Page 1 of 2

Pierburg cold start problem

Posted: 16 Aug 2011, 16:39
by phatphish_123
hi . i bought my first vw a couple of weeks ago , and im having a few problems . the moast anoying is starting it up from cold . it just dose not like it . it always starts in the end tho , but cant touch the throttle for at least 5 mins or it stalls . i have a suspition it the automatic choke playing up . has any one had a similar problem ? or is there a manuel choke conversion ? im no mechanic so it might not be the choke at all . i have replaced the plugs , leads , dizzie cap and coil , with has made no improvment :( . it is a 1989 2.1l water cooled engine . all help welcome .
thanks
phish.

Re: help im new :(

Posted: 16 Aug 2011, 20:42
by kevtherev
I take it it's a 2.1 DJ injection?
If it is then the temp 2 sensor might be playing up (on the thermostat housing)

Re: help im new :(

Posted: 17 Aug 2011, 09:13
by phatphish_123
hi kev . it has a 2E3 carb . could it be the same problem ?
phish

Re: help im new :(

Posted: 17 Aug 2011, 09:34
by kevtherev
then is it a 2.1 DJ on carb?
or a 1.9 DG?

Re: help im new :(

Posted: 17 Aug 2011, 09:56
by phatphish_123
im sorry , what is dj and dg ? it is defenatly 2.1 with a carb .
phish

Re: help im new :(

Posted: 17 Aug 2011, 10:14
by phatphish_123
ok wikipedia has answered that , so they are engine codes . still my engine has a carb ? these codes are both for ingection models ?
phish

Re: help im new :(

Posted: 17 Aug 2011, 10:35
by kevtherev
The DJ 2.1 was never fitted with a carb..
has it been fitted after market?

Re: help im new :(

Posted: 17 Aug 2011, 10:40
by phatphish_123
hmm . maybe , i only just bought it 2 weeks ago . it could be aftermarket . why would some one of done this ? ill look for an engine code .
phish

Re: help im new :(

Posted: 17 Aug 2011, 11:09
by kevtherev
engine code is stamped below the crank breather tower

Re: help im new :(

Posted: 17 Aug 2011, 11:13
by kevtherev
So any way back to your problem
Assuming it runs OK when up to temp...
When viewing the carb from the top on a cold engine, The choke flap should almost cover the venturi.. like this

Image

Re: help im new :(

Posted: 17 Aug 2011, 11:29
by kevtherev
Automatic choke..
This is the Pierburg 2E3′s Achilles heel. It has a choke mechanism that has always been misunderstood but this is the theory;

A choke is meant to actually ‘choke’ or starve the carburetor of air when the engine is cold so that the richer mixture is ignited easier. As the engine warms up a bi-metallic strip uncoils as it senses the increasing engine temperature. This sensing of engine temperature happens with the help of coolant that is ran through part of the carburetor’s choke mechanism. The choke works hand in hand with a mechanism called fast idle cam that if well set, keeps idle speed high and reduces it with increasing engine temperature. There is an additional component that helps heat up the bi-metallic strip using electrical energy from the battery. This usually helps open up the choke faster than the water would. Though in warmer climates it's no use.

The aim is to set the choke (butterfly) gap such that when the engine is at its coldest it leaves a gap along the barrel that is only small enough to accommodate a 3mm drill-bit and the fast idle cam can cause idle speed to rise to 2000 +/- 200 rpm.

Remove the choke body to reveal the bi-metallic strip/spring thingy
Open the throttle and position the fast idle cam screw on the highest step of the cam by turning it
Push the pullrod on the choke pull-down unit the furthest it could go and check the gap left when the bi-metallic strip is turned to the ‘start’ position. Turn the screw that manages the pullrod in or out accordingly until pushing the pullrod furthest in will lead to a 3mm gap between the choke butterfly plate and the barrel, when the bi-metallic strip is turned to its ‘start’ position.
Refit the choke body ensuring that it remains on the ‘start’ position when coldest.The position of the choke body can always be adjusted depending on seasons so that there is always optimum cold start engine speeds
Fast idle should also be adjusted hand in hand with the choke pull-down diaphragm but when the engine is warm and at normal operating temperature.
Position the fast idle cam screw by turning it in or out to the second step of the fast idle cam and check that the fast idle speed is between the specified 2000 +/- 200 rpm for fast idle. Adjust as neccessary

however all this is pointess if you have an air leak on the inlet side of the engine :D

Re: help im new :(

Posted: 17 Aug 2011, 11:38
by kevtherev
Pierburg schematic..
http://www.gowerlee.dircon.co.uk/2E3type.html" onclick="window.open(this.href);return false;

Re: help im new :(

Posted: 17 Aug 2011, 11:43
by phatphish_123
thats the carb i have :) im now going to go play . i have a feeling my choke flap was open all the way when i looked last time , but the engine was warn then . its cold now tho , not used it today .
thank you for all the info . i will get back to you with my progress (if any) . also kev , your van looks amazing! just had a quick peek at your pics . i am very jelous .
speek to you soon.
thanks again
phish

Re: help im new :(

Posted: 17 Aug 2011, 12:42
by kevtherev
The picture is as close to yours as I can get... it's off a golf :D

Re: help im new :(

Posted: 17 Aug 2011, 13:17
by phatphish_123
right , got the top off and the choke flap is wide open ! the engine has not been run today so should be closed nearly all the way . what would cause it to stay open ? i gave it a gentle poke ,but it dose not move . dose it work on some sort of vacume ?
phish