81 air/fuel issue?

[Guest Anonymous]

Hello all, this is my first post here. I have 4 z cars, right now it's the 81 turbo, that I'm ready to throw in the towel on.

 

 

Basically, there is very poor throttle response on the bottom end, stomp on the pedal at the bottom end, and it's a slow gradual build up on acceleration. Now, before you say, "Hey, it's an 81, that's normal", I've owned the car for seven years, and even with a 3 inch pipe and flowmaster, and mSA manual boost controller, she use to have alot of "snap" at the bottom end. The problem started about two years ago, after I parked it for a winter (I know stupid, right) Now, I can't even get first to chirp, I would guess the curretn qrt. mile time is about 18 seconds (my stock 77 is faster) I don't think it's ignition, I still believe it's fuel.

 

These are the mods:

 

auto converted to 77 five speed.

3 inch all the way, "test pipe"

3 inch flowmaster

msa boost controller

MSA/K&n AIR FILTER (BRAND NEW)

 

 

Here's what I have checked, replaced during the past month

 

 

new nissan air regulator (idle picked up alot)

new bosch O2 sensor

new nissan 82/83 distributor, new cap, new ngk wires, new rotor, new NGK plugs, timing is dead on at 20 degrees

new nissan turbo fuel pump

new nissan stock, then later switched to MSD FPR part #2222 (no change on either)

rebuilt MSA turbo AFM (resulted in NO change)

all new MSA fuel injector pigtails soldered in (no change)

swapped in another 81 turbo ecu (no change)

valves ahve been adjusted by nissan mechanic (no change, all but one were right on)

new fuel filter

new nissan turbo coil (no change)

throttle bottle removed and cleaned completely (ever so slight change)

new nissan cylinder head temperature sensor (connector looks good)

dropping resistor passes FSM test

 

 

 

all injectors seem to be ok, pulling the pigtail at idle on each cylinder results in a change, incredibly, I had a bad injector until yesterday, no change in idle, when pulling the pigtail, after I replaced the injector with a new nissan turbo injector, the idle changed when disconnecting the injector, BUT THE CAR DRIVES THE SAME!#$%^&*()

 

 

 

here's what I still have left to do.

 

Finish checking every underhood electrical connector

replace every vacuum line (I've done about half of them)

I sprayed a can of carb cleaner on just about everything, didn't find any leaks)

 

check and or replace afm boot

 

replace both ground cables (starter and battery, both look pretty rough)

 

dealer is going to be checking compression and installing new tps tomorrow

 

 

Somebody suggested to me testing the car with the vacuum line disconnected to the egr valve, I tried it with both the vacuum line plugged with a bolt, and having it just disconnected, there was no change in the way the car drove. Does this mean anything?

Last item, while checking the pigtail when I was replacing the injector, I tested the signal from the injector clip with a test lamp connected to the battery negative, the idle picked up alot even with the pigtail disconnected, the test lamp did light up. Is this normal? Bad ground somwhere?

 

Lastly, I'm wondering how accurate the "idle test" is for checking injectors.

I replaced all six a year ago with new Echlin injectors from Napa. Now I just had one crap out on me less than a year later. And again, I stupidly let the car sit for the winter. I'm wondering if the remaining five are squirting enough fuel at idle, but not doing enough at wide open throttle.

 

 

That's where I'm at, anybody have any ideas on this?