'96 Century general project thread

[LeftVentricle]

I hate the 3300 engine.


HATE IT.


Well, hate is probably too strong. It has a couple good qualities.


Despite not having a balance shaft like the 3800, it runs pretty smooth.


And as I noted in a post from a few years ago, it gets phenomenal fuel economy on the highway, which I will be needing soon.


I will be taking another trip to Kansas in a month or so. 2500 miles of driving uses plenty of fuel. So I need this car to be road ready and running well.


Neither of the wagons are suitable at this time, for very different reasons. One is mechanical, one is clerical.


The yellow sedan has been sitting in the garage since mid-2021 with a seized starter. In addition to the images you're seeing, I finally got around to that. It is not a particularly fun task, but I would do it again a dozen times if it meant I wouldn't have to do THIS JOB.


Everything you see above is about 2.5 hours of TEARDOWN to get to the thermostat on this engine. It's stuck open, which is fine in the summer but not so much in the winter. It means it didn't have anything approaching effective heat, it ran in whatever loop it is when cold and drank gas, the torque converter wouldn't lock because the transmission was cold. All of which translate to a miserable highway trip. As a contrast, when I've done a thermostat on the wagons, which have an L82 and an LX9, I'm in and out in like 45 minutes. I'm REALLY not looking forward to putting this all back together.

To answer a potential question, yeah, it may have been "easier" to pull the throttle body instead, but that risks breaking all kinds of water and vacuum hoses and the TB gasket that are quite difficult to come by, since this variant of the Buick engine was only used for a few years, and not very widely.

In related news, I robbed the radiator from the yellow car a few months back to install in the black wagon when it started leaking. So I need a replacement. Public service announcement: as cool as they are generally, I do not recommend buying a radiator through Rock Auto.



That kind of damage to the plastic portion is annoying, but understandable. THIS BULLSHIT ON THE OTHER HAND



I cannot fathom how it could have been CUT like this. I didn't take a picture, but the other side had a cut like this as well. To their credit, Rock Auto issued me a refund quite quickly and so far hasn't asked for it to be returned. I may attempt to have it repaired, though that would exceed the cost of replacing it. I know what that cost is, because I still needed something to put in the yellow car. So I yanked the core from George.



This is what ~10 years in Las Vegas looks like. I took it to a nearby radiator repair shop (those still exist!) and $150 later, this is what I have.



They cleaned it (necessary after running straight water for several months in an iron block engine) and repaired a small leak. Ready to run for another ten years!

[86euro]

Considering this at some point in the future.

https://www.youtube.com/watch?v=fbO-WqKUnjQ

Someone on the A-body forum did a write-up on making your own coilovers a while back, but the owner took the site down at the end of 2023 without any notice, and all of the years of knowledge stored there is gone.

I don't recall who originally did the coilover swap, but it left something to be desired. At one point, I did a bunch of research and came up with part numbers for everything that should have made for a real nice setup, but I never got around to doing it. Mitch (zalorian) did though, on Steve's 5-speed Celebrity and he did that nice tutorial thread. I'm betting that Mitch still has all the part numbers and sources saved.

[LeftVentricle]

If its an aftermarket crank pulley, its probably the ring and not the sensor. It sounds like you have a bad computer too though, if it didn't throw any codes while the other one did. Glad you had a successful fishing trip on that injector clip

That is the 3rd PCM I've put in it. The original one wouldn't communicate with the emissions testing station's computer (that's a fail of the test), so I swapped the white wagon's original PCM (which passed). Now it's running the '97 PCM I got from Milzy, which works well enough. Not sure what it is about the '96 PCMs that suck so badly.

As for the crank sensor stuff, I don't know if the balancer was replaced prior to my acquisition of the car. I'll find that out later, I suppose, but as I said, I'm not terribly concerned at the moment.

[SappySE107]

If its an aftermarket crank pulley, its probably the ring and not the sensor. It sounds like you have a bad computer too though, if it didn't throw any codes while the other one did. Glad you had a successful fishing trip on that injector clip

[LeftVentricle]

Finally. FINALLY. Got the black wagon figured out. I really chased my tail for an entire year on this, and it ended up being an incredibly simple, easy, and cheap (free) fix.

