Intake / Engine / Unmetered Air Leaks - Smoke testing?

Hello there,

Just wondering if anyone know of any "poor man's" techniques of detecting vacuum/engine/intake air leaks by forcing smoke or compressed air into an engine. There is equipment on the market but its well over the $1000 mark.

Plumber's smoke candles only cost about $7, but they leave residue. There needs to be a way to pressure feed the engine and passageways with the smoke for it to find the openings.

I can't get my idle below 1200 using the throttle stop screw, following the instructions on the sticker under the hood. I have plugged all of the vacuum taps on the intake one-by-one and altogether (except fuel pressure regulator, holds vacuum) and no difference in idle.

I am thinking injector O-rings, intake gaskets or something between the vane meter and combustion chamber is allowing extra air into the cylinders. Maybe even the head gasket since I have telltail signs of oil leakage on the block, just under the head.

Thoughts? I would love to find the source of this unmetered air. Thanks, Matt

Reply to
sleepdog
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did you try the water bath or propane test?

Reply to
Backyard Mechanic

Not yet, but check out this link, claims using an old inner tube and a bicycle pump works on a porsche 928. Got me thinking.

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How effective is the propane test, been meaning to do it, just haven't had the chance. Never heard of the water bath, how does that work? Thanks, Matt

Reply to
sleepdog

opined in news: snipped-for-privacy@z14g2000cwz.googlegroups.com:

Spray fine mist water over intake area with engine up to temp, if a hairline leak, engine will slow.

Have you tried with the MAF disconnected?

Reply to
Backyard Mechanic

Probably the idle control solenoid is just bad. I'll assume it's a 4 cylinder

Reply to
pick one

It has a vane air meter, no MAF.

If I did this and the engine slowed down, not sure where I would start looking.

Thanks, Matt

Reply to
sleepdog

I have a new idle control solenoid that is only a few months old, no difference in engine behavior between that and the old one.

I capped off all vacuum taps to the intake except for the fuel regulator, which checks out with a vacuum pump. No change in idle speed.

Following the throttle stop adjustment steps on the underhood sticker yielded no joy either. I can't get the idle below 1200, which is why I want to test for any air leaks from the throttle body to the cylinders (gaskets, injector o-rings, throttle body).

I got a remanufactured vane meter and that cleared I think three of the codes the computer was throwing, now I only have a lean condition with codes 41 and 47.

16 is also present but I keep the throttle stop set incorrectly because if I didn't the engine would be idling at 2000 rpms.

It's a 1990 Escort GT 1.9 EFI HO, last of the 1st gen US models.

I can't wait to find out where the *&^^&%&^ 'ing extra air is coming from!!!

Thanks, Matt

Reply to
sleepdog

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