Can a vacuum leak be caused by lower intake install

[Creomod]

Ok guys. My car starts right up(timing on point) and shuts off if I don’t hold gas down when it’s on its extremely lean and I hear it kinda sound like an exhaust leak(like a truck) . I had just redone the lower intake and swapped valve covers. Question can the lower intake or the valve covers cause a vacuum leak to where it cause my problem? No fluid leaks.How can I find a vacuum leak I’m these places?

 

[Mcmahst]

What vacuum reading are you getting with the engine as close to idle rpm? You don’t know you have a vacuum leak until the gauge says so, but if you hear a noise, I would suspect the vacuum tree in the upper plenum has either a hose missing or somehow one was damaged in the exchange. Also, you should retorque the lower manifold and upper manifold bolts; they tend to loose that initial torque.

Also check the throttle body bolts, etc, anywhere it might be leaking. And, just checking; you did put the pvc valve back in? Good luck.

 

[nickyb]

If your looking to check for vacuum leaks the smoke machine is the new thing . Me I'm old school I use carb cleaner, starter fluid, or propane .

 

[Creomod]

What vacuum reading are you getting with the engine as close to idle rpm? You don’t know you have a vacuum leak until the gauge says so, but if you hear a noise, I would suspect the vacuum tree in the upper plenum has either a hose missing or somehow one was damaged in the exchange. Also, you should retorque the lower manifold and upper manifold bolts; they tend to loose that initial torque.

Also check the throttle body bolts, etc, anywhere it might be leaking. And, just checking; you did put the pvc valve back in? Good luck

What vacuum reading are you getting with the engine as close to idle rpm? You don’t know you have a vacuum leak until the gauge says so, but if you hear a noise, I would suspect the vacuum tree in the upper plenum has either a hose missing or somehow one was damaged in the exchange. Also, you should retorque the lower manifold and upper manifold bolts; they tend to loose that initial torque.

Also check the throttle body bolts, etc, anywhere it might be leaking. And, just checking; you did put the pvc valve back in? Good luck.

I dont have a vacuum gauge on it. But yea I’m making a smoke machine as I type

 

[Creomod]

I just used the smoke Machine and it burned the wire after few min.

 

[Mcmahst]

A vacuum gauge is almost a required tool to own these vehicle with all of the vacuum hoses. You had to disconnect lots of vacuum hoses to replace the lower plenum, so you could check each hose to see if maybe one is disconnected. The fuel regulator, with low vacuum, will cause high fuel pressure at idle, so it will not run well. Get the gauge, and you’ll be able to test the individual vacuum lines.

If your wire burned, did you have at least 12” of nichrome wire? I used TEMCo Nichrome 60 series wire 24 Gauge wire. Regular wire will not work.

 

[Rdub6]

Yep….. I’d start with the vacuum gauge. Probably a plugged port on the tree that you can plug right into.

 

[Creomod]

Yep….. I’d start with the vacuum gauge. Probably a plugged port on the tree that you can plug right into.

Interesting. How much vacuum should I have? I might just get one would this one be ok?

Amazon.com

 

[Rdub6]

Interesting. How much vacuum should I have? I might just get one would this one be ok?

Amazon.com

16-18” at idle on a stock engine.

 

[Rdub6]

You want something like this

Amazon.com

 

[90trunk]

If you installed taller valve covers they can often be holding up the upper plenum a very small amount. It will look like the upper is installed properly, but it is being held up a very small amount on the driver's side by the metal Tee or 90* fittings on the plenum's overhang for the PCV system. This is where spacers are often used to gain clearance. Just something to consider, as this bit me once.

 

[Creomod]

If you installed taller valve covers they can often be holding up the upper plenum a very small amount. It will look like the upper is installed properly, but it is being held up a very small amount on the driver's side by the metal Tee or 90* fittings on the plenum's overhang for the PCV system. This is where spacers are often used to gain clearance. Just something to consider, as this bit me once.

No it’s not that in this situation. I have the spacer. Another thing I didn’t mention in this post is I’m getting fuel in between the upper lower. The fuel pressure regulator is like 2 weeks old. I’m this pic you can see it’s a little wet that’s the fuel

 

[General karthief]

Vac line suck'n fuel from FPR, as far as I know that's the only place where a vac line can introduce fuel

 

[revhead347]

I just used the smoke Machine and it burned the wire after few min.

What do you mean it burned the wire? Smoke machine is the way you find vacuum leaks.

Kurt