joshuahaynes

I just picked up a 86 turbo and it wont go more then 100mph. It seems to operate at low to mid range just fine -plenty of power. Ive checked timing, compression, boost, vacuum lines, fuel leaks, and ignition system and they all seem fine, so wtf. Its got an automatic transmission thats seen better days that going to be swapped for a manual soon. Besides the transmission what else could be the issue? My lightly modified N/A will flirt with 140, the turbo shoulnt be second best

rogerz

clip the wire from the speed sensor to the ecu. if it is faulty it may be limiting your speed thru the ecu. I think it is purple #26 but check the schematic.

NismoPick

^^^ What the? You should know better than that...

The Z31T speed limiter is set to 137mph. 100<137 right?

Cutting the speed sensor wire will also disable the MAF burn cycle (Roger, try cutting the cat5e cable from the back of your computer and report back on what it does).

Joshua, what's your RPM's at 100mph? You do know that the auto transmission is only a 4speed right?

rogerz

I already had to cut the wire on my 85T to make it go faster than 20 so i don't really think it is a big deal if worried about the maf take a torch to burn the goo off. if the speed is faulty it won't limit your speed to 137. It limits it to whatever. if it is a bad speed sensor and now he can go over 100 that was the problem. if not then just reconnect the wire. the 85 has been running that way for over two years so I don't think it is a big thing. since I have an msce ticket and an msee from Tulane I think I know what cutting a cat 5 cable will do. i also know what cutting the speed limiter will do.

AZ-ZBum

What? That is the very first time I've heard of this.

Also interesting notion considering the NA ECUs don't have a speed sensor wire connected to them...

NismoPick

From the 280ZXT to Z31T ecu swap:
XenonS130 - Z31 MAF and ECU to a 1983 280ZXT
Z31/300zx ECU/MAF to 280ZXT swap guide - HybridZ - Page 10

Without the speed sensor, the MAF won't go into clean cycle.


Turbo...

AZ-ZBum

Except for the fact that the MAF is the same for the NA and the turbo.

The XenonS130 site is just a copy of the HybridZ forum. This is to adapt the 280ZX harness to the Z31 stuff. NOT for a completely stock Z31.

BTW: The speed signal wire is purple and pin 29, NOT pin 12 y/l or r/w. So clipping the speed signal wire to the ECU won't do jack.

The issue has nothing to do with the speed signal anyway. So clipping it won't do anything to solve the problem.

I'm still guessing it's a loose connection on the spark plug wires. But to really see, he should get it on a dyno to see how much power there really is. But first, I'd do a compression test.