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

 

Definitely check your plug wires. Chances are you have a couple switched.

 

Bad O2 since you spliced it.

Burned spark plug wires. Usually 5 or 7.

 

Well, maybe you need to make sure the rest of the car is plumbed correctly and no leaks. Then I would assemble the rest of the system and see if that still happens. It could be that the car is running with too wide of an exhaust system and now you have lost some scavenging which the exhaust system might restore. Not sure.

HEGO will not help you if it is not in closed loop or cycling in and out of closed loop. HEGO has 3 or 4 wires. In the 3 wire system, there is 1 pos, 1 ground for the heater and the feeback wire. Same thing as the 4 wire system except now there is a ground for the feedback as well. The pos is spliced into a switched power line so as not to keep it activated all day long.

Could be that your plug wires are crossed which is what I suspect.

 

How did you do this BTW? I hope you used solder and not the cheapie butt connector. Know why it is called a butt connector? Because it comes back and gets stuck in your butt. There are some good ones out there with the shrink wrap that holds the wires together once it gets heated.

 

why would it matter if I spliced the o2 wire? its just a single copper wire.

I will check the plug wires tonight, do you think thats what caused the backfiring?

would switched plugs also cause it to die when I give it gas?

Thanks

 

I have header wrap, the pipes are barely warm to the touch, so its not burned wires

 

All good feedback, but as Aklim stated, I'll bet a cookie your wires are connected incorrectly. I once misran plug wires on mine and it did just that... it sounded like crap at idle, would sputter and backfire...and with any gas it'd just kill. Go through and run each wire, by hand. Make sure to run it all the way down to the plug (some would twist, right at the end for me---big difference between plug 5 and plug 7 yanno?)

 

Im gonna vote for the plug wires, even if your had your o2 sensor disconnected the engine wouldnt backfire.

 

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.

 

Where in wisconsin do you live? I live in madison, go to school in whitewater... Looking for people with thirdgen's to hang out with, talk car business, the usual.

 

Oh...and tell us about your car. Don't think I've read anything on what you have, mods, etc.

 

Must be in northern WI because in Madison we haven't had enough snow to do anything. Besides, I used to drive it even with 3 or 4 inches of snow on the ground

 

Hey aklim, how knowledgeable are you on transmissions?

Please IM me if you can... new screenname is Crimson Gild... My idiot mechanic may have just cost me my 700R. :'(

 

I live in Spooner, which is like 1hr south of Duluth.

I have only seen 1 other 3rd gen f-body around here, and it was a firebird (I think a v6)

Yeah, I dont like driving in the snow cause I have 275's on the back, and they arent snow rated. I have a hard time getting traction in a downpour.

Right now, my car is torn down to the frame for painting and some other stuff.

I will be repainting the body and ground effects white except for the hood flaps (they look good with the bra I have on the front) Hopefully some new american racing rims also.

I have the crossfire engine, so I havent put that much money into mods. Just intake porting, headers, removal of all smog equipment and AC. Rebuilt trany with shift kit. Contemplating getting true dual exhaust.

Dont really want to put that much money on a 305.


I have some pics that I will try to get on here. They are from last year when I first bought it. As you can see, it was in pretty rought shape. I got it for $1200 with 50xxx on the engine
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