transmission computer for j30

[KUL FIR CHICK N]

I have a '93 j30 which I just replaced the transmission in. The new transmission is from a '95. When driving on the highway, the trans shifts into 3rd whenever I let off the gas, then shifts back up as soon as I get back on the throttle. I noticed that the '95 has a different part # on the module. Does anyone know what the difference is? The trans was sold to me as a direct replacement.

I plan to just buy a '95 module, but would like to learn all I can about this.

Ryan

By the way, FIRST POST.

HOWDY Y'ALL

[driverdriver]

When you talk about module are you referring to the "rev sensor" on the transmission or the one that works with the transmission solenoid?

[KUL FIR CHICK N]

I'm actually speaking of the transmission control computer. When I drove the car with the newer transmission, it seemed like the shift calibration timing was off. It seems like it is far more sensitive to throttle position than it should be. For instance, when leaving a stop sign, if you accelerate at an average rate, it waits to about 5k rpm before it shifts to second. If you leave very lightly (grandma style) it will shift at about 2-2.5k. This led me to suspect there may have been some changes which affected the calibration. I looked on e-bay and the computers for sale were always listed as either 93-94 or 95, and the part numbers are different.

My concern is that if I put the updated computer to match the transmission, it will be incompatible with the engine computer, which is what has to feed the trans computer the throttle position signal.

Is there anyone on this board who is a J30 technician? It would be good to know what parts are interchangeable and those that are not. I can now see that the cars are not all the same from '93-97.

__ I see now that my screen name "cool fire chicken" after my '68 firebird, looks more like "fir chick". Oh well, but I'm not a chick.

[driverdriver]

*bump*

Q45tech, DominickJ30, Vimy, Wes?

You guys have any idea?

[elwesso]

Just want to let oyu know I've seen this, and I'm going to look into it after class and I will report back with more conclusive information.

[KUL FIR CHICK N]

Thanks guys,

I hope to have my '95 trans computer in today, but I'm constantly checking with this board to make sure I'm on the right track.

Thanks for taking time to help.

By the way, my '68 Firebird is getting a 1200hp turbocharged motor, and this J30 may be next to see boost. Just gotta keep it under the wife's radar.

Ryan

[elwesso]

certainly let us know if that does anything.

[KUL FIR CHICK N]

I just talked to the SOB that I bought the computer from, and he says he's shipping it today. So much for paying extra for second day shipping on Monday.

Wes, If you can dig anything up on this it would be much appreciated.

Thanks, Ryan

[KUL FIR CHICK N]

I drove the car last night and tried to figure out exactly what it was doing. It almost seems like the 3-4 shift solenoid and the TC lock up are swapped. When you let off the gas on the highway, the TC should disengage, which is when it shifts down to third. Also, it seems that it may be shifting while the TC is locked (hard shock during the shift). Also, manually shifting to third has no effect on the performance. Still shifts to fourth and back with throttle on/off.

There is no way to do this accidentally during installation, so I suspect that they may have changed the wiring pin outs either on the harness or inside the computer. Does anyone have access to the wiring diagrams for the '93 and the '95 J30?

I should have the computer by Friday, assuming the genius ships it 2day like I requested.

[elwesso]

It sounds like something is goofy... heres why.. The transmission for the J30 made between 1/92 and 07/95 are all the same part number... Only after 07/95 (the 96/97 model year) have a different part number....

[KUL FIR CHICK N]

That is strange. I bought the transmission from a wrecking yard, and it had already been pulled from the vehicle. It was in their computer as coming from a '95 model. The only other thing I can think of is they may have pulled some pins from the connector when removing the trans and re-inserted them wrong, but it is usually very difficult to get the pins out, and I didn't see any damage to the connectors. Also, it doesn't explain why the guys selling the computers on ebay show a different computer for the '95 models.

We may be able to learn something from this, I'm sure Nissan didn't change the trans just for the hell of it.

Where would the build date be on the vehicle? Maybe the wrecking yard went by that rather than the VIN.

Are the wiring diagrams the same for '93-95?
Modified by KUL FIR CHICK N at 7:29 AM 4/20/2006

[PopPop]

Here is what I found out for you! 1994 Infiniti J30 Alternator Automatic transmission Body hardware Brakes Cooling system Electrical Body electrical Chassis electrical Ignition system Instruments & gauges Powertrain control Air intake temp sensor Camshaft position sensor Coolant temp sensor Crankshaft sensor cover Ecm Knock sensor Mass air flow sensor Oxygen sensor Regulator Throttle position sensor Vehicle speed sensor Restraint systems Emission system Engine Exhaust system Front suspension Fuel system Hvac Maintenance & lubrication Rear suspension Starter Steering Steering column Universals & rear axle

Keyword or Part Number

Description Year MSRP Price Core Price Your Price ECM, J30, Federal 93-94 $772.84 $610.54 Part & Prices Are For Estimating Purposes Only. ECM, J30, California 93-94 $772.84 $610.54 Part & Prices Are For Estimating Purposes Only.

[elwesso]

That is strange. I bought the transmission from a wrecking yard, and it had already been pulled from the vehicle. It was in their computer as coming from a '95 model. The only other thing I can think of is they may have pulled some pins from the connector when removing the trans and re-inserted them wrong, but it is usually very difficult to get the pins out, and I didn't see any damage to the connectors. Also, it doesn't explain why the guys selling the computers on ebay show a different computer for the '95 models.

We may be able to learn something from this, I'm sure Nissan didn't change the trans just for the hell of it.

Where would the build date be on the vehicle? Maybe the wrecking yard went by that rather than the VIN.

Are the wiring diagrams the same for '93-95?

Modified by KUL FIR CHICK N at 7:29 AM 4/20/2006

Yeah i dont see how they could mess the connectors up, but its certainly not impossible, i wouldnt put too much past those guys...

The 96+ likely is just different part number due to the OBDII changeover...

The build date will be on the sticker in the drivers side door well on the frame of the car... the sticker that has the GVWR and stuff has the MFG date on it to... will be in the form Mo/Yr... Maybe they pulled it from a 7-12/95 built J, even though its 96 MY maybe they thought it was a 95 MY.....

Nissan always ends their model productions around July... new model productions (first year) generalyl start in the first months of the years...

[KUL FIR CHICK N]

Well, looks like problem solved. I bought wiring schematics on autozone.com and checked the pin outs on all of the plugs. Everything looked good. Then I wired test lights to the A and B solenoids and took it out on the road. It shifted perfectly. Apparently, waving my magic hands over it cured the problem.

Seriously, there must have been a loose connection in one of the connectors which was fixed when I pulled them loose and re-connected. Time will tell if it continues to work.

SOB still hasn't sent me my trans controller. Looks like its time to dispute w/paypal. If it comes, I'll install it and see if there is any difference. It has a different PN so maybe they refined the shift points.

Thanks for your help. Stay tuned. Time to start warming over the motor.

[elwesso]

you bought wiring diagrams?? I could have posted them here for free!!

[KUL FIR CHICK N]

I asked if anyone had any earlier in the post. No big deal, I got access to the whole service manual. Its pretty comprehensive.

[elwesso]

Man im really sorry, i have the FSM ready for download, i completely missed it......