Fuel Sender Fun

S

simon6374

New Member
Hello everyone

As this is my first post, just thought I should give some background. My father bless him recently bought a 1972 V8 3500s on ebay :oops: . In fairness to him the car was nothing like described but I wish he had removed the blindfold before handing over cash for what is really nothing more than scrap. Still I can't talk, I wish I had removed the blindfold before getting married :LOL:

Anyway, as he has the DIY skills of a duck I've volunteered to restore it to it's full glory. I'm a VW enthusiast and only familiar with TDI diesel engines, but I am 'enjoying' getting acquainted with these old skool petrol engines with things called Carburettors and Distributors?!!! I must say compared to modern vehicles these motors are amazing. Everything is so straightforward and accessible and I don't even need the laptop to fix it! 8)

Having said that, I've got a problem with the fuel sender :roll: . I had to remove the petrol tank to purge it of rust because it was fouling up the carbs, lines and filters and not allowing enough fuel through. Whilst at it, I repaired a broken wire inside the fuel sender. The fuel gauge now shows full regardless of the float position. Multimeter resistance readings confirm the sender is duff. I then went to check the voltage readings between the green and black wires and it fluctuated wildly between 0-12V. I read that the feed should be 10V via a voltage regulator supplying both fuel and temp gauges. I can't find any damage to the wiring so I reckon there must be a problem with the regulator? I'm going to have to replace the sender but I still need to establish why the feed wire is so erratic!

Sorry if it has already been covered but I couldn't find anything using the search facility and I'm keen to get this Mexican brown turd off my drive so I can finish off my camper conversion :shock:
Many thanks
Simon
 
Welcome! you never know you may catch the P6 bug :LOL: Photos ar almost obligatory :D as all the other P6 addicts on this forum need their P6 Fix (along with their coffee or latte).

graeme
 
Thank you Graeme for the welcome. :)

I must admit, despite being a committed and fully paid up member of the VW T4 forum, I'm quickly falling for the old world charms of the Rover P6 It is a beautiful car (in an ugly way) and I love all the tactile dials and switches that is so lacking in a modern vehicle. The trouble is, since this wreck managed to find a parking space on my drive, I have spent 24/7 living and breathing P6 Mexican brown hell trying to get it off again and back to my blindfolded father who purchased it :D

The V8 does sound amazing compared to my 2.5 TDI, and I am determined to get it running perfectly. So far I have stripped down the dizzy and installed electronic ignition along with a new vacuum advance. The SU carbs have had a full rebuild and don't get me even started on the bodywork. My dad bought it a couple of months ago in a moment of madness and frankly I only offered to help him because I thought he was going to book a flight to Switzerland for an assisted suicide with Dignitas :shock:

I will post some piccies in time, once it starts looking like a car again. :LOL:

Regards
Simon
 
Mexico Brown I would say is an aquired taste one which thankfully I will never get. Whilst the charm of the P6 can be purley a visual thing, for me it is the engineering the amazing drive feel and the body aesthetic as well. I once made the mistake of selling my P6 the only cure was to buy the same car back a few years later. They are quite addictive.

Graeme
 
simon6374 said:
My dad bought it a couple of months ago in a moment of madness and frankly I only offered to help him because I thought he was going to book a flight to Switzerland for an assisted suicide with Dignitas :shock:
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:LOL: That's harsh!
 
You could always suggest he runs with the tank full and fills it before it's empty - there is the reserve tap if he runs out... Otherwise i guess you just need to buy a new sender? Cant see them listed on http://www.rover-classics.co.uk/ site, but worth a phone call, otherwise http://www.winsintltd.co.uk/rover_p6.htm list them for £79, jrwadhams list them (as tank sender) https://www.jrwadhams.co.uk/shop.asp?cI ... &Submit=Go for 52+vat. otherwise look out for breaking ones on ebay and the like if that's a bit too much money :)

Rich
 
Oh... and welcome to the forum... Mexico brown's on the way back in - Peugeot has just released a metallic brown that isnt that far off shade wise to my eyes....

