S13 auto trans prob = NOT auto trans problem

[honeybus]

I thought my problem was my S13 auto trans, but after replacing the AT, the same problem popped up.

Symptoms: S13 auto trans 'down shifts' on its own from OD to 3rd, and then to 2nd with a steady and light pressure on accelerator @ highway speeds, and speeds over 35 mph.

scenario:

240SX 's auto trans runs fine

1) I replace the alternator, I run the 240SX and then determine that FI #2 is dead.

2) mechanic agrees and mechanic replaces the #2 FI

3) 30 miles and two days after mechanic work, which is also about 50 miles after my alternator R&R, the auto trans goes into 'down shift' action. When down shifted, there is no power thru the auto trans and any more gas pedal only runs the revs way, way up.

If I sit quiet on gas pedal and trans will 'up shift' to OD. Then, in a few seconds same thing happens: 'down shift' for 3-5 seconds, and 'down shift' for 5-10 seconds and after 20 seconds it returns to Over Drive.

4) mechanic said not his doing ! ! ! I took the 240SX to an auto trans specialist. Honest shop. Said ATF was pink and odorless; we (shop and me) saw no shavings in AT pan after it was pulled/removed. AT shop had no idea what the exact problem was.

5) replaced 'bad' AT with known, good used AT. Outstanding results for the first few (25) miles!!

6) 30 miles after good ued AT was installed, and occurring the next day, the exact same symptoms. EXACT!!

I have the FSM at home, but nothing there I could find describes these symptoms.

The auto trans specialty shop said to rebuild the trans (obviously not the right diagnosis!!)

Would a NISSAN dealer be able to diagnose and PIN POINT the cause of the symptom. Accurately and correctly !! What equipment should they have to do this, other than a 'code reader'?? -Yes, I am showing a CHECK ENGINE LIGHT as I have for the past three years. Code was 32, EGR code. Couldn't find the problem, so light always on...

I know this is a technical question, sorry

Barry Burneskis [email protected]
Modified by honeybus at 9:14 AM 9/16/2006

[honeybus]

Hi. I checked my engine codes. I have

32 - EGR Function

34 - Knock Sensor

Could my 34 - knock sensor be my problem with my auto trans?? It seems to be near the FI rail that my mechanic was working on (#2 FI)

[ricebike]

<shrugs> mebbe... just check connections to be sure... if knock senor was unplugged, my guess is it'll run in "safe mode" to protect the engine...

just like when it goes to safe mode when MAFS is unplugged /shot

reset ecu & drive again after checking the connections... just to see if the codes return-------------------

did you also notice in the FSM that you can retrieve/ read codes for the transmission as well?

[honeybus]

Ricebike, sorry that I cannot quote you, I have a new system, I am in school at Ft Belvoir VA the next two weeks, and this DOIM is different than my home office on what I can do.

Ricebike said

"<shrugs> mebbe... just check connections to be sure... if knock senor was unplugged, my guess is it'll run in "safe mode" to protect the engine... just like when it goes to safe mode when MAFS is unplugged /shot"

OK, I get a code 34 along with a code 32 from my code checking on the ECU. I get the code for the TSP from the help on a most previous posting. JBB

Ricebike said

"reset ecu & drive again after checking the connections... just to see if the codes return"

OK, the code come back after resetting. Come back pretty much after just a few (10??) miles JBB-------------------

Ricebike said

"did you also notice in the FSM that you can retrieve/ read codes for the transmission as well?"

OK, no, what page(s) in the FSM. I am going on the premise that the A/T is good, and my mechanic actually did put the replacement torque converter in with the replacement A/T, and that either me or my mechanic / helper (probably me with messing around with the throttle body, squirting some stuff to clean out the intake runners for the code 32 EGR) unplugged something or broke something. Thanks JBB