May 17, 2017 at 7:11 pm #3725
Does anyone know which non-Bristol a 401 sender unit is from? OR who repairs them and matches unit to guage?May 27, 2017 at 7:32 pm #3730
JDO Instrument repairs http://www.jdo1.com indicate in their advert that they can repair smiths sender units for fuel tanks, I assume it was a smiths unit Bristol used, I have not tried the company but may have to as I can not get any reading on the fuel gauge on the 401 we are working on,Holden Vintage do new units so may have one that would work on a Bristol.
Electrics are my least favourite aspect of working on old cars but my gauge is staying resolutely at empty, not even a flicker, I was told when the tank was off by a local garage that the sender was ok but I can’t remember exactly how they tested it.
As we had the loom disconnected I have established without doubt that we have the correct wire connected between the gauge and the tank unit, but nothing happens,the reading at the wire and connection is about 12.4v but if the earth wire is connected to the case of the sender the reading drops to under 3, earth wire on or off nothing happens on the gauge, with the earth wire off however I can also get a reading of 12.4V anywhere off the sender unit case itself, is this normal or does it mean the problem is an internal short in the unit?
Geoff.May 27, 2017 at 7:58 pm #3731
A new sender unit from Holden works on my 403.
Dave DaleMay 27, 2017 at 10:29 pm #3732
Have you got the Holden part number for the sender unit.
Geoff.May 28, 2017 at 5:43 pm #3733
Geoff. I don’t have the Holden part. No. but I have emailed the guy who supplied and fitted it for me. Hopefully he will look it up and reply soon and I’ll get back to you.
Dave Dale.May 28, 2017 at 9:20 pm #3734
Geoff.May 29, 2017 at 10:13 pm #3738
OK, Geoff. The Holden part No. is 070.233.
Please be warned that, when the tank has been filled, the needle does not begin to move off the ‘Full’ stop until travelled about 80 miles. Works normally after that. I think that the unit is adjustable to correct this but it has not been a problem for me, so haven’t bothered to adjust it. If you couldn’t live with this, please confirm with Holden that the unit can be adjusted before purchasing based on my suggestion. Thanks.
Dave Dale.May 30, 2017 at 6:44 pm #3739
Thanks for the further information, I would have no problems with it as supplied by Holden, we may be making a bit of progress however, John Harris was with me yesterday at a local show and afterwards had a look at the 401, he tested the resistance on the sender unit and thinks its ok going by the amount of fuel in the tank, it does need a better earth though, he also tested two spare fuel gauges and those also appear to be ok.
We did not take the gauge out of the car and on that one and the dashboard metal frame he could not get a good earth so suggested we look at that first before changing the gauge.
This afternoon I was checking the battery connections and discovered we have a bad earth, I have not been able to take the cable off yet as the nut and bolt are turning and they are located between the battery box and the adjacent storage box, the bolt therefore difficult to reach from under the dash, will have another go before the end of the week clean everything up and see if restoring a good earth connection to the battery improves things on the dash and the fuel gauge.
By coincidence I have a fuel gauge problem on my R Type Bentley except that one has suddenly started reading full. I got quite a few replies regarding the 401’s problem on Kevin’s forum which I think has given me enough information for us to sort that one out as well and I have a better understanding now of how the system works.
I do find I need more coffee breaks working on car electrics though.
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