2L 8v running rich (sorted, dizzy way off)

[davidwort 0]

bit of a noob when it comes to digifant

2L 8v (2E engine) on digifant, cat and single lambda, 1 knock sensor.

I've checked leads, plugs, rotor arm, cap etc, all seem OK and fairly new, fitted a new bosch lambda and it's still running rich I think.

haven't had it back on the MOT gas analyser yet, but after a good run the plugs are fouling up, oily black, all four the same, good compression on all cylinders but the tailpipe is a bit black for a cat car and the fuel economy is wrose than my K-jet 2L 16v.

I've even tried a spare temp sender, not new but the result is the same, wqarmns up fine, runs smooth on a cruise, but bogs down under load pulling away. Plug fouling is starting to cause starting issues.

 

Any ideas anyone :scratch:

[dannyboy 0]

alright david, if your plugs are oiling up sounds like oil scraper rings are worn.youll still get good compression though but youll burn oil quite a bit.Sorry only way around it is replace them. might be worth looking at the valve stems too,when they get old oil leaks past them into combustion chamber.

 

Worth looking at the airflow meter.lot of the old 8v gti ones were prone to the flap sticking and the contacts getting covered in grease. all i used to do was open it and spray contact cleaner on it,wipe it,spray one more time to make sure its clean.Put it back together and check to see if the flap moves freely without jamming or getting stuck.check all the vacuum hoses too.

[davidwort 0]

cheers, I've had the inlet to bits and cleaned everything including throttle body, did that a while ago, seemed to improve things a bit, sure I checked all the vac hoses thoroughly.

will keep an eye on the oil consumption, hopefully get it on the gas analyser next week and check the lambda value, it was wavering about on the old sensor although still in spec just about, from the marks on the old one it's genuine VAG but a 1997 replacement if I deciphered the readable info left on it OK.

it really bogs down and vibrates like a juddering clutch when pulling away, but it cruises very smoothly, whipped the plugs out and cleaned in carb cleaner last night, started fine after that so I'll check them again, first time I've looked at them on the new lambda.

I need to check the advance too at some point, not sure of procedure on a catalysed 2E 8v though, assume it should be hot with water temp sensor plug removed like 1.8 8v?

[dannyboy 0]

id say the bogging down could be due to the dizzy timing dave. Yeah the procedure is pretty mauch the same:-

1) warm engine up til fan cuts in twice

2)remove breather hose

3)turn off all electrical loads

4)unplug temp sender

5)loosen dizzy retaining bolt and with a strobe light check timing 6-8 degrees while engine is at 2500-3000 rpm

6)tighten bolt

7)refit breather and sensor

8)take her for a spin

[davidwort 0]

thanks again, another little job to eliminate another possibility :) at least I've got an old adjustable advance timing gun, it's been very handy when tweaking the 16v on super unleaded :)

[dannyboy 0]

no worries dave,only done mine last month(on my g60).i never trust a german mechanic,thats why i do it myself! Great when the car has OBD2 but useless when it doesnt! :lol:

 

They wanted me to fork out nearly 2000 euro for a ABS pump(i was having a lazy week!) :shock: :cuckoo: and i fixed it myself for 7 euro for a relay!

[boost monkey 0]

a leakdown test wll confirm if it's rings. Did you do one already or just a compression test?

[volksworld13 0]

im sure that ignition timing setup is correct , i have an ady, and work nxt to vw, i set myn up, using 50501b vw machine, put the car into a basic setting, 01q on 50501b, adjusted ignition timing , using tipex on flywheel tdc mark, strobe light lead on no1 cylinder, and adjust to spec, i also have a vw factory manual on the 2.0liter engine for fault finding will get a picture of it , see if i can get more info.

[davidwort 0]

im sure that ignition timing setup is correct , i have an ady, and work nxt to vw, i set myn up, using 50501b vw machine, put the car into a basic setting, 01q on 50501b, adjusted ignition timing , using tipex on flywheel tdc mark, strobe light lead on no1 cylinder, and adjust to spec, i also have a vw factory manual on the 2.0liter engine for fault finding will get a picture of it , see if i can get more info.

 

any info would be cool :)

I think the 2E engine is a bit more basic than the ADY, but similar if you know what I mean

 

I spent ages when I got home trying to check the timing

the mark on the crank pulley looked too far advanced at idle, even setting my gun to zero I couldn't get the mark back far enough

so I stopped the engine, turned it by hand to line up marks on pulley and timing cover, then looked at flywheel mark, that lined up spot on with the gearbox casing mark so I marked them white

tried running engine again, but no luck seeing mark on flywheel :scratch:

tried slackening dizzy but even with the clamp off I couldn't budge the bloody thing, gave up as I got too cold :mad2:

when I get the chance I will see if I can budge it and get a reading on the marks, very odd.

 

not done leakdown test but it's not seeming to use any oil

[RW1 0]

One thing that doesn't seem to be considered given most of the above is proving negative...........

