Hi, I recently rebuilt my stock 16V (KR) and was adjusting my ignition timing with a timing light. I noticed the flywheel timing mark(s) are jumping, making it difficult to accurately time the engine. If you don't touch the distributor, it jumps 1 or 2 cm left to right around a clear middle point. So using this middle point I can still adjust it relatively well. But I must get it stable to set the timing spot on. What could cause this ?? I'm having hot start issues since the rebuild, which could be related to the above timing issue i heard! As if the battery can't rotate the crank anymore, eventhough the battery and cables are fine.
maybe the idle is a little rough, it probably wants base idle and co looking at. worth having a go over of everything using this thread: https://clubgti.com/forums/index.ph...air-and-tune-your-mk2-corrado-1-8-16v.195423/ need a decent CO meter to get it set right the DIY ones can be a bit hit and miss though there is a method in there for doing it by ear. tbh you dont have to get the timing exactly 6deg, usually they like a little bit more 8 degrees is a good start point once you get the kinks worked out. better yet find a kjet tuning expert and get it looked at to get the very best out if it
Idle is very stable and always has been. CO% is set at 2% with quality equipment. Ignition timing is set at about 7-8deg before TDC (at idle and with vacuum hose connected, as it should be) with a decent timing light, but using the wobbly mark. Timing of the sprockets was rechecked several times as well and is fine. I know the K-jet system very well and all parts and functions have been checked already and function correctly. What I would like to know is what can cause the jumping timing mark? Who has experienced this and found the cause? My distributor is freshly rebluilt as well btw. Also the camshaft chain is new. All rubber and vacuum hoses are in great conditions, but I will recheck again for vacuum/intake leaks using propane.
Reb/black wire is connected. Idle switch adjusted to click at slightest throttle opening. ISV buzzes and was cleaned. Injectors and their seals are new. Spark plugs are new coil circuit resistance was checked leads and plugs resistance were checked. Temp. sensors and wires were checked Cold start valve checked WUR checked Idle screw O-ring was replaced
You sure about that? If I recall correctly it is to be disconnected for the CO adjustment but not for ignition timing. Above linked thread confirms this.
its what i always thought was right , jonnys guide wasnt avail back then lol give it a try wont harm it
As I was suspecting an air/vacuum leak somewhere around the inlet had something to do with this I did a leak test with a homemade smoke device. Turns out there is a leak at the bottom of the throttle body at the spindle. I cleaned and lubricated the throttle body during engine rebuild so It seems this might have created a leak I'll make a new thread about this.
