Last night I was plodding through my log data for the drives and failed warm-starts I made this past weekend, looking for clues or anything that would help shed some light on the problem at hand, and I found something peculiar. Every failed start, and every warm-start that idled a bit then died, all failed with an IAT of -38. Some quick research shows that the LS computer seeing an IAT of -38 means it thinks the sensor is disconnected/unplugged. The sensor was obviously still in place, so I knew I had a potential problem. In the past, the -38 had shown up during idle tuning, but I assumed it was a software glitch as it only showed up for a few frames here and there. The computer thinking that its -38 out when it’s really 95 poses a problem.

I first tested the IAT sensor by using a multimeter and a heat gun. To test the sensor you just need to measure resistance by putting the multimeter on the 2 prongs on the sensor pins, and heat it with a heatgun. An ambient temperature of 80-85ish will yield a resistance of 2.15 or so. As the sensor gets hotter the resistance drops. I was looking for that ‘-38′ glitch to occur (ie: random jumps in resistance measurements). It never did. My sensor was working flawlessly. Next, I moved on to hooking up the laptop and scanner and monitoring the IAT while I wiggled wires around. I was not confident at all that this would yield anything as the problems only occurred with a warm engine, but…you never know. Within 20 seconds I found the wiring fault that was causing my IAT readings to bottom-out. The IAT sensor signal wire from the engine harness was damaged in the plug that connects to the MAF/IAT sensor harness. I was able to duplicate the -38 reading at will, so I went to the local Chevy dealer and got a new pigtail ordered. In the meantime, being impatient and having hoped to get the car out for its first ‘public appearance’, I snipped the IAT sensor, surgically removed the bad wire segment from the connector pin, soldered a new wire on, put the connector plug back together, spliced it in. Viola – 100% working IAT sensor. This means it’s time to drive and see if anything has changed.

My first drive on trafficked roads took me to my first stop light, introducing the GTM to a busy intersection and testing my nerves hoping it wouldn’t stall out of its idle with 10 cars around it. All was fine, though, and I made it a few miles down the highway to the gas station for the GTM’s first gas station fill-up.  I remember others stating how slowly you have to fill up the tanks, so I took 10 minutes to add 6 gallons of fuel, and explain to another customer why the GTM appeared to not have a steering wheel. Most of the Kwik Trip work staff had vacated the building at this point and were all standing 20 feet away watching and grinning. Wow, really? Perfect time to see if I fixed the warm-start issue by repairing the IAT wiring. No pressure. The GTM fired up, I exhaled, and got out of there. Another stop light  and I hit the highway, then some back roads, which brought me back around and eventually home. Everything ran well, temps stayed below 200, stability was great at speed. Bump steer could use some tweaking, and I learned quickly how sensitive the manual steering is on this beast. I was pleased to find that Slayer could still overpower the 408ci LS2’s drone, via the Blaupunkt thin series components. Initially I reported I hated the rear view mirror; it’s not so bad now that I’m used to the vantage point of the driver’s seat, and it still has its uses, even if I can only see the lower half of the bumper of any vehicle right behind me.

It was my father-in-law’s birthday today, so I invited him out on the second drive, now that I was somewhat confident handling the GTM. The GTM started right up, so it seems the warm-start issue was nailed. 20 miles later after visiting my favorite WOT playground and slow city driving we returned safely. Some choice descriptions of the GTM experience from my father-in-law included ‘that scared the shit out of me’ , ‘that thing is terrifying’, and ‘my legs are still shaking’. His constant grin was the best feedback, though. Good times, and I can say the GTM gets to triple digits awfully fast.

Now the only thing I am really concerned with fixing is the threat of stalling after quick stoppages.  If I stop the GTM quickly the engine comes awfully close to stalling out. Not a huge issue, but it’s not something I want to be worried about every time I come to a stop anywhere – especially in traffic.  I am also researching cameras for shooting in-car video, so hopefully I will get some decent drives to post soon.

Got the new steering wheel today so I installed that.  The outer portion of the quick disconnect bolts to the back of the steering wheel, horn is connected to the quick disconnect wiring and pushed/inserted into the quick disconnect piece. I had some troubles getting the quick disconnect to work at first – I could not lock the wheel into place. I realized that one of the bolts that holds the steering wheel onto the disconnect piece was rubbing on the inside of the main disconnect hub so I had to grind that down a bit with a file.  Now it locks/unlocks as it should.

