Throttle Position Sensor

[jason S4s]

Hi all,

My S4s TPS seems to be a bit loopy, in that it reads 0% on freescan when cold and the pedal isn't pushed but rises to 5% when the engine is hot, does this sound knackered?

Also how do you adjust the closed throttle stop position?

Any help greatly appreciated.

Thanks.

Jason.

[Splashout]

Jason quickest way to check if its dodgy would be to change it out for a known good one off a mates car if one is about?

Glyn

[Splashout]

Oh so is she back on the road now then?

[DAVES_GT3]

Hi all,

My S4s TPS seems to be a bit loopy, in that it reads 0% on freescan when cold and the pedal isn't pushed but rises to 5% when the engine is hot, does this sound knackered?

Also how do you adjust the closed throttle stop position?

Any help greatly appreciated.

Thanks.

Jason.

<{POST_SNAPBACK}>

what voltage are you reading on freescan

should be 0.5v - 0.7v when idling

4.5v when at WOT

easy to adjust if not.

you dont need to buy a new one just clean the contacts.

buy some isopropanol (pure alcohol) or use yur missus nail varnish. (dont tell her though, you know how they moan!)

take the tps off and pop it in a containter so it is submerged. let it soak for 10 mins or so and constantly turn it with a screw driver as if it were on the car.

once all the carbonised crap has come out drench it in wd40 and pop it back on

trust me it will be as good as new.

then jus check you have the positioning set so you get the correct voltages.

you should find it will idle a lot smoother if there was a problem

such a easy fix id do it anyway. they get easily contaminated

Throttle stop possition is tricky if you dont have a bendy screwdriver!

the screw is obviously on the throttle

turn it clockwise i think to lower the IAC counts

they should be between 30-40 ideally when engine is warm and idling

leave it to adjust/settle once you have turned the screw 1/8 of a turn at a time.

p.s: personally id reset the IAC before doing this and the ecu.

but do those two when the engine is cold.

1) reset ecu (disconnect battery)

2) reset IAC counts via freescan (ignition on)

3) turn aircon on and fans

4) start engine and let it warm up to 82 deg c

5) carry out throttle stop possition adjustment if needed with aircon off

(clean the tps before doing that lot by the way)

hope this helps

Dave

Edited August 9, 2005 by DAVES_GT3

[jason S4s]

Dave,

Excelent. Thanks very much for the advice. I will definately do that. do you know it the stop has a locknut?

I have done the IAC, and other resets but it goes loopy quite quickly IAC counts are about 120 and I can't get idle below 1500rpm when hot, also the throttle respose is jerky so I have suspected the TPS for ages.

I'll try that over the next few days.

Once again thanks for the help mate.

Jason

S4s

[DAVES_GT3]

Dave,

Excelent. Thanks very much for the advice. I will definately do that. do you know it the stop has a locknut?

I have done the IAC, and other resets but it goes loopy quite quickly IAC counts are about 120 and I can't get idle below 1500rpm when hot, also the throttle respose is jerky so I have suspected the TPS for ages.

I'll try that over the next few days.

Once again thanks for the help mate.

Jason

S4s

<{POST_SNAPBACK}>

Hi Jason

No lock nut on the screw just an alloy protective case round it (non removable and does spin relitivly freely) adjust the screw not the protector

Did you say you had changed the IAC valve? I changed mine recently and helped the idle a lot.

just make sure your making the ecu learn the idle correctly because that maybe why you have high idle. check your vacume pipes as well. rubber elbows prone for splitting.

i definatly think if you do the tps and set it all up correct you will be spot on.

just do one step at a time because the tps adjusted incorrectly could give your fault as well as incorrectly set throttle stop but they dont usually adjust by them selves. mine was set at 60 iac counts which was just due to wear i think. 120 is quite high.

were are you located?

dave

[jason S4s]

Dave,

Cool. I'll give it a go. have done the basic resets and changed the IAC (got a spare if anone wants it). Vacuum is also OK, got the Throttle jack and EBPV and Charcoal canister and associated crap removed, Manifold vacual only does the crancase breather and BOv now, and Vacuum pump only does the heater controls so that is fine, also get proper readings from freescan.

So I'll clean it then do all the adjusting as per your instructions.

I am down near Gatwick in West Sussex.

You going ot the oxford meet?

Jason.

[DAVES_GT3]

Dave,

Cool. I'll give it a go. have done the basic resets and changed the IAC (got a spare if anone wants it). Vacuum is also OK, got the Throttle jack and EBPV and Charcoal canister and associated crap removed, Manifold vacual only does the crancase breather and BOv now, and Vacuum pump only does the heater controls so that is fine, also get proper readings from freescan.

So I'll clean it then do all the adjusting as per your instructions.

I am down near Gatwick in West Sussex.

You going ot the oxford meet?

Jason.

<{POST_SNAPBACK}>

Jason,

Yes i will be at the Oxford meet for definate. Providing i dont get lost. Might bring a driving buddy with me to map read. Unsure if im going for the meal yet. got something on early evening so i dont want to double book. just got to find out what time its being booked for.

See you there though

YELLOW GT3!

dave

[andrewp1989]

The TPS is a "coomon" General Motors product. As far as I know, 95% of all domestic GM's (at least here in Canada) pivot the reverse direction to the Lotus' TPS.

The only GM car that I found that "fits" the Lotus' needs is the 1987-1993 Optima/Pontiac LeMans/ Asuna GT. In Europe I am told this is an Opel Kadett (my spelling may be weong on this name).

These are CHEAP at autowreckers . . . . the TPS is, perhaps, $2.00 (used). Others have told me that the TPS from an Olds Quad 4 engine is a sure Lotus fit. However, I have yet to confirm this.

AP

[Kato]

Off Topic, but the Oxford Meeting Meal is normally at Lunch. People tend to head off around 3-4pm.