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Model specific boards => Golf mk2 => Topic started by: Conker on 20 October 2007, 14:38
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Spent all day trying to solve my rough running problems. I've searched and searched the forum but can't find the actual answer I'm looking for...
Symptom: General lack of power and popping missfire/erratic revs between 1500 and 2000 revs (when engine is hot or cold).
Based on info I've found in the forum I've changed dizzy cap, plugs, leads, rotor arm, and a full tank of V-Power fuel. I've also quickly cleaned the ISV with carb cleaner.
Now, two questions...
1) If I disconnect the red spade connector on the ignition coil, the popping miss-fire completely goes away, but then the car seems to run roughly and I think i can hear "pinking" at high revs. Rubjonny calls this red connector "famous" in his 16v timing guide - But what does it do?
Rubjonny: To achieve 2.0%, disconnect the famous "red lead" spade connector behind the coil ...
2) How do I "clean" the throttle body - Do I have to competely remove it???
Cheers for any help.
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There is a ground and a postive also a spade or hoop which is an earth strap from what I can recall on the top of the coil itself. It might be worth buying a new coil as they get very hot sometimes if left on ignition. The earth strap can be replaced also if needed. Does yours have a plastic cover if it does take it off and check the state of the top coil. Mines in bits from heat and age which started to give me partial spark or weak spark throught the dizzy.
Your symptoms sound like a possible Lamda problem have you disconnect the plug to see if she runs better?
Get carb cleaner and spray into throttle body or ISV, but cleaning your ISV doesn't mean its not knackered mate. The piston could be clogged and its running on piston screw or limp mode as I call it no power and low hunting. Go and find yourself a MKIII 16V ISV from breaker yards cheaper than VAG.
Don't worry about over spraying with carb cleaner as its designed to burn up into the head and will do no harm.
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Is it a mk2 16v?
Does the car rev past 2k and pull ok? If not check your cambelt timing, dizzy, then cam/cam, but before you take the inlet off check the Pins on the plug of the ECU for corrosion and check the TCI too, the ECU and TCI control the igntion timing on valvers.
Check your TB switch, that the mechanism makes good contact and you can hear it click when you open and release it too. To clean the tb, squirt carb or brake cleaner as ClipperJay said. I'd give the whole breather system a clean tho from crankcase breather pipe/inlet trunk.
Another test you could try doing is with a timing light, connect the clamp on the king lead and point the light on the inside bonnet to watch for a good pattern when the fault occurs. (i looked directly at the light :laugh:) When my TCI was packing in, there was gaps in the pattern so i knew it was an electrical fault.
Hope that helps a bit
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also check that the swittch on the throttlebody is actually being closed when you release the throttle! your accelerator cable might be sticking as well.
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Thanks for the suggestions, i'll try them out later today.
Answers to questions you asked... Yes its a Mk2 16v, it does rev freely all the way to the red line, but doesn't pull that strongly.
Just to add a bit more detail - With the red spade connector on the coil disconnected it pulls strong but sounds like a lawnmower until 2000rpm. With it connected it has a miss-fire/erratic revs between 1500 and 2000 rpm.
By the way, this is the connector I'm on about:
(http://vwtech.no-ip.info/images/golf/16vredplug.jpg)
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That should be connected to the coil regardless so your coil is up the creek buddy!
J
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Cheers Clipperjay, hopefully that will solve it as its only a £30 part from euro car parts. I've checked and theres no lambda sensor - perhaps thats on 8v's.
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Not to put a damper on things mate, but I know that on Ktronic systems the ISV plug is very close to that coil plug it might be the ISV plug mate I would still get a second hand ISV off a MKIII just to be sure. I'm used to 8V digi's, but reckon that plug looks like ISV plug. Can you trace it? I say that becuase there is a plug on your coil already which I carelessly didn't look properly. Sorry dude!
J
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I think its the ISV plug. The coil looks like an antique so I'll change that anyway as well - Can't do any harm!.
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Yeah it should buzz and vibrate when its pluged in.
My coil looks like this. I'm awaiting for the part tomorrow £25.00
You can see its cracked on top!
(http://i202.photobucket.com/albums/aa51/Clipperjay/Heater%20matrix/chargerh2opump027.jpg)
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the red lead you are on about is in the ISV circuit. It disconnects it so that you can set up the CO and idle etc...
There is no Lambda on K-jet.
And that coil does fooked
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Well... Replaced the coil tonight with a brand new Bosch one from GSF. The car now purrs like a kitten.... Except for the miss-fire that still hasn't been cured!! :angry:
Everything I've changed so far was on the "to-do list" so its not been a waste of money yet. Next item to eliminate is the ISV I guess. Interestingly, if I pull the black lead going into the actual ISV itself, the miss-fire persist, but if I disconnect the red connector previously pictured (which is supposed to be the ISV connector), the miss-fire goes away :huh: :huh:
(I've also just bought a timing gun on ebay so I can check that at the weekend as well)
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ok the ISV control unit controls not only the ISV, but the over-run cutoff valve under the throttle body. Next thing I'd check is the idel switch clicks, and that all 3 wires are hooked up ok with no damage:
1 - white - vacuum time switch
2 - black - ignition live feed
3 - black/yellow - isv control unit pin 8
If that checks out try disconnecting the plug from the over-run cutoff valve under the intake boot. Also while youre there check for damage, loose wires and dodgy vac hoses.
