Stuttering badly under W.O.T

[BigBen]

1.8T chipped.

Under wot it is stuttering badly, boost gauge is bouncing up and down violently-

I have swapped over coilpacks for known good ones, swapped ignition amp for good one, all boost pipes are good. I recently swapped out my n75 j back to standard n75 c, but it was fines for 4days previous to today.

When it is stuttering the mpg drops to like 7mpg and it smells rich.

No fault codes other than temp sender intermittent reading.....

Would the MAF cause this or N75 c. I thought the N75 would defo log a code??

Any help appreciated

 

[aragorn]

What about the spark plugs themselves?

Could be the MAF if not.

 

[B5_Avant_AAN_Powered]

As Aragon says, sounds like its "blowin" the spark out, check/replace the plugs first.

Sean.

 

[BigBen]

Thanks guys. It has iridium plugs that all look to be in good nick. Any preferred makes or types. Has anybody tried non bosch MAF's

 

[aragorn]

NGK BKR6EK's are in my turbo. Mines remapped and a few others are running them with bigger power and no problems.

 

[BigBen]

Hey Aragorn, do you run those plugs with a smaller gap? :icon_thumright:

 

[aragorn]

Nope, straight out the packet.

 

[BigBen]

Ok update time. Have swapped MAF= no change between new and old one, swapped n75 =no change, swapped coil packs =no change. Will change plugs today- have bought NGK bkr6e's.

I noted today that when the turbo spools the boost gauge is going mad- bouncing up and down, if i keep my foot in it and drive through the stuttering / surging the gauge hit almost 1.5bar which it has never done before- way to high i know. It is defo worse when the engine under load as in up hill.

I am inclined to think this is not a combustion problem but something boost related. Are hter any other bits that can cause this? Need to use the car tomorrow so need a rapid fix this car above all vag i've owned is testing my resolve...............

 

[jcb]

have you pulled the plugs since you installed them?
what do they look like?

do you have VAGCom? if you do you could get a timing log under load

 

[BigBen]

Plugs look spot on, not wet or burnt. I have vag com but am not to hot at using the advanced functions. What am i looking for

 

[aragorn]

If your using the E's then gap them to 0.028" or 0.7mm

i found the E's had a funny pattern on them as though it wasnt igniting the mix very well, the EK's dont do it however.

 

[BigBen]

Hi, yup i have closed the gap to 0.028- ****** tiny gap but no difference...............

 

[BigBen]

Well looks light head gasket is fecked, french mustard in expansion tank- no water in the oil/ engine but waterways are bunged up stinking mess.

I have played about with the plug gaps and the car is smoother but still not boosting well- could the head gasket be effecting this- (bet that is a stupid question??)

Aragorn i have ordered a set of the plugs you have to see if they are better.

Any tips for doing the head gasket? Is it a whore of a job to do