Open header issues

[zukijames]

With my mass air hooked up I had to adjust my idle way up to get it to idle around the same rpms it did unhooked(limp mode runs really rich on 1uz)

yesterday on my drive it seemed like it was kinda revving out really early like didn't wanta rev past maybe 3000 ish

So on the return trip I unhooked it reved higher but flooded going down hill coasting in gear and left me going 30 with no steering or power brakes down a hill



my question is could just having the open header make it so the exhaust pulses are not leaving the engine? Or something

 

[cjncustoms]

Are your o2 sensors hooked up?

 

[zukijames]

Yeah just got them yesterday .

and was all excited for it to run better and it made things worse but it might just take awhile for it to adjust/learn

 

[Tacoma]

Open headers screw up backpressure, which has a variety of interesting and usually detrimental effects on computerized tuning. Get the exhaust finished. On carb'ed vehicles this is a lot less of an issue.

 

[zukijames]

I ran some PVC for about 2 seconds and it seemed alot better I might have Mitch at u fab do the exhaust

 

[UFAB]

Is that a closed loop system ? Does it have two O2 sensors or 4.

How is the MAF

Also MAP sensor is a big deal

Tuning can be a parr of it.

We have ran open header ls motors with no problems.

Sent from my SPH-L720 using Tapatalk 2

 

[Tacoma]

I was thinking of the 02 sensors, which are generally downstream of the headers-- at least one, anyway. GM engines are just better in every way. Especially LS motors.

 

[reddman]

I feel pretty confident I know what your issue is, if I'm envisioning this scenario correctly. So you have open headers, with an O2, and it is running rich. I assume the O2 sensor is near the collector of the header. Each pressure pulse that fires out of that collector, is directly followed by an area of very low pressure, which at the open end of a header, will suck in atmospheric air into the collector (with more Oxygen than your O2 sensor is expecting to measure in your exhaust), therefore tricking your ECM to think oxygen levels in the exhaust are too high, and fuel levels are too low.

Put an extension on that header (or just build a proper exhaust) and I bet it will solve the issue.