Fuel pump question(s)

[punkydog]

I just want to check the position of the delivery and return fuel lines on my Bis. The manual shows the pipe nearest the rear as the return line but on mine and on my parts car it has the filter on it and appears to be the delivery pipe, the other is marked “R”  and I assume that this means “return”. I also assume that it wouldn’t work if connected incorrectly. Both pumps are different to the one in the manual.
The reason I ask is that since an engine rebuild the pump seems to struggle unless the tank is over a third full, and fails to pump the second the low fuel light starts flashing - yes, I have checked that my delivery pipe is connected to the pickup pipe on the tank and not the return.
The returned fuel is only a trickle even with a full tank. I have replaced the heat spacer as the old one was cracked. The manual has something about thinner gaskets to increase fuel pressure but the gasket kit only contains enough for the spacer and the pump.
Is just a failing pump?

I was supplied with new pump which looks like the older style but the mounting holes are closer together, is this a 650 or a 500 one? The supplier insists that it is correct and refuses to change it but it is obviously isn't correct – so I will not be buying off them again

[The Laird]

Hi Brian,

I have fitted three new pumps to my Bis, all have been different ! The 'lift '
on the pump is critical and can be varied by the thickness of the gasket. I still have the other two pumps and basically they are both full of brown sludge. hence why it is probably better to put a filter on the inlet and outlet.
My mechanic told me that the pushrod that lifts the pump wears after a while. He welded a blob on the end of my pushrod and then ground it down to size. I normally keep a spare pump in the car + condenser and points just in case.
I have had my Bis since new and have only just gone over 18,000 miles so there would appear to be a inherent problem ( other than head gasket).
Off to good old blighty early tomorrow so will look forward to finding out if you solve the problem when I return.
Best of luck.

[bis13]

yes the nearest pipe is the feed . and the pipe behind is the return. did you replace the rod at the same time ? as for the supplier he cannot refuse a return unless you have used , broke or ran over the 15 or 30 day returns deadline . if you have not send it back , you can its the law.

[Chris Lakin]

yes mic is right (bis13) they seem cheeky to insist your incorrect.

can i ask which company you have used Brian?

the new pumps are big bulky gray ones with a rubber gasket/spacer.

http://cgi.ebay.co.uk/FIAT-127-1050-1300-FUEL-PUMP-NEW_W0QQitemZ4620422835QQcategoryZ10382QQrdZ1QQcmdZViewItem#ebayphotohosting

this is a pump for a 127 but in looks is very similar to the new BIS pumps. (This is what my one looks like, which i bought from ricambio recently)

 ive had the same conversation before with someone on the preloved forums about the fuel lines locations, we all came to the conclusion the BIS manual has mixed the lines up.

Peter, i was having a conversation the otehr day with my brother, i said to him i want to put the filter before the pump to stop the dirt getting into it, he said dont worry aout the pump put it between carb and pump. After what you said about "brown sludge" i know where i will put it. Can you put two in? one before pump and one before carb?

regards

Chris

[The Laird]

Hi Chris,

Just returned from three weeks in UK, catching up on the 126 site !

Cannot see any problem with putting two filters on. Once the system is pressurised it should not have any adverse effect.

Never saw one 126 whilst in the UK. I am sure I e-mailed someone in Silverstone who had a 126 and as I was staying in my house there it would have been ideal to meet up. Can you pass on that members details please ?

My other half was driving to the airport in Malta to pick me up and some prat drove into the back of the Puttputt. There is some superficial damage to the riser panel and the nearside mounting bracket is in kit form. Judging by the problem she had in extricating the guys telephone number it is probably going to be difficult in chasing him for the cost of the repair. Fortuitously I bought a big bottle of touch up from Halfords whilst there but I did not expect to have to use it so soon !!

All the best,

Peter

[Chris Lakin]

hi peter sorry to hear about the accident, so not too much damage?

yes i will be putting two filters on, i had ago and putting one between the carb and pump but the bloody filter filled up too quickly with fuel and leaked, i tired both ways and was same. Also the hose clips i got from halfords not only were they expensive they were too big

Peter i cant think for the life of me who the member is near silverston, i know there is one, i forget where everyone is, i will trawl through the membership forms to see if i can find that person.

regards

Chris

[bis13]

darkhorse is silverstone way i do believe.

[Chris Lakin]

yes you are right!!!! but i think he has moved now.

look out for Darkhorse on here Peter his name is John Bitmead.

regards

Chris

[Bruce]

this is th eone i just purchased from my local autofactors, the nearest pipe is the  input.

[The Laird]

Hi Guys,

I like many have had my fair share of problems with the fuel pump. I bumped into an old customer of mine at our Motor Show yesterday while I was deciding on a new car. He is the Technical Director of the biggest breakdown company in Malta (equivalent to the AA ). We were discussing my on going 126  pump fiasco. Now they have computer records of typical mechanical failures on all makes going back to the early 80's. The cause according to their statistics is that you get a moisture build up in the crankcase. The moisture finds it's way up to the fuel pump and rusts the spring apart from other internal parts which causes the failure. They also believe that moisture can get into the fuel system as well. He said to me the best solution for the 126 is to remove the fuel pump completely, blank off the mounting and install a 12 volt electric fuel pump.

It seems plausible to me, but I always thought the system was pressurised.

One thing for sure the Maltese are VERY clever mechanics they can and do amazing things to cars, fabricating whatever parts they cannot procure slotting diesel engines into nearly anything you can think of ( not 126's yet though ).

I always thought the system had to be pressurised, what say all you boffins out there ?

Regards,

The Laird

[Bruce]

I thought about an electric pump aswell. My old merc had an electric pump and that was definatly a pressurised fuel system, because it used pressure to inject the fuel, the was a pressure resevour for starting aswell. Certainly be a lot less trouble than trying to find a new pump every couple of years.

[Chris Lakin]

peter the rusting would explain the brown sludge u found in you fuel pump.

electric fuel pump be easy to fit?

regards

Chris

[paul harbinson.]

Austin has an electric pump fitted to his aircooled I think.If ther is rust in there the fuel tank need's changing,dosnt matter how many filter' are in line it'll find it's way through and the wee car won't run right. :sad:

[gnash]

Yep I have an electric fuel pump fitted (by a previous owner).  It comes on with the ignition and seems to work well.  I'll take a photo or two and post them here later.  Doesn't look like to difficult a job to fit.  (Famous last words  :roll: )

[PaulB]

Bob a switch on an electric fuel pump circuit and its quite a good anti-theft device - the car won't get far on what's in the carb bowl.