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Discussion Starter #1
Well, it's the beginning of winter here in Minnesota so working on some projects. The first is the jumping TPS with the PC III installed. Tech told me to run a jumper from the Black/white TPS ground to the TPS ground (Green/Yellow). Did this, but the TPS is now stuck at 100%. Got the PC tech on the phone and he had me look for the ground, 5 volts and variable. We connected a Volt meter to the battery, then touched each of the 3 wires. ALL showed 12 volts, which should be impossible with and without the jumper. Did I fry the ECM? Any idea how to correct? PS, the tank is off, so the wires to the EFI ready light are disconnected.
Thanks.

Mods to complete: Clutch rebuild, LED 'fancy lights', New handgrips and levers, Batwing and hard bags.
 

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Well, it's the beginning of winter here in Minnesota so working on some projects. The first is the jumping TPS with the PC III installed. Tech told me to run a jumper from the Black/white TPS ground to the TPS ground (Green/Yellow). Did this, but the TPS is now stuck at 100%. Got the PC tech on the phone and he had me look for the ground, 5 volts and variable. We connected a Volt meter to the battery, then touched each of the 3 wires. ALL showed 12 volts, which should be impossible with and without the jumper. Did I fry the ECM? Any idea how to correct? PS, the tank is off, so the wires to the EFI ready light are disconnected.
Thanks.

Mods to complete: Clutch rebuild, LED 'fancy lights', New handgrips and levers, Batwing and hard bags.
Can you help this poor soul out and explain the purpose of jumpering across the TPS? Thanks.
 

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TPS

I have seen a Nissan pick-up drive me crazy because the tps had 5 volt reference on all 3 wires with it unplugged. I plugged it in and everything went back to normal. So plug the tps in and backprobe the 3 wires and see if it's OK. Good luck!!
 

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Discussion Starter #5
rsc4526

I thought the same thing. It's partially apart with the tank off, but I did plug in the speedometer housing so I could see the EFI light. Now, the EFI light is on, but I still get 5 volts with the TPS plugged in on all 3 wires.
I've unhooked the power commander as well. Same issue. Yikes!
 

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Discussion Starter #7
Update:
After adding the Speedometer housing, the following is currently true:
Negative battery ground.
With the TPS sensor disconnected:
Green / Orange 5 volts (ground I think)
Yellow / Red 5 volts (this should be correct)
Red / Yellow: Zero volts

Connected back up to the TPS:
Green / Orange 5 volts (ground I think)
Yellow / Red 5 volts (this should be correct)
Red / Yellow: 5 volts but 'wiggles' a 1/2 volt or so when I move the throttle.

EFI light red is on.:dontknow:
 

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Discussion Starter #9
Thank you for all of the help. At this point, I"m going to put the tank back on, get the hoses and sensors all connected back up and see where I'm at. It all worked before I took the tank off. I'll keep you posted.
 

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Discussion Starter #10
I can't let this die! I checked the continuity from the TPS to the wiring harness and all checks out. Does anyone know how I can get ahold of a ECM test harness? I'm wondering if during my troubleshooting, I connected the ground from the PCIII B/W wire to the hot wire on the TPS and shorted something in the ECM.
 

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I can't let this die! I checked the continuity from the TPS to the wiring harness and all checks out. Does anyone know how I can get ahold of a ECM test harness? I'm wondering if during my troubleshooting, I connected the ground from the PCIII B/W wire to the hot wire on the TPS and shorted something in the ECM.
Remove the PCIII and start the bike
 

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+5v regulators have built-in thermal and over current protection should not have a problem. Grounds should be able to handle whatever is wired to them. Is the +5v still good since you put everything back together. I see three Ground wires on the Black ECM connector; two P/G and one Green. Check those. The +5v circuit ground is probably common the the +12v negative ground except that all the sensors are returned to the ECM ground. Test for continuity to chassis ground from the G/O with an ohmmeter. The spikes on the 12v grounds are too noisy, that is why the separate sub-system ground(injectors, coils, turn signals cause large transient voltages compared to the milli-volt signals of the sensors).
Remove the PCIII from any OE wiring.
 

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Discussion Starter #13
Update. PCMIII is disconnected. All connections checked. Tank bank on and tried to start. Just a brief 'fire', then nothing. Sends a 17,8 & 9 code.

Checked for voltage between B17 and B18 at the TPS. NOthing. Checked for continuity on these two wires between TPS and the Grey ECM. all fine BUT... When I jump B17 & B18 (Battery and ECM unplugged, I show 2 Ohms. I believe this should be an open circuit. Checked for shorts All looks good into and out of the wiring harness.

Can you confirm this should be an open circuit?
 

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No +5v Y/R to G/O or any ground. BUT a week you had +5v and you saw a voltage change R/Y(wiggled) when you moved the throttle. You said +5v on all TPS leads.. Looks like open ground...
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Quote "When I jump B17 & B18" <<you see 2 ohms>>>>testing on the ECM right??? Everything disconnected from ECM except ohmmeter??. Did you swap the leads in case a diode is there? I do not have an 1800, cannot verify for you. Maybe someone else could check for you.
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I could not find code 17, 8=TPS, 9=IAT. Was it 1=MAP(no 5v=not working) and 7=ECT.. I was using 02-03 svc manual and Bare's ECU codes page.
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Have you verified good +12v to ECM? Ground wires..Trouble does not seem to be consistent. Sometimes you have 5v, sometimes you don't... Sometimes 5v on all three leads.......
Backup 10 yards, look and analyze...
 

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Discussion Starter #15
Bike is running. Had a gear head buddy come by today to look at this with a different set of eyes. The problem was that the TPS was not grounded properly.
PCMIII tech told me to avoide the jumping TPS, to cut the PCIII black / white wire near the negative ground and patch this to the TPS ground. Either I mis understood, of he told me wrong, I jumped from the PCIII to the TPS. Should have been jumped from the battery ground to the TPS.
Runs great.
Thanks for all of the tips.:firstplace:
 

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Bike is running. Had a gear head buddy come by today to look at this with a different set of eyes. The problem was that the TPS was not grounded properly.
PCMIII tech told me to avoide the jumping TPS, to cut the PCIII black / white wire near the negative ground and patch this to the TPS ground. Either I mis understood, of he told me wrong, I jumped from the PCIII to the TPS. Should have been jumped from the battery ground to the TPS.
Runs great.
Thanks for all of the tips.:firstplace:
Since I run PC's on two different bikes I'm curious about what required you to call the DynoJet tech in the first place. Can you explain the problem leading up to the "jumping TPS"? Thanks.
 

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Discussion Starter #17
In my case, it was noticed while on the Dyno. This was also verified when I had the computer connected with the bike running. You will see an indicater named percent throttle or something similar. when the bike is at idle, you will see the numbers jump from zero, 5, -2 etc. When at a more open position, you will also see it's not steady. The PCIII is jumping between map settings even though the physical throttle isn't touched. Should hold steady. This entire issue started with jumping a wire to 'fix' this issue.
 

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In my case, it was noticed while on the Dyno. This was also verified when I had the computer connected with the bike running. You will see an indicater named percent throttle or something similar. when the bike is at idle, you will see the numbers jump from zero, 5, -2 etc. When at a more open position, you will also see it's not steady. The PCIII is jumping between map settings even though the physical throttle isn't touched. Should hold steady. This entire issue started with jumping a wire to 'fix' this issue.
Thanks for the feedback. This is the first I've heard of the problem but I guess it's not uncommon since DynoJet has a fix.
 
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