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pureguava

Only 31% TPS !!!

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2000 V8-GT

The performance is not as I would expect - Have replaced a leaking waste gate actuator ( ripped diaphragm ) and still not that impressive. 

Finally got Peter's excellent scan tool to work ( I had a dodgy ELM-327 USB interface for a start ) and it is showing only 31% TPS maximum. 

The throttle is physically opening all the way so I suspect something to do with the TPS setting.

I am going to reset the ECU and reset the TPS with pressing the pedal etc. etc. 

when I got the car the battery was fairly flat ( but able to start engine with the light pods doing the up/down dip suggesting a lowish battery ) maybe its never been properly reset since at some stage being disconnected for some time? 

Am I onto the right track here ? I suspect a incorrectly set TPS after a prolonged battery disconnect could lead to lack lustre performance? 

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I doubt resetting the ECU will affect the TPS. Usually an ECU will read the TPS position at key on and and use that value to deduce the relative throttle position. The ECU will update the closed throttle position value to a lesser value if it subsequently finds it to be less than the previous read.

Observe the TPS voltage position as you slowly open the throttle, you will probably find the reading erratic or it stops increasing part way indicating a faulty TPS.

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I would also expect that your TPS is either faulty or that you have poor/corroded connections that are affecting the observed voltage.  I've seen some cases of badly corroded connectors even when they have rubber sealing boots.  

When checking your % vs. pedal, be aware that the throttle is not linear.  There is greater pedal travel for light openings, but in the end you should of course observe  a smooth increase with 100% TPS on full opening.

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1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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hi

I changed the TPS and still 31% 

Also with both TPS out of the throttle body i can get to 100% with about 90 degrees travel of the TPS. Interestingly - and this I am sure is the problem - my throttle will only go to about 30 degrees of movement at the TPS shaft! It has nothing to do with the pedal / cable movement as when I test this I have this disconnected. Have checked against a spare 918 engine in the garage ( luxury I know ) and this shaft moves 90 degrees - I can't see how i can adjust the amount of movement at the body as it comes to a small aluminium block stop.   Am I missing an obvious way to adjust the throttle travel here? 

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On 11/09/2019 at 07:48, pureguava said:

...The throttle is physically opening all the way so I suspect something to do with the TPS setting.

That seems a bit inconsistent with what you were saying yesterday.

If your TPS is able to register 100% when removed from the throttle body, then you need to check that your throttle linkage (LHS) is not fouling on anything and that the throttle is truly free throughout the complete range of movement.  It sounds like you may have an obstruction that is limiting the movement of linkage and hence the throttle travel.  You should not need to adjust the throttle body. There is adjustment possible on the throttle cable itself.

If the linkage is fine, then you should check the throttle butterflies themselves for any obstruction.  For that, you would need to remove the plenum.

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1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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3 minutes ago, mike_sekinger said:

That seems a bit inconsistent with what you were saying yesterday.

Sorry - I obviously have not explained it well enough - what I meant was the throttle at the engine APPEARED to be going all the way - as it comes to a "hard" stop that appears to be physical WOT. But when I compared it to the other engine throttle which comes to a hard stop with about 60 degrees more travel ......

I will link a video soon.....

 

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I would put my hat on there being a physical obstruction that is fouling the throttle linkage. or that the linkage itself is not true.

 


1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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2 minutes ago, mike_sekinger said:

 

I would put my hat on there being a physical obstruction that is fouling the throttle linkage. or that the linkage itself is not true.

 

I think your hat is safe - it has to be something physical as you say as it's a definite physical " stop " at the end of movement - I will look over it all and report back.

I am pretty happy though as this definitely is something that is consistent with my underwhelming performance .

A car that goes this well at 31% throttle is going to be fun when getting 100%!!!

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Yes - you will be engaging warp drive for the first time, so be careful 🙂

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1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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Glad ail got sorted,  Always nice when its a simple problem to fix in the end and no new parts are required !

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