M40 engine Vac leak diagnosis no change dipS R'move

[soul4t]

Hi Guys,

I'm trying to diagnose/eliminate vacuum leaks from my cold start grumble.

I have replaced all intake gaskets and vacuum hoses.

When holding hand over the air intake the car will choke and stall.

I've sprayed liberaly around all intake joints/areas with brake cleaner and lighter refil, no change.

When removing Oil filler cap, the car grumbles, but doesn't stall.

When removing the dipstick...no change...I've heard that with other engines, removing the dipstick should create a problem, but I want to know if the same applies with the M40?

If you have patience you may read my full thread on the issue
:http://www.e30zone.net/modules.php?name ... highlight=
but I just want to look at vac leaks as it usualy boils down to em!

[DaniTD]

Maybe you had checked all of this, but we can enumerate posible vacuum leak sources on M40:

1-rubber boot from AFM to TB
2-rubber hosefrom rubber boot to ICV
3-o-ring between throttle body and heater plate
4-throttle body gasket
5-vacuum line from FPR to intake
6-vacuum line from canister to intake (on non-cat a plastic blocked line)
7-intake manifold Split gaskets
8-intake manifold to head gaskets
9-injector o-rings
10-breather hose from valve cover to heater plate
11-dipstick
12-oil cap

Am I forgetting something?

[soul4t]

Good plan,

All above check out ok, but testing the dipstick is a tough one...the o rings on the red pull attachment are present, squeeze to fit and tight, so I presume there is ok.

All else replaced!

Cam cover seal is new, the only remaining is exhaust mani gasket, which I will test using the paper method you suggested before.

So anything else?

[DaniTD]

Take a look at this, it applies to M40 as well, although this is some serious workshop job.

http://84.45.115.78/e30zonewiki/index.p ... Sump_Bolts

[soul4t]

Yea, I have seen that before, though I don't think I have upper engine oil starvation so didn't give it too much thought... I don't think it would be too much of a mission, with the car on axel stands and a nice sunny day...

[Billwill]

Maybe you had checked all of this, but we can enumerate posible vacuum leak sources on M40:

1-rubber boot from AFM to TB
2-rubber hosefrom rubber boot to ICV
3-o-ring between throttle body and heater plate
4-throttle body gasket
5-vacuum line from FPR to intake
6-vacuum line from canister to intake (on non-cat a plastic blocked line)
7-intake manifold Split gaskets
8-intake manifold to head gaskets
9-injector o-rings
10-breather hose from valve cover to heater plate
11-dipstick
12-oil cap

Am I forgetting something?

You forgot vacuum hose to brake servo

[soul4t]

Oh yea! And I suppose the small bit that accomodates the icv to the intake mani too!