loose Distributor CAP = Perfect idle

[ira]

so idle is around 850 still with some missing every few seconds, just like before.

 

as for revving it up, (slowly, gradually or suddenly) today its very smooth with no hesitation or choppiness.  Couldn't take it for spin due to rain (tires not in good shape)

 

i feel its a Fuel air mix issue but not sure where to start.  i dont want to redo the valves clearance again 

[Zed Head]

On 11/2/2020 at 8:25 AM, ira said:

1982 Datsun 5 speed Trubo. 

Just posting this as a reminder.  The ECU still doesn't learn but it's not a 280Z ECU.  Should have an O2 sensor also.  And the CAS in the distributor.  Turbo ZX stuff.

[ira]

Is there a way i can read O2 info? im sure we can find some indications there

[Zed Head]

I would start reading from this page in the FSM, below.  The Turbo system has a lot of interconnected parts.  The ECU has lights that flash when it goes in and out of closed loop control.  Closed loop is where the O2 sensor comes in to play.  You could probably watch the light while the engine warms up and see if things change when the light starts flashing.  When you talk about what's going on it would be better to tell what the engine temperature is, instead of a "a while".  Engine temperature controls when things happen.

It's kind of a complex system that takes some real study to understand.  That's why Nissan developed the Analyzer.

Search for cgsheen's comments.  He always recommends Megasquirt.  He knows how the ECCS system works though.

Are you sure the turbo isn't jammed?  Your 30 mph limit sounds like something's blocking your exhaust flow.

[ira]

1 hour ago, Zed Head said:

I would start reading from this page in the FSM, below.  The Turbo system has a lot of interconnected parts.  The ECU has lights that flash when it goes in and out of closed loop control.  Closed loop is where the O2 sensor comes in to play.  You could probably watch the light while the engine warms up and see if things change when the light starts flashing.  When you talk about what's going on it would be better to tell what the engine temperature is, instead of a "a while".  Engine temperature controls when things happen.

It's kind of a complex system that takes some real study to understand.  That's why Nissan developed the Analyzer.

Search for cgsheen's comments.  He always recommends Megasquirt.  He knows how the ECCS system works though.

Are you sure the turbo isn't jammed?  Your 30 mph limit sounds like something's blocking your exhaust flow.

 

i do have access to the ECCS analyzer for the 1982 Turbo but it has no manual.  i have not been able to locate any

ive seen few nice vids on  Megasquirt.  i dont mind it as long as i know where the issues are!  

Prior to replacing injector, the turbo worked just fine when CAP was raised.  so im sure its not a turbo issue

hopefully when rain stops i can take it for a spin

[Yarb]

Do you have a fuel pressure gauge in series to monitor your pressure? I’ve scanned back through the post but did not see where you mentioned fuel pump pressure/activity etc. 

 

[ira]

9 minutes ago, Yarb said:

Do you have a fuel pressure gauge in series to monitor your pressure? I’ve scanned back through the post but did not see where you mentioned fuel pump pressure/activity etc. 

 

when car arrived, it would not start at all.  i had to put in a new fuel pump.  since then car starts immediately but no, i have not tested fuel pressure.  im pretty sure the pump is for the correct Turbo model

[Yarb]

Installing a pressure gauge between the filter and fuel rail is a great diagnostic tool for monitoring your delivery. Inexpensive and will  provide diagnostic feedback for the fuel system. IMO

 

[ira]

2 minutes ago, Yarb said:

Installing a pressure gauge between the filter and fuel rail is a great diagnostic tool for monitoring your delivery. Inexpensive and will  provide diagnostic feedback for the fuel system. IMO

 

no doubt, but the car would run fine when CAP is raised.  it did this regularly even with bad injector.  so if it was a fuel delivery issue then it would misbehave at all times

[Zed Head]

If the problems are still all centered around lifting the cap then it seems like it might just be a CAS issue.  Seems like lots of activity is happening but the CAS is involved somehow.  You have to loosen the screws to lift the cap which might be releasing force that's causing distortion.  Who knows.

[ira]

just took it for a short spin.  dispite the little blinps her and there w the idle the car ran very smooth,  throutle was very responsive and extremely smooth.  but if i tried to push it and engage trubo, it would hesitate 

[ira]

1 hour ago, Zed Head said:

If the problems are still all centered around lifting the cap then it seems like it might just be a CAS issue.  Seems like lots of activity is happening but the CAS is involved somehow.  You have to loosen the screws to lift the cap which might be releasing force that's causing distortion.  Who knows.

hey Zed, i have been keeping the CAP on tight and so far despite some of idle fluctuation, the car was very responsive & smooth when i was revving it.   it has been a long time since ive felt it this smooth.  when i went for a drive, it was fine as long as i did not push it.  so as long as avoided engagin the trubo, the car would accelerate and was very smooth.

tmrw should be snow, so i wont be out.  but as soon as its dry will go for another spin.