I have a 2008 Ford F-350 6.4 PSD with 120k miles. The truck is bone stock, service truck. It has tons of power up to 55mph but right after that it just falls on its face and the boost starts dropping off. I think its right around when it shifts in 3rd gear on WOT, it just loses its power.
I have a AE scanner and the truck is throwing no codes.
The vgt duty cycle is at 95% when idling, is this correct? I've done some searching and most info is on 6.0s. It seems my second turbo isn't coming online. Any help guys?
Just reread everything. Next time you go for a ride check rail pressure. Since this obviously isn't boost related at this point. When's the last time you put fuel filters in it? Are they racor/motorcraft filters?
The fuel rail pressure drops when the truck starts losing power but is inline with what it should be given the boost/rpm level. They are new and they are motorcraft.
I did a short video today of what the truck is doing. You can really hear/see the power start dropping off about 50mph, I had it on the floor the whole time.
Put a new egr valve on it just because and it made no difference. Also swapped a different throttle position sensor on because we have a parts truck. It made no difference. I'm not finding anyone online with this similar problem. I see people losing power when their trucks go into regen but this isn't my problem.
Not necessarily. Some run great for a while then bog down. Let cool off and they'll run good for a while. Remove the secondary filter (the one on the engine) and shine a light on the fuel. See any sparkles?
Not necessarily. Some run great for a while then bog down. Let cool off and they'll run good for a while. Remove the secondary filter (the one on the engine) and shine a light on the fuel. See any sparkles?
Checked this today. Fuel is clean as pin, no sparkles, no nothing.
When I pulled the filter off I turned the key on just to see how quick the bowl filled up, it seems kinda slow and it had bubbles in it. Is this normal?
Alright. There is a shrader valve on the fuel cooler. Get a gauge that you can screw onto that with a hose. You should have around 6 to 8 psi. Get the hose long enough and go for a ride so you can watch the pressure.
Random thought... Is the coolant in the fuel cooler topped off? I know of a few cases that low coolant in the fuel cooler caused some power loss. If it is too low it will throw a code, but not always... What do you think Lox?
I have a friend that ended up having his fuel system replaced because the dealer failed to check the fuel cooler itself... His ended up throwing a code after the work was done and luckily his service manager wasn't a d1ck and ate the repair bill for the fuel system.
The hpfp could still be an issue, the pcv or vcv could be taking a sh1t on you. If the rail pressure doesn't jump or fluctuate I wouldn't think its the frp sensor.
Let it warm up and pay attention to it for a few minutes. Just watch the graph for consistency. If it spikes sporadically for a split second it needs a sensor.
Another thing to consider. You said this was a stock truck, I wonder if your EGR valve is malfunctioning or possibly the choke flap is giving you trouble.
I installed a new egr valve about a week ago and it made no difference. Pulled the pipe off of the choke flap and it seems to be functioning properly when the truck starts and idles.
One of the throttles for my EGR was getting stuck before I deleted, and the truck wasn't getting any air, so must have been the one in the elbow coming from the intercooler, but you could probably try unplugging it and going for a drive?
Will someone else confirm it won't just go into limp or low power mode?
I have a 2008 F250 with the 6.4 and mine did the same exact thing. My problem ended up being the FRP sensor and wiring harness. I've heard that the wring harness has a chaffing issue on the earlier trucks. Just a thought.
The harness you're speaking of is the hpfp harness.
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