The set up:
88 CRX si
1st gen b16
obd-1 p28
obd-1 conversion harness by blown90hatch
hondata 4b
FJO wideband

Now for the problem. No matter what I do I can't get hondata to read the correct values from the fjo. The voltage from the fjo is correct using a multi meter but when i hook up the wires to the stock o2 sensor wires and connect rom editor the voltage is way off. I tried putting a diode in the ground wire like hondata says on the website regarding cars that have an earthing problem, but the radio shacks near me only had 200v 1A diodes. The reccomended diode is 50V 1A. Is the diode that different? Anyway, the diode made no difference in the voltage readings whatsoever. I also had the same problem when my car was obd-0.

I'm hooking the wires from the FJO up to the o2 sensor wires right at the ecu. They come off the conversion harness and are there to hook up to a 4 wire o2. I loaded a map in open loop so the ecu isn't looking for an o2 sensor.

I also soldered a 1K ohm resistor across the wires for the o2 heater circuit but I'm still getting a code for the o2 heater.

The only thing i can think is that there is something not compatible with the conversion harness, which I find very hard to convince myself of considering the number of people using blown90hatch's harnesses with no problems. The one thing that confused me about the harness is that the four wires that come out of it to be attatched to the 4 wire o2 all stem from another wire that goes directly from plug to plug on the harness.

Any experienced tuners run into this? Anybody at all run into this? I'm going to post it on the hondata forum too.


[Modified by racerxadam, 9:01 AM 10/21/2002]

 

This is what I mean by " the four wires that come out of it to be attatched to the 4 wire o2 all stem from another wire that goes directly from plug to plug on the harness." The boxes represent the plugs that go to the ecu and factory wiring harness. There are way more than those four wires but they aren't needed for the drawing. The blue lines are wires that were left unattached for connection to a four wire o2 sensor. They were all labeled and came with instructions as to which wire went to what on the o2 sensor. My confusion is to why the inputs for the ecu would go to anything in the factory harness.
Please pardon the crude drawing.
I really need someone's help. I'm beginning to think I will never be able to tune my car. This is really discouraging. I spent a lot on the 4b set up, then the FJO so i could do it right. When I had my obd-0 set up in there i ran the scenario by a respected hondata dealer and he said he doesn't touch cars with the obd-0 ecu's. After hearing that I decided to switch and now I'm having the same problem.

I know my equipment is good because I have used it to do tuning on 93lsivic's car on more than one occasion and everything works flawlessly. The voltages are always the same and the a/f readings are the same from the led readout to the value in rom editor.


[Modified by racerxadam, 1:59 PM 10/21/2002]

 

racer i have similar problem....and basically the same type of setup. My wideband output is not the same either. I can't get it to match up. I'm almost convinced now that RomEditor is the problem. I first tried setting it up using lambda values...and it simpy didnt work at all cause it rounded them rediculously. You can read my thread at:
http://hondata.com/bb/viewtopic.php?t=111 Where hondata ever so convienently skips replies...

The only way to get romeditor half way to work is using the a/f ratio...but then it also rounds that. (not near as bad as using lambda values) I think it rounds the A/F to the closest lambda value it has based on that a/f conversion to lambda. I see my wideband display readout and hondatas...and im more inclined to believe my LCD.... I dont know what or how RomEditor is deciding to round the values...noone seems to know...Hondata including. I emailed direct and i got some half-assed reply.

Does anyone know at what refresh rate romeditor gets the a/f voltage? Maybe thats why they aren't matching. It's usually not WAY off, but most of the time it looks like a full point at least. I guess we should ask the question who's romeditor a/f matches their widebands displays?


[Modified by true, 8:10 PM 10/21/2002]

 

oddly enough I haven't encountered the rounding of values most people speak of. I always enter voltages v. a/f not lambda values. My problem is that the voltage being output from the wideband is different from the voltage displayed as o2 voltage in romeditor. The actual voltage that romeditor uses to convert to a/f ratio is displayed right next to it and that is what differs in my application. I circled it here.

 

so many views, so few replies. I'm not going to let this thread die until I figure it out so you tuners that have the answer and are sitting on it better stand up and be counted

 

Man I wish I could help.
I am starting my newly rebuilt car this Wednesday with 4b and FJO.......hopefully I won't have your problems, but maybe I can figure out some **** then. Good luck!

 

Sorry I can't help at the moment, but I just wanted to say that shortly I will be going to almost the exact same setup. I will be running
91 Si
B16
P28 Ecu with conversion harness (blown90hatch)
Hondata 4b
Tech Edge WB

I will keep my eyes open for this same problem, and watch this thread..
Hope you get it worked out.

 

try to get in touch with GruvyTune. I think he got it to work but im not sure if he even had the same situation as you. Even if he didn't, he may know the answer. I know its a longshot but you seem pretty desparate and im just tryin to help...good luck

 

Can someone give me the ecu pinouts for the four o2 sensor wires so that i can make sure I'm using the right ones? This is a p28

 

Racer your screenshot of that voltage is the same problem that I am having...I was giving the rounding as an example of why I wasn't trusting RomEditor. I am using p28 too (obd1 conversion)

A6 - o2 heater control ORN/BLK
25 - o2 heater ground YEL/BLK
D14 - o2 signal WHT/RED
D22 - o2 signal ground GRN/BLU

That's how I have mine.

 

you should read hondata's response on their forum to my post there. http://hondata.com/bb/viewtopic.php?t=183

is it A25 as well for the second o2 heater.

 

is the diode in the correct orientation?

