If you're gonna engineer it then over engineer it - nothing is built to last today - engineered to a cost is all it is about, very few go the extra mile but those that do are at a price I couldn't justify for a car - I'd buy a steam engine first if I had that kind of money.

 

During my frustration adjusting the TPS, It occurred to me that the only real solution for the TPS is to mount it on the actual throttle body. That means it is transmitting the actual position of the blade which is what you want to know. All the other crap is eliminated. You'd only need one on one side and make sure they are in sync. Now air and fuel are permanently synced up.

I read somewhere jag- lovers that a Ford TPS from an 80s 2.3 works. Getting one mounted at the throttle body would make us all have nothing TPS related to talk about any more. It would reduce new threads by half.

Modify the shaft sticking out here, drill 2 holes mount the TPS. no more problems.

 

I have the manifolds out - I'll see how feasable this is - could do with a decent workshop - perhaps make an extended spindle with one end keyed - although it is right above the nastiness that is the exhaust

 

Ben
Do not reinvent the wheel is my advice. A TPS on one side only brings its own problems, let alone fixing it reliably and adjusting it any more finely than the OEM capstan. There is no reason to suppose that there will be any less slop or accuracy (as in TPS/throttle butterfly movement) in the entire system than there is OEM, as half the engine and the throttle actuation are still unchanged.

 

I hear ya, it is with this exact same thinking that I concluded the demand for accuracy in the hundredths was serious BS given all the linkages etc in this system where similar levels of accuracy (or better) would be required to maintain such a level of measurement relevant.

Even setting the 0.05mm on the butterfly is hit and miss - it is kind of hard to 'feel' the gauge when you're bending the darn thing, using a feeler gauge as a spacer whilst setting a pretty crude set screw and nut - how much pressure to apply to the butterfly, slop in spindle perhaps, then there is the do I set this hot or cold question.

So I hear ya, I just don't know what tolerances are built into the ECU or even what impact it would have if 'not in spec' - kind of goes back to my original statement - I'm struggling to believe that something so crude can expect plus or minus 2 hundredths of a volt accuracy.

 

no less slop or accuracy is actually a pro for the change, but the throttle adjustment procedure is still necessary. Given the the pain in the rear it is to pull and adjust, repeatedly this multi hundred dollar sensor that becomes inaccurate and messes up fueling as the slop in the linkage increases with every throttle stroke, it becomes appealing to find a <$30 non spring loaded sensor with brass bolt hole inserts that would work and eliminate a huge performance/ maintenance/ reliability issue AND you could adjust without disassembling anything. With a better sensor design it becomes set and forget. And then the only thing that happens as the linkage wears is a small (likely unnoticeable) delay when you push the pedal, but TPS (and fueling) is still spot on.
cheap, reliable, consistent... something we don't have now. Why not eliminate some fussiness out of a very sensitive system?

 

You are correct, it can't! The V12 will run perfectly as long as you are there or thereabouts within a bull's roar (copyright G Francis) of the spec.

 

Jeff
I do respectfully disagree with your points here. There is no reliability issue on the throttle system. I set mine up about 10 years ago and it has been 100% right ever since, and I only did this because I was rebuilding the car, not because it needed it. The system is neither fussy nor sensitive, and it is not, in point of fact, a "huge performance maintenance or reliability issue". Replacing a 30 year old electronic component, or adjusting a 30 year old mechanical linkage, is not a reliability issue, it is testament to a miracle of longevity!
Now I am not saying people should not improve or change things if they want to, far from it, and I have done loads; but perspective and real life experiences are important. In all the stuff I have read on the forum over the (too many) decades, the throttle linkage has been one of the least mentioned and least worrisome topics - and the vast majority of them have been about replacing the rubbishy plastic spindle bushing, or how to install and set the TPS after the old one went south after 25 plus years. Just as the OP's post mentioned.
Not to harp on; but people forget that the Jaguar V12 is the only V12 of its era to have been made in quantity, installed in non- exotic everyday-used cars, and to have proved to have been extremely robust and reliable in its anticipated lifespan. A few gizmos at the periphery going iffy after 30 years on an otherwise bulletproof engine that laughs at cosseting and is good for half a million miles is something the Ferrari/Maserati guys of the same era (whose cars were often slower and three times the price) can only dream about.

 

Thanks for your perspectives Greg, no worries if we have a different perspective. That's the great thing about our forum. (And see Doug's comment above )