Throttle Position Sensor

[coolrunnings]

Got some intermittent lumpiness just above idle, not every day, but often enough. The symptoms seem to be inline with an out of adjustment throttle position sensor and following advice on YouTube I can see I am not getting the clicking just above idle when the throttle arm is moved. The small Allen bolt which is used to move the cam is damaged, can this be replaced or do I need a whole new body?
Cannot see anyone who stocks one....anybody assist or advise?
Cheers

[itchyfeet]

engine?

[coolrunnings]

Sorry, 2.1 DJ

[coolrunnings]

The throttle cable was a little tight so I slackened it and with engine off I can pull lever back to get switch to close, but if I rev engine then turn it off, the lever hasn't quite returned to position, I can pull lever back slightly to close switch. There isn't enough spring force to overcome the last bit of mechanical stiffness to close switch. Definitely needs adjusting. Don't know how to with the cam adjuster bolt all chewed up

[muttleypup]

a Torx bit might grip the damaged allen head to enable adjustment. use a slightly oversize one and tap in. used this method to remove damaged ones before

[coolrunnings]

Half of the Allen head is missing so not an option. Before I remove and drill it it, what does the Allen screw thread into? Can I drill it and tap it with a larger thread?

[muttleypup]

sorry i have no idea what it screws into but 'logic' suggests whatever it is can be re-tapped slightly larger. before going down that route it might be worth dropping into a decent garage or a machine shop/engineering place to see if they can remove the damaged one? maybe using a screw in extractor

[itchyfeet]

got a picture?, I have one here off the van I could look at if I knew what you were talking about

[Mr Bean]

I don't know whether I am on the same job here but when my tick over RPM became erratic I found that the little micro switch in the throttle body wasn't detecting the closing of the throttle every time.

So as I come from an age of Post 0ffice 300 series relays and lever key switches which were set manually in the manufacturing process by "tweaking" I just "tweaked" the little operating arm on the micro switch with a pair miniature long nosed pliers.

Not recommended for the ham "interfered with" or inept but could save drilling and tapping etc.

CS
(AKA Bodger Smith)

[coolrunnings]

See attached photo, the yellow circled Allen head is the adjustment screw. You loosen the red circled one and adjust with the yellow circled one.

[coolrunnings]

The picture on the right is the underside of a standard TPS. The stud on the left hand side must be associated with the red circled holding screw, I cannot see how the adjusting screw moves the plate, it must be associated with that small hole??

[itchyfeet]

OK will have a look af mine later, maybe come up with some ideas

[Mr Bean]

The picture on the right is the underside of a standard TPS. The stud on the left hand side must be associated with the red circled holding screw, I cannot see how the adjusting screw moves the plate, it must be associated with that small hole??

While the previous image is not what I see when I access my TPS the design intent appears to be identical. As the switch/s appears to be a miniature micro switch I would expect to hear or maybe even feel an almost indiscernible click at the operating point. This is how I diagnosed my problem and as said tweaked the little spring arm so that it clicked just as the throttle hit the mechanical stop. This click only occurred on a random basis when the problem existed.

I am not a believer in altering or changing more than one thing at a time when diagnosing problems and if no cure is found each time I will revert the system to as is and look elsewhere. Clearly adjusting or resetting the switch/s without clear indication that this is where the problem lays may just add to your problem.
If the albeit barely discernible click is not detected it is possible that gently springing the arm without permanently bending it will produce the click.
I guess another way to check it would be to find the other ends of the wires in the loom/connector and measure the closed and open throttle positions by means of a multi meter set to its lowest resistance - the reading should jump between open circuit of many thousands of ohms representing an open circuit to ideally less than a couple of ohms representing closed contacts.

Hope this helps
cs

[itchyfeet]

smaller screw is a cam to make it easier to adjust from above, it's not needed you can loosen the bigger screw move it by hand and tighten.
If the bigger screw is rounded out you need to get it out with mole grips or similar and replace with an M4 screw of the same length.

[coolrunnings]

Great help thank you...will have a look on Saturday..