Suddenly Rich tune with AEM EMS - 3000GT/Stealth International Message Center

stealthystu · 06-21-2008, 05:48 PM

What would cause my untouched AEM EMS tune to suddely turn rich? The idle was 13.5 ish at about 900-1000 rpms, and now, with the same rpm, it's running at 10.0 to 10.8. Cruising has also gone down to 11.5. What happend?

Import Power · 06-21-2008, 06:11 PM

Are you using O2 feedback?
Could be your WB took a dump.

stealthystu · 06-21-2008, 06:42 PM

Is o2 feedback when the ems tries to mantain a specific afr? I don't think I am, but I don't really know. I was afraid I was because I started leaning out the fuel mixture and it would lean out and then go rich again. A non responsive tune from an AEM EMS is kind of ridiculous. I would believe it from a piggy back, but an ems shouldn't be nonresponsive. How could I check if the wideband went bad? It is kind of old, 2 years or so. Is it possible that one of my injectors is stuck opened? How could I check that? Thanks for the help. This is my DD and I'm a long ways from home and I have to get to work tomorrow :/

Oh, and I've tried using several different tunes that have all been fine as far as idle goes and they are all very rich now (~10.5)

BlackStealth · 06-22-2008, 04:48 AM

There's an option to turn on/off wideband o2 feedback control in the AEM EMS software. Look for that and make sure it's turned off, this will tell AEM EMS to ignore your wideband o2 results.

Also when my buddy's wideband o2 sensor died it gave out rich numbers so it's very likely just a broken sensor.

Import Power · 06-22-2008, 04:54 AM

Go To
Fuel>O2 Sensor Feedback>O2 Sensor Feedback

In the Options O2 Sensor Feedback see if O2 FBk Control is checked

You can also see what O2 sensor each injector is being controlled by under Options>injector

stealthystu · 06-22-2008, 07:41 AM

Awesome, thanks guys. I have to go to work now (in a borrowed car), so I will check it when I get back. What are the chances that it's an injector that is stuck opened? Can I turn individual injectors on and off with the EMS to help find the broken one?

Feedback was checked. I unchecked it but doubt I'll be able to use my car. It will likely change the driving characteristics because it doesn't have feedback control, right? If the car runs well and still reads way rich I think you're right that it's my wideband. I'll check it out after work.

Import Power · 06-22-2008, 09:15 AM

Quote:

Originally Posted by stealthystu

Awesome, thanks guys. I have to go to work now (in a borrowed car), so I will check it when I get back. What are the chances that it's an injector that is stuck opened? Can I turn individual injectors on and off with the EMS to help find the broken one?

Feedback was checked. I unchecked it but doubt I'll be able to use my car. It will likely change the driving characteristics because it doesn't have feedback control, right? If the car runs well and still reads way rich I think you're right that it's my wideband. I'll check it out after work.

If the fuel map is tuned correctly, you shouldn't need to rely on O2 feedback to stay on target.

stealthystu · 06-23-2008, 05:14 AM

Quote:

Originally Posted by Import Power

If the fuel map is tuned correctly, you shouldn't need to rely on O2 feedback to stay on target.

I've had trouble finding good tuners. The last place I went, Engine Logics in Texas, had my WOT set to 10.5 afr because they used their wideband, which they trusted. Funny, maybe mine was actually less accurate because it's potentially busted now, lol. I did have an exhaust leak which would cause it to be leaner at the tail end of the exhaust though. And they were dumb for a whole lot more reasons than just that.

stealthystu · 06-23-2008, 10:06 AM

I realized I could test the wideband by turning the car to the on position without cranking the engine over. The wideband turned on and was reading 14.8 without the engine being on. I'd say that settles it. I ordered a new wideband sensor for $65 + shipping

06-21-2008, 05:48 PM	#1 (permalink)
stealthystu Excitable at high speeds Join Date: Aug 2006 Trader Rating: (8)	Suddenly Rich tune with AEM EMS What would cause my untouched AEM EMS tune to suddely turn rich? The idle was 13.5 ish at about 900-1000 rpms, and now, with the same rpm, it's running at 10.0 to 10.8. Cruising has also gone down to 11.5. What happend? __________________ She's my little duece coupe....You don't know, what I got...