First things first: I bought fuel injectors that didn't work. All those times I had the upper intake off to check wiring and shit naturally resulted in tearing the new gasket.


When I got everything bolted back together last time, the engine didn't want to start, and when it did it ran even worse than before, like it had a couple dead holes or something. So I decided to just swap back to the stock injectors, which seemed to work fine. While changing the injectors, I dropped one of the retainer clips


in here


PANIK set in. I dropped to my knees, did a surrender cobra, walked away, came back. I did NOT just drop something metal down the intake. I'm gonna have to pull the lower intake now? Holy shit I'm such a bad mechanic dumb piece of shit how coul



oh yeah, magnet


Everything back together with a new gasket and battery.



It started up and ran great! Time for a test drive.


Guess what, misfire is still there, and getting worse. The converter won't stay locked in 4th because it misses so violently the computer throws the towel in. Oddly, there's no check engine code for it. So I did the sensible thing and swapped the PCM from the white wagon with a slightly rewritten tune file so I can get some real time data. This was an enormous help. It set a P0300 pretty much immediately, and I could see that the miss was indeed random. But it also set a P0336, which is a problem with the 24x crank sensor. I unplugged that sensor, and wouldn't you know? The miss magically disappeared! So I need to figure out if it's the sensor or the tone ring on the back of the balancer that's the problem, but for now, it runs great.

So George gets banished to the Spot of Shame in the driveway, while my daughter flexes on him.



Pulled the bucket seat back out and cleaned the floor.



Stole the bench seat from George.


The PO didn't like the Buick style tail lights for some reason. Instead he installed these Oldsmobile housings, but didn't want to advertise them being Olds? So he scraped the rocket logo off, poorly.



I had a spare set of Buick lights from the toilet wagon I had a few years ago.



I have a DMV appointment on the 28th to get this pile registered. We're so back, boys. Unfortunately, Nevada changed its requirements for the CLASSIC ROD and CLASSIC VEHICLE registration, and I will be unable to get a classic plate this time

[SLPRLZ9]

I read your entire thread. Wow, what a incredible journey you have been on! Thanks for sharing. I hoping my LZ9 swap goes well for my '01 Century. Planning on using as much stock parts as I can, including retaining the stock DBC throttle body. If the 7X crank sensor fits in the stock location on the Lz9 block I will more than likely pull a crank from a good used 3100 too install in the LZ9. So much to learn. I will probably have to procure a 3400 cam from a LNJ motor from a Equinox to delete the VVT as well. Wish me luck!

[SappySE107]

It wouldn't flash because the MAF is wrong.

[LeftVentricle]

While possible, its not that easy to get the injector wiring wrong with it all taped up and loomed where they go. The MAF however makes a lot of sense. Can you disconnect the MAF and get it to run at all?

I haven't done anything since that debacle, which was on May 19th, aside from confirm again the plug wires are on the correct coils. I might try that, but would the different MAF cause a flashing check engine light? My understanding is that means a terrible misfire.

[SappySE107]

While possible, its not that easy to get the injector wiring wrong with it all taped up and loomed where they go. The MAF however makes a lot of sense. Can you disconnect the MAF and get it to run at all?

[dbral]

I don't know man, but would be concerned that swapping to a different MAF sensor style would cause some issues. Best of luck bud. Maybe the correct plenum will turn up for you in the meantime.

[LeftVentricle]

All right. It's been a shitty couple of months on the Century front.

Last year, towards the end of summer and my expected usage of the black wagon, it started to develop a misfire. It didn't have a check engine code associated with it. I went through the ignition system, which I mentioned in here at the time. A couple of spark plugs had cracked porcelains. I changed the coils and module as well as the 7x sensor. It got better but didn't go away completely, so I surmised that it must be the injectors. I finally scraped a few quarters together and got a new set of injectors and swapped them.

