Str8Down

So, I have a gound hooked to my AN2 input on my datalogit, for reference for my wideband on AN1. I have seen as much as .5v on AN2. How bad have you guys seen on yours?

moconnor

iTrader: (14)

Looking at one of my logs, I see a median value of about 0.2V but up to 1V.

arghx

iTrader: (3)

what exactly are you hooking up?

cewrx7r1

iTrader: (2)

I tried using AN1 (WB output) and AN2 (WB ground) with the delta function but did not like the results as my AN2 value also fluctuated. This did not make sense to me. Also had a noise filter (capacitor) across them.

My solution was to run the WB ground to the DL box ground (an internal mod) and only use the AN1 with the noise filter across it and the ground.

Has worked great for years.

moconnor

iTrader: (14)

Hey, you don't mention that in your notes.

I don't understand what this means. You mean you use an in-line noise filter between AN1 and the signal?

cewrx7r1

iTrader: (2)

Different WBs have different oddities. Many people do not understand even basic electronics and are not comfortable in opening up boxes and modding them.

The noise filter that comes with my PLX goes across AN1 (WB +0-5vdc) to the WB to DL box ground to. If you put it in-line (series) between the WB and DL, the WB to DL interface would not work.

moconnor

iTrader: (14)

That's what I assumed. I didn't realize that the PLX came with a noise filter.

I get pretty consistent (or, at least, repeatable) results with my TechEdge (V1.1) hooked up to AN1 and AN2 using a polynomial to calculate the AFR but anything other than ~0V on AN2 is not inspiring.

As per your notes, I am about to try a filter on the TechEdge power signal, though the effect may be marginal.

Str8Down

Chuck, unless I am incorrect, the whole point of the delta AN1-An2 is because AN2 actually sees voltage from ground. So without negating that voltage with the delta, then the voltage coming from the WB analog at to AN1 (which is based off the heater ground, which is also seeing this "ground voltage")could vary by the amount that would have shown on AN2. Since Mconnor said he sees as high as 1v at times, that is a 20% variance. If not accounted for by using the delta function, your AFR's could be off by as much as 20%.

I am pretty good with electronics, but prob not as good as you are, so correct me if that doesn't sound correct.

cewrx7r1

iTrader: (2)

The ground potential between the WB and DL ground is different.
This floating ground causes a voltage difference. The ground is not 0vdc.
This intern would cause the DL measurement of the WB 5 vdc to also be off by the difference.

That is why they said to use the AN1-AN2 in delta mode.

When I tried delta mode on my two WBs, the AN2 ground voltage fluctuated on both along with the WB 5vdc output. Thus it was doing delta from two flucuating signals.

Not liking or knowing why this happened, I decided to get rid of the ground problem by connecting both the WB and PFC and DL grounds together. Now there isn't any ground difference between the three pieces of equipment!
UNIFORMITY & STABILITY!

This made using the AN1-AN2 delta usless. Now only AN1 is needed for the WB output.
The noise filter/capacitor between AN1 and ground shorts out any noise from the ignition or other sources.
************************************
If you have and read my tuning notes, I go further by calibrating my DL software on my laptop to record the same value as shown on the WB display.

It is like THX (those into AC3 Surround Sound movies) standards. If you system can not handle or is not setup properly, the DVD soundtrack will not sound like it was ment to be. That is why I use "Video Essentials" and "DOLBY DVD Spectactular" to setup my sound system and TV picture.
Those $1000 or less systems just can not do it!

Str8Down

Ahh, I see. I grounded the Heater, the WB and AN2 all to the same spot. That should also rid me of that issue.

arghx

iTrader: (3)

^ I don't know what wideband you are using, but I made a thread a while back with a diagram for my LC-1 and datalogit setup. This is using the Delta AN1-AN2 feature.

https://www.rx7club.com/power-fc-forum-47/my-power-fc-lc-1-xd-16-datalogit-wiring-diagram-707298/

For the innovate at least, they specifically recommend that the heater ground is grounded separately from the analog and system ground wires. I had the system ground wire for the wideband, the analog ground wire from the wideband, AN2, my wideband display, AND an extra ECU ground I added all grounded to the same location. But the heater was grounded separately. Then I use the Delta AN1-AN2. I have had no noise problems.

I had another friend who was having electrical noise on his LC-1 and he ran a ground wire from the block to the location of his system and analog grounds (with the heater ground separate). He did not have an extra ECU ground like I did though.

Str8Down

I know that they state that, but electrically it doesn't make sense. That will promote a ground voltage difference between the heater and the WB.

cewrx7r1

iTrader: (2)

The only grounds that are important are between the WB output and DL. The WB heater ground has no affect on the WB output.