View single post by Spongebob
 Posted: Thu Mar 18th, 2010 11:30 pm
PM Quote Reply Full Topic


Joined: Thu Mar 27th, 2008
Location: Boycottland
Posts: 147
We've got a combined Boston gas/smoke tester (not sure what model off the top of my head) which we've had for about 2 years now. Never had a problem of this sort until 2 cars recently.

First one was a petrol car which failed the BET test so was tested to specific limits. I can't remember what car but it looked to have passed until I saw the printout had shown it failed the idle test due to idle speed being below limits.

This isn't a reason for rejection I can find in the manual so I duly noted it on the sheet for both the customer and garage and let it go.

Today I was testing a focus diesel which on 6 readings started at around 7.5k but came down so that the final 3 were 3.89 2.80 and 2.20. It failed the test with a mean value when adjusted of 3.31.

Now the printout also highlights which readings the result is based on and rather than the average across the final 3 it worked out off the 4th and 5th ones and ignored the 6th. My own calculation for the final 3 less the drift figure came in at around 2.91 so therefore a pass. Even if it's working off 2 results surely it should've gone off 5 and 6 and therefore an even better pass?

Or am I interpreting the text of the manual incorrectly? Do the readings have to be within a certain amount of each other (eg 1.0k)

It's bad enough when testers start making their own RFR's up but for a machine to do so is something else.