37 replies to this topic

[pothole]

Recently my 1995 sidewalk failed the MOT emissions mixture too rich, I think I have tracked it down to the red vacuum pipe from the throttle body to air filter, the rubber has snapped on the throttle body. I have removed the filter but how do I get to the throttle body fitting. Do I need to remove anything for easy access, thanks.

[RooBoonix]

Once the airbox is off, you should be able to get your hand down from either the top or side and get to both the vacuum pipes behind there. You may need to use a torch to look before hand but it can be done and they are just a push fit, but quite a tight fit (well they are supposed to be a tight fit). The only thing that needs removing is the airbox :)

[pothole]

Thanks for the advice, as the rubber had broke onto the pipe it was hard to get in and get it off but it done now, just need the pipes as the other white one was splitting as well.

[pothole]

Well I have replaced the vacuum pipes and it is still running rich, so what's the next on the list to replace, lambda or Temp sensor.

[FlyingScot]

Make sure you have replaced them all and the fuel trap as these are all service items.
As I posted many times before start with this and don't bother to keep any of them as the cracks especially in the rubber elbows are difficult to see.
Only once you have done this is it worth moving onto anything else, apart from which the temp sensor is a beggar to get at.

If your temperature gauge is reading just below N when warmed up it won't be the temp sensor as it feeds the ECU and the ECU feeds the gauge.

FS

[FlyingScot]

Moved to injection

FS

[spiguy]

running rich is more likely to be the black pipes to the ECU, or the fuel trap. As minicomic says, replace the pipes and the trap - not too expensive. Don't look elsewhere until you have done that.

[humph]

Once you've checked these pipes I'd get a voltmeter and check the supply to the Lambda sensor. My rich running was down to breaks in the feed wire, these were caused by the engine bay loom rubbing between the throttle body & bulkhead, it's a common problem. Repaired breaks and lambda worked fine.

[pothole]

Thanks for the replies, I am not a happy man at the moment I have just been down the garage to work on the car again. I removed the air filter and the red wire came away with the filter it had broke at the elbow. This was a new part from minis pares and not cheap two pipes plus postage £17. No wonder yesterday when I started it it seemed to tick over at a lower Rev than before, then when I went back to it it was business as usual revving high and black smoke out the back. So it's a search round Leicester for the rubber elbows, which I finally tracked down to a motor factor, not the same as on the original but the thicker old vacuum pipe ones, let's see if these work.

[humph]

How about trying it with a length of screen wash pipe, just to try. I've read Mini racers replace their pipes with this for reliability. Odd that the new one should have broken, that needs investigating. 

[RooBoonix]

How about trying it with a length of screen wash pipe, just to try. I've read Mini racers replace their pipes with this for reliability. Odd that the new one should have broken, that needs investigating. 

 

Or vacuum rated silicone tubing, available from ebay. I've done this, works great, and doesn't perish/crack like rubber.

[pothole]

Well all tubes have been checked and replaced or new ends fitted and still running rich, black sooty spark plugs, so as suggested the next stop is the fuel trap, I have ordered one just waiting for it to come in. I located the lambda sensor and wondered why all four wires had been cut and rejoined, then thought how do I get that out, then it occurred to me that someone had cut the wires so a normal socket could be used and not the special split one. But I won't worry about that until I have fitted the fuel trap. Then it occurred to me that I have the same lambda fitted to my Rover 114, so I could try that once the fuel trap has been fitted, and I can get the old lambda out.

[FlyingScot]

It could be that the wires are cut as a universal lambda sensor has been fitted and the wiring joined up.

Motor Factors sell generic lambda sensors and sleeving but I wouldn't trust anything apart from a genuine Bosch one.

I gave never had any success using distributor vacuum elbows as they aren't a good enough fit.

Any one near you got a code reader? You could rule a lot out if you can.

FS

Edited by FlyingScot, 14 August 2015 - 07:28 AM.

[peter-b]

The best place for the standard vacume pipes is in the trash, they'll woeful rubbish. Get some quality vacume hose, 3mm from memory, and replace the lot. I can't see the fuel trap being a problem, it's just a chamber to separate fuel. Does your temp gauge work? Does it read correct?

[RooBoonix]

The best place for the standard vacume pipes is in the trash, they'll woeful rubbish. Get some quality vacume hose, 3mm from memory, and replace the lot. I can't see the fuel trap being a problem, it's just a chamber to separate fuel. Does your temp gauge work? Does it read correct?

If the fuel trap is leaking, therefore affecting the vacuum it could cause this problem. And my silicone vacuum hose is 3.2mm internal diameter, nice tight fit.