Heated O2's

[tkoforpresident]

Well I found a write up on how to switch over to heated o2's that will aid in my cam build since I would really like to switch to the 19lb injectors i just bought. Buying these sensors: http://cgi.ebay.com/ebaymotors/ws/eB...m=180241333266

they come with 4 wires. One for pcm signal reference, one for 12v power, the other two are grounds.

by simply cutting off the old sensor connector you splice into that one wire with the pcm signal reference wire. The 12v wire can go to any wire that carries 12v while the car is running. The other two can be meshed together and put at a good ground point.

I've got a good idea about what to use for a ground point ( the stock ground point on the passenger fenderwell will do )

but what's a good wire to tap into for 12v ? It needs to carry 12v while the car is running ideally, though i wonder if i hooked it up to a "key on" 12v wire if i could warm up my heated o2's just by turning the car in "key on" position a minute before start up



they ARE expensive at 42 bux a pop but when you think of the savings with fuel economy it only makes sense.

My 19lbers will probably run rich otherwise at start up.

Finally, a question regarding fuel pressure.

I'm already planning on going with a holley afpr for my heads/cam/intake build, the idea being to UP the fuel pressure with the stock 17lb injectors. The idea also being that if i had gone to bigger injectors i would have to LOWER pressure as to not run rich, however with the heated o2's installed would I be good to keep the high fuel pressure with the bigger injectors?


sorry for that whole mouthful but i'm still figuring out podunk ways to ghetto tune this bad boy!

I should note, the point here not being to fine tune AF ratios but rather cut down on open loop operation times.

[usp55]

Re: Heated O2's

are u planning on any other power adders on your setup? and are u sticking with the 260 cam? if so honestly i would'nt bother with the hassle of upgrading the injectors at all and them trying to add heater o2's and then trying to "ghetto tune" the system.

two points i want to make

1. Ive been told by very respectable sources and from findings in some good forum posts that it better to amp up the pressure on an injector to get more fuel and keep a nice spray pattern than to reduce pressure on a larger injector which will in turn produce a more undesirable spray pattern.

2. If your not running any other upgrades other than the cam setup than u dont "need" much more fuel that the stock ones provide. I have been running the 260 cam setup for several months now and my long term fuel trims are spot on and i only run a tad rich at idle.

The power increase was nice and I was able to realize it today when i swapped my heavey TT's with 315's out back for my stock salad shooters with 235's on them and completely smoked them at a red light today squealing from the red light almost all the way through the intersection. Got sideways a little but stuck it out and was nothing but smiles the entire way home. It was really the first time i had some fun with the upgraded posi reared too.

Again if u are planning on more power then just the 260h comps cam and 1.6 rockers then i agree with upgrading the injectors and maybe trying to put a FMU in the system aswell, but if not; just use the AFPR and stock o2's and call it a day.

just my .02

[tkoforpresident]

Re: Heated O2's

are u planning on any other power adders on your setup? and are u sticking with the 260 cam? if so honestly i would'nt bother with the hassle of upgrading the injectors at all and them trying to add heater o2's and then trying to "ghetto tune" the system.

two points i want to make

1. Ive been told by very respectable sources and from findings in some good forum posts that it better to amp up the pressure on an injector to get more fuel and keep a nice spray pattern than to reduce pressure on a larger injector which will in turn produce a more undesirable spray pattern.

2. If your not running any other upgrades other than the cam setup than u dont "need" much more fuel that the stock ones provide. I have been running the 260 cam setup for several months now and my long term fuel trims are spot on and i only run a tad rich at idle.

The power increase was nice and I was able to realize it today when i swapped my heavey TT's with 315's out back for my stock salad shooters with 235's on them and completely smoked them at a red light today squealing from the red light almost all the way through the intersection. Got sideways a little but stuck it out and was nothing but smiles the entire way home. It was really the first time i had some fun with the upgraded posi reared too.

Again if u are planning on more power then just the 260h comps cam and 1.6 rockers then i agree with upgrading the injectors and maybe trying to put a FMU in the system aswell, but if not; just use the AFPR and stock o2's and call it a day.

just my .02

your absolutely right on many counts, the stock fuel system is usually quite capable. While i'm not running forced induction, I will be running with the 260 cam, p&p heads, p&p uim, p&p lim, p&p tb, 1.6 rockers and full intake & exhaust. So as you can see, it will be N/A but it will be pretty beasty.

i'm getting the notion that sticking with the stockers at high pressure is the ideal way to go. I did buy some 19lb injectors for about 30 dollars so i will hold onto them if i ever go the route of megasquirt which hopefully i can do some day because I'd love to fool around with spark control and fuel tables.

btw, what pressure do you run on that fpr?? 47?? 50??

and can you tell me the procedure of setting the fuel pressure? I know you have to do something with one of the hoses or something of that nature.

[nascar24jd]

Re: Heated O2's

How do the heated O2 sensors shorten the open loop time? Is that something that you need to uopgrade when you switch to larger injectors? Interesting info...

[tkoforpresident]

Re: Heated O2's

open loop is not on a timed basis like some people think. The computer will go into closed loop as soon as it starts getting signals from the o2 sensors. the single wire sensors take a number of minutes to warm up while the heated ones take just seconds.

this keeps the car from running off set tables in open loop mode which are usually rich, especially if you've got bigger injectors in there.

[nascar24jd]

Re: Heated O2's

open loop is not on a timed basis like some people think. The computer will go into closed loop as soon as it starts getting signals from the o2 sensors. the single wire sensors take a number of minutes to warm up while the heated ones take just seconds.

this keeps the car from running off set tables in open loop mode which are usually rich, especially if you've got bigger injectors in there.

Makes sense. Thanks for the lesson.