A/T shifts at 4k

[6PuahButton9]

Hello,

I have a 300zx n/a that had a motor and transmission swap wth 55k miles on it the only issue i am having the car only shifts when i take it up to over 4k RPM it does not shift like it suppose to we i had taken it to nissan and they swap out the ECU for me thinking that was the problem but it wasnt it made my RPM stop working has anyone had the similar problem?

No - CEL on
car idles fine.

and i recently found out that also they have been adding 87 octain gas does that have to do anything with the car not running properly i know these cars take 91 or higher..

Thank you

[Ace2cool]

No CEL doesn't mean anything. Could be a problem that doesn't flag the CEL. Pull codes from the ECU for starters.

http://www.nicoclub.com/archives/nissan ... ostic.html

Then, I'd pull TCU codes.

http://www.twinturbo.net/nissan/300zx/t ... odiag.html

See what that yields. I'd bet a sensor is disconnected/ malfunctioning.

I also moved this to the tech section, as this is a technical question.

[ThisIsSparTTa]

1 learn how to use punctuation. 2, you must run premium, aka 91/93 Octane in these cars. 3, do not take this car from Nissan, they will likely do more harm than good and charge you out the a** for it. Find a reputable Z shop local to you if you can't do it on your own. You have a lot more troubleshooting you can do if you start searching.

[DCaff300ZX]

No CEL doesn't mean anything. Could be a problem that doesn't flag the CEL. I'd bet a sensor is disconnected/ malfunctioning.

This.
Given that there was a swap and apparently not from Nissan or a true Nissan guy this ranks as top choice.
Speed sensor is my #1, and then maybe that the AT ECU may not be connected properly or at all to the main ECU, and then maybe that someone had a HKS ALC on it at one time and the AT pump's fried or about to be...been through all 3 myself at one time or another before I swapped to 5 speed in my NA.

[nexus08]

My auto 300zx wants to run the RPMs way up before shifting too. I wasn't sure if it was malfunctioning or was running as intended.

I can however just let up the gas for a second and it will then shift. I thought maybe it was set up to allow it to rev high if you are giving are trying to gun it, but then allow you to shift earlier if you wanted by letting up the gas.

I've yet to pull the transmission codes to see if it was something I could fix as I could live with it like it is.

[6PuahButton9]

So after the sequence i did it read a #6 which is the overrun clutch solenoid located on top of the transmission.