 

Have you checked round the fuel rail pressure regulator for the condition of the vacuum hoses? One on the regulator goes to a junction piece, splits two ways to the throttle body and the other to the airfilter box iirc. Perished/split etc.???

 

If this set of pipes are leaking, it runs richer.

 

Pull the pipe off the airbox, block off & test drive, the temp sensor inside could be leaking more than it should. Deteriorated vacuum leading to richer running.

 

Regulator itself giving over pressure???

 

Engine running at idle. Fuel rail pressure is normally 2.5bar. Pull the vacuum pipe off and it rises to 3.0bar if all is normal. Residual pressure must remain above 2 bar after stopping the engine for 10 minutes.

 

On the battery side of the fuel rail, there is a fuel pressure tapping off point to connect to just for the job.

 

.

[davidwort 0]

One thing that doesn't seem to be considered given most of the above is proving negative...........

..

 

thanks for that too, I did check the vac pipes a month or so back when I did a lot of work on the car, clutch, suspesion stuff, but I'll check everything you mentioned when I can get to my dad's place and use the fuel pressure gauge,

ta muchly :)

[davidwort 0]

well just about sorted, was having more and more trouble starting, thinking the battery was on it's way out (it is probably getting tired too) the other night I tried to check the timing, as I said above, today I took it to the garage to check the emissions and lambda. Lambda is spot on (new sensor) but the emissions was all over the place and just leaping too high to meet MOT reqts.

Finally freed off the dizzy and timed it up.

Blow me the dizzy was about 15 degrees too far advanced at idle! Can't believe it's been driving as well as it has, ECU must have been having kittens, no wonder there was a knock sensor error recorded!

Set the timing right and drove it home, gave nearly 45mpg on the 10 mile trip back and that was in -3 degrees!

Runs so much better now and with much smoother pulling away.

It idles a little high now and there's no manual adjustment, but that might sort itself out when the ECU resets itself?

Pleased I sussed it in the end, quite how it got so far out is anyones guess and it was like that so long the dizzy was siezed in that position :roll: just feel a bit daft I didn't check that as soon as I got the car!

[volksworld13 0]

if you have replaced the cambelt recently , you only need to be a tooth out on the intermediate shaft which turns the dizzy, to be out on the ignition timing.

[davidwort 0]

may well of been like that since the previous owner (or two) last had the cambelt changed :roll:

having only had the 16v before I didn't think about checking the position of the intermediate pulley, but now you say that I guess that is the most likely thing that happened, you'd have thought :clap: :help: the owner would have noticed how bad it drove afer the belt change though :shrug:

[RW1 0]

That's good news, something positively found.

 

It idles a little high now and there's no manual adjustment, but that might sort itself out when the ECU resets itself?

Don't think it will sort out......

 

If the belt was out as said, the previous owner/garage could have adjusted it to pick up the idle.

 

There is a limiting screw on the throttle body. Inboard side of the throttle body below the throttle spindle line on the windscreen side. See if it has been tampered with.

 

If so, back it out so there is a gap. Now wind it into the throttle lever until it just touches and piece of A4 paper can just slide in the gap. Now wind it inwards a further 1/2 turn of the adjuster screw. That is it set.

 

Now you need VCDS.

Engine warmed up past 80'C oil temp.

 

Pull off the crank case breather hose off the roccker cover box. The one going to the intake/throttle. Block the hose off.

 

Select 01 - Engine,

select "Basic Settings" and select group 001.

While idling, field 4, far right in the VCDS display, should acheive all zero's.

 

If a 1 remains dispayed in the digit string, you still have a problem but given emmisions are OK? and timing OK, then hopefully zero's will be displayed.

 

Exit "Basic Settings" if all is well and zero's are acheived.

 

If you don't get zero's, Basic Settings does not happen.

 

- Check for air leaks.

- Check exhaust fot leaks from manifold upto the cat.

- Check lambda (which you've done)

 

If not zero's. this is what they mean.

 

01000000 - Auto selector not P or N

00100000 - Air Con not switch off

00001000 - Lambda regulation no OK

00000100 - Throttle valve not closed

00000010 - Engine Speed outside range (770 - 870 rpm)

00000001 - Coolant Temperature below 85'C

 

 

.

[dannyboy 0]

45 mpg on a 10 mile run, id never get that even if i tried dave :lol:

 

glad you got it sorted :clap:

 

just get o-ring set(always come in handy) and replace idle bleed screw o-ring.as said they get old and you idle will be all over the place.i always like to change old parts with VAG parts but for a o-ring, 50p or £11(its christmas :lol: )

[davidwort 0]

[strike:1si6wbpc]I'd love to know where the idle control/bleed is, got a feeling the digifant on this engine controls idle itself?[/strike:1si6wbpc] see below :)

[davidwort 0]

That's good news, something positively found.

 

It idles a little high now and there's no manual adjustment, but that might sort itself out when the ECU resets itself?

Don't think it will sort out......

 

If the belt was out as said, the previous owner/garage could have adjusted it to pick up the idle.

...

...

wicked, will get onto that next week, think my dad's snap-on computer should do all those functions :salute: