I just finished installing hedman long tube headers that are covered with header wrap and a heat coating on my '83
Z-28 with CFI. I havent put the rest of the exhaust on yet, so the headers are just open. I installed the stock o2 sensor that was in the manifold into the header collector, it's the one wire model. I had to cut the wire, and lengthen it to get it to be long enough.

After I was done with the install, I fired it up, and it idles rough, with backfires every minute or so. If I give it gas or put it into gear, it wants to die.

I was told that I might need to get a heated oxygen sensor, where could I get one, and does it matter how many wires it has?

Could putting the spark wires back on the wrong plugs have anything to do with my problem?

If you need anymore info, let me know

 

check the wires about 5 more times. i had just put some headers on a friends malibu a few weeks ago. i even broke out a book to check the wiring. traliered it to muffler shop but decided to drive it home. barely went down the(NO POWER AT ALL). i checked everything for about 3 hrs before he came to pick it up. well....i had the book i was using turned the wrong way, so i had the passenger side wires all wrong. swaped them around and it ran perfect.
check, check, check......then recheck.

keene

 

Open headers will run really bad on a stock computer controlled engine.

 

Hook up the exhaust pipes so the O2 sensor can read right.
Check the firing order of the spark plug wires.
1-8-4-3-6-5-7-2 easy to mix up 5 and 7.

Remove and inspect the spark plugs for a cracked porcelin. If the o2 sensor is quite a bit farther from the cylinder heads than before ( long tube headers) then you may need to get a heated 2 wire or 3 wire o2 sensor.

 

I just replaced the plugs a couple of weeks before the install. I removed all of them while putting in the headers, and they were fine.

Would the switched wires cause the backfiring and make it die when i give it gas?

Also, I have the hypertech chip, dont know if that makes any difference or not.

 

You will be far too lean and be getting major reversion with the open headers. Hook your pipe back up like was said earlier.

 

I dont have the rest of the exhaust yet, why would it matter if the headers were open or not?

Also, this prolly sounds stupid, but how do I know where the wires go? My dist. cap is marked.

thanks

 

your not suposed to cut the 02 wire its some kind of low vole wire or something. i had the same prob with my car i got a new o2 and and extention for the o2

 

o2 can't get a reading can it w/ open headers?

 

ok, in your opinion, will I need to get a heated sensor for me long tubes, or should I be ok with what I have.

irocktheiroc, where did you get your extension?

 

cutting your wire isn't the problem. The engine won't run right with open headers. It's simple as that.
If you were running a non-cc carburetor you'd be fine with very simple fueling adjustments for open headers.
With EFI you'll need very major fueling changes to make it run right.

 

Do all of the above. May be crossed spark plug wires, must install exhaust pipes to be sure, open headers always make an engine sound rough.

(Hook up the exhaust pipes so the O2 sensor can read right. Check the firing order of the spark plug wires. 1-8-4-3-6-5-7-2 easy to mix up 5 and 7.), or 3 and 6.

Check header gaskets, must be tight with no leaks. The spark plug wires go clockwise on your distributor cap, find number one and then go from there.

 

Well, I checked the spark plug wires, and that was the problem. I had the 4 and 6 mixed up (dumb mistake). I added a little pipe to the collector with the o2 sensor, and now she idles smoothlyat 1100, and drops to 750 when I put her in gear. Best of all, No backfires . As far as I could tell, she was running fine, I didnt drive very far, just around the garage (there is a ton of snow on the ground in Wisconsin). So thanks for all of the fast replies.

Also, I think I may need something to insulate the plug wires and the remote solenoid wires from the headers (even though I have header wrap). Had anyone had any experience with the stuff that they sell from summit?

Thanks again.