Have an issue with my MK5 2.0 BLX code fsi. I'm having a misfire issue, not just on idle but whilst driving. It's bad enough that it feels like it's running on 2 cylinders! There's no electrical errors coming up for the coil pack loom but how do I check all four are working? The original VCDS scan said No4 Cylinder misfire so cutting a long story short I've ended up swapping 4 coil packs and a set of plugs. Removed and cleaned the inlet manifold. Cleaned the valves (scraped and hoovered out) and re-checked the timing marks but it's still running really rough/missing. Compression figures are perfect and all about 14 bar. No. 4 plug is wet with fuel and the smell on the exhaust is strong also so I can only assume No4 injector is working. Any ideas?? The other thing I've noticed is the vacuum coming from the oil cap is quite strong, working alongside the egr valve. If I unplug the egr valve the engine stops. Is this supposed to happen? Any help greaty appreciated and I'm already bald enough!
Right I'm sitting in the car having a mess about. As it stands after 25 mins of idle I'm not getting a misfire error. The throttle seems responsive but you can still feel a judder coming off throttle and when settling back to idle. Slight fluctuations whilst sitting here, not as smooth as I'd like but not overly concernable either. Russ, VCDS isn't allowing me to reset the throttle but it seems to be ok as it'll rev up and down quite smoothly and in unison to the pedal. No hunting just a slight 'miss' every now and then. Going onto VCDS, the reading for group 16 (no4 cylinder misfire detection) still has a reading of maybe 8 in a ten second period. But lessens at high idle maybe 2000rpm+ Onto the injector if it is this, can it be tested/cleaned as I usually would, or do these play up to the point of binning? Or could I try some injector cleaner and a fresh load of fuel first and run the lot through? I need to do an engine flush due to the amount of gunk buildup so throwing a load of injector cleaner in isn't a major worry as I'll be dumping the oil anyway.
Have you cleaned throttle body 1st? Not sure how you're doing it but ignition should be on, not started and not touching the throttle. Sometimes cars won't run at all with throttle not adapted.
The injectors can coke up and reduce fuel flow to the cylinder. So unless you have an air leak, the injector is to blame. You need to look at your short term fuel trim, you may notice a +% of fuel being constantly added to combat the enleaning cylinder.
Will do Eddie, just looking it up now, Group 032 should show up something hopefully Russ, yup was doing it with the ignition on but engine off with nothing touching the pedal. I'll text you the error message Throttle bodie was cleaned with the manifold, although the egr, pipework and breather pipes are allcoming off tomorrow for a clean and checkover. I'll report back tomorrow eveing. Thanks for the help and advice
NO update due to more ABS issues (magnetic rings on the rear hubs are both shot so new ones ordered). The misfire count is really bad on cylinder 4 on idle when cold. It gets better when warm but not great. Nothing on the other 3. Looking at buying an ultrasonic cleaning tank to clean all 4 injectors. I have access to some kit that Ican setto pulse the injectors on/off. Will see how it goes and report back ASAP.
the one with the diaphragm that cracks also very common, but comes up with a fault regarding air leak by the time it see them, comes undone with 6? torx screws, and you can split it to check the diaphragm T/B is pretty much open most of the time, its the fuel regulates the rev range -adaptation is in none volatile memory injectors also suspect if the air system in good
Fault found. No4 Injector has failed miserably lol Good 2nd hand unit sourced and is being delivered. Other 3 have been checked and are spot on. I'll update when (fingers crossed) its running again
2nd hand item bought and fitted and everything is hunky-dory. I'll update my ABS thread now, more problems!
