Pocketlogger, Fuel Trim, and Wideband

[architechnik]

I have been working on updating/upgrading my entire a/f system from intake to fuel delivery. I have been using a pockerlogger (MMCd) for a few weeks to become comfortable with the stock readings before switching out the parts - I want to know when something looks/reads different.

I could use a few translations about the pocketlogger readings:
I have a few concerns about the fuel trims - The high, mid, and low read the same thing (96.8/98.4/94.5 respectively) no matter what the rpms, maf, or throttle read.

The TPS reads at around 9.7% at idle and the highest reading displayed is around 84% - even at WOT. I hardly ever recognize a change from the engine between around 65% and WOT. (And it actually spools faster at around 65% than WOT!) What could cause this?


My current upgrade/mod will involve an afc, fuel pump, fpr, and 2g maf/intake. I'm planning on getting a wideband 02 to tune everything in, but as I am reading the various posts, they seem to refer to different things.

I thought it was the sensor, but it appears to be an actual translator? Some sales places refer to just the gage as the wideband, but I'm pretty sure the stock sensor will not create the correct signal.

If I am using the pocket logger (MMcd, OBDI, or DSM Logger) what exactly do I need to get accurate readings (for the most effective use of $$)?

 

[DBordersX]

Wideband refers to the sensor itself. Wideband sensor have a 0-5v output and Narrowband (stock) sensors have a 0-1v output.

I think you can get just a wideband O2 sensor but I'm not sure how you would read the voltage. Maybe you can wire it into the ecu like a regular O2, I don't know.

Usually the sensors come in a 'kit' with a gauge or display of some sort so that they can be read by the user. Some just show voltage and some show an AFR calculation based on the voltage.

Hope this helps.

 

[bling5tatus]

Most widebands also have a simulated narrowband signal as well in which you can connect to your ecu and your blinky light gauge and still pretend you have a narrowband.

I bought an lc-1 and it doesn't come with a gauge, you can just use it to log the voltage of the wb and tune from there.

Also, the wideband o2 sensor must use a seperate controller... which is either built in to the cable like the lc-1 or some widebands have it built into the gauge... it just depends, but wideband definitely needs a controller for it. I think that's what you were referring to as the "translator".

 

[Calan]

I have a few concerns about the fuel trims - The high, mid, and low read the same thing (96.8/98.4/94.5 respectively) no matter what the rpms, maf, or throttle read.

This is normal. High, low, and mid trims are only adjusted under certain steady-state conditions by the ECU. In simplified terms, they provide the ECU with a prediction of what it's going to have to adjust, based on recent trends.

The TPS reads at around 9.7% at idle and the highest reading displayed is around 84% - even at WOT. I hardly ever recognize a change from the engine between around 65% and WOT. (And it actually spools faster at around 65% than WOT!) What could cause this?

Theoretical range is 10% to 100%, although I usually see 10.5 to 98 or so. Your TPS (throttle position sensor) needs to be adjusted... this isn't hard to do, but needs to be done with care and along with some other adjustments such as throttle cable, base timing, BISS, IPS (idle position switch), etc. Check your manual or www.vfaq.com for procedures.

I thought it was the sensor, but it appears to be an actual translator? Some sales places refer to just the gage as the wideband, but I'm pretty sure the stock sensor will not create the correct signal.

You need a WBO2 sensor and control unit. You can't "just hook up" a WB signal to your ECU, unless it's had a custom eprom burned for it. (although if you have an unused input such as EGRT for non-cali cars, you can run the 5v signal from the WB controller into it for logging purposes. Most logging software will even allow you to select this option and display the AFR).

I've had good luck so far with my Zietronix, but I've also heard good things about the lc-1 that Bling mentioned.

If I am using the pocket logger (MMcd, OBDI, or DSM Logger) what exactly do I need to get accurate readings (for the most effective use of $$)?

I use both PL and MMcd... I've recently discovered a significant difference in the coolant temperatures that they report, but I don't know which is more accurate. I'm currently looking to find any other discrepencies. See this thread for more info:

http://www.dsmtuners.com/forums/showthread.php?t=267532

 

[architechnik]

Thanks guys - this has been one of the most informative response sets that I've seen.

The throttle cable was definitely part of the problem, as it was a good 1/2 - 3/4" past prime adjustment. It seems that it actually tightens when it's hot, which seems counterintuitive. I was idling at 1k when I was done test driving the new response, but adjusted it back just a hair.

I haven't double checked TPS at WOT again, so I don't know where it will peak.

Thanks for the input on the wideband setup. As I understand, wideband O2 is just the sensor, but the stock ecu will not be able to recognize the varied voltage so a controller is required.

I'm guessing (as I have a cali model - EGRT) that I will require another display. Are there any afc's out there that have this display available? do they all?

 

[bling5tatus]

I believe the afc can show o2 sensor voltage... your best bet is a logger though.

 

[Calan]

But he has a cali car, and therefore no EGRT input that he can hijack.

If the AFC has an additional input for AFR, that would work. Otherwise, whichever company you go with for your WB should have several display options, some more expensive than others.

I can't speak for the others, but the Zietronix also has logging software (for a laptop, or palm with pocketlogger addon) that supports EGT, boost, tps, RPM, and a "user" input.. along with the AFR/Lambda values. They also have a couple of display options available.