The ISV control unit also has a temp sensor on the side of the head, there are 2 more round there, the other 2 are for the dash gauge & ECU. Test all of them by warming up the engine and swapping the red/yellow wire to each in turn, then check the dash gauge. If one reads differently or sits at min/max then you've found a faulty sender :)
That should be enough to keep you busy for a while :grin:
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Nice one, thanks Mr Rub! :smiley: The over-run valve is a cracking suggestion.
I've already tested the three temp senders and they all work, however interestingly, when I unplugged all the wires into the senders, the engine acted the same as if I had disconnected the red spade connector i.e. the miss-fire/bouncing revs went away but the engine becomes ragged/rough.
I'm on it!
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Just a quickie...
Other people keep suggesting the hall sender, but if the miss-fire goes away when I disconnect the red spade connector (but then the engine becommes ragged - a bit like its running v.rich), surely it can't be the hall sender as it is still in operation either with the red connector attached or not ????
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Well the hall sender modulates the signal for the ECU to the coil to get the spark on time correctly it should be on the dizzy shaft it a three pin plug. If its got a weak spark from the coil plug it can affect it.
I would get the coil plug in the center of the dizzy and get yourself pilars and hold the plug to the metal head and get someone to crank it to see if the spark is healthy and frequent. Saying that it could be dodge spark plugs or a break in the plug cable?
J
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if the hall sender is playing up usually you would see the rev counter going mental, though its concievable there is a weak connection at the coil and the additional drain of the ISV controller on the red/black wire could be throwing things out maybe :undecided:
Disconnecting the ISV controller shouldnt effect anything except the smoothness of the idle, and might make the engine stall when cold. Plenty of MK1 boys do away with the ISV altogether!
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I've been out and bought a whole new distibutor at lunch time, complete with Hall sendor.
If it cures it :evil:
If not :cry:
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Corker there is no point in buying new stuff untill you test the old ones if there is a spark then I would look at timming issues?
Eliminate and move on cheaper that way matey!
It could even be a dodgy earth start arcking the power away?
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Your probably right - I'm just getting irritable not being able to enjoy my new toy.
:sad:
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ah well, even if it dont fix it you got a known good spare handy :wink:
16v dizzies end up leaking oil everywhere eventually anyway :smiley:
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So what colour are the spark plugs and when was the leads last changed?
I really hope the Hall sender sorts it our but your symptoms still sound timming related?
RubJ let corker come down South and lend him a hand LOL!!! :wink:
J
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I've changed all the plugs and leads (at the start of this thread hoping it would fix it). The plugs actually looked quite good - Nice and light brown.
It might be timing. I've also just bought a strobe timing gun to have a go at the weekend.
My wallet seems to be constantly vomiting out £20 notes at the moment.
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what does it idle at with the red spade/isv disconnected?
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1000 rpm although its not rock steady. To be honest its not the idling thats the issue, its the reving.
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Hehe... Quickly tried to adjust the CO level last night with a screwdriver (not ideal!) to see if my miss-fire was anything to do with that (the car smells of petrol fumes, so thought it might be running too rich etc.).
I completely b#ggered it up, the revs were bouncing from 500 to 1500, up and down, up and down. The car was spitting out all sorts of stuff out of the exhaust, stunk the street out. My missus eventually came out and complained about the smell. I just turned it off and went inside. :sick:
You've got to laugh.
Saturday had better be a good car day.
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stick with it mate :smiley:
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http://simplythebest.net/sounds/WAV/WAV_files/miscellaneous_WAV_files/hallelujah.wav (http://simplythebest.net/sounds/WAV/WAV_files/miscellaneous_WAV_files/hallelujah.wav)
Spent many hours on the car this weekend, but I've found the cause of the poor running - its the over-run cutoff valve. Here is the diagnosis:
1) Throttle micro switch clicks
2) ...But throttle micro switch test does not cause the revs to wander
3) Unplugging the pressure diaphragm does not make a difference, although the rubber joint going into it is damaged
4) All other air hoses seem fine
5) Unplug the wire connector into the over-run cutoff valve and the car revs freely, and well :grin: :grin: :grin:
So, so pleased. Just taken it out for a thrash and loved it. I guess this doesn't really solve the problem, but at least its running well (although I have managed to give it a wandering idle by d#cking around with the timing/CO2, but not too worried about that for now). Also the rev counter went very weird - it always showed 2000 revs more than it should. Weird.
So all I need to do now is find out if...
- Its the valve itself
- Its the controller box behind the centre console
- Its the pressure diaphragm
The best bit... It can be my daily driver again! Thanks for the all the help so far dudes.