Coelacanth's '86 GN

Coelacanth

Active Member
Jul 7, 2014
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Alberta, Canada
Updated pics of the engine bay, September 2016, after installing the polished Kirban fuel pressure regulator:

FPRegulator_Installed.JPG EngineBay_Sep2016.JPG

A couple pics of ALDLdroid running and my Samsung Galaxy S2 tablet mounted, with garage lights on and off:

ALDLdroid_Tablet1.JPG ALDLdroid_Tablet2.JPG
 

Coelacanth

Active Member
Jul 7, 2014
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Some people have commented on the wing, here are some better pictures of it. The contours match the deck-lid lines perfectly, and the width matches the body width. The angle might even help with downforce, but I wouldn't know...the wing was added for looks, not performance. As I mentioned previously, my father had the wing custom-made when he bought the car. I'm pretty sure it's a modded Pontiac Fiero wing from the same approximate year...maybe it was widened to match the GN, I don't have Fiero wing specs to know for sure what was modded...but my dad said it was quite expensive back in the day and it was a one-off. It's mounted with 4 big-ass bolts & washers.

Wing2.JPG


Wing1.JPG
 

ttypewhite

Well-Known Member
Oct 1, 2001
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If you like the wing, that's all that matters.... looks like the car is in better hands now that it ever was before. Keep up the good work.
If you would like to see what it would look like without the wing, here is a little Photoshop magic for ya.
wing_or_no_wing.jpg
 
Sep 25, 2016
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Great write-up. Looks like a high option car with C68, passengers remote mirror etc. Really like the ALDL android! Will have to look into one. Seems I was not the only one who did a good job of convincing their dad to buy one of these new :) Dad's 81 now - still won't sell it to me! Had to get my own 15yrs back.
 

Coelacanth

Active Member
Jul 7, 2014
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Alberta, Canada
Thanks for the pic, Mike, but I don't need Photoshop for that...I just need to look at any other GN to know what it looks like without a wing. ;) I'm more into being an individual than fitting in with the crowd. :blackalien: (Couldn't have picked a better smiley...)
 
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ttypewhite

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Oct 1, 2001
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Another good thing to check while your under the hood is the TPS to make sure everything is in range.
  1. Hook up your scan tool/volt meter where you can see the readings clearly from under the hood (alternatively, back probe the TPS blue wire with the positive lead of the meter and ground the meter's negative lead to the chassis or battery)

  2. Turn the key ON and leave the engine OFF

  3. Loosen the two screws on the side of the sensor (passenger side of the throttle body) enough to allow you to move the sensor in the "moon shaped" grooves.
  4. Grab the "nose" of the sensor (where the wires plug in) and pull the sensor as far forward as possible and snug the screws enough that it holds the sensor in place (but can still be moved if nudged)

  5. Check the idle reading and tap the nose of the sensor up or down until you get an idle reading of between 0.40 and 0.46 volts. Anything above about 0.5 volts will not be seen as "idle" by the ECM and can cause driveability problems.

  6. Snug the screws down tight enough that the sensor doesn't move and have someone floor the throttle (make sure that the floor mat is out of the car...)

  7. Check the reading and adjust until the sensor reads between 4.55 volts and 4.85 volts. The intent is to make sure that the reading is high enough that the ECM reads full WOT. The actual number doesn't really matter as long as it is with the range.

  8. Recheck the idle reading to make sure that it hasn't changed. This can be a bit of a balancing act and require some very small adjustments and several iterations before both the high and low settings are where you want them to be.
 

Coelacanth

Active Member
Jul 7, 2014
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Alberta, Canada
Thanks Mike. With the engine warm, my idle TPS is at 0.45 volts, and it's 4.65 volts at WOT. When I'm stationary, in drive, engine warm, the car idles at between 700 - 750 rpm. Is all that pretty much where it needs to be? I have enough reference material from GNTType.org, TurboBuicks.com, VortexBuicks.com and here to fill a 1" binder already. :)
 

Coelacanth

Active Member
Jul 7, 2014
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Alberta, Canada
This summer was a write-off, weather-wise. It practically rained every day for 2.5 months. When your GN has T-roof weatherstripping that leaks and needs to be replaced, it means your car stays in the garage. I think I've had it out only twice all summer!

I didn't have any performance upgrades planned for this season, but the transmission needed attention. The last season, it started having a late 2nd-to-3rd shift under hard acceleration, like it was really reluctant to make that head-snapping, tire-chirping shift that it always used to make. At the very least, it was time to change the tranny fluid & filter, but while I was at it, I wanted to properly check the TV cable adjustment at the tranny and might as well replace the TV plunger spring and TCC solenoid while I was at it, they're both inexpensive parts to replace. My car wasn't exhibiting the downshift issues caused by a failing TCC solenoid, but I figured I'd replace it anyway.

After dropping the pan, I was happy to see the fluid was nice, clear red, with no metal bits anywhere...and was surprised to find a round magnet in the pan that at first I thought, "Oh shit, how did that washer fall out of the transmission?" :censored: There wasn't even any metal stuck to the magnet, just a bit of very fine sludge.