This setup is very nice. The steering wheel can be removed or connected in seconds, and getting in and out of the car is much, much easier. This steering wheel allows for a great view of the gauges, as it follows the curvature of the dash nearly perfectly.

I haven’t posted in a few days, but I’ve been keeping busy with small tasks here and there:

- wired up the rear view mirror
- fine tuned the intake tubing positions so that they are ready for mounting when I get the intake duct mesh silicone’d in
- formed the exhaust and intake duct mesh pieces; dropped them off for powder coat
- picked up louvers from powder coating, will install on diffuser soon
- prepped diffuser by drilling more rivnut/bolt attachment points to the body to make it sturdier
- Josh finished the exhaust mount, waiting on a new mandrel to install bigger rivnuts to mount it and complete the exhaust
- making progress on getting the motor running properly: installed a Nick Williams 96mm tb, and am currently working on tuning it with HP Tuners. Motor runs if I stay on the throttle at 1000rpm or higher, but it dies if I let off.

At this point the interior is complete, and all that remains is buttoning up the exhaust and intake, creating a heat barrier between the two, installing the exhaust and intake mesh, and installing the louvers and diffuser.  I also need to get the motor to idle, too.

Instead of using the FFR provided rear-view mirror I decided to use the Corvette rear-view since it has driver and passenger map lights built in. To utilize this lighting, I had to run a ground wire, and the white ‘dome light’ wire from the Painless fusebox up to the center of the windshield where the mirror will be. Not an easy task with the roll-bar padding/fabric in place! I ended up snaking a coat hanger down the pillar under the fabric with a hook bent on the end. Once I got it down behind the dash I was able to hook the mirror wires and pull them up the pillar. I then pushed the wires on top of the front halo bar (sandwiched between the roof and halo bar) and ran them to the center of the windshield. Tested the mirror wiring to ensure it will work – good.

Since my radio has a really great iPhone interface, I mounted a nice iPhone holster on the driver side for easy access. This holster is actually designed to mount on vents, but I just unscrewed and removed the mounting mechanism it uses and affixed it to the tunnel vinyl with heavy-duty double-sided tape. Perfect setup.

Lastly, for some reason FFR leaves a nice ugly gap between the engine cover and dash console. They don’t tell you to cover it, nor do they supply a piece to cover this gap. To fix this a cover has to be made. I cut a piece of cardboard and bent it to fit over the console and engine cover edges to get a basic measurement of the aluminum piece I would need. I have a handful of aluminum scrap left over from the build so I cut a piece to match the cardboard and bent it to match the tunnel sides. 1/4″ holes were drilled on each side, and then the tunnel frame holes were drilled out and rivnuts were installed. I trimmed the aluminum piece a bit more, then covered the top with some 1/4″ Dynamat for padding.  Left over suede from the build was used to cover it. Bolted back in place, the cover actually makes for a nice elbow rest since it’s padded fairly well. Not bad.

Finally, the interior is nearly complete. With the driver dash pod re-glued and ready for install I cleaned up some wiring that will be under the dash, wired the transmission oil cooler LED indicator, then installed the pod. Before riveting in place I attached the air duct and dash switches for camera and lights. Dash pod was then riveted into place, and then the gauge face was plugged in and screwed down.  I then threw on the steering column cover and screwed that in place.

Over the last couple days I have taken care of a handful of small tasks.

The driver dash pod vinyl had to be re-glued after pulling it back to trim the fiber glass back. Got that taken care of. The pod is ready for reinstall once I get the wiring straightened out for the dash.

Organized and loomed up the reverse/backup switch wiring and license plate LED light wiring. I used standard 14-16ga bullet connectors for the reverse switch, but I used a small screwdriver to widen out the sides of the connector so it created a snug fit with the Porsche reverse switch. Tested the reverse lights and backup camera auto-activation – good to go.

