Throttle Body

Teflon · 17th May 2020, 15:15

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

KWIL · 17th May 2020, 15:45

Cliff,

If it is the Idle Valve, just block the supplementary air inlet tube, either directly or in the air filter housing if that is all set up, revs drop? you will know its the Idle valve, if they do not, you have another leak

K

Teflon · 17th May 2020, 16:16

Thanks Ken, I'l give that a go tomorrow

Cliff

Teflon · 18th May 2020, 10:35

So, this morning I refitted my re-furbed throttle body, but only after taking the idle control valve off, and giving it another quick clean.

Result was a little better, but still no go. From cold, things seemed almost normal (revs a little high, but not too bad). Once the engine had warmed, she ticked over quite nicely, but when revved, the engine stayed at the higher revs

. An improvement over yesterday, but still unusable.

With the engine revving away happily at around 2k, I did as suggested and blocked off the top inlet (brass bit). This caused the revs to instantly fall and would have stopped the engine. Unblocking it before the engine stopped, and she idled away nicely until revved up again.

In view of the above, I'm presuming a new idle control valve is required, does this sound right?

Obviously, the simplest solution would be to swap over the valve from the throttle body that's currently on the car. Thing is though, I'm loath to try this in case I stuff up the working throttle body and end up with an undriveable car

. She's been in that state long enough this year already!

Cliff

KWIL · 18th May 2020, 11:31

Cliff,

Sounds correct to me, you have apparently isolated the problem. I was going to suggest swapping the Valve body

. I cannot really see how doing that could leave you as you fear, but I suppose there is a chance. What puzzles me is that left on warm up. it settles down to tickover, so the valve is closing as it should. There is the 5 throttle movement reset procedure, when the engine has warmed to tickover, switch off, switch on without starting, accelerator 5 depressions, switch off, then restart, might work.

Ken

Teflon · 18th May 2020, 12:56

Cheers Ken.

I've bitten the bullet and ordered a new valve from Rimmers, so should have it all sorted by the weekend I hope

.

I'll report back once it arrives. Thanks for the advice

Cliff

Saga Lout · 22nd May 2020, 09:04

Quote:

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 · 22nd May 2020, 12:19

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 · 9th June 2020, 04:31

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 · 9th June 2020, 06:59

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.

17th May 2020, 15:15	#1
Teflon This is my second home Lagoon 2.0 V6 75 Conn SE Saloon Join Date: Nov 2006 Location: Chertsey Posts: 5,203 Thanks: 2,825 Thanked 2,920 Times in 1,570 Posts	Throttle Body 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 __________________ No. 4 of 6

17th May 2020, 16:16	#3
Teflon This is my second home Lagoon 2.0 V6 75 Conn SE Saloon Join Date: Nov 2006 Location: Chertsey Posts: 5,203 Thanks: 2,825 Thanked 2,920 Times in 1,570 Posts	Thanks Ken, I'l give that a go tomorrow Cliff __________________ No. 4 of 6

18th May 2020, 10:35	#4
Teflon This is my second home Lagoon 2.0 V6 75 Conn SE Saloon Join Date: Nov 2006 Location: Chertsey Posts: 5,203 Thanks: 2,825 Thanked 2,920 Times in 1,570 Posts	So, this morning I refitted my re-furbed throttle body, but only after taking the idle control valve off, and giving it another quick clean. Result was a little better, but still no go. From cold, things seemed almost normal (revs a little high, but not too bad). Once the engine had warmed, she ticked over quite nicely, but when revved, the engine stayed at the higher revs . An improvement over yesterday, but still unusable. With the engine revving away happily at around 2k, I did as suggested and blocked off the top inlet (brass bit). This caused the revs to instantly fall and would have stopped the engine. Unblocking it before the engine stopped, and she idled away nicely until revved up again. In view of the above, I'm presuming a new idle control valve is required, does this sound right? Obviously, the simplest solution would be to swap over the valve from the throttle body that's currently on the car. Thing is though, I'm loath to try this in case I stuff up the working throttle body and end up with an undriveable car . She's been in that state long enough this year already! Cliff __________________ No. 4 of 6

18th May 2020, 11:31	#5
KWIL Precise Rover 75 Tourer 2.5KV6 Connoisseur SE Join Date: Mar 2013 Location: Fleet Posts: 2,954 Thanks: 630 Thanked 617 Times in 480 Posts	Cliff, Sounds correct to me, you have apparently isolated the problem. I was going to suggest swapping the Valve body. I cannot really see how doing that could leave you as you fear, but I suppose there is a chance. What puzzles me is that left on warm up. it settles down to tickover, so the valve is closing as it should. There is the 5 throttle movement reset procedure, when the engine has warmed to tickover, switch off, switch on without starting, accelerator 5 depressions, switch off, then restart, might work. Ken Last edited by KWIL; 18th May 2020 at 11:39..

18th May 2020, 12:56	#6
Teflon This is my second home Lagoon 2.0 V6 75 Conn SE Saloon Join Date: Nov 2006 Location: Chertsey Posts: 5,203 Thanks: 2,825 Thanked 2,920 Times in 1,570 Posts	Cheers Ken. I've bitten the bullet and ordered a new valve from Rimmers, so should have it all sorted by the weekend I hope . I'll report back once it arrives. Thanks for the advice Cliff __________________ No. 4 of 6

17th May 2020, 15:45	#2
KWIL Precise Rover 75 Tourer 2.5KV6 Connoisseur SE Join Date: Mar 2013 Location: Fleet Posts: 2,954 Thanks: 630 Thanked 617 Times in 480 Posts	Cliff, If it is the Idle Valve, just block the supplementary air inlet tube, either directly or in the air filter housing if that is all set up, revs drop? you will know its the Idle valve, if they do not, you have another leak K

22nd May 2020, 12:19	#8
Teflon This is my second home Lagoon 2.0 V6 75 Conn SE Saloon Join Date: Nov 2006 Location: Chertsey Posts: 5,203 Thanks: 2,825 Thanked 2,920 Times in 1,570 Posts	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 __________________ No. 4 of 6

9th June 2020, 04:31	#9
Bastelmann Loves to post Rover 75 Tourer V6 2,5 Connoisseur Join Date: Oct 2014 Location: Lippetal, Germany Posts: 404 Thanks: 47 Thanked 207 Times in 103 Posts	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! __________________ [SIGPIC][/SIGPIC] Gott schütze uns vor Sturm und Wind ... ... und Autos, die aus England sind. (Old German car mechanic prayer) Last edited by Bastelmann; 9th June 2020 at 04:52..

9th June 2020, 06:59	#10
WillyHeckaslike This is my second home Rovers 75 & 25 Join Date: Oct 2010 Location: Wearside Posts: 4,522 Thanks: 543 Thanked 709 Times in 511 Posts	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.