Intake Manifolds

[supna]

SZ - Non Turbo Question!!

 

History:

Car runs at approx 1280-1360rpm when warm and 1000rpm when cold. Have slight oil leak near oil filter but can't see where it is coming from and have checked tightness and seal on filter.

 

 

Problem

Is it possible to have oil leaking from an Intake manifold. After finally finding a replacement idle spped controller and changing it on the throttle body the idle problem still persists. I am on the max retard on the distributor but still runs fast. Took the car to Leon and even he can't find the fault. Yesterday I started stripping off the throttle body

 

I stripped down A, B, C and checked all the hoses and gaskets and gave them all a damned good clean. What I am thinking is that maybe there is a leak on the intake manifold? Below C in the picture and maybe this is drawing air in and causing the idle to increase? I have also changed the throttle speed sensor. This is really doing my head in so can someone please help.

[Ian C]

Any air leak after the air metering system usually causes poor idling and stalling as the engine will not be supplying anough fuel for the amount of air coming in and it will run lean. Which airflow metering system does the NA use? If this was off-calibration or was somehow measuring more air than was reaching the engine could it cause a rich condition and perhaps raise the idle like this?

 

-Ian

[Digsy]

As Ian says, an intake manifiold leak will cause uneven / unpredicatable running and, yes, you can have oil leaking from an intake manifold because of the closed breather system.

[supna]

Time to take it apart again me thinks but this time taking off the intake manifold. Looks like a bitch to get at the bolts but hey what the hell.