ECU malfunction?

[94CoupeV6]

Ever since I installed my A/F gauge by Autometer, my car sometimes loses power. I obviously disconnected the gauge, and then reset the ECU by unplugging the negative battery terminal overnight. Then it drives PERFECTLY fine 100% power until I start flooring it through the snow/ice, then afterwards it starts running around 75% power at wide open throttle and it feels like lost compression or something. Maybe the ECU thinks that I need more air? fuel? I really don't know what the problem is and I hope I explained everything so people understand what I'm talking about. Maybe I messed up my 02 sensor during install? I tapped the correct wire (4 wires, tapped the blue one). Maybe I tapped the wrong 02 sensor (I tapped the one from the front headers on the V6). Any help or suggestions would be appreciated.

[Eye8Pussies]

shouldn't really make a difference....

I"m thinking it's not the o2 sensor at all if the problem is still there after you remove the a/f gauge, otherwise, maybe the leds are taking up too much current for a proper reading...

possibly a knock sensor problem, since our first gen 1mzs have a reputation for being oversensitive

[Nad1370]

If you tapped right at the O2 before the connector, that is a sheilded wire.

If you did this this might be your problem. You should tap after the connector or right at the ecu.

[stir_fry_boy]

o2 sensor man wait till you get a check engine light, see what bank it is, and replace it.

[73sport]

Doubt your car has it but this is one thought for the 95 and up gang....

Also - Pull the plugs and look at them when it mis-behaves. They may tell a story.

Q? Does it recover from the problem if you keep driving it. Drive Normal without over-rev and spinning the tires excessively?

If so, maybe the computer is adjusting to the "light load" of spinning wheels on the ice/snow and doesn't richen back up properly until you dump the ECU data?

Just thinking - Someone please add your 2C on ECU info....

/ra

http://www.obdii.com/connector.html



Does My Car Have OBD-II?

All cars and light trucks built and sold in the United States after January 1, 1996 were required to be OBD II equipped. In general, this means all 1996 model year cars and light trucks are compliant, even if built in late 1995.
Two factors will show if your vehicle is definitely OBD II equipped:
1) There will be an OBD II connector as shown below, and
2) There will be a note on a sticker or nameplate under the hood: "OBD II compliant".
The Connector

Pin 2 - J1850 Bus+
Pin 4 - Chassis Ground
Pin 5 - Signal Ground
Pin 6 - CAN High (J-2284)
Pin 7 - ISO 9141-2 K Line
Pin 10 - J1850 Bus
Pin 14 - CAN Low (J-2284)
Pin 15 - ISO 9141-2 L Line
Pin 16 - Battery Power
Where is the connector located?
The connector must be located within three feet of the driver and must not require any tools to be revealed. Look under the dash and behind ashtrays.
The Three Flavors of OBD II
While the parameters, or readings, required by OBD II regulations are uniform, the auto manufacturers had some latitude in the communications protocol they used to transmit those readings to scanners. Naturally, each felt they had the one true way, so we have three different OBD II communications protocols in use.
The big scanner consoles costing thousands of dollars include the decoding software and firmware for all three protocols in their units, making them universal. Less expensive units, for home or small shop use, are usually customized for a specific communications protocol. Be sure the scanner you are using suits the protocol of your car.
What Communications Protocol does my vehicle use?
As a rule of thumb, GM cars and light trucks use SAE J1850 VPW (Variable Pulse Width Modulation). Chrysler products and all European and most Asian imports use ISO 9141 circuitry. Fords use SAE J1850 PWM (Pulse Width Modulation) communication patterns.
There are some variations among captive imports such as the Cadillac Catera, a German Opel derivative, which uses the European ISO 9141 protocol. If you have first hand knowledge of other such variations, please send them in and, together, we can build a more complete listing.
On 1996 and later vehicles, you can tell which protocol is used by examining the OBD II connector:
J1850 VPW--The connector should have metallic contacts in pins 2, 4, 5, and 16, but not 10.
ISO 9141-2--The connector should have metallic contacts in pins 4, 5, 7, 15, and 16.
J1850 PWM--The connector should have metallic contacts in pins 2, 4, 5, 10, and 16.
If your vehicle has this style connector, but doesn't have these pins populated, you probably have a pre-OBDII vehicle. To add some confusion, even having the connector with the contacts shown above is not a guarantee of OBD II compliance. This style connector has been seen on some pre-1996 vehicles which were not OBD II compliant.
Information on Pre-96 Cars
A reader with the California Air Resouces Board provided this list of pre-96 OBD II engine designations. Note that CARB recognizes engine series, rather than vehicle models, so the engine designations are the true key, with the vehicle models provided as a courtesy.
California Air Resources Board List of
Certified OBD II Complying Engine Families and Models

Engine FamilyManufacturerModel(s)Fully Compliant?1994 Model Year CertificationsRAD2.8V8GFEM

RFM3.8V8G1EK
RFM4.6V8G1EK
RMB2.2VJGCEK
RMB3.2VJGCEK
RNS2.0VJGDEK
RTY3.0VJGFEK
RTY2.7HGEEK
RTY2.42HGEEK
RVW2.8V8GFHM
RVV2.3VHGFEKAudi
Ford
Ford
Mercedes-Benz
Mercedes-Benz
Nissan
Toyota
Toyota
Toyota
Volkswagen
Volvo100
Mustang
T-Bird, Cougar
C220
C 280, S 320, SL 320
G20
Camry, ES300
T100
Previa, Previa All-Trac
Corrado
850 TurboNo
No
No
No
No
Yes
No
No
No
No
No1995 Model Year CertificationsSBM5.4V8GAEK
SCR2.0VJGFEK
SCR122VJG2EK
SCR2.0VJG2GK
SCR2.0VJGFEL
SDS2.0VJGFEK