RIch.
 
Thanks for the info Rich. The reserve tap is bust, as is just about everything else like the clutch, exhaust, choke/throttle/bonnet cables, fuel pump etc, even the doors are taped together with duck tape because they would fly open otherwise and none of the locks work :!: :( It came with a new MOT, but I'm convinced it's 'bent' because even the indicators, wash bottle and wipers don't work as they should. :shock:

The fuel sender is just a minor problem but one I would like to resolve having removed the tank :LOL: . If anyone could shed light on whether there is a voltage regulator? How difficult is it to get to? and if broken what is available to replace it? I need to sort out why the feed wire is flying about 0-12V when it should be a steady 10V?

Thanks
Simon
 
from memory some where in behind the instrument panel, but i think they are probably a mechanical regulator (maybe wrong here) and that would explain varing output voltage as mechanical units are load dependant.
 
If lots of the electric are duff look at the obvious like fuses and earths... the clutch etc sounds fun... ;)
 
simon6374 said:
living and breathing P6 Mexican brown hell trying to get it off again
Click to expand...

Hi Simon, welcome to the forum.

Don't diss the Mexico brown it's a great colour when properly looked after, but I'm biased :D

IMAG9027.jpg


The instrument voltage regulator is on the back of the instrument panel but I'm not sure how available spare ones are. It might be easier to get a hold of another instrument panel complete and swap them over. Alternatively if someone else close has a spare that can be slaved in to see if the regulator is the problem then all the better. Always good to have a spare anyway though.

Dave
 
Thanks for that Dave :D

I was very tempted to get some aerosols out and do a quick respray but your motor looks stunning and it's renewed my faith in turd brown. :LOL:

Very useful info thank you - will order a new sender and refit the tank for now, then do the instrument panel as you suggest. What a friendly forum thanks for all the replies!
 
Hi, I hesitate to do this for copywrite reasons. But here goes!

This article is from Practical Classics which may answer your findings and questions.
Also provide a solution to the problem of the volt stab.

Colin
 

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Colin - thank you for posting that article, very useful indeed. It says that digital multimeters tend to display random numbers with mechanical type regulators and so this explains why I couldn't make sense of the readings. :?

Dave - yes the temp gauge works fine, so there is a good chance I've been worried about nothing. :)

I will just get a new sender. Thanks so much for the replies and apologies for my earlier rants, it was posted late at night after a bottle of South Australia's finest. :LOL:

Cheers
 
One thing I would have to check first with using the semiconductor is if it gets too hot during use and engages the thermal protection. If it does, then it would need to be connected to a heatsink. In the case of the TS7810CZ (-ve earth), that's no problem because, according to the TS7810CZ data sheet, the heatsink surface is connected to pin 2 which is also the ground/earth connection. You could in theory use a metal earthed panel as both earth and heat dispersion.

As mentioned in the article and the datasheet for TS7909CZ (the +ve earth version), the wiring is different. Pin 2 in this case is the -12v input (i.e. the live of the car), and pin 1 is the earth/ground. However, the heatsink surface on this one is also connected to pin 2 , so you can't mount the TS7909CZ in the same way, otherwise you'll be potentially creating a dead-short! You'd have to use insulating washers and jelly/paste that's thermally conductive but electrically isolative.

EDIT: Sorry if anyone read the first version, I copied the same URL twice! Too much drinking at Kate & Will's party earlier! :p :oops:
 
Gents, while we're on the subject of senders, I've finally sorted the electrical problems on my white car as far as the tank sender (the guage has never worked as long as I've had the car), there are 2 terminals on the sender, one surrounder by a small plastic shroud, which does the cable from the dash connect to? Had intended looking at one of the other cars today to check while out at the workshop (the white car is in my other half's father's place), not sure if it makes a difference which way around they go.
Regards,
Dave
 
The shrouded terminal is the live one, green and black wire I think. It goes to the gauge. The other one is an earth and should have a black wire on it. If you reverse them then most likely you will blow a fuse or worse.
 
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