 

I think we need to trace SG2 in the crx helms. Maybe on the obd0 cars it grounds to chasis or another harness somewhere before it hits C12. I'll try and look tonight if you don't. Also, I have not tried the diode..but it seems like a hack. If there are impurities on that wire, I want to get them off..not just block them.

 

I forget, right now, what the correct orientation is but i know i wrote it down and had it in my hand when i soldered it in.

 

I agree that some wire tracing has to happen, unfortunately it will have to wait until thursday because i have some tests to study for.

I wonder what would happen if i just cut those two wires out of the plug that goes to the wiring harness side of the conversion harness and just had the wires coming straight from the wideband to the pins on the ecu with nothing else being attached to them.

Please post if you find anything. I am very interested in fixing this so i can get my car tuned and then proceed to beat on it relentlessly. After all the headaches i think I deserve that satisfaction...hehe

 

Hey I've gone through all the headaches as you...I think i told you to convert to obd1 on the old hondata board cause the obd0 headaches were much worse.

Right now all my wideband wires go directly to the ECU. The only one i have 'tapped' is SG2 (D22)...which is TPS ground and where the obd1 ECU's touch it. The only wire to trace is that.......and I don't see how it could cause a problem even if that 'ground' touches the chasis or another ground by the time it gets to the ecu...

 

up.

On the hondata message board hondata told me to make sure that pin D22 doesn't get grounded by the conversion harness. However, upon opening the ecu up and using a multi meter i found that pin D22 has a direct connection to pin B2 and looking at the factory wiring diagram for the civic that came with the p28 pin B2 goes to a chassis ground in the engine compartment. I also tested another car that came with p28 and has not had any wiring done to the ecu harness and pin D22 has continuity with ground. I am confused as to why hondata would say that it shouln't see ground if it does in a factory application.

Any way I got the voltage within .2 volts of the actual reading from the multi-meter but I can't get it to exactly match. By grounding D22 very tightly the voltage read by hondalogger dropped significantly and came very close to the actual measured voltage. I don't know where to go from here guys, I need some help.

 

I have not had any problems, but I am using a motec wideband. You should talk
to my friend slowteg as I think he has had this issue with his techedge setup.

 

racerx has FJO wideband.....I'm having the same problem with diy-wb.

 

mine works just fine. i use the techedge wideband that i built myself. there is a problem with the hondata system rounding voltage numbers that persists even into the new version or romeditor. i think i emailed them about it but have never heard back. you cant really enter lambda values: voltage but are obligated to enter air fuel values : voltage and its easiest to just do it in the registry settings. my hondata values are always a little bit higher than my led readout and i am soon going to try putting a diode in line with my ecu signal to see if that helps. either way, it all works for me. i just tapped into my signal output from my wideband controller and paralleled the signal to my stock o2 sensor harness.

 

Yeah, unfortunately I've been having the same damn problem. I've really been too busy to really set aside a whole afternoon and try and get it working, but I'm having the same problem you describe... The voltage read by the ecu (checked through the datalogger), is different than the voltage read by the multimeter. I tried using a diode according to hondata's recommendations and it did nothing. Literally, nothing.

Oh I'm sorry I forgot to mention, I have the tech edge wb kit, I got it prebuilt. The first day I was hooking up the tech edge kit to the hondata and I was checking the voltages I noticed something strange... If I use the signal V output from the wideband and a chassis ground instead of the correct sensor ground, the voltage matches the voltage the hondata displays... weird.. So the ecu definetly appears to be seeing the wrong ground, but I have no clue how that could be fixed.

I can't remember exactly how far the voltages were off because this was a while ago, but the difference in a/f in the rom editor and wb led display was like 1.5:1 leaner.. which is around .3v i think..

It looks to me like the only way around this is going to be just going w/ the screwed up voltages and just figuiring they're a certain % off, and tuning the car that way. I just really need to find the time to play w/ it.. Good luck..

-Mike

 

Hey Torin, as well as everyone else, where are you guys getting the power and ground for the wb from? Right now I'm using the cigarette lighter, but it really shouldn't cause a problem.. but at this point I'm up to try anything.. Maybe grounding it straight to the chassis would be a better idea...hmm

-Mike

 

Hmm.. well just tried switching the power/ground and hooked them directly to the battery and same ******* problem.. So.. it definetly appears to be something wrong with the hondata/honda ecu/or who knows what. The a/f ratios are about 1 point off leaner so I guess I'll try and deal w/ the problem..

Torin, so Romeditor v.3 doesn't fix the problem w/ the a/f values being rounded off? That sucks.

Oh well, definetly disappointed I can't get this pos to work.. Definetly makes me wonder whether it's even worth upgrading to the s200.. $300 is a good chunk of change if it's not going to do much more..

-Mike

 

I was talking to Dustin and he gave me a good idea on how to calibrate the conversion chart in hondata to compensate for our problem.

take two AA batteries and wire them in series to come up with a total output voltage of 3 volts possible. Then wire it to a potentiometer so you can vary the voltage output. Wire the outputs from the potentiometer to the inputs for the o2 sensors on the ecu. This way you can set the voltage coming from the batteries and measure it with a multimeter. Then hook it up to the ecu and see what the reading to the ecu is. Using the reading from the multi meter you can cross reference the a/f ratio that corresponds to that voltage and input it in the conversion chart for next to the voltage that hondata reads.

That is kind of confusing but maybe someone else can explain it better. You would have to do the steps a few times to fill in the conversion chart but it might make a very good solution versus figuring out why our grounding is wrong.

 

some aem guys have had the same problems, ground the fjo ground to chassis or at least farther back on the ecu ground wire.
Sensor ground to the ECU ground wire, not the sensor ground