Throttle Body

[KWIL]

Cliff, You have a PM

[Teflon]

And replied .

Thanks Ken

[janker]

Originally Posted by Teflon

Fitted the refurbed throttle body this morning, complete with new idle control valve. A massive improvement, but still not 100% right.

She ticked over quite nicely and didn't misbehave when revved, BUT, when I tried to drive off, as I took my foot off the throttle pedal, the revs dropped very low (almost stopping the engine), then rose to a very fast tick over. It then repeated this pattern a few times before settling back down to tick over. I found it would do this every time I revved and released the throttle pedal (even though it had seemed fine while sat on the drive).

The car was driveable, and it may well have settled in after a short drive, but I didn't consider it particularly safe, so the old throttle body is back on for now.

A real shame, as it looks mint and is working around 98% right

I suspect the new throttle body could be made to work properly by someone with the right skills, so my current plan is to leave it until I have access to someone with T4. I'm looking to get new discs fitted shortly, so will probably add it to that task.

Worth adding, I tried the throttle re-set procedure with no improvement.

Cliff

That is a real Shame mate,I cant understand what the problem can be as im in the same boat except i haven't purchased a new valve,Hope somebody can help you out and if so please let me no the cure.
cheers julian

[Teflon]

Originally Posted by janker

That is a real Shame mate,I cant understand what the problem can be as im in the same boat except i haven't purchased a new valve,Hope somebody can help you out and if so please let me no the cure.
cheers julian

Thanks, I'll let you know if I find a solution. I've a feeling I may not have done the throttle re-set procedure properly, so may well have another dabble in the week. Who knows

Cliff

[Saga Lout]

Originally Posted by Teflon

Member Saga lout kindly gifted me some refurbed throttle body parts that he had spare, and I decided to make good use of them.

I had a spare throttle body in the shed which I knew was in working order as it had been on the car when I first bought her, all those years ago. Anyhow, I ordered a new gasket set from Rimmers, and set about cleaning the unit, followed by masking, priming, and painting. It weas then re-assembled using new gaskets and "O" ring, plus the linkage parts from Saga Lout.

Really pleased how it came out:



Fitted it to the '75, and it looks great in the engine bay. Sadly though, it doesn't work . The car starts fine, and idles nicely, though perhaps a little fast. Wasn't too concerned at this as the engine was stone cold, however as soon as the pedal is pressed, the revs rise, and rise, and rise, - you get the idea.

The throttle does not appear to be physically sticking - everything falls back in place as it should, except the revs! I'm thinking an air leak perhaps, but can't imagine where from . Idle Air Control Valve perhaps? I really have no clue.

I have replaced the old throttle body, and everything is again working as it should, but I would love to have the refurbed unit working properly - any ideas folks?

Cliff

I had this problem with a Punto a few years ago, the throttle position sensor will be at fault as it causes the revs to be all over the place. It does look rather good though, I've now done every nut and bolt for my ZT in that spangly new finish on non pitted items.

[Teflon]

Thanks. I dare say I will be having another go in the next few days - hate being beaten!

Really looking forward to seeing pics of the ZT when it's all back together. A real labour of love.

Cliff

[Bastelmann]

Cliff, two questions about the throttle body:
2.0 and 2.5 are identical, right?
Is it difficult or a simple task to remount the springs after disassembling and cleaning?
Apart from that the lacquered throttle body looks really great!

[WillyHeckaslike]

Swapping the IACV can produce mixed results without the help of T4 to configure its stepper motor with the ECU. My Rover 25 came to me with the revs dropping off when driving off from cold and often stalling more so in cold weather. From what I could see the inlet manifold had been changed and most likely I thought as a job lot complete with IACV etc.. I was aware of the need of T4 to sort the problem but it wasn't until I called on Brian for an unrelated non-start problem that the problem was largely fixed. I say largely because Brian put a newer map on the car which all but fixed it completely but before he could check out the stepper motor the car stopped talking to T4. An intermittent problem I suspect at the time as I've since had a cheap code reader working on the car but if it were not for Brian the car would have been scrapped as a non-runner and I could not thank him enough.

[Teflon]

Originally Posted by Bastelmann

Cliff, two questions about the throttle body:
2.0 and 2.5 are identical, right?
Is it difficult or a simple task to remount the springs after disassembling and cleaning?
Apart from that the lacquered throttle body looks really great!

Remounting the springs is quite simple, provided you know precisely where they go. I took loads of photos before dis-assembly, and was also fortunate in that I was working on a spare throttle body, so had the one on the car to refer to when in doubt .

Originally Posted by WillyHeckaslike

Swapping the IACV can produce mixed results without the help of T4 to configure its stepper motor with the ECU. My Rover 25 came to me with the revs dropping off when driving off from cold and often stalling more so in cold weather. From what I could see the inlet manifold had been changed and most likely I thought as a job lot complete with IACV etc.. I was aware of the need of T4 to sort the problem but it wasn't until I called on Brian for an unrelated non-start problem that the problem was largely fixed. I say largely because Brian put a newer map on the car which all but fixed it completely but before he could check out the stepper motor the car stopped talking to T4. An intermittent problem I suspect at the time as I've since had a cheap code reader working on the car but if it were not for Brian the car would have been scrapped as a non-runner and I could not thank him enough.

That's interesting. The new Idle control valve certainly made a massive improvement, but still not 100% right, I wonder if that could be the answer?

My last attempt at fitting it had to be aborted when I managed to snap the "Tee" piece connecting the breather pipes during removal . All fixed now though, so I will have another go in a few days time .

Cliff

[Bastelmann]

Hi Cliff,

I´ve got further questions.
How did you manage to remove the axle and its bearing marked in the picture? And how did you manage to make the mechanical parts so shiny? Are they freshly galvanised?




Is it possible to remove the two marked plastic parts without damaging them?




And my annotation to your 98%-problem: I´m quite sure that a T4-session will resolve it. Haynes manual describes that this could be necessary after removing or swapping the throttle body.