280z dies when ac is on

[sblake01]

Though that isn't the best way to connect them, it shouldn't cause the problem. I'm leaning toward the possibiliby that you may have inadvertantly disconnected something while changing the connectors since the car ran okay before.

[bandoni]

Though that isn't the best way to connect them, it shouldn't cause the problem. I'm leaning toward the possibiliby that you may have inadvertantly disconnected something while changing the connectors since the car ran okay before.

i am going to check and see if i disconnected anything, i will post pics of the area i worked on for more opinions.:nervous:

[mriz]

Vac diagram if you need it.

[sblake01]

Here's the electrical info:

[bandoni]

ok heres an update! so i looked at where i did the work on the connectors, nothing out of place everything connected. so I decided since i was under the bonnet to go ahead and set the idle back to stock, because at 400 rpms it wasn't even close to what the fsm recommends. so i set it to about 800 rpms and what do you know turned the ac on and reved it, and problem is gone. drove the old girl around with the ac on and she ran like a champ no stalling or dieing. thank you guys so much for all the help and the link to the fsm.

[sblake01]

Glad you got it solved without having to mess with the vaccum lines, etc. Actually, the idle shoud be set to 800 rpm with the ac on but if it's working maybe you should leave it where you have it. I hate working on the vaccum/electrical parts of the old Z/810/Maxima AC systems and I'm a MVAC/HVAC tech.

[76Datsun280z]

Glad you solved the problem!

[TomoHawk]

Now you know why they used to say that it was more fuel efficient to drive with the window down, as opposed to using the air conditioning. Those old piston compressors ( like on vintage Mustangs) must have needed 20 horsepower just to keep them going, compared to the newer rotary pumps. Even the four-bangers now come stock with a/c now, and they still get 30+ MPG.

[76Datsun280z]

Speaking of them taking away, hp, what would you guys estimate the stock factory a/c on these cars take away? The reason I ask is I've got mine all hooked up and plan on making an appointment soon to get it recharged and was a little curious on how much you thought it took away.

[bandoni]

Now you know why they used to say that it was more fuel efficient to drive with the window down, as opposed to using the air conditioning. Those old piston compressors ( like on vintage Mustangs) must have needed 20 horsepower just to keep them going, compared to the newer rotary pumps. Even the four-bangers now come stock with a/c now, and they still get 30+ MPG.

well i never really notice the drop in hp when i am using the ac, my other car 89 acura legend drops very noticeably. this compressor looks alot like the same kinda compressor thats in my legend. all the ac equipment is new on my z. has anybody ever installed a rotary compressor on there z?

[TomoHawk]

I would say that the amount of horsepower needed to turn the a/c pump depends on the pressure inside when compressing. I forget the equation, but you can directly relate psi to horespower. Don't forget to add a little for friction, slop or the current date.

[sblake01]

...... has anybody ever installed a rotary compressor on there z?

Your's is a rotary compressor. The piston type were used on the early 240 aftermarket installs. I have non factory air with a Sanden compressor and I don't notice an appreciable loss of power when it's on. Nor do I notice it in my 810 which has essentially the same system as your 78. I'd rather be comfortable in the heat than worry about a few lost hp or a couple of mpg. I'm not racing.