hi all I posted this once before about 4/5months back but hasnt been solved yet. My 16v has a jittery/juddery/misfirey feeling most noticable at 2K rpm when in 4th (engine is just crusing) but also noticable at about 2K at 30 for example... Its not there when the revs go above 2.5K and can hammer along on the motorway at 110mph on he dial no probs (as long as i can keep fueling it!) I have had the following done: timing checked mixture/CO set at 2% replacement metering unit and then mixture reset swapped the temp sensor wires around but no joy removed the relay from behind centre console but still happens unplugged the over-run-cut-off-valve but it still happens checked condition of ecu plug, was fine I asked the garage to remove the injectors and check spray pattern which they said they did. (still look oily and grimey to me so they might not have done) replacement coil cleaned ISV New plugs New throttle cable Replacement and repositioned throttle sensor switch I'd be greatfull for any other ideas, im coming to the end of my tether and having thoughts of getting myself an Fiesta RS Turbo so please keep me in love with my 16V!! (and for those that say take it to a garage im fed up with them telling me its fixed when its not or that they cant find out whats causing it) THANKS!! PAUL edit - replacement dizzy new dizzy cap new rotor arm more money spent same problem
16v's used to suffer badly with the lift pump in the tank causing simular problems, might be an area worth looking at.
I think I replied to your earlier thread but I still think it's an ignition timing issue as mine did the exact same thing and it was a dodgy ECU connection affecting ignition advance under load. I know you've checked the ECU multiplug so perhaps it's worth swapping in a known good ECU if you can get hold of one? You can find out by sticking one of those fancy machines on it (forget what they are called) that show the igntion advance digitally, I think some strobe lights can do this? On mine when hooked up to the machine at Stealth the car was idling away happily, base advance on 6 degrees or whatever and then every now and again the idle would drop ever so slightly for a second, this coincided with the display showing the timing had changed, then back to normal. Under load the effect was more pronounced. Like yours though, if you give it some revs it seemed fine, although the rolling road showed the timing messing up was loosing about 20bhp or so at higher rpm!
Noworriesvw Cheers, I'll check this out. I take it that just feeling the circular pad in the boot should give me an indication of whether its working or not. although i would have thought that this would mean that the car would suffer at higher revs and speeds Stu Thanks for the reply, i remember what you suggested last time and have been checking ebay but havent seen recently a 16v ecu that i could get. thing is though, what can go wrong in the ecu???
I agree there isn't much to go wrong, but presumably the solder joints in them can dry out like in other circuit boards making dodgy connections? Also they get a lot of dampness in them as the rain tray can fill up with water in heavy rain if the drain holes through to the wings are blocked, can't do any good? Maybe ask if someone with another 16v could swap ECU's with you for half an hour, wouldn't take long to diagnose if that was the problem.
ok after no rice meet discovered that my dizzy was only clamped in by one bolt and that the dizzy cap terminals were rather mullered. was a new cap few months ago and cyl 2and3 terminals are worn through the metal with grooves. it also appears to be trying to spark in the middle between the 2nd and 3rd cylinder terminals in the dizzy have just bought new dizzy cap and rotor and secured dizzy to head. still not solved. Another 12 spent
What does the new dizzy cap look like now, after a few hours running? Any sign of scoring or tracking?
yeah its got loads of copper filings looks like gold leaf inside and scoring marks on 2 & 3 again. after about 20mins running im off to change the dizzy lit looks like!
ok... changed dizzy and reset timing in tesco carpark. nice and dark the marks show up really well in the strobe. Observations: * when i set the replacement dizzy to the same timing place as the first and drove to get petrol it didnt seem to misfire and shake as much.... * got optimax went to tesco - had to turn dizzy towards front of car to get mark to line up - couldnt even see mark on flywheel until i moved it loads to the front. * timed up, the mark wouldnt stay completely stationary, kept jumping to the front of the car a few mill and back every couple of seconds... * was very noticably juddery on way home at 2000rpm
yes as per the FAQ the timing is fine. checked it again this morning when i got to work. and the mark moves towards the back of the engine or clockwise round the flywheel when you rev the car. im totally fedup. Car was almost UNDRIVEABLE between 30 and 50mph so ive had to belt about really fast or at ridiculous revs looking like a barryboy and drinking optimax at 104.9 its a bit hard on the wallet. looking at getting another ecu/control unit thing. so whats next?
