19 replies to this topic

[FlyingScot]

Yep TPS should be reading 0.4 to 0.6V at idle position, check wiring as well as TPS. In fact check TPS off car by measuring ohms between middle and outer connection. Not sure about mixing metro and mini throttle bodies....

FS

[Aus]

The actual casing of the Metro TB is identical save for the large breather on the front face of the TB which points forward where the Mini one has a 90 elbow The breather hose does still fit but it runs over the top of the throttle cable but this is how the car was running when she bought it with Metro TB on. The big difference I found was the throttle spindle was different hence why I swapped the spindles over.

 

At this stage it was purely an attempt to keep the car running to continue fault finding as the sheared bolt meant that the throttle pot could not be held firmly by just one screw. The plan was to source a new TB but having searched the various Mini part suppliers I can see that they are NLA. I will have to see if I can salvage the Mini TB.

 

Yep. My dad is an electronic engineer by trade (back in the days of valves etc lol) so I'm gonna ask him to take a look at the Throttle Pots we have and see if he can test and evaluate whether any are good or can be salvaged. I read up that the SPi throttle Pot is widely used across a lot of 90's Rovers so I am so surprised that the unit is NLA, not even a pattern parts seems to be made !

Edited by Aus, 01 August 2016 - 07:57 AM.

[Aus]

Ok, possibly a stupid question but bear with me. I'm mentioned this "air leak" that stops when I clamp the breather hose from the metal pipe to the bottom front right connector on the TB. It doesn't stop when you clamp the clutch housing breather pipe, the timing cover breather pipe or the one to the top of TB in turn.

 

Now am I being stupid but is this because the TB is sucking in the air and fumes from the crankcase - ie is this "air leak" one that is supposed to be there ? It makes sense that by clamping one breather pipe nothing happens because its still sucking through the other breathers but when the "collector pipe" is clamped it stops the flow of that air and the revs drop accordingly.

 

Am I chasing my tail with this one ? Does anyone have an SPi that they can conduct this 30 second test on just to see if a normal running SPi does the same thing when the collector pipe is clamped ?

 

Thanks for any help you can give me !

Edited by Aus, 03 August 2016 - 10:12 AM.

[FlyingScot]

Sounds like you have a hole in one of the hoses?
The rubber pipes from the breathers are connected together by the larger metal tube (the smaller one being for the evaporative control (purge valve to TB). Or possibly a corroded tube?
I would whip it off and the rubber hoses and check.

FS

[Aus]

Hi FS, I've replaced the metal pipe with a spare and checked all the hoses for splits, they're all good. The only pipe that causes the revs to drop when clamped is the one that goes directly on to the Throttle body from the metal pipe. To be sure I have put a cable tie around each end of all the rubber pipes to help form a seal where it connects to the breathers and the metal pipe in case air was leaking in that way. Its only after all that seemed ok that I started to wonder whether the breather was a sort of controlled air leak - or perhaps something stupid like a poor seal on something like the oil dipstick or rocker cover causing air to be drawn in that way and then through the breathers and in to the TB showing up as an air leak ?!?