuning it the reading would not go any lower then 180 to 190 MV. I then found that I was able to turn the left air bypass ., So I set the left and right bypass screws one turn out. Then I  hooked the carb mate up. The bike was spot on at idle and 3000 RPM. I"m not sure what more I can do about the TPS reading so I think for now I will just leave it where it is.

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Nothing wrong with, "Run it. Ride it. Rev it. Rip it!" :race:

I suppose it is possible the TPS is faulty.  Does it show any jumps, drops, or opens as you slowly open and close it?

(FWIW, I cannot detect these glitches in mV, but do see them reading resistance in kΩ across the potentiometer with no voltage applied.)

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A few days back I checked my TPS reading using a 'Caspers' connector I'd bought some time ago, but not used. It read 196-I'd set it some time ago using pins, but I thought it was closer to 150 than that. I adjusted it to 157 and had a test ride. It made a dramatic difference to smooth running, particularly at lower revs.

Sent from my SM-G925F using Tapatalk

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I have not checked for resistance but when opening the throttle the voltage went up to 5+ volts if I"m reading the meter right, and I think I am.

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