MFI question

[Dougieboy1]

Car has run fine for 4 years.

Developed a fluff pulling through 1500 rpm from a standstill. Figured it was a fuel mixture/MFI issue.

Sent to garage, who fixed it, said dizzy was a bit loose and it needed retiming..Brought it home, wasnt a 100% happy but thought i can live with it. Car sat for 2 months with no use. When the rain subsided and i went to start it, it wouldnt start. Turned over a lot, odd splutter but wouldnt start.

Garage came out, cleaned plugs and it started. Took it back to theirs for some attention.

Have told me the MFI pump is 240 degrees out of alignment......

I can see how this would prevent it starting as presumably at least some of the cylinders wouldnt be getting fuel at the right time. What i cant understand is that for the previous 4 years until it started fluffing, it ran fine. Maybe a bit rich but i went to le mans and back in it in 2023 and it has been driven regularly throughout the period all with no real issue.....

Any thoughts?

[hot66]

do the garage know about MFI as a start ?

Pump being out can happen if the belt has slipped / jumped . or someone has messed with it and re installed it without checking its timing

https://forums.pelicanparts.com/porsche ... shaft.html

That might be why it suddenly started running bad.

But with an MFI motor the mixture of teh pump etc isn't something that usually changes over night ... its going to be either timing, or throttle bodies out of balance etc etc

has anyone checked the throttle linkages haven't moved, are the throttle bodies all balanced ( check airflow into each one )

[Dougieboy1]

yes, they do know about MFI.

The confusing thing is no one has touched it since 2019 when it went back on the road. The belt could have slipped i guess but the pump itself has not been touched unless the garage messed with it when trying to address the 1500 rev fluff. It is all very puzzling since it ran fine for 4 years, then the fluff, fluff 'addressed' and now it wont start.

Suggests to me that the defluffing was the cause.....