When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
99 F350 7.3L SRW. We have been having some incredibly cold days lately (-20 right now), and I've noticed when taking off, I can hear a "hissing" noise under acceleration. I say hissing because I can't tell if its a vacuum or a pressure leak. Once I let off the accelerator, it goes away and may or may not come back when I hit the accelerator again.
I am trying to figure out if it could be the wastegate relieving or the EBPV sticking. I did stumble across a code on my reading that said the backpressure was abnormal (P0470), but it wasn't enough to set a check engine light.
Anyway to check to see what is going on without dismantling everything?
At -20 that's probably normal EBPV operation. The valve will close to provide more work for the engine to warm engine/cab faster. I think outside temps < 45, engine oil < 160?. Does it sound jet engine like at the tail pipe?
With my truck, there is no change in power. I recognize the EBPV staying closed when its warming up, it goes away when I tap the brake. The sound I hear is specifically when accelerating, but I don't think there is a loss in power.
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.