Hey, I'm taking my car into my shop to have them check things out and replace a few things because I've been having some issues after my header install (incase you haven't seen my previous posts on it). But anyways, I'm having them replace the opti, spark plug wires and O2 sensors. I was wondering if there is anything else I should specifically have them look at or replace? My issues are, rough starts, an occassional slight stumbling at lower rpms, and it kind of bogs down then fires up when I hit it around 40-50mph (which it didn't really do immediately after header/exhaust install). I don't know, it just doesn't seem to be as powerful or fast as it should with my mods so far. I replaced the starter already and the ignition switch was replaced about a year ago.
Thanks

 

If you're getting the ignition system replaced on an LT1 by a shop, better take a big jar of vasoline with you when you pick it up.

I recommend if it's not your daily driver, you do it yourself. It is the perfect job to get to understand the LT1 better.

Oh yeah, been quite a few folks here that have screwed up their O2's by putting them back in before firing up the LT's for the first time. You may want to just replace them on your own and see what the car does. Be sure to tie them back so they don't touch the headers.

 

I had no idea that your supposed to run it without the O2's at first. Replacing them is just unscrewing and unplugging the old ones and opposite for installing new ones right? With my plug wires, I already have MSD's ready to put in, but I couldn't figure out how to get the old passenger side wires out, so I gave up. So any help there would be nice too. And I know for sure that I most likely won't have time to replace the opti so I think I might let that one up to the shop since I'll probably still take the car there to make sure everything else is fine and probably just have them inspect it as well so I don't have to take it back again. But thanks for helping me out there.

 

Yup, just unplug the old ones, unscrew them, screw in the new ones, connect them back up and be sure the wires are tied back so they don't touch anything hot.

The reason I suggested to try the O2's first is save you the money and aggravation of the ignition system.

 

A shop is going to give you **** for replacing an opti. Expect to come out with a bill for over $1k.

This is something you can do in ONE afternoon for just the cost of a $250 opti and some coolant.

That is *if* you even need to change it out after following speedy's advice!!

 

The O2's are cake. Did you get O2 extensions? I'd try those first before you take it to the shop. While the opti is off, the passenger side plug wires are easier to get to. Seriously though, an opti swap can be done in a couple of hours if you do them frequently. It shouldn't take you more than a day to do plug wires and opti. Just fyi.

 

Is your headers coated? Cause if they are when the coating cures it usally takes out your 02's try replaceing first like speedy said

 

I'm not sure about the LT's but my 96 Formula has Edelbrock TES headers on it, and the passenger side plugs are all accessible from the top. I found it easy to use a plug socket, and a 13/16 ratcheting wrench...the ones that look like a regular combination wrench, but the box-end has a ratcheting mechanism.

I would recommend you put the car on ramps or jack stands, and have these tools ready: 3/8" drive ratchet, 2 plug sockets - one with the rubber insert that holds the plugs in the socket (for installation of new plugs), and one without the insert (for removal of old plugs), 2 3" extensions, a swivel or universal, whatever you want to call it, and a 13/16 ratcheting wrench. You'll also need a 10mm and 13mm to remove other things from the engine in order to get to the plugs, wires, and opti.

If you're going to put the opti in, you should go ahead and replace the water pump. If not, disregard this but to do the opti and/or water pump, unhook the battery, drain the radiator, remove the intake elbow, maf, and cold air intake, remove the plastic cover (with the Catalyst and A/C information on it) from above the radiator, pull the fans out through the bottom of the engine, remove the serpentine belt, disconnect all hoses and wires from the water pump and tie or tuck them out of the way, remove the AIR pump and bracket and tie the air pump out of the way, remove the water pump, mark the harmonic ballancer's relation to the hub (I used a windshield marker, but white shoe polish, or nail polish will work), and remove the three bolts holding the balancer to the hub. You don't have to pull the entire hub to get the opti off, so just take the balancer off the hub. Unbolt the opti and remove it.

Install the new opti and new or old water pump, but leave everything else off for now.

Remove the alternator for easier access to the passenger side plugs, and you're ready for the plugs and wires.

