Rattle under load when engine is hot

[Jmac]

I know it has already been asked but have you checked your ign timing or have you had a cam belt done recently????? the dizzy could be out enough to cause your ping.

[jmystaki]

Timing belt changed at 80,000....

Timing checked by Golf Loon....

I wish it was that !

I ran the Vag-Com.... and it seems when it is pining the Hal Engine sender goes from 6 to 7... which suggests to me that the knock sensor is working as the timing is being changed....

Any other suggestions will be attempted.

Cheers

[sydVR6]

Are the spark plugs the correct heat range/correct plug?

I once bought a VR6 that had the plugs out of a 2.0 and ran like a proverbial. Once I changed all 6 to the VR6 BKR5EKU, the car went perfectly.

Maybe you have already, but if not, make sure the plugs are correct.

[jmystaki]

I am currently running - Bosch F6-4.

I ran the NGK BUR6ET for 50km..... I seemed to have a loss of power (all be it small), the engine did not seem to rev as freely....

After 50km on the NGK's there was a white substance covering the pins... something that you could rub off with a finger nail....

[GoLfMan]

white on ya sparkies usually means that you are running lean, but Im at a loss as to why that would happen in an injected car, but you never know, try that out

[sydVR6]

May be helpful:

http://www.classictruckshop.com/clubs/earlyburbs/projects/spark/plugs.htm

[jmystaki]

Using VAGCOM, what stats could I review to determine if it is running lean?

Alternatively, what can I do to test and check for running lean?

[GoLfMan]

when your engine runs lean it will ping alot and run hot, so your thermo fan will be on alot more than usual. Other than that I couldnt tell you how to detect if you are running lean on an injected engine.

[sydVR6]

It would be nice to solve the problem conventionally, but here is an alternative solution.

Back in the 80's/90's we had a '78 model 528i which was eventually equipped with this solution when Dad became tired of it pinging.

It's still popular for a lot of the turbo brigade.

Even if you (understandably) wouldn't be interested in something like this, the information here may help somehow.

http://en.wikipedia.org/wiki/Water_injection_(engines)

More:

http://autospeed.com/A_107970/cms/article.html

[jmystaki]

Ok, lets say it is running lean...

It is true, the engine fans do come on... although it tends to be after the engine has stopped... they usually run for up to 10 min...

They don't often run when the engine is running.. unless its really hot.

There must be other indicators that I can check electronically.....

Like O2 stats???

One of the sensors must be reporting this...

Ok, other than running water injection... what can I do to make the engine run richer?


Note: It only seems to get white on the plugs from the NGK plugs... the Bosch plugs seem to be ok.... although I think I get a little more pinging under the Bosch plugs....

I think the NGK's are a cooler plug...

[sydVR6]

The only other things I can think of at this time that might have an effect would be mixture related.

- O2 (lambda) sensor?

- MAF sensor?

Bear in mind that these would only effect the performance of the engine under normal operating conditions (when the fuel injection systems run in closed loop mode).

When you're using wide open throttle, the O2 and MAF sensor outputs would be virtually ignored and the engine would automatically enrich the mixture to protect the engine.

[jmystaki]

I have previously posted group 1,2 and 3 stats... including O2 Sensor...


I need some feedback on these results.... not sure if they are right...

[Jmac]

Lambda probe reading wil roughly let you know whats going on during a real time event and only in closed loop. Open loop forget it. Mate you might have picked up a bad batch of juice. I would drain the tank and fit a new filter and fill with good juice. The o2 sensor reads the amount of oxygen in the exhaust , for example if it has 0% oxeygen it is running Rich which produces a high voltage (0.7-1volt) Now the o2 sensor only goes into closed loop when the coolant temp sensor is happy the engine is at operating temp. At idle and part throttle is then when the measuring is done. At full throttle the o2 measurements are ignored by the ecu. If you think you are running lean mate you should notice an increase in temps. Blocked injectors, blocked filter and extra air entering via a Vac line or something being split. Lambda probes are great for 100k but then can get tired and give whacky signals as does the MAF too. Bad juice and crappy filter is common. Tired o2 sensor common too.
Jmac

[Bug_racer]

I cant believe this still hasn't been resolved !

Just putting up my original post so you can try the other things I mentioned . Maybe I need some more rep points so people will take notice ?

no one has suggested checking ignition timing ? Some Golf 3's you can change timing slightly .

Also what about checking the knock sensor itself ???? It could be giving an incorrect signal to the ecu which in turn controls the mapping for timing !

Another thing to check would be the air intake temp sensor on the airbox .

Fuel could be another issue , fuel pressure ok ? fuel pressure under load ok ? injectors blocked ?

So many things to check before de-carbonising the head !

[Jmac]

I cant believe this still hasn't been resolved !

Just putting up my original post so you can try the other things I mentioned . Maybe I need some more rep points so people will take notice ?

Cmon dont upset they guy do as he says!!! Check what he has recomended