'96 Century general project thread

[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?

[SappySE107]

That is incredibly difficult to go through, and so young. Really, its a lot to lose a parent but also a brother...fuck. We all process death differently. Religion probably goes a long ways here, of which I have none to offer or assume. Just don't beat yourself up for not feeling and expressing how you think you should or could. We all handle loss and pain differently.

[LeftVentricle]

Today would have been my father's 61st birthday. He left us last November. At that time, I took a trip around the Bay Area to visit family and friends I hadn't seen in many years. It felt like the correct way to mourn him, to see the sights he saw regularly, and maybe some things he didn't. I spent Thanksgiving with my sister and her mother.

I have never been good at expressing my emotions, so I hadn't written about my trip in the year since, because every time I sat down to do so, whatever I typed came out hollow, empty, as if I were writing it on someone else's behalf. Death is inevitable. The condition of "humanity" has a 93% fatality rate, after all! But though I have experienced a few deaths in our family over the last decade or so, I could never properly process them. Even this 2000 mile trip by myself didn't. It didn't help that it was around the same time that my wife decided she was done and wanted to move out and eventually divorce.

In 2010, my grandfather, Charles Trotter, passed. I didn't cry for him then, so that I could be strong for everyone else grieving. In 2012, his wife, my grandmother, Rosemary Trotter, joined him. I didn't cry for her then, so that I could be strong for everyone else grieving. In 2018, my brother, Forrest Smith, left us suddenly. I didn't cry for him then, so that I could be strong for everyone else grieving. In 2022, my father, Daniel Richards, departed sooner than he should have. I didn't cry for him then, because I had no capacity. In 2023, my grandmother, Beverly Johnson, died. I didn't cry for her, because I didn't know her.

In fact, I don't know my family at all. My dad's family is unknown to me. The only interactions I had with them, I was too young to recall, or they were incredibly brief. There are reasons for that, but I don't intend to air dirty laundry here. Aside from the lineal descendants of Daniel Richards, I consider my ties to his side of the family non-existent. There is some sadness in that.

I love you, Dad. May you improvise, adapt, and overcome any challenges you face in the next world.

[LeftVentricle]

It's finally cooling off in Vegas, and I'm sick of trying to figure out why the black wagon is still misfiring after basically rebuilding the ignition system, so it's time for George to ride again! Gonna get an alignment soon.

EDIT: Someone at the A-body board mentioned injectors. At this point, I'm leaning toward injectors, but since testing that requires pulling the upper intake, I'm not going to do that just yet. I plan to change over to the non-A-body-style throttle body, throttle position sensor, and mass air flow sensor, and get another '97 W-body PCM from Milzy. There's a '98 Grand Am at the yard up the street that's not been picked apart yet, so I'll grab the upper, TB, TPS, cruise module, throttle cables, and MAF from that. Then I'll probably just slam in some new injectors as a matter of course.

I know I said when I bought this car that I didn't plan to do any modifications, but I consider the MAF swap a necessity at this point. It's becoming more and more difficult to acquire the Buick-style MAF, since it was only used on a few cars for a few years. Whereas the newer style was used on many more cars for many more years, so it's both more plentiful at the yard and easier to buy new if I need to. The factory TPS doesn't seem to be calibrated correctly either, reporting 66% at actual WOT. And yes, "while I'm in there", why not just upgrade to the 2000+ top end, right? No time, money, or motivation for that.

[SappySE107]

Cut wires are always a good time. GM updated the tuning to remove the MAF, which had issues that I don't recall the details on. Might be worth updating it though.

[LeftVentricle]

Here's a little treat for y'all that's relevant to the thread. (just ignore the Buick lump underhood)

And here's a couple photos of work done on the black wagon.

Getting started:


On the agenda is general tune-up stuff: rotate tires, spark plugs and wires, air filter, clean the MAF, fuel filter, engine oil and filter, transmission oil and filter. I've been experiencing what feels like a misfire recently, so the goal is to chase that down.

We've all done plugs before, so here's the important image:


Looks like #2 had a pretty bad crack in it, unless that's just gunk. They're all the correct Delco plug for the engine (41-601), which is nice to see. I replaced them with Autolite 605 gapped to 0.060". Everything else went about how one would expect for a tune-up. The transmission oil smelled and looked a bit spicy but not quite burnt, and the magnet didn't have very much on it.


Couple interesting things to note. It seems as though someone has been in this transmission at some point. There was RTV gunked all around the pan's edge. The pan was unpainted, and is probably aftermarket, since it doesn't have

DIV OF GMC
Hydra-Matic
4T60

embossed into it, and the gasket was the typical aftermarket rubber style. The side pan had RTV in the edge as well. I'm not complaining about any of that, mind you. It's just pleasantly surprising.

The misfire cleared up quite a bit after all that, and it starts faster with a fresh fuel filter. However, I still feel it sometimes when passing on the highway. I'm going to try rerouting the 7x crank sensor wire to see if that's the problem. I had that issue on the white wagon a number of years ago: