Coelacanth's '86 GN

Picture of the engine bay before, and after with the intake installed and Axis translator box connected. I just need to solder the brown intake air temperature wire, tuck away the connector, and install the Axis chip. Next up comes the EGR removal.


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Next thing I wanted to do is remove the EGR assembly and unclutter the engine a bit. The new AXiS chip ignores EGR so I could've just capped it off, but I prefer a tidy engine bay as it's easier to keep clean. The one 13mm nut under the round EGR solenoid is difficult to get at until you disconnect the hoses and EGR block first. The EGR block is attached to the rear of the driver's side valve cover with a 10mm nut and also the manifold with a 13mm nut. I got at the manifold nut with a U-joint and some extensions. Disconnect the spark plug wire loom and connector plug from the block, then disconnect the hose from the T-fitting on the firewall and the block & hoses can be pulled aside so you can get at the 13mm nut holding on the solenoid. I then disconnected the hose from the round black & white check valve just ahead of the solenoid and the whole assembly could be removed.




I cleaned up the EGR mounting surface with a razor blade & rubbing alcohol, then installed an EGR block-off plate with black RTV compound. I waited 15 minutes for it to get tacky before bolting it down, and gave it at least 24 hours before starting the car. It didn't appear to be leaking when I ran it a bit last night, so keeping my fingers crossed I'm in not in the "leakers" group. I kept my EGR solenoid hold-down so I can install it if it ever leaks.

Last thing I did was run one of the existing hoses--the long one in the picture above--from the check valve to the T-fitting, and zip-tied it down. What a difference, it looks so much neater. After the pics were taken, I also taped up the open connector and tucked it out of view.

Thanks go to TurboTGuy for hose reconnecting advice. :cool:


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Last night, I took care of a few more "spring cleaning" items and also cut off some rusty chrome exhaust tips. The exhaust pipes were solid down to about the final 3 or 4 inches, where moisture had trapped over the decades where the old tips were bolted on, and the screws attaching the exhaust tips were practically rust-welded on by this point. Cutting off the ends of the pipes using a hacksaw while lying on my back under the car was a bit of a pain, but I got the new tips bolted on...just simple straight slant-cut tips. The new tips don't stick out as much as the old ones did, due to the shortened pipes, which I actually like...more of a stealthy look. I'm not too concerned about the new ones rusting because eventually the exhaust will be all re-done. No point getting too spendy.

I replaced the PCV valve and fuel filter and took the car for the first real test-drive since doing all the intake mods, AXiS interface & chip, and wow...what a difference. It really woke up! I can't remember the last time it chirped the tires from a brakestand, though it always chirped when going into third. I did a minor brakestand, not even building up much boost, and when I gunned it, it broke loose for a good 2 seconds...I actually got off the gas, I was so surprised. Nice!

Next, I need to set IAC and TPS; I wanted to wrap that up last night after the engine warmed up but it started raining so I put it off until later. IAC looks about right already, but TPS needs attention. The low was about right, around 0.43 volts, but the highest it got at WOT was only about 4.31 volts, not in the 4.55 - 4.85 volts range. BLM ranged from 126 to 138, so the low-end reading will need attention too.

Just wondering, if TPS at WOT is low, what is the effect on performance? Reduced performance at WOT, I'd imagine?
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4.31 WOT tps is on the low end but within acceptable range. There is no performance gain by raising it higher. Your BLM's are fine as well. Still within correction range of the ECM.
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Just a minor update: I was able to get my TPS to read 0.43 - 0.45 volts @ idle and 4.55 volts @ WOT. It required a bit of rat-tail file reaming of the oval TPS screw holes. The trick for me was rotating the bottom of the TPS as far forward as it would go, while conversely rotating the top of the TPS just a tad back from full-forward.
I got Phase 1 of my "electronics modernizing" project completed last night. I bought an ALDL 12-pin Bluetooth adapter from previously, but only mounted it temporarily. Plugged into the ALDL port with the thick data cable coiled in an ugly loop at the front of the console and the coiled phone-cable power line plugged into the cigarette lighter. I wanted to conceal it somehow so as not to attract attention from potential window-smashers thinking it's a radar detector or something valuable. It's not worth much but it's definitely not worth a break-in. Also, I didn't want to have to plug into the cigarette lighter every time I drove the car, because the receptacle is powered even with the car off so leaving it plugged in would drain the battery.

I made the following image of the fuse identification, location & amperage after a bunch of research and not finding all 3 bits of info in one place. It helped me find a spot to plug into for ignition-on power. I plugged into the IGN 1 plug to the left of fuse G and ran a wire over to the front of the console.


I found a good spot to conceal the Bluetooth adapter: after removing the ashtray, it would almost fit in the niche beneath. I probably could've shoe-horned it in sideways, but I wanted to be able to see the lights & access the dip switches if necessary, so facing up with the wires down would be perfect. I had to cut a notch in the plastic lip at the bottom, then the adapter slipped right in. I stuck on some foam tape strips to stop it from moving around.



