9126001675 3.0L coupe - NC Ownership & Updates

[ToySnakePMC]

Syltech combination sensor that provides oil temperature and pressure to two different terminals on the ECM. 4 wires -- the two just mentioned, 5V from the ECM, and a sensor ground wire.



I discovered this sensor by watching Tom on his YouTube channel - Ah Garage Time and his recent EFI build. The hard part was finding a M18 bushing with 1/8" female NPT threads, lol. A Subie specialist was able to obtain one from Killer B. Apparently Killer B is a Subie specialist shop as well based in Virginia. That took about 4 weeks to get this darn piece on the brown truck.

[ToySnakePMC]

And final update for the day while I scan through some recent photos... Since my fuel pump had no relay wired in until now, I went with a Resto Design 30 amp round red relay that they've recently introduced to the market. It's a modern small relay under the red anodized cover that somewhat mimics the original plastic cover (but better!). I've ready too many stories about bad round relays so I think i have a nice solution to eliminating a possible issue down the road.

[ToySnakePMC]

Weekend Update: After a few weeks of work-related travel, I had a free afternoon to insert drivetrain into square hole.

First, here’s a behind the scene look at the “back” of the engine with 4mm plastic vacuum piping, and a few short harnesses laying around. Vacuum piping includes one line off the intake manifold to ECM’s own MAP vacuum port – and it’s tee’d off to fuel pressure regulator as well. Other vacuum line from manifold has the white check valve and feeds vacuum to resonance valve/ flap and vacuum reservoir near firewall.



Line it all up and drop the car down slowly.





Hmm. I thought I had a problem with the rear cross bar after loosely bolting in the transmission crossmember. Both sides here are about ¾” back of the rear mount bolt. Texted a pro, and he assured me that there’s nothing wrong and the crossbar has some flexibility. He was right! Worry session quickly went away!





Filter assembly fits. I used an Amazon 3.25” x 3.5” reducing silicone elbow with constant torque clamps and a plump Green Filter.com from the Commonwealth of PA. Seems like a nice piece. And the fit was perfect - no trimming & filter just touches firewall insulation to the top.



Fuel Lines. I selected Red Horse Performance 6AN fittings and black coated st/st PTFE hose to plumb this thing up. I am HOPEFUL that my first time hose building will prove successful. I purchased some pressure test fittings to fill with air and dunk in a bucket of water. Several fittings needed a bit more tightening and one hose assembly was a complete failure with bad assembly. Luckily, I bought additional hose length and assortment of fittings so I could overcome this issue that I sorta expected from the beginning. You get a feel for building these and can sense when your hose assembly is “right”. When you do one that goes wrong, you can tell. Air bubbles in bucket confirm you suspicions!





This one is coming off the backside of RH fuel rail and pressure gauge to Adapt Motorsport adjustable fuel pressure regulator using a 60 degree and a straight fitting.

[ToySnakePMC]

Been working on this EFI project since…., oh – about a year now! That includes when I started ordering conversion parts/ pieces and cleaning up the 964 alum intake halves.

Things are really coming together now. I’ve scaled back work travel for the Holidays and can spend late afternoons and evenings in the shop which is a big plus. Here’s what has been happening in southern Wake County:

Upon learning that my LH rear floor mat would not fit due to ECM bolted thru the floor (but on raised platform, if you will). That was an unforced error – but nothing that a good blood orange IPA in my left hand couldn’t resolve! So, I removed the 2 offending small diameter bolts, utilized some “S” metal (HVAC galvanized metal strip for two adjoining sheet metal panels) by bending into a Z so it can attach to the rear of my aftermarket seat bracket. Now the whole contraption is off the floor and floor mat can be slid into place. Bracket consists of alum street sign (not stolen) and cutting board.







Here’s a shot of finished wiring to DBW pedal and wiring to Fuel pump relay. Cool thing is that the wrapped wiring just sits under front floor mat. Didn’t have to pull up any new carpet and not disturb the industrial strength glue that Sonderwerks used with its installation. Fuel pump trigger wire (switched ground) continues under the dash and exits into the frunk at far passenger side as I could use a somewhat hidden rubber grommet for easy peasy access.



