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Model specific boards => Golf mk2 => Topic started by: GTIMatt on 16 June 2011, 14:20
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Quite a lot to read here, but I've been tearing my hair out with this one for a while now and I can't afford to take it to a garage, but hopefully you fellas can help me sort it.
A couple of weeks ago had the front engine mount replaced because it was shot and allowing the engine too much movement. I should mention just for the sake of completeness, that after I got it back from the garage I had a water leak, which at first I thought was a split hose but on removing said hose it was clear the leak was coming from a crack in the rad itself. So I whipped it out and replaced it along with a new thermo switch.
But the overfuelling had started before this was even changed. It's hard to describe but one thing I've noticed is that the fault is MUCH worse if I try to to flat out, it's almost instant once you get to around 4k rpm, the sudden lack of acceleration chucks me forward in my seat, and I can hear the exhaust backfiring like a b!tch. But If i accelerate gradually, the fault is still there but doesn't seem as bad until higher up the rev range (i.e. I can actually get past 4k rpm). I've read stuff about "full throttle enrichment" but not totally sure which box of tricks looks after this? Is it the TCI? It was replaced around 18 months ago, with a GSF part. One from VW is £165 :huh:
I started looking at simple stuff, like the exhaust, which had a blow in it. But I had that fixed and it just made no difference.
My mk2 has started overfuelling, out of no where. Had starting problems a while ago and so the dizzy cap, rotor arm, coil, plugs and leads were changed. Along with the TCI unit. I replaced the leads as they were a bit naff but it's made no difference. Plugs are wet with unburnt fuel and the tips are black bright so I gave em a scrub with a wire brush to get most of it off. also replaced the blue two pin temp sensor with a gen VAG one, but still made no difference. I know my ISV is shot but they are expensive and surely that couldn't be causing the overfueling at 4k rpm+ (?)
I changed the coil for a bosch one out of curiosity but it just ran like a TOTAL bag of spanners, not even running on all 4 cylinders. Popped the old one back on, hey presto.. working. But still over fuelling.
Since the new leads, it started cutting out randomly. About 5 mins after I left GSF, BAM! Cut out, middle of the ring road :laugh: There was no juddering or stuttering, it just stopped. All connections seemed fine but it refused to start, turning over but just not firing. So I left it for about 5 mins, then it started... I decided to do a little test, just drove around until it cut out again- then leave it, give it 5 mins and try again, and again it cut out but after leaving it, it started up.
This was leading me to think that perhaps there is a electrical component that is faulty, and when it's getting hot it's just packing up completely. But once it has cooled, it plays ball again. The cutting out seems to be relatively consistant, and it is hot in my engine bay due to a TSR 4 branch manifold that could probably heat my whole sodding street. But thats been there since I bought the car, so I'm not sure if I'm totally barking up the wrong tree.
I feel like all these strange little goings on are being caused by something that just plain isn't working right, my timing etc should be totally spot on since I had a blown head gasket in January and the timing and work was done by a knowledgeable local classic VW place. For 6 months the car had never ran better. Started first time, every time, and it felt faster than it was previously.
So if anyone can make any sense of all this then I owe you a beer! :cool:
edit: should mention it's a 1990 1.8 8v digi II
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I was having a similar hot start issue after re-building my engine. She wasn't cutting out at first but slowly got worse and worse until she was. It was suggested that the dizzy timing was slightly out, I literally twisted the cap a tiny bit clockwise and haven't looked back. Just a simple idea but it worked for me :smiley:
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You cant really do random adjustments with a digi like you can on k jet. Needs to be spot on with a timing light.
Kjet doesnt have a knock senser either and its much more like old school tuning.
Worth checking your static timing even though a vw person did it. My mate had a headgasket and cambelt done on his golf at a garage and they phoned him up saying that it wouldnt start because somebody had put the cam pulley on the wrong way round which is balls because there is marks both sides.
Takes minutes to check and it is free.
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Sorry, I always forget the 8vs are digi. Found this, there may be somthing in it that would help
Too many people complain about flat performance and 'digi-lag' on their 8vs. Not many people know that this isn't actually
how the car is supposed to run, and is the result of the car not being set up properly. After spending an afternoon setting the timing, idle & CO properly my GTI is like a rocket with instant throttle responce and blistering performance
First thing to do is buy a new Blue temp sender from VW, it only costs £13. It's listed on ETKA as being for cars equipped with a catalyst, but it is the right one for your car! Don't bother with GSF ones as they tend to fail prematurely!
