I own a 2001 Ford SVT Lightning. After cutting off the converters to the truck and putting a 40 series flowmaster exhuast on it, it began to act up quite a bit. It was fine before I cut the converters off. I took of the O2 senors also. Ever since then my truck wont idle, but will still turn on but wont idle without holding the gas in. It does it when I am in park and in any other gear. I was wondering if the 02 sensors would have anything to do with this problem, or what could be causing this. Greatly appreciate your help. Thanks in advance!

 

YES,,more than you realize.without the 02 sensor your computer may falsey .sense an overly rich engine and lean the fuel system out to the point it will destroy you engine.
At the least you mileage and performance will suffer.the missing sensor will cause your idle problem

 

I appreciate the fast response....Would I be better off getting o2 simulators, or just cutting a hole in the pipes and welding the o2 sensors in them????

 

Most people turn the back sensors off in the program and keep the front sensors in.



Charlie

 

where is a place i can buy the o2 sensors from for a reasonable price....

 

I get mine from the local parts store.

Charlie

 

but by putting the o2 sesnors on wouldn't it still effect the way the truck will run, especially with no converterors?

 

Yes it will. That why the rear sensors need to be turned off in the tune. And the front one's put back in.

Charlie

 

so how do you get that back ones turned off.....

 

I use a SCT programmer. ( My tuner uses it, I just play with it)

Charlie

 

I have an 00 F150 4x4 with the 5.4 engine.I removed my converters and muffler and put a flow master back in their place.I done this shortly after purchase truck new.I left the 02 sensors in place and have never had Any problems.perofrmance hasnt seemed to suffer and my mileage is about 17-18 highway and I get around 15 towing an 19 foot ranger boat.

 

You cannot legally buy O2 simulators anymore. The EPA just fined the largest manufacturer of them and is requiring a recall of all units sold since 2001.

There is no reason to turn off rear O2 sensors with proper custom tuning. A good tuner doesn't need to turn them off and can provide a tune that will pass a sniffer test.

 

You might want to ask a few more tuners. I know several. And not one of then leave the rear o2 sensors on. They all said the same thing. The rear O2 sensor is a paint to tune around.

Charlie

 

Go ask Mike Troyer, tunes more F150s than anyone. That's his experience and mine as well with all the custom tuning I've done (although I no longer commercially tune vehicles since I got out of the business last year, concentrating on Ford-Trucks.com but still do my own tuning). The only time I've seen a need to turn them off is for highly custom off-road applications.

That ought to tell you something about their abilities or desire to take the time to do it.

Rather than retype everything from scratch I'll quote Mike:

"Guys, with todays' technology, for some years now we have had the ability to make BIG power *and* have clean emissions coming out of the tailpipes - doing things like removing cats, running them way lean, turning off OBD-II tests, etc., is *not* a proper way to tune, at least, IMHO."

"You make make an 800 HP Cobra with a fully catted exhaust - you just have to be a bit creative for those higher hp vehicles, but it can be done, it's not really that hard. I just do not agree with using any value files that turn off rear 02's, turn off the temperature models for cats, exhaust flanges etc (other than temporarily just for dyno tuning for those extremely few vehicles that will actually go rich at the end of a pull), etc. for any street-driven vehicle - it's wrong, causes pollution and simply isn't necessary in a vehicle that is configured correctly."

Charlie, it sounds like the folks you know take short-cuts because they can't tune around the O2s or won't spend the time. I leave the O2 sensors on with all my vehicles (and I've tuned all my Fords). The only thing gained by turning them off is saving time by not properly data-logging the vehicle, doing a wide-band O2 test and getting the A/F mixture correct. I'd rather take the time to get it right.

 

Well the O2 simulators are not hard to find around here! I talked to 5 or 6 people at different ford garages and they recommended that I buy the simulators, because its the easiest way. I also understand though why you would want it done right, but for now I am going to put the simulators on there until I get all the bolt ons and upgrades I want for my truck. Then I will have everything put on and tuned right all at one time...Thanks for everyones input