06-21-2008, 06:11 PM	#2 (permalink)
Import Power Corn Its whats for boost Join Date: Jan 2002 Location: Behind the Wheel Drives: Vicki Insane Trader Rating: (209)	Re: Suddenly Rich tune with AEM EMS Are you using O2 feedback? Could be your WB took a dump. __________________ AEM Factory Trained Tuner 91VR4 Black-5027s-3.0L-Stock heads and Cams- 707AWHP 620AWTQ uncorrected 30psi E85 Daily Driver SLTT-10.9 @ 140MPH Stock NA motor and NA heads/Cams T4 AWD 9.21 @ 154.98 T2 FWD 10.19 @ 140.31 T4-159.23 MPH Ran on 6G72 3.1L! T4-995AWHP Uncorrected 6G72 3.0L C16 T2-820FWHP 3.1L 27psi C16 91VR4 Red-17Gs w/supporting mods-sold 93SLTT/T2 91VR4 Pearl White-sold 91VR4 Black-sold 92VR4 Sandstone-sold 94VR4 Green-sold 93VR4 Pearl White-sold 3SX Performance 3SX Performance Service Email

06-21-2008, 06:42 PM	#3 (permalink)
stealthystu Excitable at high speeds Join Date: Aug 2006 Trader Rating: (8)	Re: Suddenly Rich tune with AEM EMS Is o2 feedback when the ems tries to mantain a specific afr? I don't think I am, but I don't really know. I was afraid I was because I started leaning out the fuel mixture and it would lean out and then go rich again. A non responsive tune from an AEM EMS is kind of ridiculous. I would believe it from a piggy back, but an ems shouldn't be nonresponsive. How could I check if the wideband went bad? It is kind of old, 2 years or so. Is it possible that one of my injectors is stuck opened? How could I check that? Thanks for the help. This is my DD and I'm a long ways from home and I have to get to work tomorrow :/ Oh, and I've tried using several different tunes that have all been fine as far as idle goes and they are all very rich now (~10.5)

06-22-2008, 04:48 AM	#4 (permalink)
BlackStealth Verified Seller Join Date: Apr 2000 Drives: 93 RT/TT Trader Rating: (155)	Re: Suddenly Rich tune with AEM EMS There's an option to turn on/off wideband o2 feedback control in the AEM EMS software. Look for that and make sure it's turned off, this will tell AEM EMS to ignore your wideband o2 results. Also when my buddy's wideband o2 sensor died it gave out rich numbers so it's very likely just a broken sensor.

06-22-2008, 04:54 AM	#5 (permalink)
Import Power Corn Its whats for boost Join Date: Jan 2002 Location: Behind the Wheel Drives: Vicki Insane Trader Rating: (209)	Re: Suddenly Rich tune with AEM EMS Go To Fuel>O2 Sensor Feedback>O2 Sensor Feedback In the Options O2 Sensor Feedback see if O2 FBk Control is checked You can also see what O2 sensor each injector is being controlled by under Options>injector

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06-22-2008, 07:41 AM	#6 (permalink)
stealthystu Excitable at high speeds Join Date: Aug 2006 Trader Rating: (8)	Re: Suddenly Rich tune with AEM EMS Awesome, thanks guys. I have to go to work now (in a borrowed car), so I will check it when I get back. What are the chances that it's an injector that is stuck opened? Can I turn individual injectors on and off with the EMS to help find the broken one? Feedback was checked. I unchecked it but doubt I'll be able to use my car. It will likely change the driving characteristics because it doesn't have feedback control, right? If the car runs well and still reads way rich I think you're right that it's my wideband. I'll check it out after work. Last edited by stealthystu : 06-22-2008 at 07:50 AM.

06-23-2008, 10:06 AM	#9 (permalink)
stealthystu Excitable at high speeds Join Date: Aug 2006 Trader Rating: (8)	Re: Suddenly Rich tune with AEM EMS I realized I could test the wideband by turning the car to the on position without cranking the engine over. The wideband turned on and was reading 14.8 without the engine being on. I'd say that settles it. I ordered a new wideband sensor for $65 + shipping