The data & power wires tucked in neatly down along the left side of the shifter bracket and now, all you can see is the ALDL port connector and a bit of the data cable, and nothing plugged into the cigarette lighter. While I had the console plate off, I took the time to clean everything inside & out, in particular the corrugated plastic shifter strip which was full of crud. I also learned why the shift indicator light stopped working sometime last year; the bulb was good, but one of the connector pigtails was torn off. The local parts store wanted $ heard that right, 34 bucks...for a single connector! I saw them on eBay for $5 but I ended up just soldering fresh wires into the connector.

I also bought some blue & green LED bulbs to replace the 194 bulb...need to wait for them to arrive to see which one looks better.



Turned the key to "on" and it comes to life:

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Damn, nice work bro
Thanks Dhos1. I might have to eventually fabricate a piece of black acrylic or Kydex and make a faceplate for the Bluetooth adapter in the ashtray so it looks less ghetto, but the primary goal was to make the device and wiring as hidden as possible. :)
I got a lot more done this season than I expected goal was to do the intake, chip, LS1 MAF & translator, but ended up going beyond that to upgrade the fuel system too, as it's a pretty necessary job--it still has the stock fuel pump. :sick: Added a fuel pressure gauge so I can get some "before" readings before adding a Walbro pump & hotwire kit, and added a battery-to-frame ground wire. I also received this Kirban adjustable fuel pressure regulator from a fellow member. Other than really looking it's age, everything looks intact, especially the all-important diaphragm inside. The only issue other than the dull and lifeless look is the orange O-ring off the side port, which has some nicks on the outer edge. I'll need to replace it, and probably buy a spare, too. If anybody has a few spares they could sell me, please contact me.

lol, i bought the same regulator from a board member and looks just like yours on outside, thinking about painting or coating it.
lol, i bought the same regulator from a board member and looks just like yours on outside, thinking about painting or coating it.
That would definitely make it look better! But since it's aluminum, "that'll buff out". :cool:

I cleaned all the parts with a toothbrush & WD40 to get rid of the grease and some white wax residue, then washed in Dawn dish soap & warm water. I took care of some rusty areas like the spring and steel spring cups with 0000 steel wool. Here's how it looks after a couple hours of elbow-grease and 400-grit wet-sanding. It finally looks like something I'd be proud to put on my car. I'll probably take it up to 800 or 1000-grit. 400-grit gives you a nice satin aluminum look but 800 or 1000 will bring it to an almost-glossy finish. I don't want to give it a mirror-gloss finish though.

You're missing the lock nut that goes on the adjuster.
You're missing the lock nut that goes on the adjuster.
Thanks for the heads up, I'm glad you pointed that out because I would've overlooked it. I'll pick one up at work. Is it just a nut or does it need a spring washer underneath? The one on Kirban's site looks like a normal nut more than a nylon lock-nut.

Here's how it looks after 600- and 1000-grit wet-sanding. (I ran out of 800, d'oh...) I'll finish it off with rubbing compound, that'll hopefully buff out the swirl marks.

Looks like the car is going in the right direction. If it was sluggish there are some mods you can look into in order to wake it up. I would look into a Racetronix upgraded fuel pump and hotwire harness for starters. Change out your fuel filter, and look at getting the car a aftermarket 3" factory style downpipe to eliminate the stock elbow, and a good aftermarket 2.5" dual exhaust, like Pypes. The car will pick up huge power over what you are seeing now. Cosmetically, I would opt for the factory rims with 275 tires on the back for a healthy stance and take that wing off the car.
Thanks Mike, I appreciate the performance tips! I already replaced the fuel filter this spring, and have an upgraded fuel pump and Racetronix hotwire kit ready to be installed. Hopefully will take care of that before the end of the season. I'll get around to exhaust & downpipe next year because it's a lot more expensive. Upgrading to 60# injectors and a corresponding chip are also in the plans. I'd like to go wider with the tires, but the 255's already rub a bit with bigger road bumps & dips, even after I upgraded to variable-rate coil springs in the rear. My rear wheels are 8.5" so they should be able to take 275's.

As for the wing, that's a personal preference with some sentimental value as my father had that wing custom-made when he bought the car, it's based off of a Fiero wing from the same period, and is a one-off. The other reason is because I like it, it makes this GN different from all the others. :cool:
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Here's a little trick I invented to make polishing complex little objects easier...I've restored and polished a lot of vintage RC cars over the years and especially the little aluminum wheels that were corroded and dulled by decades of abuse. Don't throw away your used toothbrush heads...X-Acto-off the bristles and epoxy on some little round polish pads, they're a perfect fit. Then use the charged-up toothbrush to gently polish the aluminum with some high-gloss polishing paste.

The half on the left is wet-sanded up to 1000-grit; the right half was "toothpolished". :D Just don't forget to change brush-heads when it's time to brush your teeth... :eek:

Fuel pressure regulator resto is done, can't wait to put it on the car! Better-than-new, because this is polished much more than the original machined finish. :cool:


Because everyone loves before/after pics: