cbaumy34

Its a manual 1982 n/a 280zx and it takes forever to warm up to operating temp and surges the whole time until its warm. I tried searching but was unable to come up with anything useful. Any ideas?

sjb15316

RE: "Taking forever to warm up"... that sounds like something to do with the thermostat. Do you know for fact that it has one? If so, it could be faulty and "hung open". Usually, the opposite is the rule... they usually stick closed and cause over-heating. It's not the easiest thing to get to, but not that hard either. If it's surging (while cold) that sounds like your cold start valve might be faulty. You can check the valve by "squeezing" the hose while it's cold. If it "staggers" the engine while cold and no results when it's hot, it's functioning properly. Good luck.

FricFrac

The Z thermostats fail open any time I've had one fail. Takes forever to warm up....

cbaumy34

Well the thermostat seems to have done the trick. The only other main issue I have is when I accelerate then lift off the throttle especially at low speeds the car get jerky almost like I'm down shifting. Any thoughts?

NismoPick

Without any other description or background on the problem (meaning - please give us more info), I'd say a tune-up does wonders for a tired motor.

cbaumy34

Tune up has recently been completed cap and rotor,plugs and wires etc..It is slightly hard to describe its happened since I purchased the zx last year. basically the second I lift my foot off the throttle there is a jerk.... this happens intermittently however when I am cruising at higher speeds you don't notice it as much. The jerk feels like a hard downshift if that helps. I have checked the U joints and replaced the diff. Bushing and the two on the rear cross member still no luck.

cbaumy34

Could the throttle switch cause symptoms like this? That may be a long shot.

NismoPick

Ok... I'm trying to piece this together. So is there a noise or clunk associated with this deceleration "jerk" ? If so... where does it sound like it's coming from? (front, rear, left, right, engine bay...)

cbaumy34

Sorry about the poor explanation. On a good note the surge is gone and it warms up faster. The jerk/clunck feels like it is coming from the front after I replaced the rear diff bushing. Before it felt like it was coming from everywhere.

NismoPick

Since it changed when you changed the diff bushing, I would be leaning more towards a drivetrain / suspension problem rather than engine problem. Have you checked the motor mounts? Transmission mount? Drive shaft?

cbaumy34

Motor mounts look great but have not yet checked the trans mount.

Zkelmhd

My 79 had a clunk or thud when you let off the gas. It ended up being the rubber bushing the rear end mounts with .. i would let off the gas and the clunk was the rear end shifting ( im assuming) Install a new one along with other bushings while i was under there and Problem solved !