Lumpy Idle and steady Rev

[bevis]

today i did the vacuum check with the cab cleaner came up with nothing...running out of ideas

 

[bensmith907]

Deffo looks like a vacuum problem I get a good -50psi @idle I think. Do you have all the black condoms over the throttle ports?

 

[bevis]

So I changed the knock and the intake manifold an I still have no vacuum pressure but I have good compression... I have no clue what to do now... Does any one have any idea of what's going on??

 

[danr]

 

[Fusion Ed]

Deffo looks like a vacuum problem I get a good -50psi @idle I think. Do you have all the black condoms over the throttle ports?

No you don't The lowest possible vacuum theoretically possible is only 14.7psi. Assuming atm pressure is 14.7... Your scale will be reading in bar and your probably seeing about -0.5bar relative.

Bevis, if you have nearly no brakes then that's a clue. Check your vac line from the brake servo to the inlet manifold. If your car idles at all you have vacuum. If your over fuelling then your ECU is reading too much load. (airflow) Your next option would be to get nissan datascan and see what kind of values your seeing on your sensors.

 

[bensmith907]

Yep your right edd will stop posting after a night shift. Sorry Bevis

 

[bevis]

Bevis, if you have nearly no brakes then that's a clue. Check your vac line from the brake servo to the inlet manifold. If your car idles at all you have vacuum. If your over fuelling then your ECU is reading too much load. (airflow) Your next option would be to get nissan datascan and see what kind of values your seeing on your sensors.

i had no vacuum coming from any vacuum lines, boost/vacuum gauges were reading next to nothing...

so after changing the knock and the plenum an getting the same results i took the engine out...haven't done any digging into it as yet but as soon as i do i'll update and let u guys know what i found..