300zx bogs on acceleration and startup
 

Hey, so I recently purchased a 1984 300zx that has been sitting for 15 years, I replaced the fuel pump, fuel filter and cleaned the gas tank. On startup the vehicle runs like shit and if I touch the gas it'll bog down and die, once it warms up it will be good for a while but occasionally it'll bog down and die on acceleration. No idea if the check engine light is on as my digital dash is still under repair, but i was thinking it was the MAF or TPS sensor, any second opinions?

here is a start:
check your fuel pressure, check your vacuum, replace the CHTS
Get your battery load tested. Be sure you have clean, tight corrosion free terminals on both ends of your battery cables. Be sure the ground (negative) cable goes to a bolt into the frame before going to the starter. grounding through the starter is not a reliable connection. Z's don't like low voltage. causes the electronics to act funny. it is possible to have enough amps to crank but not enough voltage to run the electronics. If you have one size fit all cheapo clamp on terminals they are a problem waiting to happen. Usually on a rainy night around Oh Dark Thirty.

Clean the connectors for the maf or afm, ecu and tps. Deoxit by CAIG is probably the best connector cleaner on the market. spray with CorrosionX after cleaning and before putting together this will help prevent any further corrosion. DON'T USE DIELECTRIC GREASE.

Replace outer tie rod ends, and ball joints. replace the bushings with poly (don't forget to lube them as directed unless you like squeaky things). New shocks. Get new boots for power steering. all those things will make you think you are driving a different car. doing them piece meal is a waste you won't see a great improvement until you do the complete job. You need to get the car realigned after messing with the front. Have your tires in good shape and rebalance. Rear bushings nice too but more work and you won't notice as great an improvement. Rear shocks also because if the fronts are gone so are the rears. if car squats when you jump on the gas the rears are gone. If you have the electro adjustable shocks they are DEFINITELY GONE.

I'm having what sounds like the same issue. Between my group of friends, we're all thinking it's an Air issue and not a fuel issue. Have you checked the air hoses that run off of the air intake elbow, nearest the throttle body. I rebuilt 2 out of the 3 hoses (oem hoses don't seem to be for sale anywhere) I can send pictures of what I did. While it did not fix the issue, it has significantly improved the issue. (i was unable to start the engine at all) now I need to figure out what is causing it to bog down and cut off after it idles for about 10 seconds. If you find a fix, please shed light and send me a message. Good luck!

Hey again, so I got my Z to start and idle on its own, but it still dies with acceleration or putting the car in drive (automatic). I unhooked my MAF sensor and replaced the old rotted vacuum lines with new silicone ones. Startup could be smoother, but it idles great. Try disconnecting your maf cable and see what happens.

Cheers!

I know this is an older thread, but the MAF really needs you to add an extra ground wire to the black wire. It is the main cause of MAF related issues on all old Nissans.

also the TPS is for throttle position switch not sensor at least to 87 , my 86 is a switch
I drill out the two rivet heads to adjust the idle and full throttle contacts

also the TPS is for throttle position switch not sensor at least to 87 , my 86 is a switch
I drill out the two rivet heads to adjust the idle and full throttle contacts

Just curious why do you say not to use dielectric grease? First thing I did when I bought mine was clean and dielectric grease all my connectors

I have the same problem with my 1984 300zx Turbo, and I was told that I need to replace the AAC Valve. Problem is, I can't find one. Any suggestions? Thanks