SFM3.828G1EK
SFM3.8V8G1EK
SFM4.6V8G1EK
SFM4.6V8G1GK

SFM2.318G1EK
SFM3.028G1EK
SFM3.018G1EK
SFM3.028G1FK
SFM4.018G1EK
SFM4.6VJG1EK
SFM4.028G1EK
S1G3.8V8G1EK
S3G4.319GFEJ
S3G4.329GFGJ
SIG2.3VJG2GK
SHN2.7VJG1EK
SHN2.7VJGFEK
SHN2.5VJGKEK
SHN3.0VJGKEK
SJC4.0VJGAEK
SJC6.0V8GFFK
SJC4.0VJGFEK
SKM1.8VJG1EK
STK2.3VJGFEK
STK2.5VJGFEK
STK1.5VJG2EK
STK1.8VJG1EK
SFM2.318G1EK
SFM3.018G1EK
SFM3.028G1FK
SFM4.018G1EK
SFM4.028G1EK
SMB3.6VJGFEK
SMT1.5VJG2EK
SMT1.8VJG2EK

SMT2.4VJG2EK
SNS2.4VJGFFK
SNS2.0VJGFFK
SNS3.0VJG1EK
SNS3.0VJG1FK
SNS2.4VJG2EK
SNS1.6VJG2EK
SNS2.0VJGFEK
SNS3.0VJG1EK
SLR4.0H8GOEK
SFJ2.2VJGFEK
STY3.41JG1GK
STY3.42JG1GK
STY3.0VJGFEK

STY2.42HGJEK
STY2.71HGEEK
STY1.5VHGFEK
STY4.0VJG1GK
STY2.41HG1GK
STY2.71HG1GK
STY3.41JGFEK
STY3.42JGFEK
STY4.55JGFEK
SVV2.3VJGFEK
SVV2.4VJGFEKBMW
Chrysler
Chrysler
Chrysler
Chrysler
Diamond Star


Ford
Ford
Ford
Ford

Ford
Ford
Ford
Ford
Ford
Ford
Ford
GM
GM
GM
GMC
Honda
Honda
Honda
Honda
Jaguar
Jaguar
Jaguar
KIA
Mazda
Mazda
Mazda
Mazda
Mazda*
Mazda*
Mazda*
Mazda*
Mazda*
Mercedes Benz
Mitsubishi
Mitsubishi

Mitsubishi
Nissan
Nissan
Nissan
Nissan
Nissan
Nissan
Nissan
Nissan
Rover
Subaru
Toyota
Toyota
Toyota

Toyota
Toyota
Toyota
Toyota
Toyota
Toyota
Toyota
Toyota
Toyota
Volvo (TC)
Volvo750cl(V12), 850ci(V12)
Dodge Neon, Plymouth Neon
Dodge Neon, Plymouth Neon
Dodge Neon, Plymouth Neon
Dodge Neon, Plymouth Neon
Eagle Talon, Mitsubishi
Eclipse, Chrysler Sebring,
Dodge Avenger
Windstar
Mustang
T-Bird, Cougar
Grand Marquis, Town Car,
Crown Victoria
Ranger
Windstar
Ranger
Ranger
Ranger
Continental
Ranger
Camaro, Firebird
S10 Pick-Up, Jimmy, Blazer
S10 Pick-Up
Cavalier, Sunfire
Accord LX, EX (V6)
Accord LX, EX (V6)
TL
NSX
AJ16 (SC)
V12
XJS
Sephia
Millenia
Millenia
Protege
Protege
B2300
B3000
B3000
B4000
B4000
S 320, C 280, SL 320
Summit, Mirage
Summit, & Summit Wagon,
Mirage, Expo, LRV
Summit Wagon, Expo, LRV
240 SX
G20
Maxima
Maxima
Altima
Sentra/200 SX
200SX SE-R
Maxima
Range Rover New Model
Legacy
T100 2WD
T100 2WD & 4WD
Camry, Camry Wagon,
ES300, Avalon
Previa, Previa All-trac
T100 2WD
Tercel
LS 400
Tacoma 2WD
Tacoma 4WD
Tacoma 2WD/4WD
Tacoma 4WD
Land Cruiser
850 Turbo Sedan/Wagon
850 Sedan/WagonNo
No
No

No
No


No
No
No
No

No
No
No
No
No
No
No
Yes
No
No

Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
No
No
No
No
No
No
Yes
No
No

No
Yes
Yes
No
No
Yes
Yes
Yes
No
No
Yes (A/T models only)
Yes
Yes
Yes

No
Yes
No
No
No
No
No
No
No
No
Yes
A note accompanying this list indicated that certification is for the engine group only. The models listed are believed correct, but the engine is the deciding factor.

[CCCP]

until I start flooring it through the snow/ice,

Maybe your tranny just goes into safe mode, which can happen when u spin your wheels alot. And when it goesw into safe mode u will have only 3rd gear, don't know about toyota but on nissans it resets with a restart of the engine or, unpluging the battery.