1989 C4 Functional Restoration

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SirReal63

SirReal63

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I bought the parallel flow A/C condenser several months back and now was a good time to install it. I had to have a small leak somewhere in the system but my R134 sniffer could not detect it, I checked everywhere but the condenser as I could not get to it when it was all buttoned up. My UV dye detector was mostly useless as it lights up all over the place around the system. Time to replace the condenser which also lit up under the UV light, I suspect the leak is there.

These are marketed a direct fit but in reality they are not, the issue is the rubber grommets they fit into to hold them in place. The size and shape of the attachment ends of the new condenser is very much different than the original equipment. I knew going in this was the case but the benefits to the efficiency greatly outweigh the minor adjustments to the rubber.

The problem, shape and overall size...

The old...rounded off and overall height less than the new...

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In order to make a proper fit you need to not only make the rubber accept a rectangular piece but you also need to account for the height difference. At first I tried to just hog out the rubber to fit and I got it close but not really close enough, this rubber is at least 36 years old and not really that pliable. (The nibs that are supposed to hold it in place were either missing of bent and deformed so much there was no straightening them. I don't think they are needed as the cavities the rubber fits into securely holds it in place.)

I could see the bottom was too thick but did not have a clean way to remove it. I decided I could cut all of the bottom out, trim off the excess and glue it back where it came from. This was easily achieved with an old wood chisel heated up enough to push right through the rubber. It worked so easily!

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Once the bottom/top was removed I simply had to remove enough material to make it fit properly without having to crank down too much on the top cover that holds all of this together. Since this piece has a curve in it on both the top and bottom pieces I duplicated the curve in hopes it would help add enough pressure to the condenser to hold it securely.

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All trimmed and glued back together.

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The final product, nice and level and the top fit on like it is supposed to.

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I recharged the system and dash temp came right down to 40 degrees, it was 80 degrees in the shop so that is a 40 degree delta, I just hope it stays that cold when it is 105 outside.

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The vents switch correctly between defrost, bi-level and dash. I still have the rebuild kit for the controller but will not try and fix it as it isn't broken yet, the vacuum hose refurb seems to have fixed the issue of blowing out all vents at once. Time will tell of course. If it loses charge again I am going to replace the compressor, it appears to be original or replaced long ago and the UV lights it up all around it, except where the hoses connect, and the hoses, crimps and connections do not light up. If I replace the compressor I will replace the hoses as well.
 
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SirReal63

SirReal63

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I don't think the car will ever be "done". With that said, it has been drivable for most of the past year, and has been driven. I have a list of what I still want to do in 2025...

Drop exhaust to wrap it and replace temp gauge wire that is burned and corroded.
Refinish the stock 89 wheels and get them back on the car.
Replace the ECM with a better system that is far more user friendly to get the idle correct. Either Holley or FiTech or other.
Replace shocks and possibly springs. The car sits too low at about 26.5" to bottom of fender well. I scrape on everything.
Replace the leather on footwell with the correct carpet as I found I can buy just the pieces I need.
Replace steering wheel.
Replace heads and cam after ECM is on the list but still investigating the right combo.
Replace injectors as appropriate for use with heads/cam.
Replace headlights.
Re-paint hood to match the rest of the car more closely.

With a total of 7 owners in its life, there has been a lot of deferred maintenance that will be done as time allows. I have no idea what I will do next, probably shocks and see if I can schedule a dyno day at a semi-local shop. This car really runs better than it should and I want to establish a baseline to decide if I really want to do heads and cam. I have no idea if anything was done when the block was changed other than the tune being messed with, hence the 1050 rpm idle, which really drives me nuts. I haven't done anything to the car in the past week. I am currently fixing the clutch on the Suzuki Carry and when that is done I am going to insulate the rest of the shop. The car will have to take a break from being worked on.
 
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SirReal63

SirReal63

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I had been fighting a high idle since I bought the car, no matter what I did, it would idle at 1050 rpms. A good friend suggested checking out the ECM and making sure it had not been changed, this poor old car has been messed with a lot, different block, wrong year intake etc. Sure enough, someone replaced the correct Memcal with this one. It does have an 89 6 speed 3.33 rear end ratio ECM but it is not the correct one, it is some "custom" memcal that for whatever reason had the idle set to 1050 rpms. Who would do that to an otherwise stock engine? If it had too large of a cam I can see raising the idle but the cam seems to be a stock Vortec cam which is almost identical to the L98 cam.

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After a year of beating my head against a wall I replaced it with a stock APYP memcal and everything works as intended. The idle is now correct, minimum idle set, TPS and IAC set and base idle set. A shout out to Brian at TunedPerformance for helping me get the correct memcal and his guidance, as well as those in the Tech/Performance section of this site for the education.

This has bought me some time before I need/want to replace the ECM or do any performance related upgrades. The car runs fine for now and I will enjoy what it has to offer in stock form for the time being.

I really haven't done anything else to the car since my last post as I have been working on Suzuki Carry clutch and other issues. I doubt anyone wants to see that fiasco but a word of caution, if you buy a vehicle designed to be used on Mainland Japan and you are not Japanese sized, these vehicles can kick your butt. I fit in the cab to drive it (barely), but I do not fit upside down under the dash and that has made it tough. biggrin5.gif
 
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SirReal63

SirReal63

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That brings me up to today. I have had a blast the past 14 months of working on this car. I have learned a lot, spent very little money and have my actual blood on most parts of this car. :D I had always been told you cannot paint a car with spray cans piecemeal and get a good consistent paint job. I had no intention of painting this whole car, just the doors needed it but as usual the project snowballed into painting the whole car, minus the hood, for now. I will revisit some areas where I skimped too much and get them sorted out better.

The car does not need to be faster but the 240hp and 335 ft. lbs. of torque needs some improvement. The low end torque is fun, it pulls like a freight until 4500 rpms but falls on it's face after that, all due to the TPI long runner intake. For a street car this is ok and I do not want to change that, but I do want more in the rpm range it has to operate in. Better heads and a cam designed to improve the overall hp and tq below 5k is on the list. I can still get better runners for the TPI to help boost the numbers
 

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