So Ive been working hard on my 93Z lately and now that Ive totally written this post up.. wow sorry for the long post. Ive met up with a few guys parting out 93-97 Z28's in the past few weeks and Ive grabbed quite a few things. Anyways, I figured the first order of business should be the regular maintenance items and DTC issues. As yall may remember I was getting a few codes when I got the car, EGR, Evap Emissions Solenoid Circuit, Pass. side O2(lean), and AC systems. The EGR and Evap was simply a disconnected hose off the air filter housing I come to find out. Plugged it back in and no more codes for them. My AC has a leak where a large can of R134 lasts 2 weeks and a smaller 12oz lasts 1 week. I figured 5-6 bucks every week to have AC in the Florida heat is worth it until I can get to fixing it. The O2 sensor seemed pretty daunting and Ive put it off until today. On Friday I bought a new fuel filter, new ngk iridium plugs, duralast plug wires, a Bosch Oxygen Sensor, and a Duralast knock sensor. I got the knock sensor because one of the guys that was parting out a 94 Z28 heard my story of bad gas mileage and said he didnt think that an O2 sensor would hurt my mpgs(9 when i first got the car, 12 after a seafoaming) that bad. He suggested a knock sensor and at 32 dollars I figured what the heck.

Yesterday I did the fuel filter in about 20-30 minutes. Easy peasy. Then right as I finished and was about to start the plugs/wires/o2/knock sensor.. Im standing by the passenger side door and I see my 2 year old nephew.. who I was taking care of outside while his mother was relaxing inside.. come running around from the back of the car with a broken blue ink pen just getting little splotches of ink on my white paint. I ****ing panicked! First thing I did was make it worse obviously by getting soapy water and a rag and smearing it. Then I used rubbing alcohol, wd40, whiskey, vodka, gasoline, low odour oil-paint thinner(for my model kits), 3m adhesive remover, watered down degreaser.. and finally that really caustic paint stripper ooze. i thought it was only on the rear passenger quarter panel but he also got it on the front near the pass side headlight on the black and the white, the driver side door.. but i didnt even notice the other 2. i got like.. 85% of it off at the cost of making my clear coat bubble a bit(its really unnoticeable) and I only hit the driver side door with rubbing alcohol cause I came to my senses wasnt willing to risk it anymore. So.. paint job time it is unless you guys know any other options. Aaaanyways..

So today I dove in and wrangled with the oxygen sensor. I had the long 3/8 autozone O2 sensor and an offset 3/8 o2 sensor wrench I got from advanced auto in my arsenal and on a whim I grabbed a 22mm ratcheting wrench. Turns out the 22mm ratcheting wrench I got worked better than the both of them and I was able to get it after a few hours of trying(yes, sad I know lol). Getting that sucker off was borderline orgasmic as I danced in the driveway proclaiming my joy to the heavens then ran inside and told everyone of my victory to mildly bemused smirks. I found that unbolting the starter and pushing it towards the front of the car and propping it up on the right front wheel stuff helped alot. I also tried the knock sensor which I will explain further down.

I then started the spark plugs and wires, and in about 4-5 hours I was able to complete the entire driver side. Yeah, pretty ridiculous but Im new to all this so forgive my newbie-ness. The duralast wires I got were ALOT longer than the ones that were on mine. They were 8mm as well and the ones I took off were Autolite(i think) 7mm. Runs fine though.. if anything it runs BETTER.. the idle is alot smoother and it feels peppier. Whats the benefit to using bigger diameter wires? Also is there any benefit to using longer wires or is it possibly bad to use longer than the original wires? I tried to match them up as best I could but the new ones only had 2 short ones and the rest are at LEAST half a foot longer than the old ones. Hell some I even had to tape up away from the engine all ghetto so they wouldnt hang too loose. 118k miles and Im not totally sure if they had ever been changed. I pulled out "AC Delco 14" spark plugs(they have "2k" and "208" engraved on them, not sure what that means). Only having the car for 2-4ish months, Im wondering when the last time they were changed. I thought the 14 on it meant "hey maybe they were done in 2014?" then i googled them and its just a name lol. In the process of undoing the starter I figure the passenger side shouldnt be too bad either and Im gonna remove the alternator again(took both off with the intention of getting them all done but time ran out before work). I didnt find the driver side to be that bad but I took my time because I didnt want to have to redo it AND I wanted to make ABSOLUTELY sure that I routed the plug wires exactly the same way that I pulled them out. Im going to tackle the passenger side tomorrow

