Author Topic: Suddenly dying at 2000 rpm (Read 16259 times)

Chuck in Indiana · « **on:** March 23, 2018, 05:10:00 PM »

x posted from the V11 forum.
I hate it when I don't understand what is happening. I just finished going through the Mighty Scura. Most of the tank off check list, plus one of Scud's nice fuel lines, and a new fuel line from the right injector to the PRV. I had to remove that fitting from the injector so I wouldn't break something, but that is the only thing I changed over there.. oh.. unplugged the injector and TPS.

Finished everything up, pushed it out in the hanger, and it started right up and did it's lumpy idle thing. :)

Started to ride it up to the Guzzi Garage, and it stopped dead as soon as I gave it some throttle. Hmmm. Tried it again. Same thing. As soon as it went to 2000 rpm, it died dead as a mackerel. I've *never* heard of this before. Yeah, it's repeatable.

Hooked up Guzzidag, and looked for faults. Nada. Hooked up my tester to the TPS, and it wasn't where I set it last. Not terribly far off, though. It was about 175 mv. Moved the throttle a little off idle, and the tester said OL.

Can someone explain this to me? I'm *assuming* the TPS suddenly magically went bad? <scratching head>

TIA..

RinkRat II · « **Reply #1 on:** March 23, 2018, 05:25:20 PM »

Hi Chuck,
Methinks maybe something crawled inside over winter and it's shorted the resistor. I've never tried it but I've heard you can clean them out if the bottom plate comes off. My spare is sonic welded so no go there. The other thing is it is electro-mechanical so a magical failure is possible.

Paul B

guzzisteve · « **Reply #2 on:** March 23, 2018, 05:26:12 PM »

175 ain't bad, sounds like a dead(worn spot)on the TPS.

rodekyll · « **Reply #3 on:** March 23, 2018, 05:41:50 PM »

I agree. If you don't get continuous readings from the tps it's bad.

dsrdave · « **Reply #4 on:** March 23, 2018, 05:48:36 PM »

If you very gently try to rev the engine is it ok ? As opposed opening the throttle as we normally would to accelerate and have it fall on its face ?

Wayne Orwig · « **Reply #5 on:** March 23, 2018, 05:48:47 PM »

Quote from: Chuck in Indiana on March 23, 2018, 05:10:00 PM

Hooked up Guzzidag, and looked for faults. Nada. Hooked up my tester to the TPS, and it wasn't where I set it last. Not terribly far off, though. It was about 175 mv. Moved the throttle a little off idle, and the tester said OL.

What is OL? How is this 'tester' connected?
Are you measuring voltage, and is the voltmeter set to manual mode? If so, maybe it went over 200mv.
Odd that the TPS would suddenly fail.

I would disconnect it and make resistance mesurements of the TPS before declaring it dead.

Chuck in Indiana · « **Reply #6 on:** March 23, 2018, 05:59:29 PM »

Quote from: Wayne Orwig on March 23, 2018, 05:48:47 PM

What is OL? How is this 'tester' connected?
Are you measuring voltage, and is the voltmeter set to manual mode? If so, maybe it went over 200mv.
Odd that the TPS would suddenly fail.

I would disconnect it and make resistance mesurements of the TPS before declaring it dead.

I'd assume it's "Overload." It's a Fluke, set on MV, probing the two outside wires, purple and black. Slowly moving the throttle plate, it gets to around 390 MV, then "OL" which I'm assuming (again) is over 1000 MV.

Wayne Orwig · « **Reply #7 on:** March 23, 2018, 06:09:33 PM »

Quote from: Chuck in Indiana on March 23, 2018, 05:59:29 PM

I'd assume it's "Overload." It's a Fluke, set on MV, probing the two outside wires, purple and black. Slowly moving the throttle plate, it gets to around 390 MV, then "OL" which I'm assuming (again) is over 1000 MV.

I'm sure it is. And the MV setting must overload as you say.

Still, hard to imaging it suddenly failed.

Can you disconnect the harness, probe the TPS, then measure resistance?

rodekyll · « **Reply #8 on:** March 23, 2018, 06:21:20 PM »

OL = open circuit on an ohm mter.

Chuck in Indiana · « **Reply #9 on:** March 23, 2018, 06:39:16 PM »

Quote from: dsrdave on March 23, 2018, 05:48:36 PM

If you very gently try to rev the engine is it ok ? As opposed opening the throttle as we normally would to accelerate and have it fall on its face ?

