VR6 Bora Hesitates on acceleration

[Dyldo]

Howdy dubdubs

OK, here's the issue. At idle, she 'seems' fine and i can rev her t1ts off with no issue. It is at any time under load that she hesitates and misfires (not loudly).

She has brand new coils (Bremi, less than 100kms) and NGK plus (same) and now also has a brand new Bosch MAF (massive props to Goodfella). Still same issue.

I am cleaning the K&N air filter as we speak, but I don't think that will help.

I've come up with a few ideas for what it might be:-
Coil plug wiring harness
fuel pump
lack of V9f supercharger
fuel filter
injectors
ECU

I picked up one of fuzion's Launch CReaders and I have yet to get any codes etc as I have the baby by myself and can't get out there, but anyone have any ideas?

[h100vw]

Baby on the back seat!

Have you fitted the new parts to clear the fault or has the change of parts caused the missfire to start?

Gavin

[Dyldo]

i had a coilpack fail, so had a temporary one in there whilst i ordered 6 newbies from ecs. then i thought i should replace plugs too, and strangely didn't think of a maf. the hesitation, i believe, was not there till i changed the parts - but i can't be 100%.

[Coralon]

I am no mechanic but I would be checking the plug gaps. Under load fuel trims combined with the new MAF may be causing a misfire if one plug is a bit bent. Babies love speed but you must face them forward, in the middle of the back seat so they can truely appreciate what is happening

[h100vw]

I'd try refitting old parts a bit at a time until you work it out. MAF first I guess then maybe do 3 coilpacks then the other 3. Then do the sparkplugs the same way.

Gavin

[Bora _Pies]

I had a similar problem where it would occasionally misfire revving through the gears as well as hard start. I had the oxygen sensor replaced and haven't had any problems since.

Geoff

[Dyldo]

dammit! just plugged my Launch CReader V in and it looks back at me saying "no fault codes". yeah right!!

what should my idle maf amount be (g flow) and peak amount at hard rev? what values should i be looking for in the data stream?

[WhO]

Since you replaced stuff have you reset the ECU / reset the fuel trims? Not sure if it'll help but its worth a shot! A dirty or otherwise non ideal afm would've made the ecu trim to suit and the new afm might be throwing that out as it's no longer suitable for the new maf.

Info about fuel trim's VWVortex.com - Fuel Trim Information

Also resetting your codes (even if there are none) should reset your fuel trims apparently

[Dyldo]

so reset ecu by discon battery for 10mins?

[Dyldo]

hey when i reconnect the battery, i have read that some folk have to realign the TB. is that right? Or does it learn new values?