My problem was ultimately with the knock sensor. i hit it with pb blaster for 2 days prior to trying to remove it and I used a deep well 7/8ths 1/2in socket and it fit properly.. just it ended up partially rounding the edges. I tried that socket, 6 in adjustable and a much bigger adjustable, as well as pliers, and slip joint pliers.. and no luck. What would you guys do? Im tempted to take it to a shop for it but maybe you guys might have some advice or a suggestion that I can try first.

I nailed various points on the engine(o2, knock, starter bolts) with pb blaster. When I reconnected the alternator and battery to fire it up, it was smoking quite a bit. Not billowing but I after the fact I figured it was just the pb burning off and the anti seize on the o2 cooking. I hope thats the case and I didnt somehow(inadvertently) cause some other issue. While it was cold I looked at the stock exhaust manifold and saw that in between where it bolts.. I could see the exhaust manifold gasket fold out in a V shape between the last 2 pipes towards the back of the engine. I poked it with my finger but didnt mess with it any further. When it was smoking my first thought was "oh crap, did i make an exhaust leak?" I drove it 45 minutes to work and no issue, no excessive smoking so Im hoping it was just burning off the pb.

Also, when I went to check out a guys parted out 95 and 96.. I bought 2 bose speakers, a mini-amp from the passenger side door, and the subwoofer box. I rolled the dice and hoped that at least some of it would work. So i get home and notice that the subwoofer has 2 wires coming off it to plug into and my car only has 1 plug. I opened it up and instead of just the speaker and one circuit board, it has the speaker and 3 circuit boards. One was similar to what was in mine so I took it out and connected it to my setup and took the speaker and replaced mine as well and it works great. I also hooked the 2 bose speakers up to my existing mini-amps and they work as well. Heres the thing, the mini-amp I got from him does not work with mine even though the circuit board for it looks beautifully preserved. I tested it on either side with both working bose speakers and I just cant get that mini-amp to work at all. Whats the deal? The subwoofer I got from the 95/96(not sure which one), seemed like it may have contained some kind of central amplifying circuit board but why would that even be necessary if each individual speaker is amplified from the mini-amp? Do you guys know if there is any way to modify my 93's wires to work with the 2 wire setup from the new subwoofer if I were to put the subwoofer back the way I got it? I googled about the differences between the 93's system and the later system and couldnt find squat.

Even though I only finished half the job today, it felt really good to make progress. Im very proud of myself for even coming this far. Doing all this work to these cars really makes the cars really feel like they are mine you know? I feel confident that the passenger side wont be too bad. Ive got really small arms so between going at them from the top and bottom of the car, I should get it knocked out tomorrow morning much faster. The smoking ruined my victory dance but it seems good now. If you made it this far, thank you. Im rambling but Ive been up for 24 hours now and still got another 8 to go lol.

 

lol, passenger side plug is the toughest side. rear plug can be a pita

 

I just got it took less than 5 minutes after I got the starter off then crawled up top and had my knees on the radiator with my left hand between the manifold and the passenger side wheel well. Routing it haha much more difficult..

 

use high quality plugs? so you dont have to do this again for a long time.

 

8mm is better then 7 so that's fine

 

I'd smack that person on the back of the head. Absolutely an O2 sensor will cause bad fuel mileage. Once the computer goes into closed loop, it uses feedback from the O2 (as well as other sensors) to set the fuel trim. If the O2 sensor is sending the wrong signal to the computer, then it'll dump more fuel into the combustion chamber than is necessary. As you mentioned, with the possible age of the wires and spark plugs, those as well would lead to poorer mileage.

A knock sensor will retard timing if it detects knock. That's it. The only thing you'd notice is a slight decrease in power, but it'd have to retard quite a few degrees to make it noticeable.