I was able to remove all of the plugs from the passenger side while standing at the front passenger corner of the car...I had to lie across the engine with my feet towards the driver's side and my hands towards the passenger side in order to get one or two of the passenger side plugs back in, but no major deal.

The driver's side is easy. They can all be reached from the bottom of the car. I was able to reach 1, 3, & 5 by lying under the radiator and using my right hand to remove the plugs. 7 was a little more tricky. Your chest should be under the engine cradle...reach between the engine cradle and y-pipe to get to 7. you can actually kinda *hug* the engine cradle and put your left hand through from the front to help hold the ratchet. If you have any trouble finding it, it's hiding directly above the oxygen sensor, so use that as a guide or remove the sensor for easier access if you plan to replace it.

Installation is reverse.

Plug wires...lay all of them out on the floor (or ground) and seperate them into pairs of two going from longest to shortest. Now take the longest of each pair and seperate them into two sets of 4, one set of longer wires, and one set of shorter wires. The short wires go on the driver's side, long wires go on the passsenger side.

Be careful of 6 and 7 because they're easy to burn.

I ended up running the 7 wire backwards toward the firewall and hooking it inside the little bracket that runs along the bottom of the head from the front to back of the block that your old wires were secured to, I also ran 5 and 3 inside this bracket. After getting all the driver's side wires hooked up to the opti, zip tie 3, 5, and 7 to the bracket where they all exit, and then run them through the factory wire holder on the metal EGR tube, and zip tie them in place.

Passenger side: I ran 2 & 4 in the factory location. 6 & 8, I ran up and over the headers along some custom brackets on the valve covers, and down behind the alternator to meet up with 2 & 4 and run through where all 4 originally went, under the metal power steering nipple. This keeps the wires far away from the heat. You could get away with only running the number 6 wire over, but 2 looks a little better, and it's extra assurance that number 8 won't burn either. I can take some pics of the brackets if you're interested.

Now, pick the correct coil wire (there should be two in the box) and put it on, put the alternator back in place and hook the battery back up. Then fire it up to see if everything's alright. If not, troubleshoot, if so, put everything back together.

Sorry, I'm not too good at explaining things, but hope this helps a little bit. You should be able to do this yourself in 8 hours...more than likely less time, but it would be a good learning experience. A shop will probably charge you $600, give or take, to do everything. I would rather spend 8 hours working on something than pay $600 for somebody else to do it. You could buy an MSD opti and a mail order tune with the money you save. Or put it towards your suspension, brakes or tires.

Good luck, hope you get it straightened out.

Paul

 

Ok, thanks for all the help so far. I just got done measuring/labeling my new wires according to the diagram on shoeboxes site. All I need to do now is go out and get new O2's. Damn their expensive though, $53 at Pep Boys and Advance Auto for one little O2? That's crazy.
To answer some of the questions, yes I have coated headers, and yes, the O2 extensions came with the headers I believe.
Thanks a lot for all the help

 

EuroticCustoms, thanks for the explanations on everything, I'll definately use them, but you put a little too much info. I have already replaced the spark plugs themselves. I should of mentioned that probably. lol, my bad. But thanks a lot anyways.

 

Sorry, I misread the post. I thought you meant... well nevermind it doesn't matter but anyway lol The only thing holding the wires are the plastic seperators and a small metal tab. You won't hurt their feelings if ya just yank the **** out of them haha j/k But you should be able to get them out if you jerk hard enough...they're old, no need to save them.

 

Are they genuine Delphi (AC/Delco) O2 sensors? If not, don't buy them. Since you are already aware of Shoebox's website, why not use the parts sources he lists there for deep discounts on factory parts? Cheaper than $53.

 

Didn't even think of it, I'll check it out, thanks.

 

Update:
Wires are installed, took a few hours, but their in. Starts up a little better but not perfect. I'm gonna try to get O2's tonight or tomorrow and put them in tomorrow.
Another question though, I don't really know where the coil wire goes so I left it out and I'll put it in probably tomorrow if I find out everything. Will it help out a lot or not? Is it like a key component to installing new wires or something like that?

 

It's only going to help out if it's degraded or the source of the problem.

It is a key component in the sense that w/o it you get no spark I'd replace it since you're replacing everything else, only makes sense.