Next replace all the vacuum lines from the inlet manifold, these are VERY important as the Fuel Pressure Regulator is controlled by inlet vacuum, any leaks and it will lag behind the throttle!
Don't forget the blanked off line BEHIND the throttle body, its easy to miss [:Y:]
Invest in an exhaust gas analyser & timing light, it will save you money and time in the long run. Plus you wont have to gamble that your local numpty mechanics know how to set up a Digifant properly!
Idle/CO:
1. Get the engine up to temp, at least 80 degrees on the MFA oil temp display
2. Turn the engine off and remove & plug the intake side of the breather pipe between the 'flying saucer' on the rocker cover & air intake
3. Hold the MFA button in and turn the ignition on, off and on again, then start the car. This puts the MFA into a 'secret' mode. Put the MFA switch to setting 2 and press the button till you get the digital rev counter, position 2 I think
4. Unplug the blue temp sender and rev the engine cleanly over 3k rpm 3 times, letting it return to idle each time.
5. Check the RPM display, adjust the idle with the idle screw on the throttle body to about 850-900 rpm. Clockwise to decrease, anticlockwise to increase
6. If you have a CO meter, block off one of the talipipes (i use a load of duck tape) and shove the probe up the pipe. Follow the manufacturers instructions, and set the CO to about 1.8ish using the allen screw on the MAF, clockwise to increase, anticlockwise to decrease. NOTE: You must take the reading when the rad fan ISN'T running, once it cuts in it'll throw outr the reading a little!
If you don't have a CO meter, turn the screw in until the engine starts to sound rough then back it out gradually till the idle sounds smooth & even. Check the aerial or bonnet stay for vibration, you want it smooth as possible. This will get you close, then take it to a garage to get it set properly.
7. Reset the idle to 850-900 rpm if it has changed, and adjust the CO accordingly, repeat till you get 1.8 at 850-900 rpm
Timing:
1. Take out spark plug #1 and turn the engine over by hand with a spanner on the crank pulley nut until the piston reaches the top of its travel. Check by either shining a torch doen the hole or putting summat long & thin down there like a dowl rod.
2. Next check the punched hole on the inside of the camshaft sproket lines up with the head surface, with the cam cover removed. If not slacken the tensoner and move to suit.
3. Take the dizzy cap off and make sure the rotor arm is lined up with the mark on the dizzy, which should correspond to spark plug lead #1, if not loosen the tensioner and turn the intermediate shaft. This is a little tricky with the cambelt cover in place, though I managed to do it by removing the bolt here and bending the cover outwards.
Once you've done all that the timing should be pretty close, the next step is to set the dizzy advance. You MUST set the timing to the factory spec, 6 deg BTDC, there is no need to set any further advance as this is done automatically by the ECU. If you don't set it to factory spec, you'll likely REDUCE performance & MPG as the ECU cannot adjust the timing properly.
Heres a nice pic of the marks you're looking for, shamelessly stolen from the vortex, link found by the legendary 'TSC' from ClubGTI
You can see the arrow on the gearbox casing, the large notch with a bit of red paint is the 6degree BTDC mark, and the small round 'dent' to the right is the TDC timing mark. Before you start I'd highlight both marks with tippex to make them more visible
http://vwtech.no-ip.info/images/golf/flywheelmark.jpg
1. Remove the green plastic screw in cap in the top of the gearbox, not just the little seethru cap in the middle, the hole isn't big enough to see the timing marks.
2. Get the engine up to temp, at least 80 degrees on the MFA oil temp display and turn the engine off
3. Hook up your timing light as per the manufacturers instructions
4. Start the engine again, switching on the 'secret' MFA rev counter if desired as per above, then disconnect the blue temp sender
5. Rev the engine between 2k-2.5k, and point the timing light into the hole, the 6 degree BTDC mark should now be aligned, if not loosen the dizzy clamp bolt and turn the dizzy as required
6. Rev the engine to 2.5k again, then reconnect the blue temp sensor. The timing should advance by about 30 degrees
7. If the timing only advances about 20 degrees, loosen the knock sensor bolt and retighten to 20 Nm (15 Ibf ft) and repeat. If there is still no improvement, check the wiring and if this is ok replace the knock sensor.
