Wiggle the harness near the ecu when it's running like crap.

You will probably find it affects the running.

Also...........did you set up the proper gap between the crank angle sensor an the tone wheel?

 

wiggling the harness never does anything. all the points are clean and tight.

the gap is set el perfecto

 

So does the 81 CAS have the same 4 prong round connector as the 82-83 CAS? Does it send the same signal?

 

the 81 and 82-83 have the same hookup if i remember right. it's a black round plug with 2 male and 2 female pieces.

Last i remember it sends the same signal, the 81 is just a pos though

 

You would think it sends a different signal but someone somewhere posted waveforms that looked identical.


Actually the 1981 crank angle sensor can tolerate higher revs because it doesn't have to travel through a timing chain and a distributor drive gear.

 

This car is driving me nuts...

I drives like a bat out of hell sometimes and others i get that total loss of power, chugging and all that jazz....

The amf was spottless, cas seems to work fine, tps is brand new, all the connections to the ecu are clean and tight....

Could a coil cause this? I have 1 other sitting in the garage and i swapped it out. The problem changed it's timing from random to right when i hit boost at any time. It's just like before but 2000x worse.... the car justs stalls, the exhaust and engine sound stuttery and it won't go anywhere.

I was thinking about grabbing a msd coil and giving it a shot...

 

do you know what your fuel pressure is running at?

 

no clue about the fuel pressure. it should be acceptable since i upgraded to a walboro fuel pump.

I'm about ready to just call it quits on the nissan...

It starts, runs perfect sometimes, like a stuttery backfiring turd most of the time and is proving to be quite the black hole for money lol.

I changed the harness out just to make sure it wasn't something electrical and the same stuff happens.

The only thing I can think of is sell the car or throw it back in storage until i can afford megasquirt..

I'm just completely out of ideas about why it sputters and backfires for no reason at all, then runs perfect the next second.. It's not wiring since the problem is consistent with a different harness.

The only things i haven't replaced thus far are the coil and tps sensor. I have a spare one from my n/a engine but i doubt it would work since it's a 3 point switch and turbos are 2.

 

if i find out it's fuel pressure, is it acceptable to just buy 20 feet of hose and reroute the lines from the tank to fuel filter so i'm not using the original stuff from 83?

 

lines can get clogged, but if clean gas was always ran through (as in not super old varnish crap) then the lines should be fine, gasoline acts as a cleaning agent so those lines can get clogged but not blocked up in a way you couldnt fix. if you think there is something in the fuel lines blow compressed air from the engine bay lines (after removing the fuel filter) back towards the tank. that should clear anything out that is in there, but there probably isnt anything in there. if your worried about them rusted and falling apart though, they use hardlines for a reason, i would just get a tubing bender and some long long tubing, its not that hard to route its mostly straight shot all the way up.

 

my big concern is that the car sat and accumulated rust in the tank. I've been driving it for the last 3 years with the n/a engine and i'm assuming thats more than enough time for it to clean itself out. If the fp is low I'll just run new lines.. it can't hurt.

It's probably not the fuel lines though.. i'll be chasing demons in this car forever

 

Do you guys know what sensor this is?
It sits below the #1 spark plug and a water tube.

The wires are cut and I can't really find anything that matches it.

 

Looks like a piece of crap block heater (uses 110v power... someone cut the electrical plug for you). Someone stuck one on my stock 280z motor. I hope they didn't drill into anything to secure yours...

 

lol... that would pisssss me off.

Thanks again man.

 

Well i started going to town on all the a/c and other accessories in the engine bay, cleaned it up and got everything secured and the car is running perfect

My next step is going to either be a fmic setup or convert over to a 300zx ecu/maf/82-83 dizzy setup.

So far the only beef I have with my car is the 81 cas setup... it sucks..