Time to do the Fastwomen yogurt cup test. You should be able to find all your vacuum leaks with it.

  On 5/23/2015 at 3:16 AM, lord_of_the_z said:

The engine is warm it doesn't get too hot

It just will randomly change its need for air

EFI just requires more accuracy and precision than this.  Seriously.  "Random" and "need for air" just won't get it done, you have to get numbers.  It seems difficult but once you make some progress you'll see the value.  The EFI system just can't be beat on like old carb systems can.

 

Here's a case study on how to go from bad to good - 

 

http://www.classiczcars.com/topic/51367-project-boondoggle-or-so-i-went-and-bought-a-z/

 

http://www.classiczcars.com/topic/51531-sanity-check-on-280z-fi-tests/

You're way ahead of many in that your car runs.  And that it used to run well before you "cleaned up" the intake manifold.  But you'll need to get in to the fine details to get it back to where it was before.  Even that little vacuum port will change the air-fuel ratio a small amount.  Add up several like that and it's a big effect.  Good luck.

Let me explan the situation a little better

When I got the car it ran like crap everything I replaced had no effect on how it ran the idle was fluctuating from 2500 to 3000 rpms and when I would press on the accelerator the car would bog out and start to die

I messed with the AFM and it had no effect

It was only after I got rid of everything on my intake and plugged it all up when my car started to run good

Now about once a week the car will start to shut off while I am driving it

I found out that if I tighten my AFM it will run like it did before it shut off and vice versa

I'm not sure if it is a wiring issue or something mechanical

Now the only vacuum leak I can tell I have is the little hose on my bcdd which I will plug ASAP

And I also have a new fpr

  On 5/23/2015 at 8:13 AM, lord_of_the_z said:

the car would bog out and start to die

Now about once a week the car will start to shut off while I am driving it

 

Have you measured anything?  Fuel pressure, timing, engine temperature (there's a gauge in the dash, with numbers), resistance values at the ECU?  The bogging out could be a clogged fuel system, maybe in the fuel tank.  Leaving a pressure gauge hooked up until the problem happens is the best way to see that.  

 

When you say "shut off while driving" do you mean at idle, while going 50 mph, while accelerating, dies then restarts, loses power like it's about to die, makes dying noises?  See the problem?  Those are all "shut off" but there are different possible reasons for each one.  If it happens while driving it could be the ignition module.

 

I've solved a lot of problems just by trying to figure out how to tell someone else what the problem is.  You need to do more work on the description.  "Die", "shut off", and "bog" are not enough.  Sorry, that's just the way it is.  All we have out here are the words you write and the pictures.  You've only posted three numbers, one was the year of car, and the other two were RPM.

 

Did the car sit for a long time before you got it (how long) or was someone driving it?

yes the car had sat for roughly 10 years

I also forgot to mention the tank had rust in it so I replaced fuel lines and cleaned the tank with muratic acid then red koted it

and got a new fuel pump

sorry its hard to keep track of everything I've done

I have not had the chance to get the to get proper measurements but I seem to be getting great fuel pressure

I will be getting a pressure gauge on my palnet fuel rail I am planning on getting

when the car starts to die it will not idle and it starts to run very rough all I can do to keep it alive is feather the throttle but it won't rev higher than 1500

after I loosen the cog on the AFM it will seem to run fine until it eventually happens again with the same symptom's only this time I have to tighten the cog

this is making me wonder if it could just be my wiring being bad and sending the wrong signal to my ecu

I've never had it happen but maybe if you could swap in a different AFM and see what happens?  They're all gone from the junked Zs around my area.  You could search the junkyard car parts website.

 

I deleted all that stuff off mine a few years ago when I rebuilt the motor, it all works good and I'd be happy to take some pictures for you.

 

Here's one without all the markings.

 

 

 

Edited May 24, 20159 yr by siteunseen

  On 5/24/2015 at 4:19 AM, lord_of_the_z said:

when the car starts to die it will not idle and it starts to run very rough all I can do to keep it alive is feather the throttle but it won't rev higher than 1500

after I loosen the cog on the AFM it will seem to run fine until it eventually happens again with the same symptom's only this time I have to tighten the cog

this is making me wonder if it could just be my wiring being bad and sending the wrong signal to my ecu

Might be that the it's not the AFM work that's fixing the problem, but the ignition module cooling down.  What happens if the car sits for the same amount of time that it takes to diddle with the AFM?  Does it start normally and then have the same problem?  What is the tachometer needle dong when the problem happens, does it start jumping around or is it steady and normal?  If the tach needle acts weird and doesn't seem to follow RPM, and the engine doesn't run right, might be module.

 

The key for you now is to make good observations about what's happening and only small changes so that you're always able to start the engine.

yeah I don't think I have a bad AFM

and I agree I think my adjusting it is just working around the problem

the tach doesn't go crazy it seems to follow the rpms fine

I'll try a couple things you guys suggested

siteunseen, I'm glad to know I'm not the only one with a zip-tied AFM cover, ::

My guess is that for it to run right only when you tighten the living @#$% out of the AFM clock spring, you've probably got an open coolant temp sensor circuit.  Normally when that sensor opens up, the engine will belch black smoke out the tailpipe.  I wouldn't expect the engine to run as well with all the emissions stuff deleted, but I also wouldn't expect it to have this magnitude of problem.

 

IMO, the best thing you can do is to download the factory service manual and the "fuel injection bible" (both free at xenons30.com).  Work your way systematically through every single part of the EFI system:

1. Start by replacing every bit of old vacuum line you may have left, if any.  Make certain it's connected properly.
2. Do what I call the "yogurt cup test" (search it) to verify your intake is tight.  (Yoplait works best.)  Fix/address any leaks.  This often involves replacing the intake/exhaust manifold gasket (a joyful experience).
3. Clean and lightly lube (with silicone dielectric grease) every electrical connection in the EFI.
4. Verify that every part is functional and measures to spec.
5. Verify that every part is connected correctly (e.g. wiring).
6. Set your AFM back to spec spring tension.  Look for the "beer can" method on Atlantic Z.
7. Carefully verify that the internals of your AFM aren't messed up.  Clean the potentiometer trace.  Put 12V across the thing as instructed in the FSM.  Then with an analog volt meter, measure the voltage at the wiper as you open the vane.  It should vary smoothly and not jump.
8. Measure/verify EVERTHING from the connector to the ECU as a final check.
9. Verify that your FPR is really regulating at 36.4 (?) psi with the vacuum line disconnected.
10. Your engine should be able to idle now, so let's work on timing:  Check that your distributor breaker plate rotates freely under spring tension and that your vacuum advance works.  Disconnect and plug the vacuum line.  Set your timing to 10 - 13 deg BTDC.  Reconnect the vacuum line.
11. Put a vacuum gauge on the intake manifold.  You should ideally have a vacuum of 18-19 in Hg, but probably have somewhat lower.  Once you get to this point, we can help you to tweak your fuel/air mixture to get this higher vacuum.
12. Somewhere along the way, you should also adjust your valve lash.  This will help, but it's quite unlikely to be the problem.

There's a 12 step program for you.  Along the way, you will consume both yogurt and beer, which don't mix too well.  Good luck!

Edited June 1, 20159 yr by FastWoman