Throttle position potentiometer

[lefvl]

The Throttle position potentiometer has been always disconnected since I bough my 350i.
The engine runs apparently well, but the fuel injection cuts off suddenly if i depress the throttle quickly (like when dubble-clutch for engaging a lower gear), or when I push the revs too high.

My potentiometer model is the one with three screws (BOURNS 3802C-1-502 K)

Is there any chance to find a replacement one elsewehere ? (Morgan dealers ???).
What reference (and source) for an equivalent pot ?

Thanks for any help.

Francis

[honestjohntoo]

Since your TP is disconnected you have a consequently low performance because the TP is solely responsible for telling the ECU to fire its acceleration and full load enrichment circuits.

If it is indeed faulty, there are three options.

• Replace: With a Jaguar part, very expensive, if still available, need to change connector

http://www.sngbarratt.com/catalogue/parts/show.asp...

• Repair: as described in the following link to my website

• Substitute: ditto

http://www.vintagemodelairplane.com/pages/Rover_Te...

Navigate to the PDF and download.

Edited by honestjohntoo on Monday 23 July 14:59

[marcus1875]

Really stupid question from a drive way weekend would be mechanic but what the f**k is a potentiometer? What does it do?

[vampire222]

marcus1875 said:

Really stupid question from a drive way weekend would be mechanic but what the f**k is a potentiometer? What does it do?

easily said its sort of like those light knobs you can turn around to dim/brighten a light.

The one in this case changes resistance based on the position of the throttle flap in the intake, so the ecu knows how much its open

[marcus1875]

Oh. dont recall seeing one on mine. I take it a 280i would have one?

[mrzigazaga]

marcus1875 said:

Oh. dont recall seeing one on mine. I take it a 280i would have one?

I should hope you havent got one on yours..Ours have an ignition amplifier which acts similar to an ECU but not so complicated..Or it seems problematic...Ziga

[marcus1875]

Oh thats a relief! Thought i was going to have to add another thing to my list of woes. going to do the accumulator on saturday mrzig, tried everything else. should have done as you said tho in the first place. cheers.

[honestjohntoo]

marcus1875 said:

what is a potentiometer? What does it do?

potentiometer is a variable resistance on a shaft, not dis-similar to the volume control on your mum's steam radio and for the Flapper Efi system is solely responsible for telling the ECU to fire its acceleration and full load enrichment circuits.






A broken one messes with the brain of the system resulting in kangaroo performance.

[lefvl]

honestjohntoo said:

Since your TP is disconnected you have a consequently low performance because the TP is solely responsible for telling the ECU to fire its acceleration and full load enrichment circuits.

If it is indeed faulty, there are three options.

• Replace: With a Jaguar part, very expensive, if still available, need to change connector

http://www.sngbarratt.com/catalogue/parts/show.asp...

• Repair: as described in the following link to my website

• Substitute: ditto

http://www.vintagemodelairplane.com/pages/Rover_Te...





Navigate to the PDF and download.

Edited by honestjohntoo on Monday 23 July 14:59

Well, I took the expensive way but I don't regret it !
It took just the time to swap the connectors and all my troubles were cured ! Idle perfect, no more injection cutoff, great !
Many many thanks for your advice and references.

Francis