I have a few newbie questions for you guys.

First, when the ECM is in Limp home mode, does it turn on the service engine light? Or how do you tell when you are in limp home mode? The new combo doesn't throw a code at all, it just runs funny sometimes.

Also, I still have the single wire o2 down in my y-pipe (very close to where the header collector flange is). So, it rarely goes into closed loop (I'm guessing). In open loop the car runs on the smelly rich side, but run's pretty damn good. When the car is nice and warm and when it's warm outside, the car seems to lose ALOT of power (thats when I think it finally goes into closed loop). If she's cold, or if I disconnect the o2, the car is alot stronger. So my question is what tables in tuner cat do I start with for this issue?

I do have a brand new heated o2 from a 92 Astro Van (code Z), but I haven't installed it yet. Would installing this heated o2 help the car run better? Or will it make the motor feel weaker if closed loop perameters are the problem?

I dont have the scanning equipment yet, so I couldn't give any data, but I will have some data soon! I'm guessing BLM's arround 108 by the smell.

Thanks in advance for any help, it is appreciated!
Mike (1bad91Z)

 

Guessing gets you nowhere.
Unless your really good at tune up stuff you'll often be 180 degrees from where you think you are.

Get some sort of scanning stuff going and see where you are, and then make informed decisions..

 

The above actually is a direct question that I do not know the answer to, that is why I'm asking.

Hopefully soon, I'll have a laptop and ALDL cable to get some real data.

Thanks again for being patient with me. This PROM stuff is ALOT to learn, but I'm getting there slowly!

Mike (1bad91Z)

 

Having been there a few times, I can tell you that YOU WILL KNOW!
I have been in "limp home" due to poor chip programming or insertion. In short, the service engine light does come on, the idle is very high (2000 rpm in my case), and the throttle response is almost non-existant. You really do not want ot drive the car at all.
If you had to ask, I doubt that you were in limp home.

 

Thanks for the responses!

However, I read something in a different post that I'm confused about. I think it was Grumpy who said that for "drag racing" purposes that it is better to disable closed loop and just tune open loop perameters and just be in open loop all the time. If this is correct, then how do I gather data in open loop. From what I understand so far, you need to be in closed loop in order for the scanner to collect any data to tune by. Is this correct? And if so, what tables do I modify (tuner cat) to tune open loop perameters and to disable closed loop?

Also, will unplugging the o2 sensor keep the car in open loop or does the ECM need the o2 sensor plugged in to run right in open loop?

Please help guys, it seems the more I learn, the more I get stumped!

Thanks again!!
Mike (1bad91Z)

 

Anyone?

 

For all-out drag racing, you tune the car by
exh temps, plug cuts, and a WB O2 if you have
the means.. I don't think this is what you're
after.

As Grumpy put forth, until you have a scan tool
and data, you're just guessing, and asking others
to guess along with you..

You don't want to run/race the car in limp mode,
and building a true alpha-N open loop race setup
is not for the faint of heart or street car
(IMHO)

Your car will run in a form of "open loop" when
it's in PE (WOT) mode.. You can tune this
cheaply at the drag strip (using a scan tool)
and your O2 voltages, or you can tune it better
(more expensively) on a chassis dyno and a
WB O2 sensor.

I guess in summary, I'd have to say to make sure
you want to talk about a true "open loop" mode
for racing, or the more common PE (WOT) mode
that you can scan and tune in your tunercat
editor..

mike