72T fuel distributor issue, information needed

[Greg D.]

For you experts ;-)

I just got my 72T after over a year of engine rebuild and restoration, so the fuel injection pump sat on a shelf for long time. We can't get it to adjust mid range properly, the screw/allen/whatever won't budge and the mechanic doesn't want to break it... the rack is a little seized up. He got some of the adjusters to adjust, high rpm runs fine and it also idles fine, but gentle throttle mid range is hesitating a little too much...

He says he's seen that happen a million time on old 911s on which they have done long rebuilds where the pump just sat for a while... Also said that on race engines, 4 hours on the dyno "banging the shit out of the engine" generally frees it up, but in my case, he suggested 500-1000 miles of driving to help lubricate things and hopefully restore adjustment...

To that end, he did sometimes about adjusting the fuel distributor timing 3 teeth over to deliver fuel sooner, said it was neither ideal nor a long term solution, but that would not damage anything and provide me with a smoother running car for a few hundred miles required to restore adjustability to the unit... If that fails, the Fuel distributor will have to go get rebuilt for $$$$... Is that common? I read on MFI getting sticky, not so much on them freeing up from driving... maybe you can educate me there, or share some tips that might help speed this up ? Seafoam in the tank anyone ? ;-)

Thanks !

[edmayo]

Could you post some pictures of what will and what won't adjust. I just want to be sure we're talking about the same adjustments here.

[Greg D.]

I really can't, I'm repeating what the mechanic told me. I wouldn't have a clue ;-) I'm disappointed because after a full engine rebuild/tranny/exhaust/body paint, I've got a car that looks like a million bucks but drives somewhat like crap - I've been hearing about how great MFI feels for years but so far I'm not feeling the love ;-) Clearly the fuel distributor is not happy... Can you recommend a place that rebuilds these ? What should I expect to pay for the service ? (it was running fine before sitting for a year so I doubt it's broken, probably needs some lube/adjustments, unfreezing the "rack" - again I'm parroting the mechanic here)

[mike curnow]

I remember reading a factory bulliten back when the MFI cars were new that if replacement pumps were on the stock room shelf for longer than 6 months that they were to be returned to the distribution center,and would be replaced.

[Haasman]

pacific fuel injection service (SF) is highly recommended. These fuel injection pumps are remarkably complex and when right, are phenomenal performing devices. PFIS know their stuff.

Haasman

[Greg D.]

Thank you Haasman, duly noted... That'll definitely be plan B ! I'd like to find an "atlantic" side shop if possible to minimize turn around time, my bad, I should have specified I'm in FL. But if I can't find expertise closer to me, I will use them !
I ran it for an hour today, and it's not too bad, but compared to other similar vintage 911s I've owned, it doesn't feel as "free" as it should yet, not sure how much is the Fuel distributor vs. the new rebuilt engine being tight... It's a bit loud too with a resonance at idle and 2800 rpm (and I thought my 3.0 was loud), I wonder what the deal is with the stock exhaust and new SSis... I guess it's gonna take a while to sort this car out ;-)

[Haasman]

Greg- hang in there, you'll get. There are great resources on this site and the pelican site.

Are you sure of basics- Valves adjusted correctly? You are sure of your cam timing? Distributor timing correctly set at idle and when warm at the high RPM measure? Plugs are spec ones?

The resonance at both idle and 2800 RPM makes me think of loose sheet metal. Can you determine where that is coming from

A rebuilt engine is tight but shouldn't shudder or have unusual resources, it should just feel/sound tight and new.

Is the engine laboring, that is trying to reach a given RPM?

The great thing about 911 engines is that they are simply amazing power plants. They are unbelievable when set correctly. When not set correctly they definitely talk to you.

Keep posting.

Haasman

[Haasman]

Just found this on the pelican site. Thought this might be useful, albeit probably more than one would want to know .... but there is also a list of companies that work on MFI pumps.

Haasman