Fuel system - Pierburg

From VW T25(T3)-Tech
Jump to navigationJump to search

Useful links

Carburettor 2e3 refurb kit Part No ZE511 and £33.09 inc delivery or £13 from VW (if you can get it)

Diagrams/exploded views


Item Description Item Description
1 Upper body 21 Tamperproof cap
2 Fuel inlet filter 22 Float chamber gasket
3 Float pin 23 Main body
4 Float 24 Part load enrichment valve
5 Needle valve 25 Secondary throttle diaphragm
6 Idle jet (primary) 26 Secondary throttle diaphragm pipe
7 Accelerator pump valve 27 Choke housing
8 Idle cut-off solenoid 28 Bi-metal choke assembly
9 Idle speed control screw 29 Choke flap
10 Mixture screw 30 Choke pull-down diaphragm
11 Accelerator pump diaphragm 31 Choke pull-down diaphragm pipe
13 Float chamber gasket 32 Roll pin
15 Vapour canister 33 Star clip
16 Fuel hose feed from pump 35 Fast idle adjustment screw
18 Main jet (primary) 36 Earth strap
19 Main jet (secondary) 37 Throttle body heater

Table borrowed from Gower and Lee [1] who can supply most of the parts

Note: If you require the 'choke flap repair unit' (van choke not working, no power at all until it warms up) then the Pierburg part number you need is 4-07301-13 (or possible 4-07301-10 might do). Gower and Lee don't have this in stock but they did have (May 09) 4.07301.09 2EE kits, the spindle is incorrect but I'm sure the plastic cam would fit. Image from Gower & Lee of this part number.


Other cars that use the Pierburg 2e3

Jetting carbs

Aircooled.net (Carbs 102: Basic Jetting Theory and Procedure)

toomanytoys: Using a 1.9DG pierbug on a 2.1 DJ engine

If the truth be known.. it possibly would benefit from running some smaller jets. as the engine should give a bigger vacuum.. in reality the standard jets in a 2E3 work very well and give the same or better than DG mpg (I used to get same mpg but travelling faster) as the cam timing is longer so allows for the charge to get into the engine.

One thing with the DJ is you will have to consider what timing and fuel to use.. UL95 use 5 deg BTDC, or with UL98 you could go a bit higher maybe 8 deg BTDC but I would be a little wary of runnng 10 deg on UL98.. the Fuel Injection has better control over fueling than a carb.. unless anyone has put a lot of miles on a "DJ'd" DG.. I have, but on LPG which is a different kettle of fish..

Air filter.. if an early square type then dont worry, same as in Audi 5 cyl turbo's so flow plenty of air.. but I would make sure you rebiuld the carb before using it and set it up properly. If you can stretch to a rolling road session with someone that knows carbs, then you could fine tune the timing and carb settings/jets, but it will cost you.. but you would know whats going on..

Its a great conversion, lots of usefull torque, without compromising the mpg.. Oh and think about using the oil cooler from the DJ as the extra heat needs to go somewhere, plumb it in to the coolant return from the carb heating.. make sure the cooling system is in good nick and fit a new genuine thermostat (been some problems with some aftermarket ones.)


Don't Forget - There Are TWO filters

- (CovKid)

I'm posting this, peppered with relevant keywords in the hope that should anyone experience the same problem, they may just find a solution here.

Some months ago I ran entirely out of petrol at a busy junction in the pouring rain with my five year old son onboard. Fortunately a sympathetic bay owner going the other way saw the situation I was in and towed me off. I returned to the car park I'd left it in the next morning and it started with little problem with a gallon of petrol poured in, plus a dash down the inlet bore for good measure.

However, I had noticed a definate drop-off in power, mild hesitation on acceleration and what appeared to be a speed governer at around 65mph (mine will normally do 80mph fairly effortlessly). Last week I replaced the main fuel filter near the tank but this made little difference, neither did new plugs and a non rev-limiting rotor arm.

Its worth pointing out that the Pierburg carb in fact has its OWN filter (part 2 in above diagram), almost unseen as its fitted right inside the brass fuel inlet pipe - cone shaped, and only removable with a screw around the same diameter.

Heres the inlet pipe (photo courtesy of member 'Edoh'):


Using a screw extractor or self tapping screw to grip the inside of the plastic filter (photo courtesy of member 'Edoh'):


Filter removed (photo courtesy of member 'Edoh'):


Today I removed this and discovered it was totally crudded up with limescale/rust and with a careful and repeated wash in detergent and rolled between finger and thumb, it was finally clean once again. Refitted, power restored, smooth acceleration and no top speed limit. So, worth remembering if you have the same carb, don't forget to clean out this filter as well as replacing the one near the tank. You need something like a self-tapping screw to grip it and pull it out. Easy job though.

If you tend to run low on fuel or run out altogether, you could well find your bus runs like a box of loose spanners because of this with it dying at junctions, holding back at speed etc. For reference, the float bowl was free of any muck.

Pierburg overhaul kit and adjustments

Two excellent videos produced by Jamesakers on using a rebuild kit and checking carburetttor adjustments.



Electrical plugs/connectors

We recently found fairly good substitutes for the original male/female spade connectors that join the carb choke etc to the wiring harness. They can be purchased from:


Rubber Boot on secondary throttle diaphragm

DG Pierburg Secondary Diaphragm Booot 01.jpg