Other places for a vacuum leak?

[Nick Triesch]

I have a bad misfire. I have found, checked, replaced all leaking parts including intake gaskets, behind throttle body, hoses next to oil fill cap, hoses up way to the left of throttle body. fuel injectors are tight. Oil cap is tight. Nothing seems to be leaking topside using the starting fluid method. I notice now after all the work, engine no longer lowers RPM's when I remove the oil cap. But car cold starts fine and has an 800 idle. I need more ideas where to look for vacuum leaks. Holy Cow!

[Bob Kontak]

Brake booster hose. IIRC JW mentioned he found a leak under the body as it heads towards the front.

[Nick Triesch]

Thanks Bob, I’ll take a look. This mis is killing me!

[steely]

Originally Posted by Nick Triesch

Thanks for the info. I did check the drivers side intake for vacuum leaks and it did have some . So I tighten that side up and stopped the leaks . The passenger side was not so easy . Could not stop the vacuum leak so I replaced the intake gaskets on that side. All is well in the vacuum department now! When I get time (mother’s day). I will change out the injector.

What happened with the bad injector theory?

[SalParadise]

Did you actually physically remove the fuel injector sleeves in each of the manifolds, clean, replace with new and re-peen them? If you did not, you still have six leaks...each injector has two o-rings, one to seal the sleeve and the other on the injector...

[Walter_Middie]

Did you actually physically remove the fuel injector sleeves in each of the manifolds, clean, replace with new and re-peen them? If you did not, you still have six leaks...each injector has two o-rings, one to seal the sleeve and the other on the injector...

I was amazed at how bad my injector sleeves were when I replaced them. They literally crumbled as they came out. Like thin dried out plastic - which they were. The car has run amazing ever since.

[Nick Triesch]

Well, I thought I had a bad injector on cylinder number 1. I just replaced that one injector because I really thought that was the bad cylinder. When I pulled out the number 1 plug wire there was no change the way the motor ran . I did have spark. I did a test to see if the extra injector I had would make a difference. It did not. I checked with my meter, I do have 12 volts to that injector.

[Nick Triesch]

Dumb question, What is a injector sleeve? My 3.2 Just has injectors. Are you taking about the orings ? Yes, there is one in the top and bottom on my injectors.

[gazzerr]

Also check the cork gasket around the sender unit for the oil level on the oil tank.

[SalParadise]

Originally Posted by Nick Triesch

Dumb question, What is a injector sleeve? My 3.2 Just has injectors. Are you taking about the orings ? Yes, there is one in the top and bottom on my injectors.

Yes, you don't have them. Only for CIS. Carry on.

[76FJ55]

In your previous thread you stated. "Thanks for the info. I did check the drivers side intake for vacuum leaks and it did have some . So I tighten that side up and stopped the leaks . The passenger side was not so easy . Could not stop the vacuum leak so I replaced the intake gaskets on that side. All is well in the vacuum department now! When I get time (mother’s day). I will change out the injector."

If you are still having an issue with dropped cylinders on the left bank I would consider going back in and actually replacing those intake gaskets as well. If you had a noticeable leak and just tightened the manifold bolts it is likely the gaskets have already degraded and are in poor shape.

If you have an infrared temp gauge, you can check exhaust runner temp to determine which cylinders aren't heating up (missing) as fast as the others.

[Bob Kontak]

Originally Posted by 76FJ55

If you have an infrared temp gauge, you can check exhaust runner temp to determine which cylinders aren't heating up (missing) as fast as the others.

This is good. The Freight has the laser gun thermometers on sale for $28 now.

You can run a compression test on a suspect cylinder to see if a burnt valve seat or the like but that is not a routine occurrence for a hobby car.

[Bob Kontak]

Originally Posted by 76FJ55

If you are still having an issue with dropped cylinders on the left bank I would consider going back in and actually replacing those intake gaskets as well. If you had a noticeable leak and just tightened the manifold bolts it is likely the gaskets have already degraded and are in poor shape.

Brake / carb cleaner spray test should confirm this.