abf digi 3.2-suspected h/g causing bad idle. fixed now back with a vengeance

They worked for a day, so the next day i ordered up some new ones from tps. then had probs with old sensors, then new

 

Have you sorted it yet? I have exactly the same problem, won't pull under load, however it clears instantly the revs get past 4000k(slipping the clutch), all the usual coil, leads,dizzy cap, fuel pump, filter changed.
Once it has 70 deg on oil, no problems and good fuel economy.

Could it be the lambda heater? what should the resistance be? (I believe after 4000k goes open loop)

 

is not lambda. i get it from idle, and i believee that at idle, lambda is closed loop and not functioning

 

if Vaccum lines and relays have been changed. Maybe the fuel pressure regulator. I had a problem with mine.

 

i may have a spare one of these. good call!
ecu has been swopped to the original. seems an improvement. maybe in my mine.
still definitely not right in 5th though.
and still not checked my timing!

 

so i gave her a full service today (plugs oil coolant etc). checked timing, all ok there, and compression tests all came up at over 14bar/200psi with inlet off.
also swopped over tb and fuel rail/fpr.

i put x2 1.5 litres od g12++ in, which i know is too much, got her up to temp, fan kicked in. coolant light wont stop flashing. hmm!

i went around the back, and the exhaust fumes smell very very sweet! so, im thinking the h\g has gone letting coolant into the cylinder. but would this not show up on comp test? or is that more for rings?

 

so the head came off today. went well apart from one snapped ex stud.
and to my supprise the gaskett and head seem fine! on closer inspection, cy4 seemed wet. but carefully inspecting the gaskett, block and head face revealed nothing!

all 4 pistons have alot of carbon build up on them. id describe them as a mound of, rather than deposits!
the breather system from the block to pcv had alot of mayo in, yet nothing at all in the catch tank.

the major concern is that the head bolts were all very easy to undo. the last 2e block i pulled apart, i had to wrestle to get the bolts out!
i used a breaker bar first. easy. but i then tried a 1/2 inch wrecnh and amazingly they came out with ease.

all in all im miffed! had the original vag stamped gasket on. and full history to prove. so im sure the bolts have never been touched. but how else will the combustion gasses smell of coolant?
the good news is that the bores are perfect! no lip at all.

Paul

 

it never really used any coolant. just on occassion you could smell it. esp after the change. it was a heavy 60/40 mix though

 

so guys this is happening again. at whits end!

as soon as i changed the HG it was perfect. 6 months excellent motoring and its back with a vengeance.

idle rough enough to start a tsunami, and a when i press the go pedal it just coughs and splutters, almost sounds like its bakfiring through the inlet, then it spins its heels and pulls. f'ing thing.

is it a coincidence about the HG? can a failed HG give these symptoms?

it just feels fuel or spark related. as far is spark is concerned, iv replaced all usual abf suspects from a known working abf ibiza. tb, dissy, vac hoses, relays, iat, ecu temp sender, ecu, battery, earths, leads, plugs the lot.

the only thing i can think of is fuel related. im running the 1.8 digi twin pump set up. its 18 years old. a D_D machine last month suggested they are fueling correctly, if not a little lean @ wot high rpm.
not changed relay, but have done fpr.

any clues guys as its doing my nut in.

just spoke got in contact from the guy who did the head. hae said he didnt skim it as it was perfectly flat.hmm

 

last time it was doing this, all measuring blocks were testing and everything came back within tolerences. il try the lambda now!

wiring is all good, isv buzzing, vac hoses all new, and plugs are fine too.....

 

My car threw a massive wobbley similar to yours Paul. It ran sooo pig rich from cold start up that it started to flood & missfire. Turned out that the MAP sensor vacuum tube had moisture in it that had frozen up. This in turn made the ECU think there was no vacuum, i.e. full throttle and hence the super rich running.

Gurds

 

as i see this is a common problem for ABF. i was in love with this engine when it idled at the donor car before i did the swap... ehhh... only problem vagcom showed was the map sensor which now is ok, but i still miss that perfect running idle. ill do a fuel pressure test this week. autodata says
system - vacuum off - 3 bar
regulated - vacuum on - 2.5 bar
holding - after 10min - 2 bar min.

 

so symptoms today. always fun to drive in the snow

car started and idled fine for say 3 minutes. then started to deteriorate. foot down throttle fully open, and it coughed its way up to 3k and would not budge. coughed a little more, then souned like a bakfire from the inlet. and reved to 6k

on the journey home i didnt get out of third. this is the longest time the problem has ever persisted.
i had my throttle very lightly pressed along a straight snowy road. the engine kept cutting the power for say 5 seconds, then power came back. i hadnt moved my foot at all.
it was like it was misfiring, then normal, missing, then normal, on very light throttle (2k) i want to say 'feels' electrical. not mechanical.
if i drive a little quicker, at wot it will cough to say 3k, keep coughing then all of a sudded full power returns resulting in a nasty smell from the clutch and being pulled into incoming traffic

the only things i havent changed is the fuel system, which i have a vr6 setup in the garage. and the loom. it just feels like somethings getting 12v /5v power then its not.

il get it on vag-com again and check the parameters

unplugging lambda didnt make a difference
all vacs were changed for new yesterday

 

ecu, perhaps?

 

been changed over already

 

today i measured the fuel pressures. everything ok. but realized that the EGR valve would buzz but the incoming air would not be affected. tomorrow im gonna change the valve and the canister to see if anything happens.
throttle position sensor paul?