As we all know, the 3100 engine, and all engines in the family, has a two piece intake manifold, with the fuel rail in between the two halves. This means you have to pull the upper manifold to get to the rail. Lots of fiddly disassembly required: various wiring, intake housing, throttle body, ignition system, and so on. Long time followers of my threads will find some of this familiar since this particular bit of tear down also has to be done to pull the drivetrain.

Upper intake off:


The relevant bits:


More tedious fiddling with retaining clips followed, but I successfully installed the new injectors and buttoned everything up.


And that's when shit went awry.



For reasons known only to GM engineers, a wiring harness running across the front bank has a metal L bracket clipped to the connector. I completely missed that and proceeded to torque the manifold with that bracket in between the two halves, cracking it immediately. And not in a way that I could just JB Weld and ignore—no, fully in the runner.



At which point I very carefully cleaned up all my tools, gently placed them back in the garage, and gingerly closed the hood.

Now, as we all know, I am a fool when it comes to what cars I like. As such, it would not surprise you to learn that the A-body L82 has a different upper intake from EVERY OTHER L82 EVER BUILT. I may have talked about this before, but GM must have had a surplus of throttle bodies for the Buick 3.3 or something because it uses a 3.3 throttle body setup, which mounts differently from all the others. As such that means this manifold is a 3 year only, A-body-specific part. And wouldn't ya know, the local yards are fresh out of A-bodies even when their online inventory says otherwise.

So plan B: get parts from another car and retrofit. I did something similar with the LX9 swap on the white wagon.

Our donor: 1996 Chevrolet Monte Carlo, which drove to the scene of the accident. I had my choice of this or a 1998 Century.


Very dirty but complete.


Done.


Haul: upper intake, complete throttle body (sensors and bracket), cruise cable, mass air flow sensor, and throttle cable from a nearby 1995 Lumina. The Monte Carlo's throttle cable was pretty badly frayed.


As the Haynes manual states, installation is the reverse of removal. Except I had to do the entire job thrice because I can't be bothered to pay close enough attention to interferences. I didn't take any pictures because it would just be the same ones from earlier, so reference those if you need to.

After swapping all the parts on, it wouldn't start. Then it did start but ran like a bag of smashed assholes with a flashing check engine light. Nah bruh, I did NOT cross the plug wires on the coils again, did I? After checking and double checking that the plug wires were in the correct order, it still didn't want to run correctly, or at all.

I am defeated. The best guess I have is I, again, didn't pay attention to what I was doing and put the injector harness on the wrong injectors. Which would require me to tear it all down a FOURTH FUCKING TIME to correct. So instead of riding in air conditioned comfort during the early onset of Vegas summer (hit 110 last week), I'm sweating it out in my fish bowl under a heat lamp white wagon.

[SappySE107]

I didn't watch much of the video but making coil overs wasn't that bad for the grand am or the grand prix. The spring choice is going to be important to how it rides though. The grand prix had 300# springs and probably could have used 250# for daily driver use. I wonder if they have the database still from the a body forum. Would be nice if the data wasn't lost even if the site is gone.

[LeftVentricle]

Considering this at some point in the future.

https://www.youtube.com/watch?v=fbO-WqKUnjQ

Someone on the A-body forum did a write-up on making your own coilovers a while back, but the owner took the site down at the end of 2023 without any notice, and all of the years of knowledge stored there is gone.

[SappySE107]

Me either but the facebook group was very aware it seems. With enough cars and time, shit like this is bound to happen but I wouldn't have expected only 1 cylinder to be down from a coil pack.

[LeftVentricle]

I had an interesting failure on the car the other day. Slowed down for traffic on the highway, and when I tried to accelerate, there was a sudden distinct lack of power. When I arrived at my destination, I heard the exhaust puffing irregularly, rather than smooth as normal. Clearly a misfire or dead hole. Armed only with a mechanic's stethoscope, I eliminated the injectors as the source. Checking the coils the hard way revealed no spark on number 3, but 6 was fine. Which seemed really odd to me. I replaced the coil when I got home, as I have several spares lying around. But I've never heard of a GM coil half failing. Is that a thing?