Took my 1.6 Mk2 out this morning for a quick run after an oil change to check for leaks. As the car warmed up it started bogging down. Any other position on the throttle than wide open it pulses/jumps. A while ago I replaced all the seals on the Weber and all the jets too, as well as accelerator pump and it's been running okay since with a couple of issues here and there. When I got home and put it in reverse to get into the drive it stalled, when I started it back up it seemed to run fine with none of the previous problems; any thoughts?
If it ran fine after the second start up that may indicate a timing issue. Worth checking your timing isn't slipping. Also, plug leads and plugs. It's also worth spraying copious amounts of carb cleaner in the carb to make sure you haven't picked up a blockage in the jets.
Both great suggestions thank you. I did try bringing the choke back out with very slight improvement but I'll give it a good checking over. I'll definitely give the timing a look over too as my dizzy was slipping before but that was entirely my fault! Plugs were changed 1500-2000 miles ago but I'll check them over just in case.
My bike has all your symptoms when the mixture isn't set just right. It's amazing how much incorrect idle mixture will affect the rest of the rev range. Another thing for you to check
To be honest the carb has been a lot of trouble over the time I've had it, so I wouldn't be surprised if there is a problem with the mix. Based on the rest of the 'repairs' that have been made to the engine over the years I'm sure it's not set up entirely correctly so I've been replacing parts as I go to get it back to standard. I'll give the mix a tune with the timing the afternoon and see if it helps, thank you for the suggestion!
Okay, blasted all the jets out, replaced the pump jet and pulled out some old gasket from the hole it sits in, adjusted the choke (now very sensitive and less travel in the pull), and it seems to run okay apart from a couple of little pops/stumbles on idle. Assuming this is a symptom of bad timing but I can’t match my timing marks to anything I’m reading in manuals. I have two tall blocky bits either side of a punch mark, could anyone give me an idea of which mark to line up please?
I used the mark on the lower cam belt pulley (crank pulley). If you have one it may be easier but I'm sure someone will be along to answer your question properly.
the punch mark on the flywheel is your TDC marker used to setup the timing belt. the BTDC timing marker is further to the 'right' if looking at the engine from the gearbox side, for the carby its 18 degrees BTDC so you cant see it at the same time as the punch marker unlike GTI which is 6 degrees BTDC. You set ignition timing at idle with distributor vacuum line connected, and usually you can add a couple extra degrees advance if you use decent petrol though with the 1.6 not a great deal of gain to be had The big blocky things are for the VW workshop timing equipment so ignore those
Fantastic thank you very much! I'll try give it a couple degrees advance if I can get the mix and everything right too
Okay ran into the same trouble again this morning in the way into work after trying to get it right yesterday. It looked like when I had the notch lined up on the flywheel, my rotor arm was pointing at plug no.4? I fiddled around and it seemed to be running fine anyway but obviously not :/ Can I just swap the plugs over into the right order or will this damage something? Tried the turn it off and on that worked before but no luck this time
check cam is lined up to TDC when crank is, the crank turns twice for every single rotation of cam/dizzy so you probably caught it 180 degrees out
Aha, think my issue is I had the cam on the OT mark on the front when, as I now know, I should have been looking at the back; must be why it was out! oh well on to other solutions to try and get it home! I had considered it might be icing from all the other posts I’ve read but I’m not doing long runs and it’s pretty hot today. The in-line filter under the bonnet looks pretty brown and the hoses look old if that might affect it at all?
the OT merker on the outside is fine to use, as is the punch marker on the inside. only thing to check is if the sprocket is on the right way round, though if it actually runs and you used either of these marks to time engine then you're fine. have a looky here, ignore the digifant parts but all the timing marks are the same: https://clubgti.com/forums/index.ph...ose-and-tune-your-mk2-digifant-gti-8v.124949/
Thank you I’ll check that out. The reason I was dismissing the OT mark is because the flywheel and distributor were out when I had it lined up. I have a new belt and tensioner to go on so I’ll get it right when I change those. My initial problem seems to have been accumulation of dirt in the carb which was blocking something up.
