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Hello - I've got a 2019 F250 6.7 PS, 16kmiles, completely stock, no mods. Problem just started a couple weeks ago. Under moderate acceleration unloaded I started to feel the truck surging and noticed the turbo boost pressure was fluctuating on the gauge between 20-30psi, which seems high to me considering no load. When I let off the throttle the boost pressure drops and things remain smooth until I accelerate again. If I accelerate hard the boost fluctuation gets worse and eventually will go into limp mode. I did get a P259F code once and took it to the dealer who couldn't find anything wrong but did say there was a TSB for that code and updated the PCM. I'm still having the problem after the PCM update but no codes and dealers won't do anything without codes. I also noticed the turbo "coughing" when the problem happens and if I let off the throttle sometimes I will hear it fluttering like its releasing pressure. If I baby the throttle then all behaves normally.
I loaded Forscan on my laptop because I see a lot of posts about checking EBP, MAP, MAF, etc so I thought I would take a look. Honestly not sure what I'm looking at so I thought I would post to see if anyone had any thoughts. The yellow box shows the time at which the fluctuations were occurring. Couple things I noticed on the data that look strange is the EBP pressure doesn't consistently match the EBP voltage. The pressure curve peaks looks like they got clipped for some reason. Also strange is the VGTDC readings fluctuating from 0 to 89, that doesn't seem right based on everything I've read.
Turbo wastegate actuator sticking, (not reacting soon enough) and over boosts, then it cuts boost more than needed, (over reacting), or vacuum hose leak... IMO
around post 25 there are screen shots of various air flow numbers at different parked rpms….it would be easy to compare to yours and determine if you have an EBP, MAF, MAP problem.
around post 25 there are screen shots of various air flow numbers at different parked rpms….it would be easy to compare to yours and determine if you have an EBP, MAF, MAP problem.
@scraprat Thx for the reply. Just curious, when they replaced your turbo did they tell you what was wrong with it?
Yes, there was play in the turbo shaft. They figured that was causing it to be an erratic overboost code and getting a little worse as time went on. Sincs having the turbocharger replaced no issues at all. Side note while they had everything off to get the turbo had the shop change the CP4 to the DCR fuel pump.
Turbo issues start at 50-55k miles can remember exactly.
Hello - I've got a 2019 F250 6.7 PS, 16kmiles, completely stock, no mods. Problem just started a couple weeks ago. Under moderate acceleration unloaded I started to feel the truck surging and noticed the turbo boost pressure was fluctuating on the gauge between 20-30psi, which seems high to me considering no load. When I let off the throttle the boost pressure drops and things remain smooth until I accelerate again. If I accelerate hard the boost fluctuation gets worse and eventually will go into limp mode. I did get a P259F code once and took it to the dealer who couldn't find anything wrong but did say there was a TSB for that code and updated the PCM. I'm still having the problem after the PCM update but no codes and dealers won't do anything without codes. I also noticed the turbo "coughing" when the problem happens and if I let off the throttle sometimes I will hear it fluttering like its releasing pressure. If I baby the throttle then all behaves normally.
Turbo on these trucks are VGT, variable geometry, and there is an actuator that moves a collar in the turbo to make it vary the size of the volute. This is also what makes the exhaust brake work.
Looking around at various sources, it looks like the P259F code is linked to the operation of the actuator, P259F being a code for the pcm commanding the actuator to make adjustment that is outside of its normal operating range.
Sometimes the VGT collar in the turbo will stick, usually due to soot buildup.
Turbo on these trucks are VGT, variable geometry, and there is an actuator that moves a collar in the turbo to make it vary the size of the volute. This is also what makes the exhaust brake work.
Looking around at various sources, it looks like the P259F code is linked to the operation of the actuator, P259F being a code for the pcm commanding the actuator to make adjustment that is outside of its normal operating range.
Sometimes the VGT collar in the turbo will stick, usually due to soot buildup.
Exhaust brake usage is the best way to keep the soot buildup down on the actuator collar.
As to repair, dealer will just R&R the turbo.
If it is on your dime, then a good shop can get your turbo rebuilt way cheaper than a new turbo.
I only use the exhaust brake when towing the 5th wheel which is 3-4 times per year. The truck isn't my daily driver, I typically only drive it on the weekends and never use the EB. Should I try driving it around using the EB for awhile? Is there a way to use Forscan to tell if the actuator is working properly?
I only use the exhaust brake when towing the 5th wheel which is 3-4 times per year. The truck isn't my daily driver, I typically only drive it on the weekends and never use the EB. Should I try driving it around using the EB for awhile? Is there a way to use Forscan to tell if the actuator is working properly?
I don't know what forscan can tell you about it.
You definitely should use the exhaust brake anytime you drive it, as I said it helps keep the soot buildup in the VGT actuator down, every PSD owner should be doing this.
You can try driving it around with the EB turned on, but it may not be enough after the fact for clearing any soot buildup.
I don't know what forscan can tell you about it.
You definitely should use the exhaust brake anytime you drive it, as I said it helps keep the soot buildup in the VGT actuator down, every PSD owner should be doing this.
You can try driving it around with the EB turned on, but it may not be enough after the fact for clearing any soot buildup.
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