I just finished converting my 83'zxt to the Z31 ecu and maf and now when its cold it runs like crap when i give it some gas it boggs down and starts front firing and wont go anywhere . And then when it warms up to operating temp it will stutter under 2k rpm unless full or close to full throttle meaning i cant just cruise and keep it in vacume could this be caused by me not running an air filter i was thinking when im driving in vacume at like 40mph that the air coming threw the radiator support hole which the maf is directly in line with could be making the maf read diffrent and run rich. any ideas?

Thanks -Robert-

 

And it ran fine before? You might have missed or crossed a wire somewhere. Were you following the write-up instructs or doing it all by yaself?

EDIT.... according to your previous thread ( https://www.zdriver.com/forums/280zx-performance-technical-79/need-help-83zxt-19430/ ) it wasn't running good before the swap???

 

I know I have been pushing the afm a lot lately, but try and operate your afm manualy and pay atention to your results. they could be shocking.

 

you could even try pushing the gas pedal down a little bit while cranking, till it starts then let up and see what that dose.

 

Nismopick-
yes I was running fine before i fixed the problem from the previous post before the conversion. And also I followed Afshins writeup on Hybridz.org on how to do it.

 

If he did the Z31 ECU swap then he no longer has the AFM. He's got the MAF now,nothing to manually operate.

 

I'm not familiar with the swap or the wiring involved but have you checked to make sure the TPS is wired correctly with the ECU and that it's working properly. If the TPS is giving off a signal at part throttle then it will cause driveability issues at part throttle.

 

Check the fuel pressure. You should be at 30-35psi fuel pressure.

Here's some questions I have:

Did you ground the fuel pump onto the body?

Did you wire the AFM to MAF wiring correctly? (There are 2 black MAF wires that a lot of people mix up)

Did you swap ecu pin 16 & 108 so the fuel pump & air regulator still work correctly?

Did you make sure the Z31 distributor chopper wheel is facing the correct way? It will run very crappy if that wheel wasn't installed correctly.

 

Yes I did all of that correctly only thing is that i dont have a guage to test the fuel pressure.But the idle does smooth out a lil if i take the vacume line off the FPR.

 

Get yourself a fuel pressure gauge... and also an air/fuel ratio gauge.