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Electric fuel pump

Posted: 24 Jun 2016, 20:49
by adrianbutter
I've just had a carb overhaul on my T25, 1985, 1.9L engine (DG). I had a new weber carb fitted - new coil, new fuel pump.

It runs like a dog - Monday morning is not going to be pretty when I return after the bill I paid.... It is total flat, unless I have the accelerator to the floor. Good news is it runs lovely, until I try to cruise - it actually starts to drag, unless i take my foot right off, then it rolls nicely. I'm hoping this is just a poor accelerator linkage fit.. That said one of the 3 screws holding down the air filter to the carb is missing, so the seal is probably bad - this will draw dirty air - am I being precious, or is this poor/bad?

Anyway - should the fuel pump be running when the engine is off - but ignition is on - key turned to first position? Where is it pumping fuel to? Doesn't feel right...
Secondly my VDO gauge (I fitted years ago) doesn't register well now with this new coil - it is bouncy between 1000 and 2000 revs say, at idle - and goes beyond 5000 rpm when i rev a bit.... Is this a simple one - maybe the new coil is at a diff frequency. I did check the wiring, and it is attached to the negative coil terminal.

Thanks very much if you can help me.
Adrian

Re: Electric fuel pump

Posted: 24 Jun 2016, 22:11
by ajsimmo
Well...where do I start?!
OK, firstly the awful Weber conversion is no longer available new. It was discontinued last year, so maybe you have the wrong carb, or it's old stock (maybe from somewhere that couldn't give them away).
You will probably, by now, have picked up on the fact that I'm not a big fan of the Weber. There's nothing wrong with the original Pierburg 2e3. It's a very good carb but for some reason people struggle with sorting any apparent problems with it. They're usually pretty easy to sort, maybe a rebuild kit and a good clean, but I believe the best fix for a totally knackered old one is an identical genuine brand new one (still available from VW Classic for under £400).
You mentioned the missing 3rd screw - that's because there's only two stud holes on the Weber, the front one on the pancake should be plugged. You're right that the carb top doesn't always seal and you can draw dirty air. The centre jets often get blocked with gunk, and the majority run carp.
I don't know what caused the change to an electric fuel pump, but imho if that was the best solution VW would probably have fitted one. I like to keep it original (to benefit from all the design and development work that went into the vehicle) so would recommend returning to the mechanical fuel pump. I'd also be checking that coil is the correct one!

Re: Electric fuel pump

Posted: 25 Jun 2016, 09:06
by CovKid
Ditto on Webers. Its not helped by the (often) introduction of a 009 distributor because all the vacuum points are not always there to couple stock the stock (and correct) dizzy for the engine. They can indeed be made to run but prefer the pierberg as its about the best compromise and other than perhaps having to replace the choke pull down unit, all thats normally needed is a really good clean and a full gasket kit. Nothing exciting about the standard carb but it does work well. Sticking a Weber on does have some plus points but rarely in isolation - needs a better breathing engine to get the best out of one.

For the record, my pump is wired like that. I prefer it even if not correct as I can leave the vehicle for weeks and even if the line is dry it primes the line with ignition on prior to starting so it starts immediately.

Re: Electric fuel pump

Posted: 25 Jun 2016, 09:36
by silverbullet
Who did the work then?

It does sound like its going very lean the moment the throttle is opened from your description.

Ich fahre einen Bulli. Ich hilfe mir selbst...meistens!