Transmission Vacuum Line (1of 2) Connection

2Quick4u928 · 10-15-2009, 04:40 AM

Hey guys, am at a stands still, have finally completed my motor installation (88' 32v Automatic), after many grueling hours of lack of motivation, work, and family matters...Only need 1 vacuum line connection for which I cannot locate.
There is 2 lines coming up from the bell housing area, is not the large line but the smallest black vaccum line. Is very similar to the ones connecting to the 5-way T connector just aft of the Intake/fuel regulator. Was thinking there may be a connector hiding behind the MAF, but nada. No luck with the PET, nor the internet how-to forums I have saved, and lastly Reeinlist. Any assistance would be very helpful especially a foto, thank yo in advance!!

MPDano · MPDano's Garage

Can't say much for the later cars, but my OB Auto only has one vac line to the Tranny, which connects to the front of the Spider.

Mrmerlin · 10-15-2009, 07:31 AM

the 2 black lines would be one for the transmission modulator and the other is for the HVAC feed, it goes to the bottom of the HVAC system to power all of the vacuum pots.
There may also be black lines running for the fuel dampers (2) and the FPR (1) on the RR fuel rail.
And lastly the flappy needs vacuum from the same source as the HVAC feed ( the vacuum reservoir)

2Quick4u928 · 10-15-2009, 07:39 AM

Guess I need to do a spell check before submission haha...thanks, will have a look again but it "appears" everything is connected. I double checked this 5-way vacuum connector but nothing where this small ID line would plug into, am thinking I may be missing one connector somewhere under the intake/fwd of the MAF....will look up the HVAC to see where all connections are. thanks

2Quick4u928 · 10-16-2009, 04:03 PM

Unplugged the MAF & the 5-way vacuum connector to go on a search mission...managed to get my hand & some light in there but still not seeing the obvious..... The transmission vacuum line is relatively short so know there much be a connector under or around the MAF somewhere but...

2Quick4u928 · 06:46 AM

In a hopeful conclusion to my delima this past weekend, many thanks goes out to the posters here, and especially Adrian (928Org.uk), John Speake; (Porsche Electronics Specialist - JDSPorsche)
UK 01223 709915
INT 44 1223 709915

who provided me with the Highly detailed Dwayne's Garage for this great how-to post on an Intake Refresh; Executive Summary:

Was able to conclude with the resources above, the 2 motors I swapped (88' Auto removed, 87' Manual installed), the 88' should have had a 7-Way vacuum connector just rear of the MAF, the 87' a 5-Way but both motors had the later. The R/H Air Pump Diverter Valve (According to Dwayne's article above), should have had a main vacuum feed line from the throttle body... with the main 5-Way (my case) vacuum feed line which was correct was routed correctly on the 88' motor I pulled. Instead this diverter valve had a vacuum line from the 5-way (87' installed motor now) going to it, also the RT the Fuel Pressure Regulator (FPR), Left bank was; FP Damper & Front FPD. Happily since I installed a "non-air pump" option Pksn'r I capped off the line on the Diverter Valved mentioned above and replaced with the transmission vacuum line.

Hope this assists anyone in the near future.
Chao guys!