Advice on lumpy, erratic 2.0 16v - being a bit crap again..

[Jim 1]

I think I need to get to the bottom of some of the characteristics that are starting to get in the way of me enjoying driving my car, and wanted some advice on things to check / change..

 

Firstly, on a morning, the car can sometimes (but not always) be slow to start.. so I turn the key, starter fires and the engine sort of slowly builds up revs and it seems to be running. No sort of clean start, just a 2 second or so spluttering into life. Now I say it does this 'sometimes' because I left the car unused for 4 days last week, hopped in it, and started it up - it fired really enthusiastically on the merest little turn of the key. So its intermittent.

 

Secondly - the car is so so lumpy to drive sometimes - if you drive along with your foot just lightly on the throttle, the car is almost like kangaroo'ing and spluttering and - its basically just not smooth. Again - I say it does this sometimes as I feel for a 170k mile engine, it is bloody smooth and when it wants to drives really nice and smoothly.

 

Thirdly - idle. The classic 2.0 16v problem. My idle, usually when cold is a nightmare but again sometimes it doesn't want to know regardless of how warm the car is. Sitting in traffic I can get bouncing revs, revs sticking up to 1000RPM randomly, and sometimes it might even cut out (drove to cambridge - approx an hour on the A14, dipped the clutch, car cut out).

 

Clearly there are some gremlins here and I don't doubt that it could just be something as simple as the ISV.. but they cost so damn much I can't really afford to splash out on something that isn't at least going to improve the situation. Reading some other threads, injectors sound like they might be a fairly good place to start also..

 

Cheers folks.

[Supercharged 2]

Jim, as the water temp guage was out I reckon it's worth changing the other one too as this one feeds the ECU and on ETKA it says 'idle stabilisation'...

[Jim 1]

Which one is that sorry mate? The blue temp sender type thing?

 

I don't think I mentioned btw - we found the water leak when doing my front engine mount the other week (classic front flange) so bought a new one / gasket / bolts / washers and a new blue expansion tank cap! Tackling it this weekend over at Erics :)

[Supercharged 2]

I think it's the one the other side of the plastic flange at the side to the one we changed.

 

A long shot but you never know - it could smooth the idle and up the MPG figure...

[Jim 1]

Well - has to be worth a shot mate. You got a part number from ETKA (and a rough price?) - I could order it from VW before the weekend and change it when the coolant is out..

[dr_mat 0]

Temp senders, MAF, ISV. I doubt that all these problems could be caused by the ISV, I'm much more inclined to think the engine isn't doing cold start enrichment properly (temp sensors) or isn't getting the fuelling right at fast idle (MAF).

Having swapped the MAF on my VR a couple of weeks ago, I can tell you it can make a surprising difference, particularly on small throttle openings in traffic. Even if you don't think there's anything wrong with the old one ..

[Jim 1]

I'm not sure there is a MAF on a 2.0 16v..? Or am I really wrong?

[dr_mat 0]

There is, but it might be called something else.. Is it the "metering head"?

Actually I was pretty sure the 2.0 engines had standard MAFs. Worth a check though.

I've reached the point in my Corrado owning life where it's worth keeping a spare of each of the expensive engine sensors, just to rule it out when (not if) you start having troubles ...

[dr_mat 0]

http://members.dslextreme.com/users/vwt ... ning3.html

 

This mentions idle/bucking problems on the 2.0 motronic cars and seems to point to bad connections as the cause. (Makes sense, as these bits are all solid state, mostly.)

[corradophil 3]

I'd check the basics first, i.e. spark plug condition and gap, HT lead, rotor arm, dizzy cap. Basically check there is no obvious damage. I know you are not descibing a missfire, but its easy stuff to check first, without spending any money.

 

When you are happy with that, I would go for ignition timing next as a check, and adjust if required. There is also a procedure for setting the fuel mixture correctly, which I carried out on mine, which runs and starts perfectly. If you want to give it a go I can scan the page in the manual and upload it for you. My emmisions on the mot were spot on after setting it up using this method.

 

As far as the idling goes, apart from the usual isv cleaning, I would check the switch on the bottom of the throttle body is operating correctly. If it is not, the ECU won't know the engine is at idle and the isv won't operate.

 

These are all things you can do, without spending money, so I'd start with them first.

[Lippy 0]

Phil, id be interested in seeing that scan if posss. Cheers Andrew

[davidwort 0]

There is, but it might be called something else.. Is it the "metering head"?

Actually I was pretty sure the 2.0 engines had standard MAFs. Worth a check though.

I've reached the point in my Corrado owning life where it's worth keeping a spare of each of the expensive engine sensors, just to rule it out when (not if) you start having troubles ...

 

 

no, the KE-jet 2.0 16v's are basically K-jet mechanical injection with the ECU controlling warm up and enrichment rather than having a mechanical Warm Up regulator. There's no MAF just the air flow plate as regular K-jet.

