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Topic: 1.6 Driver Carb/Running issues (Read 60 times) previous topic - next topic

1.6 Driver Carb/Running issues

Hi all,

I noticed that the carb flange was split on my 1.6 driver. This was causing the car to run/idle poorly (it would improve if i leaned on the carb and closed up the split). I replaced the part, but now the car wont tick over at all.

Is there anything glaringly obvious that I could try?

Failing that, could anyone recommend a mechanic in the Sheffield area who would come to the car? (The car has no MOT so couldn't be driven even if it did run)

Thanks

Re: 1.6 Driver Carb/Running issues

Reply #1 –
Does it have the original Pierburg carb, or a weber?

I'll assume it has the original.  The Pierburg carb is a fussy carb and look very complex on first appearance, but you can get your head round it with the help of some you tube videos.  If you have sorted the rubber mount, then the next thing I would check is the vacuum hoses behind the carb for splits.  I prefer good fitting silicone hose cause it lasts longer.  When you start the engine from cold, the idle is initially set by the 3 point unit on the left hand side, then it drops after a few seconds (up to 30s), and the idle is controlled by the waxstat.  The waxstat as it warms up causes an arm to turn causing the idle to drop.  If you remove it and find wax or coolant is leaking out of it, its knackered and needs replaced (assuming you can find one).  In my experience, they are slow to react causing the idle to stay higher than you need for a quite a while. But it has no affect on the mixture, just the idle speed.

The vacuum hoses control the 3 point unit only.   There is a solenoid on the carb that should click when you turn the ignition  on, if it doesn't the 3 point unit will retract fully and it wont idle.  You can test it by putting 12v through it.  The choke is on the top of the carb.  It controls the mixture only.  It has a 12v wire feed, but its also controlled by the coolant.  The 12v feed comes from the grey thermo switch on the top hose.  Next to the head.  When the engine is cold you should get 12v from the wire that goes to the fuse box, and from the thermo switch to the carb.  You also need to check that the carb is earthed.  If not the electric feed to the choke wont work.  This is important, as it causes the choke to back off whilst the coolant is still cold.  A simple check is to remove the air box and switch the ignition but not start the engine.  After a minute you should notice the choke flap starting to open.  If the choke will only back off once the coolant pipes get hot it will run far too rich when cold and cause the carb to flood and it bogs down the car, giving very rough running. 

If you have checked all this and it still wont idle it may have a blocked jet in the carb.
https://youtu.be/taTBdkrQouI?si=KyG7qe4UiuHW4-a_

Re: 1.6 Driver Carb/Running issues

Reply #2 –
Hi,

thank you for taking the time to reply, much appreciated.

Yes, it is a Pierburg. I will try the things that you have suggested. I was confused that it now wont run at all after swapping the mount, and wasn't sure if it was not getting enough air now that the split isn't there to suck air in. (although granted I have no idea if this would be the case).

The car has a manual choke, and wont idle no matter what position the choke is in.

I have no experience with carbs and was a little sceptical about messing with it, but may just bite the bullet and have a go.

Re: 1.6 Driver Carb/Running issues

Reply #3 –
No problem.  I spent a lot of time doing research on the Pierburg, and ended up stripping mine (the one in the video), to clean it.  The video explains the various parts of the carb, and how they work.  There are other videos as well.  If you have a manual choke that gets rid of one potential source of trouble, i.e. the mixture.  However, the idle will still be set by the three point unit, and the waxstat, neither of which are controlled by the choke cable, which explains why adjusting the choke does nothing.  There are two electric connections on the back of the carb, the solenoid, which when activated stops the three point unit fully retracting (via the vacuum hoses), and the thermo time value, its only job being to allow the engine to rev higher (about 2k for up to 30s), when you first start it up, again by adjusting the vacuum in the 3 point unit.  If you do the checks above, you should hopefully get to the bottom of it.