indyfoxgt

iTrader: (3)

i have an 01 z28 and i recently put a set of tsp 1 7/8 long tubes on it, ive been driving the car open headers for about a week with no problems and all of a sudden it started going into limp mode so i drove it as little as possible but being my only method of transportation ive had to drive it more than i wouldve liked, i just installed 02 sims and it took care of the 02 codes an it doesnt go into limp mode but im still getting the po300 random cylinder misfire code, i put new ngk tr55 plugs in it when i did the headers but wiith it going into limp mode its been running really rich and you can smell raw fuel, so basically im wondering if i may have fouled out the plugs driving it in limp mode, any help would be appreciated im doing this on a tiny budget which is why the car is still open headers but i need to get it running right its my only car right now

LS6427

iTrader: (2)

Open headers?? You mean literally open at the collectors?

So do you have the two 02 sensors in the collectors?

You may have a spark plug wire touching a part of the exhaust manifold piping...if so you will get misfires for that cylinder.

As far as running rich...usually a bad or failing 02 sensor will do that, and it will cause misfires and gove you a code for that. But I think open headers will also act like a big exhaust leak and cause the 02 sensor(s) to wig out and make you run rich also. By gulping too much air from the open collector.

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indyfoxgt

iTrader: (3)

That's what I've been hearing, an yeah its open headers, but the thing is if it was the 02's making it wig out wouldn't it throw an 02 code? Im coming from an 89 Mustang so all this stuff is kinda new to me

LS6427

iTrader: (2)

NO, one thing most people don't know about these PCM's is that they do not throw codes for some things until that part/component is totally failed. Also, all PCM's in these cars are not created equal. Some will throw codes for every damn thing and throw them while that part is still working, but on its way out. Then other PCM's will not throw a code till that part is 100% failed.

My car will not throw a code for failing 02 sensors until the engine is running so bad it'll hardly move the car. I also didn't get codes for crank shaft position sensor, TPS sensor, MAF and IAC valve. Kind of suckes because it makes it kind of like an idiot light of the 1970's cars....it tells you something is bad AFTER it fails.

You're probably sucking air into the collector and the 02 sensor is getting little sniffs of that fresh air.....making you run rich. Its just like having an exhaust leak after the 02 sensors in the collector, that is too close to the 02 sensor....air will get sucked into the collector through that leak and the 02 sensors will get a sniff of that fresh air and throw everything off. But the 02 sensor is not bad....its just sniffing too much fresh air. So you run rich.

I had this happen when I had a little hole in my collector about 8 inches after the 02 sensor. A shop told me to just go get that hole welded shut. I did and it was instantly fixed. But I was running rich and the engine had power loss at certain rpm's.

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indyfoxgt

iTrader: (3)

ok thanks for the info, pretty much what it comes down to is i need to get the rest of the exhaust lol,

LS1aiden

If you have open headers the system is going to run lean, just connect the rest of your exhaust and reset your code and you should be fine if not you might need a tune! and to be on the safe side i would get new o2 sensors. And make sure your battery cables going to your starter are free of those headers cuz if they touch and the heat eats past the insulator on the wire you'll fry your battery,cables, and your whole car will just shut off!