At the firewall, I needed to weatherproof my rear, lower LH opening. I stuffed some closed cell insulation pieces around my two wires as the finished interior piece has some open area within itself. I then cut two pieces of alum trim (think aluminum window trim for houses) with RTV sealant around the perimeter. Should be fine until the car sits in 3’ of water as these cabins are not water proof at transmission!



Early Fall, I decided to proceed with rebuilding my CV axles. With this ’76 having a 1982 drivetrain, I ordered 2 new CV joints (think larger 108mm version) to replace two original that showed slight galling in one or two spots. Well, that didn’t work – as my car is still utilizing the smaller 100mm CV joints left over from the 912E days. Lol.

I guess the NY shop that did this swap 20 years ago decided to just swap the smaller flanges over to the 915 transaxle. Anyhoo, I just cleaned mine up really well and repacked the 4 CV joints with their original ball bearings. My original boots are in great shape and got a good soaking of 303 Protectant. I swapped LH and RH axles around to put the forces onto the lesser used side of the CV joints. All new Bel Metric hardware and Schnorr washers. Pro Tip: Replacement 8mm Allen head bolts need to be no more than 50mm length! Ask me how 55mm length bolts did going into wheel hub ---- Not too good! When fully torqued, the rear wheel would not roll – at all. 2nd set of hardware ordered quickly thereafter.

Also, axles were date stamped something like 4/76. I have since learned all about 911 CV axles!





Working with Sports Purpose Garage in Raleigh area on tuning the EFI and assistance with setting up the ECU Master Black, I discovered that I needed to move my oil temp wire to the Coolant Temp input on the ECM. Luckily for me, those pin locations were in the same harness plug and only 2 pins apart. De-pinned and reinserted.



And as I get ready for the initial START UP, I installed Dansk muffler and rear valance. This was also a good time to torque down new CV bolts at rear hubs.





Next chapter here we will talk about Initial START UP !! This just occurred, and boy.., is there some more self-inflicted drama to talk about. I’m still soaking in all the highs and lows from this event.

[GothingNC]

Awesome work !!
Thanks for the updates !

[ToySnakePMC]

Quick update --

Single DBW Throttle Body - EFI project reached a fresh milestone today. Erik of Sports Purpose Garage spent the better part of the day installing a tune into my ECU Master Black while also getting the DBW pedal and Bosch 74mm throttle body synched up & calibrated. The black magic that I still cannot wrap my head around is the synching up of the hall-type cam & crank sensors. His adjustable Snap On timing light verified what he needed to see and lock in the ECM. Good stuff for sure!
Car cranked up pretty quickly once the above were dialed in.





He did show up in his client’s 930 Safari build that’s been underway for the past 8 or 9 months. Not sure these photos capture the color – but Moonstone is just wicked and perfect for such a unique car. I don’t know the specs, but you can definitely hear it coming and going as the turbo whistles loudly like a modified F350 Super Duty at a stop light.





Late this afternoon, I decided to hit the street and cruised some wide-open country roads around me in the ’76 coupe. I set the laptop / Black ECM on for AutoTune and started a data log file. After 15 minutes or so, I made it back successfully to the shop. Let me tell you, this car sounds and feels great right now!! I definitely have a lot to learn and tweak going forward, but no stumbling, nothing odd happening that I’m aware of. It may be running rich. And if I was successful turning on (and subsequently saving) the autotune and log file, then I have something to review and play around with. My clutch cable needs adjusting – as I now have it too close to the pedal board. And the DBW pedal needs adjusting so it’s less linier and mimics the analog pedal I’m used to.

I did toss on these 993 brake cooling scoops that I purchased from our host about 3 or 4 years ago and had never installed. I remember reading about them here on the forum. They simply tuck in nicely against the caliper and rotor backing plate. We shall see … I’ve never run out of brakes on my mountain weekend rallies in the past, and I’d guess the more fresh cool air the better.








Good times – Hope to slap more miles on this on-going project in 1H2025!

[GothingNC]

Woo Hoo !

Glad you got it back on the road !!
Erik is a Master with that ECU stuff !

[ducatiroger]

Beautifully documented build Patrick!

Been thinking about a 964 intake conversion and seeing the steps required really helps understand what all is involved. Slowly realizing that for me focusing on the CIS is the better short term plan.

