FRESH BUILD - after a few miles became hard to get into gear

Hello friends,

After a few years of work my son and I (this is his car) finally have his 1986 N/A 944 running with a freshly rebuilt 5.7 in it.  We have a few bugs, but the biggest just started on our last test drive.   We probably have a total of about 5 miles on the build so far and the car always shifted very well with the exception of grinding into reverse.  Now it is really struggling to get into gear, with first gear being the hardest.  

Some info on the car:
It is running TPC everything.   I have a C5 2-pce bellhousing, SPEC Stage 1 clutch/flywheel and pressure plate. Tilton 7/8 master cylinder also supplied by TPC.  Hydraulic throwout bearing from TPC.   I measured the tolerances between the T/O bearing and clutch fins and I recall it being within spec (this was over a year ago) so I did not add any shims.  I have adjusted and slop out of the clutch pedal at the clevis so it starts engaging the pushrod of the clutch master cylinder as soon as the clutch is engaged.   I have bled the system using a pneumatic brake bleeding technique which uses a vacuum to suck fluid through the system.   I cycled more the a full 32fl/oz bottle of DOT4 brake fluid through so I feel like it should be bled well.  

Is there anything else you would suggest to assure it is indeed bled properly?  I plan to get the car in the air and remove the bottom of my bellhousing to inspect the T/O bearing operation.   Does anyone know the amount of throw is needed to fully engage the SPEC stage 1 clutch?   Does anyone have any other suggestions on things I should look for or measure to determine if the T/O bearing is working properly?  

One other factor, we are still running the N/A transaxle (for now, it has 91k miles on it).   When the car was first started, I had some issues with proper MAP sensor readings and it would 'buck' back and forth at low RPMS .  I eventually fixed this by using the internal MAP sensor on my Holley Terminator ECU.   Right before I experienced this new issue with the car not going into gear, I was playing with the MAP sensor and the car started doing this 'bucking' again.   It actually caused the car to do mini-burnouts a few times.   Is there a chance I hurt the N/A trans when this happened and that is why I am having a hard time getting into gears?

Any input would be greatly appreciated.  My son is so exciting to drive this car, but now so disappointed we are having negative progression.   I'm ready to drive this thing off a cliff!   I need help for my own sanity

Lowform & son...

Your gremlin is a challenging one as it seems you did everything right.

I'm at a similar place with my build and have used the exact same TPC components.

It definitely sounds like your clutch is not fully disengaging.  When I had this issue, it was indeed air in the hydraulic line... and yes it was after multiple manual bleed attempts.  Nothing seemed to work.

I know you used a power bleeder, and I'm not familiar with that specific procedure, but it only takes one bubble of air to negatively impact clutch performance. The solution to my gremlin involved discovery of the tiny designated reservoir in the brake master reservoir at the very front DS corner. This partition has a very small capacity and will empty out with one manual bleed effort,  then every time after that, air will be introduced into the line.  This "clutch reservoir" only fills when the brake reservoir is nearly full. 

Something worth checking.

Below are some links to my experience from my Project Post Index:

The link below is relative to the reservoir.
12 - [You must be registered and logged in to see this link.]

This link is an update addressing the clutch pedal travel:
[You must be registered and logged in to see this link.]


Also... I did some extensive testing and measuring of clutch/throw-out bearing operations to see if i needed the spacer plate or not.

Check that out here:
[You must be registered and logged in to see this link.]

I hope this helps!!