Hi, Had a problem with my 8v digifant gti since satuday morning - i first noticed it felt a bit misfirey at about 3000rpm ish - it was chucking it down on the motorway so i put it down to dampness getting into the engine somewhere possibly. But sunday, from cold, it was really jerky and bunny hopping a little bit as you pull away. ONce warmed up, it seems to be better, but is still not feeling happy when driving - kind of feels like it could back fire / misfire at any moment. The engine was fully serviced a few months ago by me and has run fine since them until now. The only thing i can think of is that there is abd oil leak from the headgasket which is putting oil on the front of the block and possibly the dizzy area a bit. The other thing is that unstead of using standard unleaded, i switched to using super unleaded a week or so ago (coincidence !) - the first tank i put 20 of bp optimax (expensive!) - ran fine. Friday, i filled up with sainsburys super unleaded as i had to drive to 250 miles on saturday. I then put and another load of the same super from saunsburys in again last night. If it was the fuel, i`d expect it to run a bit better though surely! Its going in to have the head gasket changed and oil leak fixed on thursday, but i`m not sure the garage will have time to look at the misfire issue at the same time. Any help appreciated! Thansk, Mike
Unlikely the oil weep would cause dizzy issues, it'd want to be literally spraying it at it. Sounds like low fuel pressure, or like the timing is out, does it start easily?
have a look at the cap, arm and leads. were they good quality items or cheapy? with the leads there are 2 types of fitment ones that clip onto the nipples on the plugs and others need the nipples removed and they clip direct to the threads. worth having the plugs out too see how they look how far did you get on the supermarket fuel before it started going bad? possibly it was contaminated
i think the timing is right - its the best running 8v i`ve had before this issue - starts on the button still. i think when i serviced it i didn`t replace the leads i have to admit - rest of the bits were bosch or possibly beru i think? leads have big metal ends on them where the fit on the plugs. i reckon i filled it up on friday night with 12 of normal unleaded and then i remembered i was putting super in and added 20 of super. Engine felt a bit rough on the motorway driving the 250 miles the next day. Then it got worse on sunday and i then put another 20 of the super in last night hoping raising the level of fuel in the tank might help as it less than a quarter. Probably used the same pump i reckon. Got just under half left in the tank at the mo. I wanted to run it down a bit more before refilling, but i`m tempted to go and fill the rest up with normal unleaded (at a decent station!) to try and dilute it in case its the fuel. Have to drive another 60 miles home from work later!
Strangely - it was running a bit hot when i was sitting in traffic once i got off the motorway. Water temp needle was going over halfway to the next line when sitting in traffic which it has never done before. It was enough for me to lift the bonnet when i got to work and check the radiator fan was kicking in - which it was.
bosch/beru are tip top so should be fine. run it at night and spray a mist of water round the leads see if you can spot any arcing. digifant should be run on super, and ive always used sainsburys super on mine never an issue so the fuel should be fine so long as its not been contaminated. maybe try a different station to rule that out
its the 7 pin thing on top of the ecu under the plastic tray driver side, same for all mk2 with electronic ignition so not hard to find another to try
I've never ran mine, or any of the ones around on Super, can't get it here, and they always ran fine.
Digifant 2 engines either run or do not. If the vehicle is jerky as you describe, my experience with this cars has been, a short in or intermittent open circuit in ground, split intake ducting, and maybe hall wire insulation breakdown (very very rare)
the night before this started happening, i was messing around trying to fix my speedo cable - i wonder if i knocked an earth or something? - there are loads of wires round that end of the head
Have a look for busted off wires, loose wire on the coil etc. Digifant 2 cars either drive or do not.
Well - had a quick look under the bonnet before i left work and nothing appeared loose wires around the coil or head etc. Started it up and it drove perfectly the 60 miles home - what gives heh? Will see how it goes tomorrow, but i guess i can rule out duff fuel. My guess is a loose wire although i couldn`t see any - maybe i disturbed something when rummaging around that area?
Didn`t use the car yesterday then this morning worse than ever! Started it up and it immeadiatly felt rough - stuttering, jerking bunny hopping - not a happy bunny! Once the engine got warmed up, jerking etc got a lot better but the engine still didn`t feel 'right' at all. Weather has been awful here the last few days - i`m wondering if there is water getting into the electrics round the engine possibly. Its booked into the garage tomorrow for the headgasket change to cure the oil leak, but i`m thinking i may have to re-prioritise what they`re doing! edit- Sorry, i seem to be using two users here somehow - 'mike.s' is a really old user i had - my other laptop must be set to log in as that one whoops!
I was actually looking for another more epic thread where the fix was the TCI, but have a read through this it was the hall sender. http://clubgti.com/showthread.php?253383-8v-GTI-Not-starting-Stalling-under-load-Misfire-Solved
