Intake manifold Vacuum leak?
 

1989 civic 4 door Dx
b18a1 block b1 head
P75 intake manifold
dc headers
Everything else stock
P75 ecu

Okay I bought my self a used working condition intake manifold.
Took out the old one.

Put in the new intake gasket.
And installed Intake manifold. Put it on "On position" and checks out good
Cel comes on and off. Have a leak on one of the fuel filter lines.

So i go ahead and start it up. Heard a Very Loud whining noise!
Like it sounds like a super charger but at idle. Try to listen where its coming from
but its too loud. Loud that it hurts my f*CKN EARS. LOL

Tried adjusting idle nothing. It also idles very high. 1500
It has a jumpy idle it goes from 100+/-

Never heard of this before. Any suggestion before i pull it off again.

Re: Intake manifold Vacuum leak?
 

You can check vacuum leaks with many substances,but one of the more common-safer ones is wd-40 which will make engine "bog" when sprayed onto a vacuum leak such as @ the gasket or throttle body. (propane is used in alot of shops,you can use most canned aerosol solvents (they make engine rev up in rpm) but some are highly flammable so spraying on hot engine surfaces involve some danger of fire when using them!!!) You can check vacuum lines by "pinching" them flat momentarily whilst running if suspected leak there... G' Luck! :)

Re: Intake manifold Vacuum leak?
 

Okay It was a vacuum leak from the intake manifold gasket.
Apparently i took out the whole intake manifold again.
And found out that i forgot to scrape the old gasket off >.< FML
Making is leave space for the vacuum to go in. Also coolant went inside #4 cylinder intake manifold. -_-

Will fuel pressure effect if its leaking from the banjo bolts on the fuel filter?

Re: Intake manifold Vacuum leak?
 

Yeah,even a pc of an old gasket not thoroughly scraped off BOTH mating surfaces will cause a vacuum leak! :)

Replace the aluminum crush washers that are between both sealing surfaces of the banjos,you do not want fuel leaking onto a hot engine/manifold,etc... But yeah,a leak will affect fuel pressure if it's big enough,but NONE are acceptable!!! = FIRE if not repaired!!! G' Luck! :)

Re: Intake manifold Vacuum leak?
 

Okay another ISSUE:
Fixed leak so checks out okay.

Cold start it idles at 1700-1800
Then when it warms idles at 8-900 No probs.

When i take it for a drive i go 30-40mph and braking/coming to a stop car idle drops and wants to die.
Went to gas station to see any probs cant seem to find but i hear hissing noise not sure if its intake or a leak again

Then drive out gas station i die out but starts right back up. Died like 3 times even when driving 15+mph

Re: Intake manifold Vacuum leak?
 

STILL having the same prob. Took out manifold and cleaned it up more with a razor.
Reinstalled everything.
FUEL pressure at idle is 39-40 psi

when driving/cruising ill let the car roll/idle/neutral
The car idle drops and slowly dies.
I tried pressing the gas pedal to keep it from stalling but ends up dying.

also when i brake idle drops
tried adjusting idle by disconnecting the iacv but it rpm drops all the way to 100-200rpm
then played with the idle screw no change.

Re: Intake manifold Vacuum leak?
 

What ECU?

Re: Intake manifold Vacuum leak?
 

p75 ecu

Re: Intake manifold Vacuum leak?
 

OBD1?

Re: Intake manifold Vacuum leak?
 

yes sir

Re: Intake manifold Vacuum leak?
 

Jump the service connector to check for CEL codes.

Here's the proper method (B18B1) to adjust the idle speed:

Re: Intake manifold Vacuum leak?
 

THanks will try this.

The only codes im getting is Code 41.
Nothing else.

Re: Intake manifold Vacuum leak?
 

Also try resetting the ECU and driving the car to see whether a new code pops up.

Re: Intake manifold Vacuum leak?
 

Reseted ecu and test drove it nothing new

Also noticed when i first installed the intake manifold fuel pressure at idle was about 36.
It went higher after 3rd attempt of reinstalling it. 39-40 psi