cgalas

i bought this car about a year back now and have slowly started changing out parts and doing basic tune up stuff. the car came from washington, good ol rain all the time kind of weather up there. the guy i bought it from didnt run it at all for about a year. dual su carbs, 2.4 engine, changed out the points to an electronic dizzy, oil changed with new filter, coolant flushed and refilled, carb oil topped off, tranny fluid good, carbs tuned, new fuel filter. along the way ive encountered a couple problems.

i changed out the fuel filter cuz the old one looked muddy as hell. in hindsight, i probably should have cleaned out the fuel tank first, any suggestions on what to use? i notice a lot of what look like rust chips in the filter, is that going to cause any kind of long term damage if the filter doesnt happen to catch it all? granted the engine probably needs to be rebuilt anyways.

second, after a change oil and topping off all the fluids the car still feels sluggish at times. it tends to jerk every now and then and i notice a kind of popping noise coming out of the tailpipe when it jerks. any ideas on what the hell that is?

third, the car jerks even more violently when in 4th gear. i tried taking this car on the freeway just to see how it ran and 3rd gear going into 4th it starts sputtering on me. cant get the car to go past 55 mph without feeling like the bodys gona come off the frame! i thought it might be the tranny needs fixing but im not sure.

fourth, yeah theres a lot i cant figure out. i cant get my low or high beams to work. ran a voltmeter all up and down the car and cant figure out which wire is tripping me up if thats even the case at all. time for a new harness? worn relays? i replaced all the fuses already. all the mechanical stuff i figure out eventually but the electrical stuff perplexes me to a whole other level

any help on any/all issues greatly appreciated.

280zWraith

Congrats on the Z!!! I bought my '77 280z in February and performed a tune up/maintenance on it, and afterwards, I had some problems as well. I can help you with some of your issues:

-These cars are very prone to rust apparently, including inside the gas tank. Therefore, I suggest removing the tank and having it cleaned out professionally. I took mine to a radiator shop and it cost about $200. They weren't able to coat the inside due to baffles (not sure if the 240's are the same way) so I'll just be taking it down and cleaning it myself in the future. If you are doing it yourself, then I suggest getting some Calcium Lime Rust cleaner (Zep brand, since it cleans better than CLR branded liquid) from Lowe's, or wherever you can find it. Some people suggest using pebbles inside the tank, but I am COMPLETELY against this. They may get stuck somewhere you can't see and cause a ton of problems later. When reinstalling, do yourself a favor and replace ALL your fuel hoses with the correct psi rating and use fuel hose clamps (the sides are curved to prevent cutting the hose.) Also, I installed a clear fuel filter between the tank and the pump. This is a must!!! It will greatly aid you in seeing when/if you have problematic rust in your tank, and catch any large rust specks before reaching the pump (a new OEM pump costs around $350 or more.) Also, these filters should be changed out perhaps every 2 oil changes since they are inexpensive.

-The popping noise from the back could be from your engine backfiring, but this is a just a guess.

-As far as the electrical issues, I suggest getting yourself the Factory Service Manual for your vehicle (try ebay), and study the circuit paths you are having problems with. Also, get a can of Deoxit D5. It is a contact cleaner and should be use to remove any corrosion from the electronics you are dealing with. I found mine at an Alltex store. I am not super savvy with electronics myself, but I still needed to dedicate my time to understanding how to read the diagrams properly and tracking down issues. The manual has troubleshooting instructions to help diagnose and repair your issues.

Hope this helps you a bit. These cars are journey in themselves to repair/restore. Enjoy!

Turksspeedwerks

Mine is about the same here except it's carbon fowling all the. Plugs

SpeedRacer

Yup, sounds like the engine is running lean because of rust in the gas tank restricting gas flow. Rust in the Z car gas tank is a very common problem and it is made worse because the dumb EPA requires the gas companies add ethanol to the gas. You would not believe have fast and how much water ethanol can absorb.

Anyway, you might want to check and see if you have a "Gas Tank Renu" Gas Tank RENU - USA store near you. They did my tank over 12 years ago and it is still holding up just fine. Get the tank fixed and replace the filter again and see if that fixes the problem although you might have to clean out the carbs.