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HybridZ

won't go past 85 mph


zmaster

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ok, if you are pulling good to 85, then slowing down for a few MPH, then pulling back to 85, then you deffinatly have a gov of some sort, or maybe an ECU prob. if it IS a gov, it ISNT stock.

 

a few questions:

 

1. have you drivin the car faster than 85 before?

 

2. have you done any mods recently?

 

3. does the car have or seem to have any upgrades? mainly in the ignition department?

 

My best guess with the info you have given, is a previous owner bought the car for their son/daughter and had a gov installed so they wouldn't "kill them selves." If that is the case, then i cant help you much; speed governers are outlawed at my house, so i know very little about them!

 

i suppose it is possible to have a gov driven off the the speedo cable, but i would suspect that it is electronic. But really, i just dont know enough about them.

 

-MIKE

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yeah, that sounds like someone really did govern it somehow. a Z can do 90 in 3rd gear (i've done it in my 78 haha). run it up as fast as you can into 3rd. if it is really governed it'll totally stop at 85 then once you shift into 4th it should totally stop accelerating at whatever RPM 85 is. that will totally eliminate any chance of it being a power issue, and being truly governed

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ok, if you are pulling good to 85, then slowing down for a few MPH, then pulling back to 85, then you deffinatly have a gov of some sort, or maybe an ECU prob. if it IS a gov, it ISNT stock.

 

a few questions:

 

1. have you drivin the car faster than 85 before?

 

2. have you done any mods recently?

 

3. does the car have or seem to have any upgrades? mainly in the ignition department?

 

My best guess with the info you have given, is a previous owner bought the car for their son/daughter and had a gov installed so they wouldn't "kill them selves." If that is the case, then i cant help you much; speed governers are outlawed at my house, so i know very little about them!

 

i suppose it is possible to have a gov driven off the the speedo cable, but i would suspect that it is electronic. But really, i just dont know enough about them.

 

-MIKE

 

 

...after thinking about this a little more (im drunk, so im a lil slow lol) I find myself questioning one of my asumptions. My experience with s30s lay only in carburated models, so im not sure if the ECU in FI models have any speed data. Im thinking that it does NOT. if this is the case, then you prolly have a mechanicaly driven gov of some type. That means you should be able to find it before or after the speedo cable.

 

One more thing i kinda goofed up in my first post and forgot to ask:

 

What is the RPM reading at when you hit 85 MPH, and can you pass that RPM at lower speeds?

 

....hope im not talking out of my drunk ass lol

 

-MIKE

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the ECU in the Z's are dumb. litterally. a calculator is smarter than them. so there's no way to use the ECU to govern the car. there could however, be a way to mechanically govern it based off the speedo cable speed.

and do the rpm test. that's also a good thing to test, though at 85 in 4th gear, the rpm isn't too high i don't think. it's even lower in 5th obviously

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EvanPurple made a very good suggestion and it would be the first thing I would check.

A weak fuel pump, clogged fuel filter, bad pressure regulator or a clogged in tank pick-up sock are all known to limit your top speed and should be checked before assuming there is a governor.

Especially since you mentioned that the car hits 85 quickly then surges and slows a bit from there. That sounds like fuel starvation.

My own 83 ZX wouldn't go above 85 and it turned out to be a bad thermostat which caused the car to run really rich all the time.

Good luck.

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is it surging and slowing really quick?... my parents put a rev governor on my corolla (AHAHAH!) when i was in high school and 4 grand( I'm really not sure what rpm it was at, corollas dont have tacs.) it would just kind of... man how to describe that in text... it would just but its max and cut back a few hundred rpm and bump again... like wahwahwahwahwahwah but rapidly like just enough to almost sound like bad timeing.

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