Check for play in the rotor arm/dizzy shaft, you should only have a very small bit or rotaional play, and I mean small. If the timing is driffting then you need to check the things that effect it. Check the vacuum pipe that goes from the throttle body to the ECU. Check that the interupter plate and hall sender are secure inside the dizzy. Check that the coolant temp sender for the ECU is connected and giving the right resistance. Finally, check the throttle switch and wiring. If this is faulty it will try and kick in the ISV early and give similar symptoms to those you've described.
ok... * dizzy has been sdwapped so i presume that area can be ruled out * timing is good this morning appears to line up nicely >< ruled out * should the vacuum pipe to the ECU be a certain length?? * ECU sender is connected and ive tried swapping the location with the others makes no difference. to rule it out what should the resistance be? * throttle switch is good condition and clicks when you come off the throttle. white wire was broken but i fixed that some time ago. switch works as per haynes manual test. PAUL
The ECU pipe should be a certain length but as long as it's nothing wierd then it shouldn't give you the problems you've got.
PLEASE READ DISPITE BEING A BIT LENGTHY!!! i bought the car in february and on the way home from norwich to south london i noticed a slight jerky feeling when cruising almost like a slight misfire. shortly after i got it home i did the usual - new plugs, new oil, new dizzy cap, new rotor arm. Then the car decided to start stalling at junctions or when i changed gear up a hill. So i noticed the throttle cable was bodged to shorten it so bought a new one. I cleaned the isv to try and help it too. on the way to work one day the car cut out dead. thought that the fuel pump relay had gone because it would crank but not start. When i tried it the next morning it started however. But when i drove it the car would almost bunnyhop upthe road with violent lurches. new fuel pump relay seemed to cure it, however the jitteryness has always been there, especially when cruising about 2Krpm. So i bought a new throttle assembly off ebay that had all been cleaned up. Fitted it and adjusted the microswitch to touch and push in against the throttle lever. So I checked all the inlet for vacuum leaks and bought a replacement hose as one was split near the throttle mechanism but still no joy. Then suddenly one morning it cut out on the way to work and started doing the bunny hop thing again. so obviously the fuel pump relay wasnt at fault last time. I called the breakdown company and he came and started fiddling with all the wires around the ISV and pulled back some insulation. when he wiggled some wires it seemed to rev up a bit. However we could not repeat it consistantly to draw any conclusions. After about 30hour of looking i got in a drove to work and its been fine since. But the jitteryness has been getting worse. feels like its stuttering even if your foot is off the gas pedal and its sitting at 40mph and 2K on the dials. so i bit the bullet and put it into a bosch specialist who told me the CO was out and some of the earth wires needed spreading out so that they werent on the same place. bit odd i thought but he assured me it was cured. 30secs down the road i knew it wasnt and went back the next day. the chap said he would check the injectors and i asked to have the fuel pressure checked. Upon returning i was told everything was fine and they couldnt solve the problem. He said if i replaced the metering unit he would re-set the mixture. which i did. still no joy. I have since replaced the coil but this hasnt solved it either. last night the dizzy, rotor arm, cap so now im stuck and the car is now.... ALMOST UNDRIVEABLE and ive had to cancel my plans for tonight as ive had enough so im screwed.
One Last Check I see your still not having much luck. Try the last thing I suggested! Get someone to check that the fuel return pipe is slightly blocking or completely blocking. Its another good thing to rule out!
right, ive tried a full bottle of redex and its not made any difference! As far as checking the return pipe how would i go about that? Cheers PAUL
Have you checked the plug gaps? My mates GTI 8v ran like **** when he put brand new plugs in, turns out one of them had been bashed in at the end! If they're 3 electrode ones it's not so likly to happen, but the single ones are prone to being bashed about in the box. Also what make ignition system bits did you get, quality bosh/beru?
