Fordman1994

I pulled the vacuum line off the egr. There's no vacuum. I followed it all the way to where it hooks up to that little vacuum tree by the coil pack with two lines running into it. I swapped it with the one on my other truck. Still no vacuum. Bad connector maybe?

Fordman1994

Is this a wild goose chase? Is there even any vacuum going to the egr while its idling?

Fordman1994

Think I found the problem.

Fordman1994

Fordman1994

Anyone know how much vacuum a 90 5.0 should make? It's a little over 15hg.

Steve83

Read this caption:


(phone app link)

Vacuum is not dependent on engine size; all 4-stroke-cycle pump-gas engines run the same way, and should have steady 18-22"Hg manifold vacuum at idle.

Fordman1994

Thank you. I think my vacuum reservoir has a leak. When I hook up my other one it has a little bit more vacuum. It's like 16"hg instead of 15 but when I unhook it I can hear it releasing the air. The one on the truck I dont hear anything after I disconnect the vacuum lines.

Steve83

Vacuum does not come from the reservoir - it comes from the pistons moving. The hose from the manifold to the reservoir is not large enough to affect manifold vacuum even if it's open to the atmosphere. But it's very common for coffee can reservoirs to crack &/or rust through.


(phone app link)

You also need to put ALL the truck's details into your signature so we don't have to dig back through the thread to find out what truck you're talking about. The one implied by your username has a different reservoir that's not affected by cracks or rust (which is why you should get that type for this truck). Read this caption:


(phone app link)

Fordman1994

I know vacuum isnt generated by the reservoir but if its leaking vacuum wouldnt that effect the egr?

Fordman1994

This one is on the passenger side and it doesn't go to the manifold. It looks like it goes around to that egr vacuum check valve thing by the coil pack. Then another one comes out of that and goes to the egr.