Question about wideband 02 sensor

[teedoff00]

Hey I am using a AEM UEGO sensor coupled with 550's, lex afm, and aeromotive afpr. So lately no matter what I set my fuel pressure at, usually at like 38 with the vac connected (to high) my AEM gauge reads (---) at idle and then under acceleration it seems to bounce around alot ranging from 10 to 16:1. Is there a way to clean the sensor? It seems like it isnt measuring correctly...? I mounted it right at the bend of the downpipe where it levels with the ground, at about a 2 o'clock position like stated in the instructions? Any ideas or advice any one can give?
Thanks

 

[turbojuiced]

Usually the AEM sensors are good and accurate. I used one for awhile as well. As long as you followed the directions I am not going to ask you questions about the installation process other than making sure your wiring is accurate. If you are certain your wiring is accurate then obviously there is something either seriously wrong with your car or the parts. I would assume it woudl be the parts instead of your car. Now usually its the sensor and soemtimes you get a bad sensor not often this happens but it does.

You should see your afr's high under idle. Then obviosuly they should drop under boost especially at WOT and significantly @ peak.

 

[teedoff00]

Usually the AEM sensors are good and accurate. I used one for awhile as well. As long as you followed the directions I am not going to ask you questions about the installation process other than making sure your wiring is accurate. If you are certain your wiring is accurate then obviously there is something either seriously wrong with your car or the parts. I would assume it woudl be the parts instead of your car. Now usually its the sensor and soemtimes you get a bad sensor not often this happens but it does.

You should see your afr's high under idle. Then obviosuly they should drop under boost especially at WOT and significantly @ peak.

Well I just set my fuel pressure at what I think is high because the afr seems to be way too lean, like 16 at idle, so when I turn the afpr down and the fp goes to like 35 (with vac connected) then the afr's read (---). Which makes sense if I was running lean but that fuel pressure should be about right...Right?? It just seems like I can never get it to read correctly, which makes me worry, cuz I dont want to be running lean and boosting 12-15 pounds...
Thanks for the help guys...

 

[Fletch124]

You could always try a new sensor. Or send it back to AEM.

 

[turbojuiced]

Well I just set my fuel pressure at what I think is high because the afr seems to be way too lean, like 16 at idle, so when I turn the afpr down and the fp goes to like 35 (with vac connected) then the afr's read (---). Which makes sense if I was running lean but that fuel pressure should be about right...Right?? It just seems like I can never get it to read correctly, which makes me worry, cuz I dont want to be running lean and boosting 12-15 pounds...
Thanks for the help guys...

Ok well when its idle its very normal for it to run lean and there is no problem with that. However, under boost if its still reading @ 16 then we have a problem. Either its not reading correctly or you are infact running lean. Here is another way to check if you are running lean.

Do you have a egt gauge? If so if your egt's skyrocket then you are running lean. A lean afr will increase egt's and rich does the opposite.

 

[zurud]

Take the afpr off and put the stock one back on . It happen to me too with afpr. Mine was worst ranging from 20 to 10 during cruising. I put the stocker back on and it behaving normal again. What a waste of 200 buck on the afpr.

 

[bigaaron]

Take the afpr off and put the stock one back on . It happen to me too with afpr. Mine was worst ranging from 20 to 10 during cruising. I put the stocker back on and it behaving normal again. What a waste of 200 buck on the afpr.

That makes no sense at all.

Usually people just don't understand what they are seeing on the wideband display. It's not always going to read 14.7 at cruise, and 12:1 under boost.

If it was really sitting at 20:1 during a steady cruise it would hesitate like a mofo and probably stall.

If it didn't go really lean after you let off the throttle it would be back firing and smell terrible, then bogging when you got back on the throttle. It's called deceleration fuel cut. On standalones it's adjustable, you set the vacuum point for decel fuel cut just below idle vacuum.

