Changed Tps And Ht Leads And Now Idle Is 3000 Rpm?!

[ATK 137 1 Cars]

Fitted a brand new TPS today and some new HT leads.

 

Immediately prior to doing so idle was 1400rpm cold before dropping to a rock steady 900rpm when warm.

 

Still struggled to start without feathering the throttle when cold, so a new TPS and HT leads were the last things to try to get it starting without throttle when cold.

 

Fitted the new parts, new tpc clicks when throttle spindle returns to rest, and now the idle is 3000rpm even with the air idle screw all the way in.

 

Any ideas?! Still does it if I leave the TPS unplugged.

 

Help!

[jackherer 543]

Put the old TPS back on!

[ATK 137 1 Cars]

Would the tps cause this issue though? The one i put one was brand new. and if it was unplugged it would be bypaased anyway wouldnt it?

[jackherer 543]

Actually thinking about it, on an 8v I don't think it does. Mi16s with the same TPS go into some sort of fault condition when the TPS is open circuit at idle and open the ICV fully which causes this symptom.

 

Try readjusting the TPS, if you have it rotated too far it can hold the butterfly open at idle and it doesn't need to be open much to rev quite high.

[ATK 137 1 Cars]

Ok maybe I rotated it too far anticlockwise. it was almost all the way anticlockwise and was clicking just as the throttle spindle moved.

 

It just needs to click immediately as the throttle spindle is moved by hand/pedal is pressed, i.e virtually a splut second, yes?

[jackherer 543]

Yes, and it also has to click when it returns to idle without assistance every time. Try loosening the two bolts just enough to release the TPS with it running and see if the idle reduces.

[ATK 137 1 Cars]

OK will give that a go tomorow morning. It was pretty much doing that anyway, despite it being at the extreme anti clockwise.

 

I don't suppose HT leads being changed would affect it, as if I had messed up the firing order it wouldn't fire up properly at all?

[jackherer 543]

It could only be the HT leads if it was running on three cylinders or less to start with on the old leads and the new set brought one back to life but I think you'd have noticed that

[acox99 73 1 Cars]

Have you adjusted the throttle cable causing it to hold the throttle open slightly.

[ATK 137 1 Cars]

Not touched the cable and at rest it feels loose mate

[Anthony 1,000]

8v TPS being unplugged should rule it out unless it's fitted in such a way that it's holding the throttle open.

 

AFAIK all the TPS does on an 8v is the overrun fuel cut and WOT throttle enrichment. Indeed, some tuners deliberately mis-adjust the switch to stop it clicking on with the throttle closed in a bid to reduce kangerooing - it works to a point, at the expense of reduced fuel economy and the revs not dropping quite as quickly.

 

It's not like an Mi16 where unplugging the TPS makes the ICV misbehave.

[unariciflocos 49 1 Cars]

Check for air leaks. Some hose must have broken or cracked while you replaced the TPS.

[Daviewonder 533 3 Cars]

It's dead mate. I'll give you scrap value and trailer it away today.

 

 

[ATK 137 1 Cars]

It's dead mate. I'll give you scrap value and trailer it away today.

 

 

 

Thow in a case of beer and it's a deal

Update - it was indeed the TPS keeping the throttle butterfly open. Started from scratch and set up as per Haynes and she's now running wonderfully....for now!