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I guess it would be classified as very intermittent but in the past year I have had 3 separate times when my truck has after a short drive suddenly had zero boost..
Pull over and turn it off for 30 sec or so and all is fine. Cycle the ignition faster than that and issue persisted.
It has only happened in colder temps.
In all the reading I have done on FTE I've not come across anything similar.
How are you reading the boost? Intermittent boost loss could either be a failing Map sensor, or the ebpv closing. If your seeing it from a mechanical analog gauge, then I'd bet on the ebpv.
That makes sense. I guess that didn't jump to the top of my mind because it seems to be working fine during the warm-up process. And in these cases it was functioning normally until I pulled away from the stop sign on there was no boost.
Boost is run by an autometer gauge on my a pillar. I have Torque Pro as well but it wasn't hooked up at the time.
How do I tell what is causing the malfuntion? The exhaust back pressure sensor and tube replaced two years ago. Two weeks ago when I was running Torque Pro the EBP in the map matched at key on engine off. If that tells us anything.or the valve physically malfunctioning?
That makes sense. I guess that didn't jump to the top of my mind because it seems to be working fine during the warm-up process. And in these cases it was functioning normally until I pulled away from the stop sign on there was no boost.
Boost is run by an autometer gauge on my a pillar. I have Torque Pro as well but it wasn't hooked up at the time.
How do I tell what is causing the malfuntion? The exhaust back pressure sensor and tube replaced two years ago. Two weeks ago when I was running Torque Pro the EBP in the map matched at key on engine off. If that tells us anything.or the valve physically malfunctioning?
It is supposed to come on at low load conditions when oil and intake air is cold. Next time it happens, give it some more throttle and see if it opens up. If not, the valve may be getting stuck inside the turbine housing. Are you throwing any codes that may be related to this?
If it truly is the EBPV causing the issue, you should be able to hear it. Especially if you have modified exhaust. Next time the issue occurs, hop out of the truck and listen to the exhaust. If it is hissing, you have confirmed it is the EBPV causing the issue.
Malfunction? My friend, this is a feature carefully engineered in by Ford. I run with Torque Pro active, and the EBPV will close under low-load conditions as Justin mentioned. This occurs until the Engine Oil Temperature tops 140 degrees F, depending on the Intake Air Temp. While the EBPV is active on the highway at 65 MPH, my backpressure is about 15 PSI, the boost is half of normal or less - but my EGTs are riding 250 degrees F warmer than normal. That added 250 degrees warms the oil (and the heater) much faster than without the EBPV. It was 10 degrees F yesterday - bring on the fire, baby.
If you are really hankerin' for a hunk-a-hunk-a-burnin' rubber, go ahead and drop the hammer and the EBPV will back off. Know this, though - diesels don't like being pushed when cold. To put an exclamation point on this, factory tunes and many aftermarket tunes intentionally whimp out the truck when the engine is cold. You're not gunna win many races with a cold truck - lest you're up against a Chebby Cruz. My Prius (with a full charge) can kick it's azz, so I figure it's safe to take that one on with a cold 7.3L.
I get the EBPV and how it is supposed to function. Since i bought it in 02 i have heard it do its thing every cold morning for 14 years. And yes i agree that until things warm up our trucks lack enthusiam, hell so do I!
My problem is that when this happens I have not heard the tell tale sound of the EBPV and I have applied throttle, rpms increase of course but very little response and no boost gauge at all. Hit the brakes no change. Not to mention that the block heater was on for 3 hours before the last occurrence and i was several miles down the road.
I'm hoping this happens again soon so i can listen more closely and check the position of valve. I just don't get the randomness of the absolute 0 boost vs restricted,
Everything in my sig has been done with the knowledge i gained from FTE, so thanks to all for your help!
The Intake Air Temperature introduces the random factor, but the one factor that is relatively stable and you can't get around is the Engine Oil Temperature. I plug in when I can, and the best I can hope for is about 80 degrees F on a winter morning. I'm still down 60 degrees F with 1000 pounds of iron/steel, 4 gallons of oil, and 8 gallons of coolant. It's gunna take a while to warm all of that up. Hell... I've seen it take longer to warm my feet up when I come in from the cold. I usually get about 5-10 miles down the road before I cross the 140-degree F finish line.
You should also be getting high EGT's while this is going on.
My EGTs will be about 250 degrees F above normal. That is the whole point of the exercise - warm things up. If I need to kick 'im in the pants, the EBPV opens so you don't roll the EGT gauge needle into the lava zone.
Not sure how you guys know it's the ebpv without any supporting info. I had a fuel system problem cause similar symptoms.
Originally Posted by JWink
...It has only happened in colder temps....
I'll grant you the EBPV is a jump to a conclusion, but based on the input from the OP... it's more like a jump from the road to the top of a highway stripe.
