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Re: loss of power and poping

To: Richard B Gosling <Gosling_Richard_B@perkins.com>
Subject: Re: loss of power and poping
From: "T. .R. Dafforn" <td214@cam.ac.uk>
Date: Fri, 14 Jul 2000 11:23:37 +0100
Richard,
Thanks for all the suggestions, I was just coming to the conclusion that maybe I
should get the car tuned properly. The only trouble being finding a mechanic I 
can
trust, and who can still remember how to tune twin SUs. I have only recently
installed a fuel filter after a long lay up due to restoration, it could be that
it has pciked up rubish (ie dust from the kilos of bondo I gound out). Fuel pump
is new (100 miles) so that should be OK. I agree that fuel blockage should 
produce
later sputtering. I ave put standard engine oil in the carb dampers, would that 
be
a problem? I did this for many years in an old rover metro which had a single SU
and it was fine... The strange thing is the fact that it seems to happen as the
car gets hotter, so perhaps  a vapor lock?
As to the temperature guage I'll try a thermometer, but where do you put it?
Thanks for the help
Cheers
Tim
Richard B Gosling wrote:

> Tim,
>
> Two thoughts occur about this - tuning or fuel starvation.  If you've tuned it
>  using a Color Tune then tuning should be OK - I've never actually used one of
>  these, so I don't know how good they are.  What I do know, after a fair few
>  attempts at tuning myself using the
>  push-up-the-lifting-pin-and-seeing-what-happens-to-the-engine-note method, is
>  that I am no good at it at all, and now tuning is one of the (very) few 
>things
>  I leave to a professional who does know what they are doing!
>
> The other thought is fuel starvation.  Have you checked your fuel filter (in
>  the top of the pump on the LH of the engine) - could be blocked?  Also, does
>  this happen particularly when you are low on fuel - you could be picking up
>  crud in the tank and that could be causing a blockage - my wifes Panda used 
>to
>  do that if the fuel ever dropped below 1/4 level.  If neither of these are
>  correct, then it could stil be a blockage, but it could be something lodged 
>in
>  the system somewhere - this may require dismantling and cleaning out parts of
>  the system, which sounds like a hassle!
>
> Although, thinking about it, a fuel filter blockage shouldn't cause a problem
>  until after several seconds of sustained acceleration, unless it is a very 
>bad
>  blockage - after all, the carbs have their own little float tanks, so until
>  those are empty there will still be fuel for the carbs.  Very small particles
>  from the tank, that pass through the filter, and then block the carbs may be
>  more likely.  I'm not going to go into this any further, as carbs remain
>  beyond my comprehension, I still don't really understand what goes on in
>  there!
>
> As for the funny coolant temps, have you checked your voltage regulator?
>  Admittedly, when these go, you usually get a high reading not a low one (I
>  spent a couple of months fighting what I thought was an overheating problem
>  until I replaced the regulator), but it might still be this.  If it is, your
>  fuel guage will be funny too - does it read full when the tank is full?  If
>  not, then it is almost certainly a regulator problem.
>
> Hope this helps!
>
> Richard and Daffy

--
Tim Dafforn
Structural Medicine
Department of Haematology
CIMR
University of Cambridge
Wellcome-MRC Building (Level6)
Hills Road
Cambridge
CB2 2XY

Tel. (01223) 336829
Fax. (01223) 336827
http://smokeroom.cimr.cam.ac.uk/




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