Stamering 2.0 16v... and getting worse!

[cameraspeed 0]

I am a recent convert to the Rado and a newbie to the Forum but am hoping/am certain that the right advice is out there.

 

I have a 2.0 16v L reg/1994 that I have only had a few months and is just shy of clocking 123k. Bar the BBS RA wheels and the CAT 1 alarm/immobiliser the car is original. It is in pretty good condition if a little tired and has certainly been used rather than pampered over. I have always wanted one of these and am pleased to own one... except for the stammering/juddering engine which I did not detect when I first got it but which has developed; that is not to say that the problem did not exist beforehand: the previous owner refuses to return any contact which perhaps does not bode well.

 

That's enough background and so to the issue. The car is so lumpy to drive sometimes and especially in 1st, 2nd and 3rd but not unnoticeable in 4th and 5th- if you drive along with your foot just lightly on the throttle the car stammers and if you remove your foot completely then it almost feels as if you are in the wrong gear... only who goes around a mini roundabout in 1st gear- its basically just not smooth and of course a garage's nightmare in that the issue is intermittent- it's not all of the time but a lot of the time. When whizzing around the car pulls nicely though I feel it could be a little punchier for a 16 valver but even at a ton, when you take the foot off the gas there is a really feint hesitancy in the engine.

 

The car is also a little lumpy on start up as it also can be idling... but I kind of expected this from 16 valves... not sure if I'm correct to think that. Sometimes when I'm sat in traffic or waiting at lights or at a junction the revs bounce between 700 and 1000 rpm... and a couple of times when doing a three point turn or changing gear when parking the engine has simply cut when I have dipped the clutch.

 

This being a new type of car to me (owning an MGB for the last 10 years) and not knowing a great deal about mechanics, I took it to my local (highly recommended) garage. After three visits to them and a subsequent visit to another garage the following have been replace and or checked.

 

Cam belt has been replaced

Lambda sensor replace

Coil checked- apparently running fine

HT leads- apparently running fine

Spark plugs replaced

Dizzy cap and arm are not old and have been checked- apparently running fine

Injectors cleaned (not sure how?) and reorted to be running ok

Fuel pump checked- apparently running fine

Fuel filter replace- old one reported to be in good order

Timing checked- was found to be out and has been adjusted

Engine mounts- checked with the front being replaced

Fuel metering head checked and cleaned- not sure about the

With the exception of the fuel tank the system has been purged. The fuel tank has had fuel injection cleaner fluid added to between half and a quarter of a tank of fuel and the car ran on that just shy of the red on the fuel gauge. The fuel filler neck is a little rusty so thought to replace this and have the tank flushed in case there is crap making it's way into the fuel system and ultimately into the fuel metering head or worse still to the injectors. That said the removed fuel filter was in good nick.

 

Both garages have plugged it into a 'computer' and anything that has come up has been dealt with. So in total the car has been to the garage four times in the last three months and each time it comes back feeling better but it very rapidly returns to it's normal pattern of behaviour- the stammering come on little by little. I have just driven 300 miles to Wales and the car behaved fine to the point of parking and returning to the car having checked into my hotel: very lumpy indeed.

 

So what next... do I replace the coil, HT leads and dizzy cap and rotor arm and if so do I go for an uprated system such as Luminition blue silicone leads etc. or is this just spending money and possibly not resolving the problem. Should I seek out a replacement fuel metering head or perhaps remove my current head and have it stripped down and reassembled by a Bosch engineer.

 

I am also wanting to upgrade the air filter and would like to do this whilst I'm getting the above sorted and fine tuned- any thoughts on this?

 

I know that I am not alone in the fault I'm experiencing as I found the following thread: Advice on lumpy, erratic 2.0 16v - being a bit crap again... viewtopic.php?f=1&t=47311&start=0#p556738

 

p.s. Thank you for reading... any ideas would be gratefully read... laymen's terms only please and explanations of what things are when abbreviated: for example what are MAF or ISV. I'm willing to learn.

[davidwort 0]

ISV is the idle stabilisation valve, front right of head, elec connection to rear and in/out hose into breather system and back to inlet pipe. When they stick/go faulty they can sometimes be cleaned out with a liberal application of carb cleaner. The usual symptom is a idle speed too low or high that is sometimes ok, other times not.

You might have a dodgy hall sender on the distributor, I'd have thought a garage could diagnose that though.

You should really change the fuel filter under the back of the car if you don't know when it was last done.

the 2L seems quite sensitive to dodgy sensors too, but you've already done the lambda although I have heard of issues with generic pattern ones rather than the genuine correct part.

It's worth getting the system fuel pressure checked to make sure it's in the correct range and you could do an injector spray pattern test, and it's cheap to replace the rubber o rings on the injectors too, they can leak in air when old and hard.

also make sure all the vacuum hoses around the inlet manifold are in good condition.

Once you've tried everything else it could be the metering head, there's at least one tiny gauze filter inside them that can be cleaned out and checked, some cars have extra ones inside the fuel supply pipe union.

[Henny 0]

does the 2.0 16V have a knock sensor? sounds to me like a knock sensor that's on its way out, but having not owned a 2.0 16V, I wouldn't stake much on that... :shrug:

[Gareth_16V 0]

Have you checked that the idle switch on the throttle body is 1) working and 2) adjusted properly? Mine was a bit t@ss at low throttle openings when I first got it, and I found that the power wire to the idle switch had burnt, possibly the wire had been allowed to droop onto the exhaust manifold.

 

If you find that it wasn't working you may need to re-adjust the ignition timing, as the ECU retards the ignition when the switch tells it that the throttle is closed. Got mine working and the base timing was way off.

 

Check all the "free" stuff you can before shotgunning all the expensive fixes. Might it also be worth having the idle mixture set by a VW specialist at the same time?

 

HTH

[cameraspeed 0]

Thank you all for your responses. Am working away from home right now so unable to act upon your suggestions. Will respond once I've got my hands dirty. Cheers all.

[cameraspeed 0]

A long time later... and being busy with work my mechanic was the one to get his hands dirty... the 16 valver 'seemed' to have stopped stammering (much work carried out including a new exhaust + cat from MIJ exhausts) but then I ran the motor to the end of the fuel tank... re-fuelled, and the stammering began again. Grrrrr... the frustration!!!

 

Might this mean that there is crap in my fuel tank? Are there three fuel filters on a 2.0 16valver?

 

Secondly, and quite separately I have replaced ALL rubber bushes for the suspension and mountings (ie engine, gearbox, rear subframe) but now the steering wheel keeps twitching, sometimes quite drastically....

 

... any thoughts?