6.0 low power code p123b & p0401 (Have autoenginuity) - Ford Powerstroke Diesel Forum
Powerstroke.org is the premier Diesel Truck Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 04-19-2013, 11:41 AM
Powerstroke.org Rookie
 

Join Date: May 2011
Posts: 20
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
6.0 low power code p123b & p0401 (Have autoenginuity)

I have a 2004 F-450 that has been nothing but trouble the last few years. The current issue is code p0401 EGR and p123b turbo. The truck is gutless below 3000 RPM and not great above 3000. It takes forever for the truck to reach 3000 RPM. We use it for towing and tow quite a heavy load every day. The EGR was deleted last year by a local shop. I'm not sure if that leads to permanent p0401 or not. When they did the delete I asked them to service the turbo since they had to have it off anyway and it seemed like the boost was a little low back then. I don't know if they actually serviced it or not. I ended up with a high pressure oil leak as well so the truck was in and out of the shop three times before they found the braided line that was the issue. I am not the one that drives this truck, but I own it. The guys that drive it aren't super mechanically inclined so they don't always give good answers when I ask them things. They normally drive from job to job and stay at a job for at least an hour or more so the truck never gets super warm. They have said that if they have job that is really far away it appears that the problem goes away a little if the truck has run for quite a while. I took a half day off work today in the hopes that I could solve the problem between this afternoon and Saturday. The truck needs to go back in service and I have to work on Monday.

After picking up the truck just now and connecting my Autoenginuity I see that BARO pressure is about 12.9 (I live about 4500' elevation) and MAP was exactly the same at KOEO. At idle MAP is slightly higher than BARO, maybe 1 PSI tops. When I drive it MAP has a hard time getting above 20 PSI until I'm at about 3000 RPM then it will top out at 29 PSI floored once I'm over 3000 RPM. Is boost pressure the difference between MAP and BARO? If so, that means I'm topping out at about 16 PSI of boost. Getting on a downhill freeway on ramp I floored it the whole way and never exceeded 29 PSI MAP. For fun I tried actuating the VGT solenoid and it would hardly run at all. Meaning I clicked VGT solenoid command open in the AE software. When I did that I was going down the road with it floored and the truck would not exceed 3000 RPM at all. I unclicked it and the turbo kicked in immediately making me thing the VGT solenoid is working.

Reading through other treads I see you should check the MAP hose, which looks good but I haven't removed it yet. Also check the EBP valve for gunk. I am not sure if the truck has been flashed to infer EBP or not. It has been serviced at a dealer after the update was released. I thought I read somewhere that the p123b code was unique to the update? Not sure about that. I have yet to examine the EBP, but I will after I post. There is an exhaust leak, not sure if it is large enough to cause such a problem. Looking in the passenger wheel well I can see 1 bolt missing from the exhaust manifold. I'm sure this isn't helping the problem, possibly it is the whole problem? I sort of hope not I've seen posts about how awful the manifolds are to get off. I appreciate any and all input.

If it is just the manifold is it easiest just to grind off stubborn bolts and replace them? Should you get a gasket once the manifold is off?

Thanks again.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old 04-19-2013, 01:04 PM
Powerstroke.org Rookie
 

Join Date: May 2011
Posts: 20
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
EBP was clean and MAP hose was fine. Took water shield out of passenger wheel well (PITA) to see the exhaust manifold. Looks like both rear bolts are broken on the manifold, there is clearly soot on the engine where it has been coming out. Not sure if this is the root cause or not, but definitely needs to be fixed. If anyone has tips I'm appreciative.
Reply With Quote Quick reply to this message
  #3  
Old 04-19-2013, 06:35 PM
Powerstroke.org Rookie
 

Join Date: May 2011
Posts: 20
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Before I ran out of time I got all the bolts out but the second from the back on the bottom. What a nightmare to get to and it rounded off before breaking free. I guess I'll grind it off in the morning. Also need to buy a set of easy-outs since the two broken bolts are broken off inside. Can these bolts be replaced with a higher grade bolt that won't break so easy?
Reply With Quote Quick reply to this message
  #4  
Old 04-20-2013, 06:34 AM
Compression Ignition Addict
 

Join Date: Jun 2011
Location: Colorado Springs
Posts: 415
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Put some nickel based antiseize on them and you should be fine.

MikeB
Reply With Quote Quick reply to this message
  #5  
Old 04-20-2013, 09:03 PM
Powerstroke.org Rookie
 

Join Date: May 2011
Posts: 20
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Low power, showing code p123b. Solution

I'd say that was the most miserable 12 hours I've spent working on anything, and I've done some pretty miserable stuff. I could see there were two broken bolts on the passenger exhaust manifold. It was the upper and lower on the rear most cylinder. The bolts that weren't broken were terrible to remove since they were so rusty. One snapped off making three broken bolts. Just my luck all three were broken below flush so I had to drill. I got a some lefthand drills on the off chance the bolts might spin out when the bit took hold, no such luck. After drilling holes through all the bolts I tried an extractor. It snapped off in the first bolt I tried. I'd say that added about 2 hours to the job since I then had to drill the extractor which wouldn't drill. After finally getting the extractor out and all the holes drilled to the proper size for the tap I rethreaded them. What a treat that was sitting hunched in the wheel well running a tap in and out. In the end I used a gasket and new bolts and spacers from the dealer. I buttoned it up enough to test and she worked like a champ. The boost built up really quick and all the power seemed to be back. The whole job would have taken about half as long if I'd known it was going to be such a nightmare and prepared for the worst from the outset. I ended up making 4 trips for parts and tools because I had to keep escalating to get the job done. My suggestion would be to have everything you might conceivable need on hand if your going to do this. The space is incredibly tight, I had to shorten all the drill bits in addition to buying a small right-angle air drill. Hopefully yours won't be so bad.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Ford Powerstroke Diesel Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -8. The time now is 07:56 AM.


Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.1
Garage Plus, Vendor Tools vBulletin Plugins by Drive Thru Online, Inc.

vB.Sponsors