If there is no advance at all, check the wiring to the blue temp sensor.
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I'l have a bash at checking the static timing, I've already read RJ's tuning guide but a timing light and gas analyser are stuff I just don't have access to. I've checked the vac lines and they seemed fine but I replaced them anyway.
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Pick up a tming light on ebay for 20 squid :wink:
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Wayne... I do worry about you somtimes. Whats the very first thing the guide says?
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Ok so just checked my timing and with the mark on the inner sprocket lining up to the head (cam cover off) piston #1 is at TDC and the rotor arm on the dizzy is pointing to the corresponding lead for that cylinder.
From what RJ's guide says that is bang on.
Timing lights seem cheap enough but with a half decent gas analyser on top it's gonna be £100+. Not a lot to some folk but it's a lot to a unemployed grad student.
Anyone got any info on what I mentioned in my first post about full throtle enrichment/the tci unit?
cheers all!
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first thing guide says mr bmx is to buy a blue sensor. op has allready done that.
Carefully remove the green bung out the gearbox with a hammer and screwdriver and tip ex the 2 marks on the flywheel and the notch on gearbox.
Do what you ve done allready but line the TDC mark up on flywheel and then see if the mark on the OUTSIDE of the cam pulley lines up still.
Mine had O T on with an arrow on the plastic on the rocker cover and it was 2 teeth out.
I couldnt really see how many teeth it was out with the inner mark lining up with the head.
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Search static timing and you should find my pics
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Forget 'full throttle enrichment' and worries about the tci unit, borrow/buy a timing light - preferably one with with a rev readout on it as this makes life a lot easier - and set the timing, followed by the idle and adjust the co as described by rubjonny. If it improves take it to a garage and get it on a gas analyser to set the co correctly, they should only charge you a few quid. If it doesn't improve then start looking at other things. If you're based near huddersfield drop me a pm and I'll give you a hand.
Also, isv for a tenner here;
http://www.edition38.com/forums/index.php?showtopic=384413
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Thanks for the offer dude but I'm in Coventry!
Found weaz's static timing thread here (http://www.golfgtiforum.co.uk/index.php?topic=175565.0), it's a little strange though because there isn't a OT mark on the outside face of my cam pulley. Don't think it's on the wrong way round 'cos I can read all the audi/vw stamps. There is a tiny little mark on the outside of the cam pulley, just like the mark on the other side really. Is this my OT spot? If it is it's MILES out.
heres a pic of what I'm talking about:
(http://i287.photobucket.com/albums/ll127/111id/GTI/cam.jpg)
and heres the inner mark lining up with the head
(http://i287.photobucket.com/albums/ll127/111id/GTI/caminnermark.jpg)
and heres the marks in the gearbox
(http://i287.photobucket.com/albums/ll127/111id/GTI/gearbox_flywheel_marks.jpg)
these marks don't quite line up, how is it adjusted?
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If you're unsure about which timing mark to use look at the camshaft. Th e first 2 lobes by the pulley should both be pointing upwards at tdc. Kind of like an M if you look along the shaft through the pulley.
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heres a pic of the cam as it is:
(http://i287.photobucket.com/albums/ll127/111id/camshaft.jpg)
they are both pointing up. when i put a screwdriver into piston #1 it doesn't go in far at all so i'm pretty sure it's at tdc. but if thats the case then the problem i'm having isn't related to bad timing, i haven't actually adjusted anything, just turned it over by hand to see if the marks line up.
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Take the dizzy cap off and look at where the rotor arm is pointing. Should be towards the notch.
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the arm is pointing to ht lead for piston #1
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.....This was leading me to think that perhaps there is a electrical component that is faulty, and when it's getting hot it's just packing up completely. But once it has cooled, it plays ball again.
Hi
I would definitely go down this path.
What does the coil look like on this engine? If it is the coke can type, then remove one spade connector at a time and pinch it a little bit and push it back on. Then do the next spade connector.
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As long as the dot lines up to the edge of the head your fine.
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I had a timing issue with mine.
Same problem with the cam pulley etc.
TBH the guide confused me a bit so I just set the gun at 36 deg and adjusted the ignition timing till the diamond mark lined up @ 2.5k revs (ish). Engine up to temp, new temp sensor before i did that. Its been spot on.