One day I hope to have patience and skill that you are exhibiting. Hope you enjoy the updated fuel delivery system. Fantastic work!

[Joesmallwood]

Missed this update. This is coming along nicely!! So much fun to take on these style projects!

[ToySnakePMC]

Well……, Decisions were made in Feb 2025. Ever since we got it running in late December, I’ve been suffering from excessive blue smoke out of the tailpipe. I also had a few new leaks under the engine, but I could address those. I was hopeful that I had a ring, perhaps, that needed to be unstuck so I did some aggressive driving, several times, after warm up with hard acceleration and hard de-acceleration just wishing that my blue smoke situation would magically disappear. Did. Not. Happen. Unfortunately.

I took as much outside recommendations & consultations as possible. Some were long distance Pelicans – most were local air-cooled Raleigh-area folks. One of those that I visited with the smoking car is a local celeb in my eyes. He knows air-cooled engines, has decades of experience, and has a knowledge base rooted in practical experience with these motors. He said I have a certain case of burned-up valve guides. Made me sad that I knew I would need to remove the engine. But it also brought out some relief that I now knew we could make a plan to split the case, inspect the bearings, and start from scratch to build a solid motor to take me to my final sunset, lol!

He advised against just a top-end as I have no real knowledge of what’s been done to this 3.0L. I only had verbal confirmation that this motor had a top-end done 15-18 years ago – but no receipts for solid proof.

So, my local engine builder (who will remain nameless unless he suggests it’s okay to share his name here) requested that I pull the motor, take it down to a long block, and get ready to drop it off at his shop in the next few weeks! I’m quite excited to have him do the work and get the party started sooner than later. It looks like I’ll miss out on some upcoming mtn rallies in late Spring/ early Summer – maybe. But, I don’t want to rush him for the wrong reasons. So there is that.



Dressed down and rolling on furniture dollies



Using the above steel I-beam and two chain hoists, I can yank off the transmission.



Located a Flyin Miata crankshaft holder tool to secure my flywheel and remove the nine 12mm triple square bolts and three pilot bearing bolts.



She is now ready to be loaded in the back of the pickup for an hour journey to engine builder. As soon as he says the word GO, I’m ready!

[mikedsilva]

Originally Posted by ToySnakePMC

Late this afternoon, I decided to hit the street and cruised some wide-open country roads around me in the ’76 coupe. I set the laptop / Black ECM on for AutoTune and started a data log file. After 15 minutes or so, I made it back successfully to the shop. Let me tell you, this car sounds and feels great right now!! I definitely have a lot to learn and tweak going forward, but no stumbling, nothing odd happening that I’m aware of.

Cool thread; not sure how i missed it.
Curious to learn more about the autotune function ; i have it in my car (same ecu) but after all this time not sure I'm using it right!

I've been pulling over and then opening the autotune function and then making adjustments. But I have a feeling there is a way to set it so that the autotune makes changes on the fly... ie while you're driving.. is that right?

looking forward to more updates on your engine build.

[ToySnakePMC]

Originally Posted by mikedsilva

Cool thread; not sure how i missed it.
Curious to learn more about the autotune function ; i have it in my car (same ecu) but after all this time not sure I'm using it right!

I've been pulling over and then opening the autotune function and then making adjustments. But I have a feeling there is a way to set it so that the autotune makes changes on the fly... ie while you're driving.. is that right?

looking forward to more updates on your engine build.

Thanks Mike! I’m a loyal fan of your YouTube channel & your posts and comments on this forum. I like how you present info engine builds and tackle questions like effects of sealant on certain flanges or surfaces versus none. Good stuff. Your work is very sanitary too!

Honestly, I have to learn more about tuning my engine. Just rebuilt - but not first start as of yet. I’ve watched Erik turn on autotune and let it run for 30 min or so. Save it, perhaps? And then respond to a pop up or similar that asks do you want to apply 100% or 50% of the corrections.

Joe Smallwood in southern Indiana and Erik Lind of Sports Purpose Garage in Wake Forest NC both know how to get the most out of autotune features with the ECU Master Black. You may have talked or communicated with Erik in the past. I’m hopeful that I can lean on these two for technique and helpful tips.
Thank you for reading thru some of this...! Patrick