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Rough running 2.5k to 3.5k
#4
Hi Hubb:

Welcome.

Re: Ohms testing a carb'd bikes TPS.
From what you state in your post, you're actually doing the test wrong.
Test procedure below:

Ohms testing any electrical component is to determine if it's outside of manufactures specs ie) Open circuit / high resistance.
All components under Ohms test must be unplugged.

Ignition pickup coil = (248 ~ 372ohms) unplugged, test across 2 pin connector behind right side panel near fuel pump.

TPS = (4~6Kohms) unplugged.

Ohms test is a static test, you gain nothing by rotating a tps during an Ohms test.
Set meter on 20K Ohms, touch leads together for a few seconds, what does display read?
Any resistance displayed is in the meter/leads & must be deducted from components tested value.
Connect multi-meter (Black/Negative) test lead to TPS Blue wire & meters (Red/Positive) test lead to TPS Yellow.
Display should read (4~6Kohms), if in spec, continue to DCV test TPS, if out of spec, replace TPS.

Voltage Test TPS:
Since TPS is a basic rotating 3 wire potentiometer it needs volt testing in motion to verify a fault.

Fully charge battery before any Volt testing.
Cold test first, then run motor up to temp, retest & compare values.
Connect TPS back up to bikes loom.
Set meter to DCV.
Touch meter leads together for a few seconds to zero meter.
Avoid touching meter lead ends, some meters pick up body voltage.

Connect meter (Black/Negative) lead to battery Negative.
back probe at 3 pin connector with TPS plugged into loom).
Turn ignition "ON".
Back probe TPS plug on Blue & Yellow wires, one of these should be a 5v reference, use the other wire that is the signal wire to test TPS.
Throttle closed, what does meter display = ? DCV, should be around 0.2v ~ 0.5v
Slowly open throttle up to full throttle, display voltage should increase, any sudden drops or jumps, TPS is faulty, it's usually dirt ingress up the shaft that causes a TPS to play up.
I use a small Ultrasonic cleaner for jewellery, ideal for sensors & injectors, use stainless lockwire to suspend TPS with shaft end upwards, often get a good amount of crap out of em, sometimes this sorts em, sometimes not, suck it n see deal.

Hope the above helps?
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Messages In This Thread
Rough running 2.5k to 3.5k - by Hubb96 - 19-09-25, 08:25 AM
RE: Rough running 2.5k to 3.5k - by unfazed - 20-09-25, 12:30 AM
RE: Rough running 2.5k to 3.5k - by Hubb96 - 20-09-25, 05:07 PM
RE: Rough running 2.5k to 3.5k - by Gaz66 - Yesterday, 01:00 AM
RE: Rough running 2.5k to 3.5k - by Hubb96 - Yesterday, 09:29 AM

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