Instead of chemicals, you should have bought some 2500 grit sand paper and wet sanded it off, then used some 3000 grit to remove the marks from the 2500 and then buffed the rest of the scratches out. It would have taken more time and work, but it'd do the job. If you do go this route yet, sand very lightly, you don't want to go through the clear coat, just take the layer that has the ink off. Use lot's of warm soapy water too and a good buffing compound. I wouldn't use this any where you had air plane stripper though.

If you're careful, you can apply some heat from a small propane torch. The other route is use some CRC or Loctite Freeze Off. I don't know if you can still get it, because I know some places discontinued it. Spray that for 20-30 seconds on the knock sensor, tap it a few times lightly with a hammer and then try getting it off. If you can't get the Freeze Off any where, you can use a can of compressed air that you can find at Wal-Mart. Put a mask on, invert the can and spray. That will freeze it real quick. I say use the mask because that stuff sucks getting in your lungs. Been there. Done that. Also, make sure you're using a six point socket and get yourself a nice long breaker bar. It will come in handy. Alternatively, you can use a piece of pipe on a ratchet but you risk breaking the ratchet.

Also, the only difference between 7mm and 8mm wires, other than 1mm, is the thickness of the insulation that surrounds the core of the wire. Each has it's pros/cons.

 

ok you guys are probably going to think im crazy but honestly... i thought the passenger side was EASIER than the driver side! lol. the only thing was routing those plug wires in that tight space right behind where they plug into the distributor. all in total, estimating out the time i messed with the o2 and knock sensors and the time i wasted smoking cigarettes and bsing around.. it probably took me all of 4 or 5 hours

mkcoconuts, thats a great idea about the 2500 and 3000 grit! im definitely going to try that in the morning as theres still a small amount of blue on my driver side door. and i think im good without the mask. in my heavy drug doing days i would inhale that stuff intentionally(although i would do it through a shirt/sock to catch the bitterant in it). cars got me off dope and drugs so i got that going for me.

ok heres some pictures i need you guys to look at: some rusty spots - Album on Imgur

i have another couple questions for you guys while i got you here. i just linked a few pictures of that metal bar the runs along the front of the engine bay and water pump. ive had the car for a bit and shortly after bringing it home i noticed that some previous owner had used a small piece of metal drilled all ghetto with like galvanized or drywall screws plainly visible sticking out 1.5inches.. to cover up a rust patch that was eating through that metal bar going across the front of the engine. how i didnt notice this before i bought the car.. beats me. probably just the excitement of getting my dream car and youthful ignorance. thats what i tell myself to help me sleep at night at least. its a pretty big hole as it probably has eaten through at least 3/4 of the width of that bar for about 4-6 inches in length.. and i was wondering if that whole thing can be replaced? i googled high and low and i cant figure out what it is called to even search and see if it can be replaced. the metal bar that runs along behind the headlights and in front of the battery. it also looks like i may have some where the radiator sits on the underside. while i had it exposed i hit it with some por15 but it looks like its going to need to be replaced as fixing it just doesnt seem like a possibility unless you guys have any suggestions. i didnt snap any pics of it while i had it exposed and open but heres a few i just snapped while im here at work.

i also was looking at the bottom of the water pump while i was putting on the passenger side plug wires to the distributor and noticed a little hole on the bottom of the water pump. is that supposed to be like that? please say yes lol.

 

thats a bleed hole in the pump, its to let out coolant if the pump is failing, it looks like your water pump is leaking. better get that replaced if it is. opti does not like coolant

 

Oh nice thank you so much craby and all you guys. I did the 2500 grit/3000 grit/rubbing compound /polishing compound /waxing and buff on those ink spots and it cleared right up.

Ill go get a new water pump right now. Good looking out yall

 

The "bar" you're referring to is unfortunately part of the uni-body structure. As far as I know, they do not make an aftermarket replacement. You could find a junk car, drill out the spot welds and then stick it in your car. You'd have to make a temporary brace though to hold everything together. On the other hand, you could have some who is very good with metal, cut and replace the rust area.

I don't feel the area in question is an immediate issue as I've seen many people cut that area out to stand up their radiator to fit turbos at the front of the engine. But that was only the center portion. I just wouldn't want to get in any front end collisions without it.