abf ecu changed, now head gaskets blown! coincidence?
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abf ecu changed, now head gaskets blown!
its a converted golf mk2 running abf 16v digi 3.2. full loom and engine.
i was having an idle/hesitation problem with the car. all sensors were changed, and still the problem persisted. the ecu was the only unchanged item.
so i swapped it out for a known working item, coded it through vag-com. All seemed well, apart from the same idle/hesitation issue
i was driving home down the a38 (fully warmed up), and had a play to see if the rev limit was the same. was (6800) as iv heard some models have different limits (hoping for 7100).
all seemed fine. went into a 40 traffic zone, slid it into 5th and slowed down. as it went back to 70, i slipped her in 3rd, foot to the carpet and boom, white smoke plooming out the rear. i managed to make it home. pressure looked ok, as were temps. no oil in water, and vice versa. scratched my head. started her up again after letting her cool, terrible idle. redudced power.
i have a good engines place just 5 minutes down the road, so off we went. sniff test, turns green. gaskets gone, looks like its gone through one of the water jackets?
so, an absolute coincidence this happend driving back from having the ecu swopped?
and these abf's are meant to be bl00dy tough!? engines only got 80k on her, never uses a drop of oil/water, and pulled above std figures on a dyno_dynamics machine.
would it of caused any bottom end damage? suppose its had a nice steam clean and a excuse for some porting work
Paul
its a converted golf mk2 running abf 16v digi 3.2. full loom and engine.
i was having an idle/hesitation problem with the car. all sensors were changed, and still the problem persisted. the ecu was the only unchanged item.
so i swapped it out for a known working item, coded it through vag-com. All seemed well, apart from the same idle/hesitation issue
i was driving home down the a38 (fully warmed up), and had a play to see if the rev limit was the same. was (6800) as iv heard some models have different limits (hoping for 7100).
all seemed fine. went into a 40 traffic zone, slid it into 5th and slowed down. as it went back to 70, i slipped her in 3rd, foot to the carpet and boom, white smoke plooming out the rear. i managed to make it home. pressure looked ok, as were temps. no oil in water, and vice versa. scratched my head. started her up again after letting her cool, terrible idle. redudced power.
i have a good engines place just 5 minutes down the road, so off we went. sniff test, turns green. gaskets gone, looks like its gone through one of the water jackets?
so, an absolute coincidence this happend driving back from having the ecu swopped?
and these abf's are meant to be bl00dy tough!? engines only got 80k on her, never uses a drop of oil/water, and pulled above std figures on a dyno_dynamics machine.
would it of caused any bottom end damage? suppose its had a nice steam clean and a excuse for some porting work
Paul
Yeah coincedence, you just cooked it!
Electrical/E.C.U changes wont give you such drastic mechanical faults/issues.
Maybe some symptoms but they would occur instantly and do damage over time.
When you get your shiny new engine back take it easy for hundred miles, its just had open heart surgery. Dont kill it!
Electrical/E.C.U changes wont give you such drastic mechanical faults/issues.
Maybe some symptoms but they would occur instantly and do damage over time.
When you get your shiny new engine back take it easy for hundred miles, its just had open heart surgery. Dont kill it!
Edited by smashedV8 on Thursday 4th February 21:01
my suspicion is you may have wasted a lot of time and money buying parts when you should have had a compression + sniff test done.
It is very possible that the headgasket has been leaking for some time and most likly letting coolant into the combustion chambers.... take all your spark plugs out and look for the very clean one - that will be the problem area.
A ABF head gasket is a tripple layer steel item and is tougher than the material ones that other 16v VW engines have but it is not indesctructable.
Whip the head off and see what is going on, if as i suspect the coolant is leaking into the chambers then DONT try and run the engine anymore as when engine it is cold the coolant wont get boiled into steam and water doesnt compress.
A set of new head bolts, a gasket and all the gubbins is less than £100 and can be fitted in few hours... it usually takes longer to have the head skimmed than it does stripping an rebuilding.