[Jim 1]

Just a bit more info on steps i've taken..

 

Car was recently serviced so has new spark plugs in there. I've changed the dizzy cap (old one was fine though tbh) and the leads seem to be in fairly good nick though i'm considering changing them just to eliminate them as a problem.

 

ISV has been given a through clean / soak in carb cleaner - had no discernable effect.

 

Thanks for the tips and suggestions so far chaps :)

[dr_mat 0]

Ok, I stand corrected. :)

[davidwort 0]

Just a bit more info on steps i've taken..

 

Car was recently serviced so has new spark plugs in there. I've changed the dizzy cap (old one was fine though tbh) and the leads seem to be in fairly good nick though i'm considering changing them just to eliminate them as a problem.

 

ISV has been given a through clean / soak in carb cleaner - had no discernable effect.

 

Thanks for the tips and suggestions so far chaps :)

 

Jim, the Haynes passat manual describes how to disconnect the KE jet specific stuff so the car runs as if it were on k-jet, this could help you to narrow down some of the possibilities, I can take some piccies of the pages if you need.

Like Phil says it's a bit of a 'check things off the list' type job to work out what is OK and what might be suspect.

If you can 'borrow' bits from a working valver, that might be a good bet, I've got a spare ISV and injectors and fuel pipes, but might be a bit too far from you in Northampton just to try them out.

Some of the things you can't easily check yourself are the emissions (lamda sensor?), ECU recorded faults, fuel pressures and warm up/enrichment unit.

Ideally you wan't a whole metering head and possibly other sensors to swap from a good car onto yours.

 

re-reading your original post, I reckon it's more likely to be a fuel problem, injectors, metering head or fuel pump do seem likely, is the pump noisy or varying in pitch?

[Jim 1]

A spare, known good ISV for a 2.0 16v would be good. VEEDUBBED was kind enough to send me one all the way from Italy but i'm not sure what it came off as the fitment for the pipes seems to be different!

 

Fuel pump doesn't seem excessively noisy or variable in the noise it puts out.. certainly no noisier than those on any of the Corrado's i've owned previously.

[Jim 1]

Well just popped down to Listers to order that temperature sender.. £26 f@!%ing quid!! :| Who are they having on!!

[Phil K 0]

Don't know if this will have anything to do with your problems but all mine have been related to the MAF! The problems range from no power over 4K, lumpy idle, lack of power/life, and most recently engine not running! I've had 4 units on there since I've owned it and they have all caused problems!

 

Next plan is to lose the sensors and get the engine tuned up using purely the mechanical side of things - which may also improve my power too, although there is a slight danger of emissions being too high :D

[Jim 1]

I have occasionally experienced sort of lack of power but that seemed to happen most noticably during both laps at the Nurburgring when I was really wringing it out.. about half way round when the car was well up to temp, it started to feel really flat and gutless but I put that down to the car having a drilled airbox and pulling in lots of warm air from the engine bay?

 

Hmm..

[pete nice 0]

I have a 20.l 16v of afriends at the moment with the same problem. it has just had the metering head reconditioned by VW but it has made no difference. I opened the airbox & can see fuel dripping onto the air filter. This can't be right surely?

 

Could this be the trouble?

[Jim 1]

Thanks to Eric for his help all of Saturday also doing the flange replacement job.. what we thought would be relatively easy became a total pig - we had to end up taking part of the manifold to get at it as the top bolt had rounded off completely and was totally stuffed.

 

Had to refit the manifold with its old (and knackered) gaskets.. so that looks like another bunch of stuff to rebuy again in the near future.

 

Think this is the problem with old cars.. everytime you do one job, you find about 4 more that need attention :|

 

Good old VW supplied me with the wrong temperature switch thing - we looked up the correct part on ETKA and despite my shock at the other one costing £24, this one looks like its meant to cost £50!!! Who are they having on!! :(

[Jim 1]

Revs seem even more bouncy now at idle. I think reusing the old gaskets was a mistake.

 

I think i might start saving up to go the whole hog - new injectors + seals, gaskets, ISV, HT leads, etc.. would cost a few hundred quid but I think it'd totally transform the way the car run.

 

And here I am by myself, er, talking to myself. Now thats chaos theory..

[dr_mat 0]

I'd guess you're not talking to Vince about this for a reason .. ?

[Phil K 0]

I'd still put money on the air flow meter tbh ;)

[Jim 1]

I'm not talking to Vince yet because I have no money - and I don't just want to go and badger him for free advice with no promise of work in exchange for his time ;)

 

Might pop up and see him soonish though.. problem is the fault is intermittent and only really acts up first thing in a morning. So I could drive there and ask for advice and the car will sit there and idle perfectly like nothing is wrong with it...