No. Right at 2000 rpm, it just dies. Like I've said, I've been reading about this stuff for 20 years and don't remember this one. Of course, my memory just might be a little suspect.

Chuck in Indiana · « **Reply #10 on:** March 23, 2018, 06:40:40 PM »

Quote from: Wayne Orwig on March 23, 2018, 06:09:33 PM

I'm sure it is. And the MV setting must overload as you say.

Still, hard to imaging it suddenly failed.

Can you disconnect the harness, probe the TPS, then measure resistance?

I did that, and didn't notice anywhere that it suddenly changed. In the morning, I'll do it again and get some hard data.

rodekyll · « **Reply #11 on:** March 23, 2018, 07:11:00 PM »

If you have guzzidiag you can start it up and watch the voltage/throttle angle change. The TPS is a simple potentiometer (variable resistor). It should increment smoothly, with no backward dips or dead spots.

Guzzidad · « **Reply #12 on:** March 23, 2018, 07:23:31 PM »

It usually stands for open loop, another way of saying there isn't continuity.

Original answer: it means OVER-LIMIT
beyond the limits of the meter to register, such as "infinity" on a resistance scale

lucian · « **Reply #13 on:** March 23, 2018, 07:39:10 PM »

Quote from: rodekyll on March 23, 2018, 07:11:00 PM

If you have guzzidiag you can start it up and watch the voltage/throttle angle change. The TPS is a simple potentiometer (variable resistor). It should increment smoothly, with no backward dips or dead spots.

:1: You can go to "graphs" and watch it in for linear irregularities.

Tom · « **Reply #14 on:** March 23, 2018, 08:33:21 PM »

Quote from: RinkRat II on March 23, 2018, 05:25:20 PM

Hi Chuck,
Methinks maybe something crawled inside over winter and it's shorted the resistor. I've never tried it but I've heard you can clean them out if the bottom plate comes off. My spare is sonic welded so no go there. The other thing is it is electro-mechanical so a magical failure is possible.

Paul B

Carefully drill a small hole in the TPS. Large enough for a spray carb cleaner straw. Spray the cleaner in there and see it helps. Others have posted that it helps when the contacts are clean. Don't know how long that would work after spraying. Get a replacement too.

pehayes · « **Reply #15 on:** March 23, 2018, 09:08:34 PM »

Quote from: Tom on March 23, 2018, 08:33:21 PM

Carefully drill a small hole in the TPS. Large enough for a spray carb cleaner straw. Spray the cleaner in there and see it helps. Others have posted that it helps when the contacts are clean. Don't know how long that would work after spraying. Get a replacement too.

The white spot is where I drilled the EV TPS. Worked for many miles thereafter.

Patrick Hayes
Fremont CA

how do i upload pictures

Kiwi_Roy · « **Reply #16 on:** March 24, 2018, 11:26:18 AM »

Set the start position on the 200 mV range but then switch to the Voltage range to check full travel, it should go from 0.160 to about 4.5 Volts.

The TPS is not a simple resistor, I think it has some other resistors that set the output to a default value if the slider loses contact.

Chuck in Indiana · « **Reply #17 on:** March 24, 2018, 11:35:55 AM »

Thanks. That dawned on me last night, but I'm driving Miss Dorcia today and haven't tried that,yet.

RinkRat II · « **Reply #18 on:** March 24, 2018, 05:05:17 PM »

And another thing is the pin alignment in the TPS. Possibly got bent reattaching the plug?

Paul B

Chuck in Indiana · « **Reply #19 on:** March 24, 2018, 05:21:53 PM »

Quote from: RinkRat II on March 24, 2018, 05:05:17 PM

And another thing is the pin alignment in the TPS. Possibly got bent reattaching the plug?

Paul B

That's a thought. I'll give it a look tomorrow. Thanks. I *always* look where I've been when stuff stops working.

LowRyter · « **Reply #20 on:** March 24, 2018, 08:11:05 PM »

The TPS became unplugged on the Greenie after I serviced it. It idled fine but ran like crap and misfired when I tried to rev it. It would still get down the road but ran terribly. I am not sure how far it would've gone.

Luckily I looked down at my right foot and saw the plug dangling. Plugged it in and was good to go.

