Rocket-J

Anyone have question on putting on their own headers, I can answer them now.
First question should be, do you really have to do it yourself? You better be flat broke and need those headers real bad.
You need a full tool box and a lot of experience with solving problems. Like how to get a button head torx head stainless steel machine screw out when it strips.
But now I need help.
My built 383 ran great when I first left the garage. I was very happy but tired and beat up. Lots of bandaids.
A few of miles later the motor leaned out and sounded like I lost have the engine from fuel starvation. I comes in and out. I can work the throttle and get it back. Comes on real strong then burbles and sputters when I let up on it for a light. Nearly dies at the light then comes on strong again.
Question. Can an O2 sensor cause this condition. I tried to keep them clean. I have no air leaks or fuel leaks. No exhaust leaks either.
Sure sounds like one side of the engine goes dead lean. Just runs out of gas. No work was done in the area of the fuel rails.
Thanks for any help.

qws

An exhaust leak (header gasket) can cause a lean condition too.

Rocket-J

No leaks any place. This condition comes and goes. Thanks for the info.

383vett

A scanner will help you determine if the O2 sensor is heating up enough to go into closed loop. Sometimes with headers, the sensor is mounted farther downstream and the exhaust heat is not hot enough causing drivability problems. On your first point, I always do as much work as possible on my cars (including header installs on my C4 and C6Z) simply because I don't trust anyone other than myself to do things correctly. Good luck.

SouthernSon

Burned wiring harness
contaminated O2 sensor from handling
fuel filter problem
adjustable regulator loosened setting
false air from loose connections or fitting of headers can make driveability problems but I am thinking more rich.
MAF contamination from handling during the R/R.
Loose wiring at TB or MAF

Rocket-J

I do appreciate the responses.
I like to work on my own cars/toys. A rack would make life more fun on some projects.
All of your suggestions are good.
I am leaning toward O2 sensor. I know not to touch them. When I lay them down, they might have gotten bumped. I can't rule that out.
I never touched the MAF, intake, fuel rails and other parts near the top.
Fuel filter was not disconnected. There are no leaks on anything. I was a journeyman mechanic back in the day. 1960-1970's. I have good habits. There were no computer, 02 sensors and regulator like now. That is where I am lacking.
Back then it was "Mechanics" not "Computers".
I guess it is time to take it to the shop. Dang.
Thanks all.

Rocket-J

Will an 02 sensor clean itself if you run the snot out of it. This thing runs fine at WOT.
How about 15 minutes at 5K?

STL94LT1

Your car goes into open loop at WOT. So, it may be an o2 issue.

Just curious. Since you're in Ca, are these short tube headers?

SouthernSon

You mentioned a built 383. Did you ever have it tuned to the 383 to begin with?

Rocket-J

It was tuned to a 383, heads, valves, cam, maf, throttle body and all the other new goodies on it.
It puts out 400+ hp with stock exhuast manifolds and really bad spark plugs. I was told by the previous owner that it was close to 420 with long tubes but he took them off before I bought it. I am getting ready to take it in for a new tune, with these headers and new plugs. It ran very strong the first hour I took it out. No traction at all. It was fun.
I put short tubes on it to stay Ca. legal. 10 hp +/- does not make that much difference to me. I can't afford to change them evey two years. I am not a regular racer but want a track day on occation or an auto cross. The suspension was built for autocross. He went regularly with it.
Thanks Guys.
I know I leaked some antifreeze into the pipes while I was working on it. That might have done it, but why did it run so good at first?

383vett

Antifreeze will usually kill an 02 sensor pretty quickly. Maybe it died a slow death.

Rocket-J

Here's what I did.
I took it out three times. Two miles of city lights and stop signs, 10 miles of freeway. I ran it hard. 50 to 90, hard pulls, then back to the house to see if I had any problems. Each time got better and the third time it runs great.
Is there a chance that coated headers will effect the O2 sensors? If not, then I must have cleaned the O2 sensors. I will see what happens tomorrow when it is cold again. Hopefully I am cured.
I sure do appreciate all input. Anything I can help with, just ask.
I know everthing I need to know about installing Pacesetter Shorty Headers on a 94 C4.
Thanks guys.

383vett

The first time I read this post, I thought you ran 50 to 90 hard pulls (didnt pay attention to your comma). I thought it would be better to buy a new 02 sensor than a new motor. Hope it works.

thearborbarber

You can also "foul" older 02 sensors if your headers are coated causing a lean condition

Rocket-J

I would slow to 50mph and pull hard up to 90mph. Get some fuel and heat cycled through them. I read on a Googled link that the sensors can be cleaned in gasoline. I tried it the lazy way. Let the car do it.
Another thought is, I have three sensors, two in front of the cats and one in the rear on the right side. Do all of then control fuel mix or only one of them?
There is a tuner expert, here in Northern Cal, that specializes in C4, LT1&4 engines, that I have contacted. I plan on him freshening me up, but I would like to be able to drive to his location, rather than tow it. Anyway, we will see in the morning.
Thanks all.

STL94LT1

No, the rear o2 does pretty much nothing on the 94/95 cars and on 96 they just monitor the cats. The two front o2 sensors control the A/F.