One heck of a '78 280Z

[IdahoKidd]

Curious, have you actually driven the car or just revved the motor while in the driveway? Does it puff when you shift? Does it smoke on deceleration and upon acceleration? What color is the smoke? Does it have any kind of smell/odor? What do the plugs look like after an hour drive? (Pull each on-not just one). Do you have to add engine oil and how often? Have you changed the oil recently? Of course if it isn't a driver some of these you can't determine. Am trying to determine if it is even engine oil that is causing the smoke or just overfuel. If it is black and waters the eyes, its fuel. I'm with the others in that it probably isn't a ring problem. Of course it could be, but.................

[5thhorsemann]

Im not familiar with the EFI system on the L motors, but a faulty crank case venting system could also make the car smoke at high R's, and could cause a fuel delivery problem as well.

[z_ya]

We have taking it around for a bit, and the after awhile the plugs were nasty. Black an ashy that's why I went and got new plugs and new plug wires. While driving it it smoked blue out of the exhaust upon acceleration, i have not yet jammed my foot into the gas pedal yet nor do i intend to until im sure what the problem is or more than likely could be. I have not had to add oil yet but ive only drove it once, i will be taking it out again today though. I had gotten new connectors for my water temp sensor and my TVS but haven't been able to see if that fixed the running rich problem yet. When i change the plugs later today i'll take a picture of them for you guys. And 5thhorsemann i will look into that thank you.

[Zed Head]

Had the car been sitting for a longtime before you got it? What you really need to do is download the Factory Service Manual,if you don't have one, and start testing components as shown in the Engine Fuel chapter. Save yourself time in the long run and just go through the tests. There are many causes of running rich and each one can add a little bit of richness. You will most likely not find a single solution to the rich mixture problem.

And, regarding a new engine, you'll still have the same problems with a new engine, unless you get all of the EFI parts with it, and they are all in great condition. You're on the typical path of a new owner of an old 280Z.

www.xenons30.com/reference

p.s. You're way ahead of many people with new Z's since yours actually runs and drives.

[Ben's Z]

I have a 77 280z with 93k on the clock. I just pulled my N/A engine because I am doing the 280zxt swap. My engine also smoked when cold under acceleration. I never investigated the problem fully but can tell you that a dry compression test yielded anywhere between 138PSI and 141PSI across all 6 cylinders. Having inspected that engine a little more the other night when I took the manifolds off I believe the motor would have been fine with a rebuilt head. I just had my turbo head rebuilt and the shop did it for 200 dollars. While my 163k turbo block was at the shop they evaluated the condition of the block, and even with all of those miles, and it being a turbo engine, a simple ball hone restored the cylinder walls to satisfactory condition. These blocks are really tough, I doubt this is all from the rings.

[z_ya]

yeah i have ran through the FSM about when i first purchased the car, the only thing that i found wrong was the TVS. running rich is an issue i would kind of like to put off for a bit and put more attention on the smoke, i know they are both problems that need to be fixed but i can but new sensors if need be for the running rich issue. And Zed Head yeah the reason i bought it was cause it is a 5 speed manual, it's a damn sexy car and it started an ran. Plus it was only 900 dollars haha. But yeah i have ran through the FSM and came back with the TVS not being correct (corroded connector). I just dont know where to start to find out what is causing the oil to be burnt. I really appreciate all the responses guys again any ideas or thoughts will be looked into and checked out the best i can. Thanks

[LeonV]

(1) Fix the rich condition.

(2) Drive around.

(3) Report back on how many quarts of oil were burned after driving 1000-3000 miles.

[grantf]

(1) Fix the rich condition.

(2) Drive around.

(3) Report back on how many quarts of oil were burned after driving 1000-3000 miles.

Good advice. Easier and cheaper than a new engine (or worse bad used engine).

[mjr45]

Yup, agree with LeonV, fix the rich condition, it may take a while, I've been trying to fix the rich on my 75 for about 3 months, but it will be worth it in the end.

[z_ya]

well she smokes no more, and i think the cause of the richness is injectors, i know for a fact one is the wrong size (it's pink) the rest are a dark green but i plan on replacing all injectors on the beast, then fixing the exhaust. I know this is in the wrong part of the forum and i don't want to switch topics for to long here but are the results with the exhaust system into a straight pipe good? cause mine has holes all over getting into the cab and it NEEDS to be replaced.