Ultimate chip O2 readings. BG, help.

[Eluding]

I installed my Ultimate Ver 7 chip today. The truck runs great. I recorded some full-throttle runs in T1 15 psi and I'm puzzled about the O2 readings. I run in a place that is about 1/4mile long. From the launch to 3340 rpm in 2nd the O2 readings were in the .070s . The average knock retard was 5 degrees. After thatl, for the remainder of the run, the O2s were recorded averaging .880. Still with an average knock retard of 5 degrees on 91 octane. Throughout the testing the truck felt VERY strong. Now I know that there is NO way that that it was running as lean as .070. At the very least the truck would have dogged and fell on its face. But I'm not sure why it is showing these numbers. I never had this phenomenon before. In fact, I reinstalled the stock chip afterwards and throughout the test run it was showing O2s in the .920s, never showing a .070. Which is the approximate to the stock chip numbers I had before the Ultimate install. I'm just wondering why I am seeing these funky O2 numbers?

 

[TurboTony]

Just to make sure...

You did install a 3 bar sensor and adjusted the fuel pressure for the ultimate right?

Just wanna cover the basics


Tony

 

[Eluding]

Yes, brand new 3-bar sensor and fuel at 50 psi. I just know that it is impossible the truck is that lean. It simply would not have accelerated as well as it did...and the engine would be blown. But it runs very well. But for some reason the O2 millivolts are incorrect when processed through the ECM and recorded on my scanner.
I thought the O2 sensor might becoming lazy, but when I swapped the stock chip/2 bar sensor back in, the O2 reading was normal throughout the run.
Ultimate/3 bar goes back in and again the O2 is reading funny. I don't get it.

 

[smeagol]

The stock chip does run rich.

Again, basics, what mods does your truck have? Curious if the v7 is too lean for yours first off.

 

[Eluding]

Brian, the Sy has mildly ported LB4 heads that I recently installed because the stockers had leaking valve guides. The runners are untouched, the bowls are blended and the combustions chambers are polished. I also have the Dequick AFPR, a Walbro 255 pump, Jabsco pump(grounded to run constantly), rubber IC lines, Spal on the heat exchanger, KB cold air, and a 3" after cat exhaust with a Flowmaster muffler. Fuel pressure is rising properly with boost.
I'm thinking it is just a processing error in the ECM. I can't have O2s in the .070 range and the truck run as well as it does.
When I first bought the truck the stock fuel pump was dying and I was seeing O2s around .780. The truck was very slow and retard was maxed out. So I'm sure that less than .780 the truck would not accelerate at all.
The truck is just running too good. Your Ultimate chip has the Sy running strong.
For information, I'm at 5,800ft above sea-level.
Thanks in advance.

 

[Eluding]

Did another run today. The O2 readings were the same. In the .070s. I. E. almost zero fuel. However, I pulled the plugs and they looked good. I'm going to try a new O2 sensor. It is the only thing I can think of causing this weirdness. It is only a year old. But ya never know.

 

[Eluding]

Well, tried a new GM O2 sensor, no change. The stock chip has realistic O2 readings. However, the Ultimate is basically reading almost NO fuel until the second half of 2nd gear. Any ideas? It is kind of frustrating. Is this a problem anyone else has experienced? What am I missing? Thanks in advance. Any help would be appreciated.

 

[smeagol]

I've seen this before, but not associated with our chips.

I think it is either of 2 things causing it

1- the chip calibration, in your situation (the slight mods done & the elevation)

2- a mechanical problem on your truck, where the rich stock calibration masks it, but the ultimate running leaner exposes it


thoughts:

try version 6 chip, which is richer

check your fuel pressure, i know you said you made sure to see it was following boost, but try and make sure there is no lag to the fp rising to follow boost. have you tried higher fuel pressures? is it possible your gauge is off ?

are you confident in your ability to swap an eprom ?

 

[Eluding]

Brian, thanks for taking the time to help me with this problem.
I know that I've swapped the eprom correctly, I've done it a few times and your chip installs easily.
The fuel pressure seems to rise just as quickly as the boost gauge. I haven't consider that the gauge may be off. I'll round up a gauge to borrow to cross-check my fuel pressure. So far I have only tested 50 psi base. I haven't tried a higher psi, which I will do when I verify my gauge is accurate.
Mike, at AR, is actually sending me a Version 6, that I intend to use for a 20g install. The 20g will have to wait until I fix my problem. I'll try the Ver. 6 on the stock turbo when I get it.
Thanks for the ideas. I'll let you know what I find.

 

[smeagol]

Brian, thanks for taking the time to help me with this problem.
I know that I've swapped the eprom correctly, I've done it a few times and your chip installs easily.
The fuel pressure seems to rise just as quickly as the boost gauge. I haven't consider that the gauge may be off. I'll round up a gauge to borrow to cross-check my fuel pressure. So far I have only tested 50 psi base. I haven't tried a higher psi, which I will do when I verify my gauge is accurate.
Mike, at AR, is actually sending me a Version 6, that I intend to use for a 20g install. The 20g will have to wait until I fix my problem. I'll try the Ver. 6 on the stock turbo when I get it.
Thanks for the ideas. I'll let you know what I find.

I wasn't questioning your install, I was just asking so as to be able to send you a version 6 chip to swap in. The eprom is the actual chip that has the cal info on it, even though we refer to the whole assembly as the chip.

Let me know how the v 6 or the fuel pressure changes affect it.

I'd do the fuel pressure testing first, since the v7 *should* be fine for your truck.

 

[HighPerformanceTrucks]

Maybe something else to consider is the lack of resolution of the stock 02 sensor.

I've learned from my Mitsubishi Galant VR4 experience not to trust the O2 mv readings, rather tune by KR. A wide band setup would be the exception. As far as I'm concerned the A/F monitor is an expensive means of telling me the O2 sensor is clogged or functioning properly.

Adam Auerbach
Sy #2419

 

[smeagol]

This is a good point. FWIW, I believe Tony's truck shows like 800mv range in boost now, and those guys did a LOT of wideband 02 tuning, so his is right on as far as tune goes. I don't think that trucks should tune for 800mv or anything like that, just that this *may* be a case that shows what the stock 02 is worth.

 

[Eluding]

HeeHee, whoops. Sorry I see what you mean by the eprom. I shouldn't have a problem, however, any special trick to it?
I'm borrowing a friend's fuel pressure gauge on Monday to double check for the correct psi.
Thanks.