thebronze Posted August 30, 2012 Share Posted August 30, 2012 The TPS at idle is now at 635 mV. The sneeze has moved up ro about 3200 RPM and is more manageable. The bike is now rideable but not as it should be. Going to pull the tank this weekend and replace all the fuel line inside the tank will replace the TPS with the Harley unit. Reset the throttle body sleeves, they are just fine. Cannot find an intake leak anywhere. The search continues. Man I just went through this with mine. I was ready to drive the bike into the lake. Before you change anything try the TPS FAQ. Where are your air bleed screws at? Link to comment Share on other sites More sharing options...
drewladams Posted August 31, 2012 Author Share Posted August 31, 2012 what happens if you move the tps to lower voltage say 450mv? sounds like too much gas is being fed for the speed of the motor. are the air by pass screws open a half turn or so? Air screws open to one full turn, and tuned per Greg Bender, Guzziology procedure. The less voltage at idle, the worse it runs. At 525mV and below it is unrideable. At 625 mV at idle, it still spitts and backfires, but not as bad-often. The more voltage at the TPS, the higher in the RPM range the misfire takes place (most of the time) At 625mV the misfire is at around 2800-3200RPM. Pulling the tank this weekend to have a look at all connectors-hoses-connections ett. etc. Link to comment Share on other sites More sharing options...
felix42o Posted August 31, 2012 Share Posted August 31, 2012 Could be a dead spot in the TPS. Try swapping left to right and see if it follows. There's a harley p/n for a TPS that is supposed to work for much cheaper than what MG charges...search the forum for it. Link to comment Share on other sites More sharing options...
68C Posted August 31, 2012 Share Posted August 31, 2012 Hi Felix420, Don't understand your last post. Surely there is only one TPS sensor, how can you swop it over? Link to comment Share on other sites More sharing options...
thebronze Posted August 31, 2012 Share Posted August 31, 2012 Well here's the harley TPS, http://www.ebay.com/itm/Throttle-Position-Sensor-Harley-Davidson-Softail-2001-2006-/330643969503?pt=Motorcycles_Parts_Accessories&hash=item4cfbea95df&vxp=mtr#ht_465 0wt_906 (Replaces HD# 27629-01, Part Number: 82723) ebay Item number: 330643969503 What in the hell is harley doing w a marelli TPS? I still havent fixed mine. I think its going in the lake or the shop tomorrow. Link to comment Share on other sites More sharing options...
drewladams Posted September 1, 2012 Author Share Posted September 1, 2012 Pulled the tank, checked all the sensors. The air sensor in the airbox shows ZERO resistance. Perhaps this is the cause of the lean condition. If the default is, say 0.102 Kohm, the engine thinks its 125 degrees and leans the mixture, this could explain the spitting and sputtering at around 3K. I will replace it and see what happens. At least I may FINALLY be on to something!!! Link to comment Share on other sites More sharing options...
thebronze Posted September 1, 2012 Share Posted September 1, 2012 Pulled the tank, checked all the sensors. The air sensor in the airbox shows ZERO resistance. Perhaps this is the cause of the lean condition. If the default is, say 0.102 Kohm, the engine thinks its 125 degrees and leans the mixture, this could explain the spitting and sputtering at around 3K. I will replace it and see what happens. At least I may FINALLY be on to something!!! How did you measure that? I may have the same problem. Link to comment Share on other sites More sharing options...
drewladams Posted September 1, 2012 Author Share Posted September 1, 2012 Digital multimeter. Am also in the process of removing the throttle bodies and injectors for a good cleaning. I will swap the injectors-left to right, to see if the miss goes to the right side. BEWARE...the screws holding the injectors into the throttle bodies, and the screws holding the throttle bodies to the brackets have RED lock-tight. UM BASTERDO! Pretty sure I am the first one to take them off. One prior owner. (Best friend-died last year) Link to comment Share on other sites More sharing options...
Kiwi_Roy Posted September 1, 2012 Share Posted September 1, 2012 The air sensor should read quite high, 3,7K at 20 C (68 F) If you unplug the ECU connector you can check the resistance of most external components at the female connector. The pins are the same size as used in old fashioned computer cables or Radio Shack carry them. Note:Not all TPS sensors read the same resistance, but it should change smoothly without a jump ECU Test Points.pdf The way your bike changes with different TPS settings makes me suspect that. BTW, sorry to hear about your friend, the bike is there to bring back the good memories. Link to comment Share on other sites More sharing options...
fotoguzzi Posted September 2, 2012 Share Posted September 2, 2012 if you could get a VDST hooked up it might be easier to diagnose. it can read out faults from the sensors..probing with a meter was always tricky for me.. If it will help I'd be glad to ship over my spare tps for you to test with..from Mpls it would only take a couple days.. Link to comment Share on other sites More sharing options...
fotoguzzi Posted September 2, 2012 Share Posted September 2, 2012 BEWARE...the screws holding the injectors into the throttle bodies, and the screws holding the throttle bodies to the brackets have RED lock-tight. UM BASTERDO! Pretty sure I am the first one to take them off. One prior owner. (Best friend-died last year) they are lock tighted for a reason.. taking them off would be the last thing I'd do.. Link to comment Share on other sites More sharing options...
fotoguzzi Posted September 2, 2012 Share Posted September 2, 2012 what happens if you move the tps to lower voltage say 450mv? sounds like too much gas is being fed for the speed of the motor. are the air by pass screws open a half turn or so? Air screws open to one full turn, and tuned per Greg Bender, Guzziology procedure. The less voltage at idle, the worse it runs. At 525mV and below it is unrideable. At 625 mV at idle, it still spitts and backfires, but not as bad-often. The more voltage at the TPS, the higher in the RPM range the misfire takes place (most of the time) At 625mV the misfire is at around 2800-3200RPM. Pulling the tank this weekend to have a look at all connectors-hoses-connections ett. etc. 525Mv is with both throttle stop screws all the way out not at idle ? Link to comment Share on other sites More sharing options...
drewladams Posted September 2, 2012 Author Share Posted September 2, 2012 Thanks for the offer, fotoguzzi. I have cleaned the injectors, and swapped them left-right(to see if the miss follows). Bike is now back together, and waiting for an air temperature sensor. One I get that, I will set the TPS back to where it should be at 525 mV give or take, and take it for a ride. If it still doesn't run right, I will take my happy ass off to the Harley store for a TPS ($42 american dollars). But I am hoping that the air temperature sensor (broken) is going to fix this thing. Link to comment Share on other sites More sharing options...
Kiwi_Roy Posted September 3, 2012 Share Posted September 3, 2012 You may be able to fix the sensor, it's a bead type thermistor at zero ohms sounds like the leads are shorting together. When I removed the airbox on my bike I carefully cut the sensor apart and extended the thermistor out to the front of the bike with a pair of wires. While you're waiting for a new one just substitute a resistor around the right value for current temperature say 3.3 K Ohms (~ 25 C) Link to comment Share on other sites More sharing options...
drewladams Posted September 3, 2012 Author Share Posted September 3, 2012 Thanks Kiwi-Roy, that is exactly what we did. My buddy the electrician helped my install a resistor in place of the sensor, so the bike thinks it's 80 degrees. FIXED IT! Runs great. So the air temperature sensor plays a big part in telling the computer the mixture to use, and at zero resistance, by V11 thought it was 120 degrees outside, and leaned the mixture accordingly. Thanks everyone for all your help. My sanity has returned, and my wife and kidds are happy for that! Link to comment Share on other sites More sharing options...
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