 

[jdub]

I have the same set-up, Lex/550/Aeromotive...my AFR at idle (warm engine) is 14.5 +/- with FP at 27 psi with vac line connected (normal config). With the Lex/550, TRSM fuel pressures still apply...33-40 psi vac line disconnected, 23-30 psi with the vac line connected:
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?S=FI&P=73

Teed - Is this on a stock fuel pump and have you tested it for proper pressure?
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?S=FI&P=71


Zurud - I have no idea what you did or what AFPR you had, but I suspect the reason was the same as SC's quote in my sig

 

[tlo86]

That makes no sense at all.

Usually people just don't understand what they are seeing on the wideband display. It's not always going to read 14.7 at cruise, and 12:1 under boost.

If it was really sitting at 20:1 during a steady cruise it would hesitate like a mofo and probably stall.

If it didn't go really lean after you let off the throttle it would be back firing and smell terrible, then bogging when you got back on the throttle. It's called deceleration fuel cut. On standalones it's adjustable, you set the vacuum point for decel fuel cut just below idle vacuum.

i personally have a very vague idea when i look at a a/f ratio... is there any writeup anywhere to help people on this?

 

[isnms]

A/F tuning

 

[turbojuiced]

I wonder if the OP got a handle on it?

 

[sneakypete]

i think you should go over your wiring to make sure your grounds are correct.

 

[turbojuiced]

^Yeah I told him about that too. Even though it looks simple you would be amazed sometimes what gets overlooked.

 

[teedoff00]

Yeah I am running a walbro that I just put in, JDub and pressure is good. So I should probably try lowering the fuel pressure way down to about 28 psi at idle with vaccum on... I will definatly give that a try. Under wot it usually reads fairly rich, nothing close to 16:1. But I am guessing that it is mostly a fuel pressure issue. Thanks for your suggestions guys! I really appreciate it. Now to further bother the forum, what would you guys suggest to check on my attempted but failed 12v upgrade. I ran the 10 gauge with in line fuse from the battery, hooked up the relay, according to the diagram correctly..., I made sure the ground was solid, and connected the relay to the fuel pump. I linked the correct connectors on the fuel pump resistor and then linked the two on the relay. Removed them and it tried to fire it up and it keeps blowing my efi fuse. I tried it with the relay (fuel pump, in engine bay) and resistor still installed with the same issue. I dont get why it is not working, is there something I overlooked?
Thanks guys...

 

[turbojuiced]

man I hate electrical stuff. Ok so you say your ground is good but it sounds like a grounding problem. Where do you have the ground at?

 

[figgie]

teedoff

you do understand the higher the numerical value (16, 18, 20) the LEANER it is right? Lower numerical values is richer (Below 14.7:1 of the Gasoline AFR scale). Under WOT it should be sub 13's and preferably around 12.4 - 11.8.

 

[bountykilla0118]

I will definatly give that a try. Under wot it usually reads fairly rich, nothing close to 16:1. But I am guessing that it is mostly a fuel pressure issue.
Thanks guys...

lol sounds like he is going to blow some shit up ........ "fairly rich, nothing close to 16" wow. I hope you mean very far away from it like 11 or 12's. If not you need to re-read the post with A/F tuning link

A/F tuning

 

[turbojuiced]

^I think that might be a typo. I think he knows what is lean and rich on the afr scale. But I could be wrong.

 

[figgie]

^I think that might be a typo. I think he knows what is lean and rich on the afr scale. But I could be wrong.

never underestimate the power of the JDM Tyteness y0!

 

[teedoff00]

Hey I know that 16:1 is running lean, what I was referring to was my earlier post of how my gauge never seems to read correctly, it fluctuates a lot. By no where near I mean no where near, like 13 or 14. About the relay issue, I have it grounded by where the rear seat backs are bolted to the frame, I grounded my amplifiers there and have never had a problem with them, I also tried another ground before that and then decided the first mentioned was a better ground. So I am lost as to why it wont work.?!? I followed the couple of post that I found on it exactly (Shaeff's as well as 12 V mod with pics), but no luck thus far. Any ideas?
Thanks again