Doing a lot of top-end refresh to my 91 Base L98. Got the it pulled apart down to the injectors. Lower manifold is next.

While I am doing all this, decided to “slap” a new O2 sensor in since the one in there looked very very old. I’m thinking I got the proper O2 sensor removal kit. Shouldn’t take twenty minutes. Ha! First pull, the “sensor” portion pulled out leaving only the sensor nut in the bung. I can’t turn back now. I got a big hole in my exhaust. The hood part of the sensor breakup is I can use a regular six point half-inch drive socket.

Much grumbling, cursing, torching, crawling, PB Blastering, banging later, I ended up ordering a 6-point Striking Wrench.
Had to grind half the handle off to get it on the sensor nut. See pic. I also ground a small notch in the lower handle to fit my crow bar blade into it for my hammer strikes.
I highly recommend this little piece of iron. Before heating with my torch, I hit it with a couple of test strikes to see how my bar would work.
Sensor nut broke free immediately. Came on out.
There was not loss of energy with this little wrench. Worked like a charm.

 

I'm betting you are right that the 02 is original since nothing in car fax made any mention over and above some battery related services and oil changes. The 02 sensor on my 95 had to be changed due to setting codes pointing at it for drive ability issues. Changing it resolved any issues. How did you make out with the brake line?

 

It has been running great. Starts w’in 1 second. Runs smooth. Just those annoying oil drips. Occasionally it will high idle. I suspect old vacuum lines or the IAC was erratic. The IAC pintle is VERY cruddy. Original??

Brakes - I ended up running new Nicop lines throughout. Not too bad a job for a 55-yr old. Would have been easier back when I was 35. Put new master cylinder, new rotors, pads, new rubber brake hoses, reman calipers. Only thing not changed was the ABS. Brakes are tops.

when done, will have new water pump, new intake gaskets, new CTS, IAT sensors, new IAC, new EGR solenoid/valve, new O2, new plugs, all new vacuum hoses. Throttle Body and plenum were nasty and now sparkle.

I recall the oil pressure sender and oil switch are new, so not changing them.

This 30-yr L98 with 113K miles runs as smooth as any of my other, much newer cars.


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Great news ! Only things I changed on engine were CTS, Map, TPS and oil sensor on back of block. Non motor items were Bose amps on driver side front and rear, sent dash display to Batee for re-build and installed later year targa top holders in hatch (much better design). What convinced me to buy it was how well that L98 ran.

 

The clunking you had was definitely the half-shaft u-joints. After I changed those with new Spicers, there is absolutely no noise or vibration during engagement or at any speed up to 85.

Good solid driver. I got the little hood body work finished also. Used epoxy and painted to match.

Give me a couple of months and I will be done with the refresh she needed. Good car.

 

Have you been able to find the short tripping the breaker for the seats and door locks?

 

I don't have those issues with my O2 sensors because I like to toss them in 5 years. They are, IMO, wear items. https://www.knowyourparts.com/techni...o%20compensate.

I would take the TB off, take the top plate off, take the IAC off and take the IAC housing off. Clean it all and then see what happens. I really don't like tossing parts at it just because. Get a scanner and see if the temperature sensors are reading right when compared to an IR Thermometer.

 

Yep. That was my first project.
Wires on back of switch bound together when someone re-installed after working on the center console.
Both power seats and mirrors working fine for a couple of months now.
While I was tracking the wires through the dash, I found and removed a mouse nest behind the glovebox and in the a/c duct. AC is blowing great air now and will freeze you out.

 

Good advice, aklim.
I know the IAC is very crusted and is in terrible shape, so I will change it. I got a high idle (1300ish) after driving for a while a couple of times. When I shut the car off and immediately re-started, the idle was normal. I am pretty sure the ECM re-sets the IAC on shut-down, so I suspect this crappy IAC is in need of changing. Am I way off base? There were no codes when this happened, so I don’t think it would be the O2 sensor - that would throw a code, right?

As far as the EGR, I had a Code 32 pop up twice after driving for a while. The EGR valve looks dreadful. Since I don’t want to take all this off again, I I figured I would go ahead and put a new valve and solenoid to go with the new vacuum lines to eliminate those as possibilities when I get it back together, if that 32 should come up again.

You are absolutely correct about changing the CTS and IATs. I really am doing that for nothing. I may just keep the new ones in the box in my little inventory.

I am changing the O2 sensor based on my readings from you and other research on how important that thing is to a smooth running engine. I have the Bosch brand replacement. Any opinions on that brand? From what I have read, the Bosch appears to be superior to other brands.

New valve cover gaskets going on also.

Oh...I am also ditching the date-coded “11-89” Multec injectors for new Bosch 3’s from Fuel Injector Connection when I put it back together. Got the rail pulled apart and cleaned up on my bench right now waiting to be reassembled with new Orings and fuel regulator.

I am looking forward to using this car as a daily driver when I get it back together.

Questions are likely to be coming when I start re-assembly in a few weeks. My first L98 project.

 

I was guessing it was the wire running through console to the switch, but never got to around to taking it apart. Thing is the seats and locks worked when I bought it, but all of a sudden just stopped and I could hear the breaker tripping and resetting over and over. I just thought a wire must have come loose and shorting to ground. The knee panel on passenger side was partially hanging down when i bought it and I had to push wires back up under panel and tighten screw, but never laid on my back to look up there.

Be careful down there on all those icy roads.

 

Maybe clean it with brake cleaner and be done with that. DO NOT PUSH OR PULL THE PINTLE OR YOU WILL NEED A NEW ONE. Resets the IAC to what? I would think it would change it to what the ECM needs based on previous settings even if it fully extends it on shut down. IF you don't have a problem with it, and you have not determined that yet, each time you change something, you add a variable. Also, with many of the suppliers being cheap and Chinese, IDK what you will get. Let the evidence lead you on what to change as opposed to justifying the change. As to the codes, they are old ECM sand the window is larger so I suspect it isn't as sensitive. Just because the code doesn't appear DOES NOT mean it isn't old and lazy. It just means that it has a plausible value, not necessarily right. Another way to look at it is this. I haven't been caught speeding this year. Does that mean I haven't been speeding?

Don't know. I don't have an EGR and it has been programmed out of the program.

Or return it and buy it when necessary.

IDK. Some swear by Delco, others by Denso and yet others by Bosch.

That you might as well buy several. Haven't succeeded on stopping the leaks for any length of time. A year or so and it's back.

Multecs will definitely be good. That will prevent you from being chained to a few stations that sell pure gas.

I would buy an OBD1 scanner before going anywhere else. It will; help you set idle and see if there is an air leak. It is better than the paper clip code reader. I have 3 myself and one goes with me. That and the Factory Shop Manual.

 

My mistake, it is a Denso O2 Sensor I got. (Not Bosch).

What is the brand/model of the OBD I scanner you use, if you don’t mind sharing that info?

 

1320 Electronics or Auto Xray (older one) and Snap On MT2500