Dave
It is very possible that the headgasket has been leaking for some time and most likly letting coolant into the combustion chambers.... take all your spark plugs out and look for the very clean one - that will be the problem area.
A ABF head gasket is a tripple layer steel item and is tougher than the material ones that other 16v VW engines have but it is not indesctructable.
Whip the head off and see what is going on, if as i suspect the coolant is leaking into the chambers then DONT try and run the engine anymore as when engine it is cold the coolant wont get boiled into steam and water doesnt compress.
A set of new head bolts, a gasket and all the gubbins is less than £100 and can be fitted in few hours... it usually takes longer to have the head skimmed than it does stripping an rebuilding.
Dave
Oh well at least you know its a head gasket and not a electrical gremlin as these can be far harder to find. Stripping the head off isnt too bad a job, id apply a tonne of WD40 to the exhaust and inlet manifold studs before attacking them and make sure that if you have the allen key bolts on the inlet manifold you use a decent allen key end on a ratchet an hammer the bugger in as you really dont want to round these bolts - been there done it and got the T-shirt :-( Aside from the manifolds everything else will come off easily!
Id suggest that when you have the head off go a little further than a skim, get the cam chain replaced if it is slack and get the valve stem seals done to - last 16v head i had done cost me £100 to have the head chemically cleaned, lightly polished inlet/exhaust ports, new valve stems, exhaust valves x8 and a cam chain. Well worth the extra as you dont want to end up doing a Head gasket now an in few thousand miles find it smoking due to valve stems as they are a head off job.
good luck
dave
Id suggest that when you have the head off go a little further than a skim, get the cam chain replaced if it is slack and get the valve stem seals done to - last 16v head i had done cost me £100 to have the head chemically cleaned, lightly polished inlet/exhaust ports, new valve stems, exhaust valves x8 and a cam chain. Well worth the extra as you dont want to end up doing a Head gasket now an in few thousand miles find it smoking due to valve stems as they are a head off job.
good luck
dave
when i put the lump in last summer the block/head were stripped and every gasket was replaced with vw/tps items. all except the head gasket of course. new water pump + stat (vw). and since then, all new sensors from vw/tps (ecu water temp, inlet air temp, crank sensor).
so all manifolds have been off. no probs that i can see.
the heads being sent over to vagobonds on the main gti site. he's done my heads before and iv seen good figures.
so all manifolds have been off. no probs that i can see.
the heads being sent over to vagobonds on the main gti site. he's done my heads before and iv seen good figures.
test done at 80'c oil temp.
1- 12 bar 175psi
2- 12 bar 175psi
3- 12 bar 175psi
4- 12 bar 175psi
exactly the same on each cylinder. i suppose the rings are ok then. but surely if the sniff test came back positive, one cylinder would be slightly down?
c0ck. i didnt open the throttle! would this mean results would come back better or worse?
1- 12 bar 175psi
2- 12 bar 175psi
3- 12 bar 175psi
4- 12 bar 175psi
exactly the same on each cylinder. i suppose the rings are ok then. but surely if the sniff test came back positive, one cylinder would be slightly down?
c0ck. i didnt open the throttle! would this mean results would come back better or worse?
new results in- opened the throttle this time 
1- 12.9 bar
2- 12.8 bar
3- 12.0 bar
4- 12.9 bar
so it looks like no.3 is down a bar from the others. are we thinking this is where its leaking into the water jacket?
drove it today. no overheating, not smoking too much, only on start up. definate loss of power. wont really pull in 5th at all
1- 12.9 bar
2- 12.8 bar
3- 12.0 bar
4- 12.9 bar
so it looks like no.3 is down a bar from the others. are we thinking this is where its leaking into the water jacket?
drove it today. no overheating, not smoking too much, only on start up. definate loss of power. wont really pull in 5th at all
new compression results in-
cy\b cold warm
1 12 12.9
2 12.1 12.8
3 10.5 12
4 12 12.9
so cylinder 3 is 1.5 bar down cold, .8 bar down warm. well witin spec. do we think this is where the gasket has gone into the water jacket? as the sniff test was positve for combustion gas in the coolant.
cy\b cold warm
1 12 12.9
2 12.1 12.8
3 10.5 12
4 12 12.9
so cylinder 3 is 1.5 bar down cold, .8 bar down warm. well witin spec. do we think this is where the gasket has gone into the water jacket? as the sniff test was positve for combustion gas in the coolant.
SO its driving ok now without any smoke etc, just a bit down on power??
Try going back to the first ECU and try again.
That smoke could just have been a load of oil after a long vacuum period (over run)
Find a deserted road (daylight) Drive along at very hight rpm, say 6000 in 3rd or 4th if space permits, get off the gas and let it slow down all teh way through the revs down to 2500 ish, then jump hard back on the gasm do you get teh smoke then. Is this the same sort of driving/throtle positions/engine load, as teh first time you had the smoke.
We have had quite a few odd vacuum faults with the VR6 engine, including them sucking in rear main seals and sqealing and smoking after long overrun, especially when the oil is hot after a thrash. Happen to me I thought the engine had blow it pinked like mad at the same time. Was caused by a valve in the cam cover, new camcover, fixed.
Try going back to the first ECU and try again.
That smoke could just have been a load of oil after a long vacuum period (over run)
Find a deserted road (daylight) Drive along at very hight rpm, say 6000 in 3rd or 4th if space permits, get off the gas and let it slow down all teh way through the revs down to 2500 ish, then jump hard back on the gasm do you get teh smoke then. Is this the same sort of driving/throtle positions/engine load, as teh first time you had the smoke.
We have had quite a few odd vacuum faults with the VR6 engine, including them sucking in rear main seals and sqealing and smoking after long overrun, especially when the oil is hot after a thrash. Happen to me I thought the engine had blow it pinked like mad at the same time. Was caused by a valve in the cam cover, new camcover, fixed.
If its doing what I think that explains the smoke, to see if i'm right you can try and make it do it again, as described.
But I dont think I can explain the lack of power, unless that came from the ECU swap.
When we have seen these faulty cam covers (is just a breather valve problem, but its part of the cover and you cant get it separatly) noise is the normal way the customer notices, but to confirm try and take the oil filler cap off with it running (it will have some vacuum holding it down), should feel resistance but should be posible, if you cant get it off at all, then there is something wrong with the breather.
But I dont think I can explain the lack of power, unless that came from the ECU swap.
When we have seen these faulty cam covers (is just a breather valve problem, but its part of the cover and you cant get it separatly) noise is the normal way the customer notices, but to confirm try and take the oil filler cap off with it running (it will have some vacuum holding it down), should feel resistance but should be posible, if you cant get it off at all, then there is something wrong with the breather.
iv been running the car, it seems ok as i swopped back the ecu. just 5th gear seems a little lacking.
the black smoke was a simple over fill of oil, i found loads in the airbox (1/5 pint!)
so i fully serviced her yesterday. checked compression, and all 4 are over 14bar/200psi. changed the coolant (g12++), ran up to temp, and i noticed white smoke out the exhaust. and guess what? it smells very sweet! so, im thinking hg between water gallery and chamber?
the black smoke was a simple over fill of oil, i found loads in the airbox (1/5 pint!)
so i fully serviced her yesterday. checked compression, and all 4 are over 14bar/200psi. changed the coolant (g12++), ran up to temp, and i noticed white smoke out the exhaust. and guess what? it smells very sweet! so, im thinking hg between water gallery and chamber?
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. the lump was warm, but no where near hot. and not registering on the temp sender. so oil below 50'
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
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. the lump was warm, but no where near hot. and not registering on the temp sender. so oil below 50'
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
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