Chuck in Indiana · « **Reply #21 on:** March 25, 2018, 10:21:11 AM »

Quote from: Kiwi_Roy on March 24, 2018, 11:26:18 AM

Set the start position on the 200 mV range but then switch to the Voltage range to check full travel, it should go from 0.160 to about 4.5 Volts.

The TPS is not a simple resistor, I think it has some other resistors that set the output to a default value if the slider loses contact.

Well duh, it's *not* the TPS. Set it using the mv scale, then changed to DC volts like KR said. Watching it very carefully, it goes from .150 to 4.75 volts very smoothly. I guess I was just seeing what I expected to see..

Tried to crank it, but the battery was down. I don't expect anything different, though. <scratching head>

lucian · « **Reply #22 on:** March 25, 2018, 10:40:40 AM »

Pin connector ok? perhaps the tps is fine but the signal isn't making it to the ecu. Check chook's temp ?

Chuck in Indiana · « **Reply #23 on:** March 25, 2018, 10:53:17 AM »

Quote from: lucian on March 25, 2018, 10:40:40 AM

Pin connector ok? perhaps the tps is fine but the signal isn't making it to the ecu. Check chook's temp ?

I'll give it a look after a bit. May have to source a very small thermomoter. That should be rectal, right?

Vagrant · « **Reply #24 on:** March 25, 2018, 10:58:23 AM »

did you clean the cam position sensor. next clean / replace all relays. that unit had a plastic temperature sensor in the right head that was prone to breakage.

Chuck in Indiana · « **Reply #25 on:** March 25, 2018, 12:02:17 PM »

Quote from: Vagrant on March 25, 2018, 10:58:23 AM

did you clean the cam position sensor. next clean / replace all relays. that unit had a plastic temperature sensor in the right head that was prone to breakage.

Yeah, the cam position sensor was weeping, so pulled it, cleaned it, and reinstalled with some hi temp sealer around the o ring. Relays are the new high current Omorons discovered at the V11 forum. They've been in for 17 miles. Was running normally. Relay bases sprayed with DeOxit at that time. Honestly, I can't imagine the temp sensor making the engine suddenly stop.
Idles normally. When it gets to 2000rpm it suddenly dies.
Here is what Idid when servicing it.
Adjusted valves .002 and .003 (titanium pushrods)
Leakdown L 80/75 R 80/76
Cleaned resealed timing sensor
New insulated fuel line from shut off valve to fuel pump
New high pressure line from injectors to PRV
DeOxit and crimped bullet connectors at headstock
New intake rubbers

I'm at a loss as to where to go from here..

rodekyll · « **Reply #26 on:** March 25, 2018, 12:19:59 PM »

I can't comment on the valve lash since I'm unfamiliar with titanium pushrods. But if I was to take a guess of which thing to check (due to having messed with it) I'd go with the cam position sensor, first. There's a gap threshold that I can't remember. The sealer around the o-ring may have changed the gap or somehow insulated something that needed to go to ground (don't know what that might be).

I'm picturing it idling nicely and then suddenly dying as the needle touches 2k. How does it run as you approach 2k?

If you can't pump air you can't accelerate the engine, on account of it's just a big air pump. Any chance the intake air is restricted? Someone stuff a golf ball in the tailpipe? Missed on the valve adjust?

Does it stop dead like someone pulled the plug, or does it stop dead like bad fuel delivery? One check might be to squirt starter fluid down the intake (or in the airbox) as you approach 2Krpm. If the fluid keeps it running, it's not an electrical problem.

Chuck in Indiana · « **Reply #27 on:** March 25, 2018, 12:39:14 PM »

It starts, idles, and accelerates to 2000 normally, then suddenly dies. That's why I originally thought it was electrical.

Chuck in Indiana · « **Reply #28 on:** March 25, 2018, 12:55:08 PM »

Changed the title of the thread since it isn't the TPS..

Diploman · « **Reply #29 on:** March 25, 2018, 01:37:17 PM »

This thread seems like an unintended advertisement for carburetors. The advances in fueling and emissions made possible by FI can sometimes be offset by the occult mysteries involved in troubleshooting FI systems. I hope I never have to get into my 390 Duke's FI. Flawless to date, but fingers crossed.

News:

Author Topic: Suddenly dying at 2000 rpm (Read 16259 times)