96 trans repair won't start

[ScottyB]

Somewhere in here I started a build thread but lost track of it. Last June, I bought a 96 SE for $300 and towed it home knowing it had a trans problem. It had no battery when I bought it so when we got it home we threw an old battery in it and jump started it. Engine sounded great but we saw the trans was pissing fluid.

 

This left us knowing that the vehicle ran.

 

My 19 year old son who is going to school to be a mechanic has done most of the labor on this in his limited spare time. By December, he had finally managed to finish pulling the transmission and we discovered the input seal was shot. This turned into an easy fix. We pulled the pan and an inspection lead us to believe the rest of the trans was in great shape. The reinstall went much quicker than pulling it but no nearly as fast as some of you, I'm sure. As a side project we pulled the front bumper and grill to clean those up. The bumper was in rough shape.

 

My son was excited two weeks ago for me to come home from work so that I could be the first to start it. I got home and we went to start it and turned the key and nothing. There is a relay click, but no solinoid click. I know that the starter works because when we jump starter power to the solinoid it fires.

 

We used a test light to verify that the signal wire to the starter is not being energized.

 

Problems we are experiencing:

 

1) We are unable to find a relay that says starter.

2) We have several relays we are clueless about such as the ASCD and ATP relays.

3) With the key in the on position, the ATP relay gets quite warm. This seems a bit odd.

 

I tried to rule out the Neutral Safety Switch by holding the key in the start position and running the shifter through the gears. When it goes into Reverse or Drive there is a brief buzz. To me that indicates that the neutral safety switch is doing it's job properly.

 

At this point, I am thinking that the computer has taken a vote somewhere along the line and decided to not allow signal to starter but I can't be sure.

 

We pulled codes, the only code we are showing is a P0505. I don't believe that is the source of my problem.

 

I'm looking for any wisdom you folks have to share with me on this.

[Saturn]

Make sure the crank position sensor is reinstalled and all the way in. Nissans are finicky about cam and crank sensors in my experience.

[Slartibartfast]

A bad crank sensor shouldn't keep the starter from cranking.

 

I'm not familiar with the starter wiring on the R50s but the starting system wiring starts on page 30 of the EL section of the '96 manual. It doesn't look like there's a proper starter relay, but there are various interlocks that could be causing problems. (The other sections of the manual are here.)

 

The ATP relay is a new one on me, but it looks like it's part of some kind of safety system intended to warn you that the truck will still roll away if you put the truck in park while the transfer case is in neutral. I'm not sure how it's wired (it's probably in that same section of the service manual) but I doubt it's supposed to get hot; I'd check the relay itself to make sure it's functional, and if it tests fine, take a look at whatever it's feeding to see if it's taking too much current or something.

 

Oh, and ASCD = automatic speed control device = Nissan-flavored cruise control.

[ScottyB]

After much trouble shooting and wire tracing (and a reluctance to try to get at the neutral safety switch connection) we have traced the problem to the neutral safety switch circuit. We will probably start digging into that this weekend. He's thinking he may have broken the switch trying to remove it though.

 

Progress has been made!

[adamzan]

That is what happened to mine. I picked up a new one off rock auto, and was running fine again.