You might want to check the condition of the spark plugs and get the thing on an emissions test also
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.....This was leading me to think that perhaps there is a electrical component that is faulty, and when it's getting hot it's just packing up completely. But once it has cooled, it plays ball again.
Hi
I would definitely go down this path.
What does the coil look like on this engine? If it is the coke can type, then remove one spade connector at a time and pinch it a little bit and push it back on. Then do the next spade connector.
it's the coke can type, i've had those dam little spade connectors off loads lately and the connection seems fine. the coil does get quite hot, but i think thats just the position it's in, all those hot water pipes and it's not far away from my hot exhaust manifold.
I had a timing issue with mine.
Same problem with the cam pulley etc.
TBH the guide confused me a bit so I just set the gun at 36 deg and adjusted the ignition timing till the diamond mark lined up @ 2.5k revs (ish). Engine up to temp, new temp sensor before i did that. Its been spot on.
You might want to check the condition of the spark plugs and get the thing on an emissions test also
i've never used a timing light before and RJ's guide is a bit confusing on that bit, why did you set it to 36 deg? which diamond mark? the one in the gearbox peephole?
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.....This was leading me to think that perhaps there is a electrical component that is faulty, and when it's getting hot it's just packing up completely. But once it has cooled, it plays ball again.
Hi
I would definitely go down this path.
What does the coil look like on this engine? If it is the coke can type, then remove one spade connector at a time and pinch it a little bit and push it back on. Then do the next spade connector.
it's the coke can type, i've had those dam little spade connectors off loads lately and the connection seems fine. the coil does get quite hot, but i think thats just the position it's in, all those hot water pipes and it's not far away from my hot exhaust manifold.
I had a timing issue with mine.
Same problem with the cam pulley etc.
TBH the guide confused me a bit so I just set the gun at 36 deg and adjusted the ignition timing till the diamond mark lined up @ 2.5k revs (ish). Engine up to temp, new temp sensor before i did that. Its been spot on.
You might want to check the condition of the spark plugs and get the thing on an emissions test also
i've never used a timing light before and RJ's guide is a bit confusing on that bit, why did you set it to 36 deg? which diamond mark? the one in the gearbox peephole?
oh, and as for the spark plugs they aren't even a couple of months old, but all this over fuelling is just getting them covered in soot.
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..... the coil does get quite hot, but i think thats just the position it's in, all those hot water pipes and it's not far away from my hot exhaust manifold.
Hi
In that case, as an experiment, put some heat reflector around it and see if that cures it.
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Could it be the fuel relay ive had the cutting out and not starting for a few minutes problem twice it was the relay both times but it wasnt over fueling.
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I might give that a go then, still got the problem but it's just so inconsistent. Last few weeks I couldn't nip to the shops without it cutting out. Then yesterday I did 160 miles and never cut out once.
One thing I have noticed is that sometimes it turns over but won't fire until I release the key, giving up hope, then it suddenly bursts into life. Again sometimes when I start up it definitely sounds like it's not running on all 4 but it soon comes to life.
Checked my AFM flap was opening/closing and it was fine. Checked ohm resistance at injectors and it was 3.7, well within the range of the digi II manual.
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.....One thing I have noticed is that sometimes it turns over but won't fire until I release the key
Hi
When was the ignition switch last changed ?
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.....One thing I have noticed is that sometimes it turns over but won't fire until I release the key
Hi
When was the ignition switch last changed ?
good call! no idea when it was last done. today it wouldn't start again so went down gsf for a new ignition switch. took off dash undertray, steering wheel, other bits but the plastic panel where the hazard switch sits is refusing to come out.
do i need to remove the ignition barrel? i disconnected the old switch and tried gripping it with pliers to remove it but it seems pretty well in!
cheers
matt
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Hi
I have never removed one yet. But, to confirm that the fault is with the switch, I have read somewhere that you take the electrical plug off the old one and connect it to the new one, then put a flat screw driver into the slot to turn the ignition on and to start it.
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tried that trick, nothing at all! doesn't even try. but with the old switch connected it turns over.
:undecided:
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tried that trick, nothing at all! doesn't even try. but with the old switch connected it turns over.
Hi
If the two switches are exactly the same, then the GSF one may be faulty.
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its fixed! :grin: :grin: :grin: :grin:
when i fitted a new coil and it was banging and popping i took a chance on a new ignition amp and hey presto back up and running!
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Hi
Well done.