Soldered the turn signals and high-beam LED indicators on the gauge face. All the gauge face wiring runs through a pair of weatherpack connectors now for easy plug-n-play. I wired the speedo and tach up as well. The speedo and tach are a bit trickier as you need to use a resistor for each. In a nutshell, you need to place a 1/4 or 1/2watt resistor on the +12v power wire that the tach and speedo use. After the resistor the 12v wire Y’s off – one wire goes to the gauge, the other goes to the computer. With the gauge face all wired up I plugged in the weatherpacks and gave the gauge face a quick test. Looks like everything is a go. I need one more weatherpack connector pin for one of the connectors – after that is in I can install the dash pod. I will also be installing a trans oil cooler LED that will illuminate when the oil cooler is on, so I extended the wires for that so they are easy to solder to the LED when that arrives. Picked up a few switches for interior lighting and front-camera/video activation (so no need to pull the e-brake to allow for video viewing). These will probably go in the driver dash pod on the left side.

I also trimmed the hood release mounting plate so it looked cleaner than just a big clunky square.

Today I finished up bolting the passenger seat in, and then wired up the license plate LED lights. The seat was a chore, as it took forever to get the bolts to line up perfectly with the rivnuts at the front of the seat. Also, since rivnuts and I get along so well, I ended up having to re-tap the rivnuts at one point since they got scuffed up trying to line up the bolts blindly. All good though, as the passenger seat is rock solid.

Afterwards, I soldered up the LED wires and connected them to some quick disconnect plugs and spliced those into the taillight wiring.

After a long battle, the hazards finally gave in and started working. The proper wiring for the hazards is:

1. Painless harness wire #951 (brown) to black wire on FFR supplied relay
2. Pin A on the turn signal harness connects to the green wire on the relay
3. Red relay wire connects to Pin 2 on the console switch for the hazards
4. White relay wire is grounded
5. Pin 1 on the console switch for the hazards takes any +12v hot wire

Today’s project was the speaker installation. I scoured the web for the thinnest 6.5″ woofer I could find for the doors since Ken (StreetRodPainter) modified the door frames and moved them inwards an inch. I ended up going with the Blaupunkt Thin Series 6.5″ woofers with separate tweets and crossovers. Once I cut the speaker holes I was immensely relieved to find that they just fit. Anything deeper would have been trouble. I decided to mount the tweets above the door handles a couple inches, as this is the best spot in the doors to place them – acoustically, and space-wise. The tweet mounts require a 1.75″ hole, so I drilled those out with a hole saw and mounted the tweets. Nice and easy.  I mounted the crossovers on the bottom edge of the door with some double-sided adhesive tape. I then wired up the speakers on the passenger side first and went to test them, but was distraught to hear garbled and static-filled metal.  Apparently the speaker cable I ran last spring was bad. Luckily, all I had to do was tape some new speaker cable to the old stuff, and pull it out through the door and it routed the new stuff into place. Re-wired the passenger speakers and gave them a quick test – Perfect!

With the speakers in place I set the door liners back in and drilled out some more rivnuts into the door frame to make the liner more ’solid’ feeling. With the rivnuts added I finished the wiring on the driver’s side, then attached the liners. The black flanged button head bolts I received from McMaster-Carr look great.

Sat in the car a bit and listened to some tunes – I’m pretty pleased with this setup.

I’ve delayed the fog lights installation until now because I simply did not know what to do with the lights provided by Factory Five. They have a funky bracket on the top, and do not have a rear post that mounts through a hole in the fog light recess as shown in the build manual. FFR advised me to ‘just flip the bracket back and attach through that’, however the bracket is positioned so that it is impossible to center the light, plus it would stick out way too far. No thanks.

As a solution I did the following:
1. Remove the brackets, silicone the holes left from the bracket screws.
2. Remove the wire grommet
3. Drill a 3/8″ hole next to the wire grommet hole, recess the edges a bit with a dremel tool, and push the grommet/wires through that new hole.
4. Push a long bolt w/ washer (I used a 1/4-20)  through the former wire grommet hole and secure it on the back of the housing with a jam nut. The hole is centered perfectly so this bolt acts as a post to mount the light through the recess with.
5. Drill a 1/4″ hole centered in the fog light recess. Drill a smaller hole next to it for the wires.
6. Run the wires through, push the fog light into the recess, secure with a lock nut and washer.

Having to prep the lights is a pain, but it works. After the lights were installed I attached and loomed their wiring up.

After all that, I took the clamps off the side louvers since the adhesive has cured – solid as a rock and they look great. Silicone’d the rear mesh pieces into place.