I read that the plunger spring weakens after thousands of depressions, which is why I wanted to replace it. I was still quite surprised at the difference between a newer, stronger Sonnax spring and the old original spring I pulled out. The springs is supposed to be about 1.90 inches, and the new Sonnax spring is exactly that. The spring I pulled out--not so much. At first, I thought I must've got the wrong replacement spring, but closer inspection showed both springs have the exact same wire thickness and diameter, and the old spring was simply compressed much more. Check out the difference 30+ years makes:

Spring.jpg


Replacing this spring is a pretty easy process once you've removed the pan, but one thing was giving me headaches that I never saw mentioned anywhere else, and thought I'd bring it to anyone's attention who does this service. You have to remove the TV plunger bracket to remove the spring, there's only one bolt that holds it in. There's a little bent wire that connects the end of the TV cable to the plunger swing arm, and of course, that wire popped out and my bracket assembly dropped to the floor. When it was time to reassemble the bracket, when I tested the TV cable action with a full depression, something was binding. The bracket assembly has a captured spring for the swing arm rotation, but there's another thin, very soft spring that's about 2.5" long and something like a cotter pin with one side bent 90 degrees captured inside that soft, thin spring. Something in that cotter pin/spring alignment upon reassembly just wasn't working until I figured out what the hell was wrong...after nearly losing the bloody spring TWICE when it jumped out while I was playing with the assembly to figure out how it worked.

So, to spare yourself the same frustration if you do this job, note that the straight arm of the cotter pin slips into a hole on the underside of the transmission housing, which captures it and keeps it in place when the TV cable/plunger assembly is pressed. The 90-degree bent arm of the cotter pin will easily slide up & down in the slot on the side of the TV plunger bracket once the straight arm is inserted in the little hole underneath the tranny housing. It's a bit of a challenge to get the long straight pin arm into the hole when reassembling the bracket assembly, while at the same time connecting and holding the bent connecting wire between the swing arm and end of the TV cable. Just be aware of this, if you don't install that bracket assembly properly, that spring and cotter pin could very easily end up popping out and into your tranny, which would NOT be a good thing. It's so important to mention this because NONE of the articles I read on replacing the TV plunger spring even mentioned a word of this.

I also installed a drain plug in the pan. I spent a few hours searching online for anything to show exactly where to drill the hole in the pan, but the only thing I found was one guy who put his drain plug in the bottom of the pan, near the dimple where the round magnet goes. This unfortunately means the nut on the bottom and drain plug hang down and could easily tear off if you hit a speed bump or bottom out. The GNTType articles only say to "check everything before drilling" and have no pictures...the problem being, even if you "check everything before drilling", once you've drilled, it's too late to say "Oops" and do it over again. Sheesh...

So if anybody else is wondering where to put your drain plug, with it NOT being on the bottom of the pan where the drain plug could potentially tear off if you bottom out, here's what seemed to work for me:

Pan 1.jpg

Pan 2.jpg


It looked like a good location that had more than enough clearance was on the driver's side, just above the second bolt hole, as shown above. This location is also quite easily accessible from the driver's side of the car. I used the nylon washer to see how far down on the ban I could install the plug, pressing on top & bottom of the washer to make sure I wasn't putting it in the rounded part at the bottom. If you're too far down, pressing the nylon washer on top or bottom will make the opposite end pop up a bit. If the surface is mostly flat, the washer will look flush with the surface and pressing on top and bottom won't make the other end of the washer lift up.

So, that's where I put mine; now anybody else think of doing this will hopefully find this useful instead of trying in vain to find pictures online and getting nowhere.
 

Coelacanth

Active Member
Jul 7, 2014
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Alberta, Canada
For some reason, the forum won't let me edit my posts after 10 minutes. Weird. Important EDIT above: I installed my drain plug a bit too close in line with my mounting bolt. I could still get at the tranny mounting bolt by unscrewing the inner drain plug and giving my 13mm socket a bit of an angle, since they don't need to be on tight anyway, or also use an open-end wrench...but please offset your drain plug by a half-inch to either side of the tranny mounting bolt to avoid repeating my brain-fart. :oops:

Here's my drain pan with some hard drive magnets added; they're super-strong compared to the big round one...you need a flat screwdriver to pry them up from the pan. I've tied the gasket to half of the holes with dental floss, a trick I read somewhere that helps keep the gasket in place while you're trying to position it to start all the bolts, before cutting and pulling out the floss. Even then, wouldn't you know it but the bottom-most hole at the narrowed end of the pan wouldn't thread in without cross-threading, so I unscrewed all the other bolts 2 turns and gave the front of the pan (the squared end) a tap and the stubborn bolt at the "V" end finally threaded on smoothly.

Pan-Magnets.jpg


Here's a close-up of that TV plunger bracket showing the cotter pin spring-guide thing with the bent leg. In this pic, you're looking towards the rear of the car from the front of the transmission housing. The passenger side and TV plunger on the left. This should hopefully clarify the correct positioning of the "spring guide" cotter pin or whatever-it's-called.

TVPlungerBracket.jpg
 
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