Author Topic: 2008 ford f650 with cat c7 engine lacking power uphill.  (Read 449 times)

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Offline Lonetreeqh

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2008 ford f650 with cat c7 engine lacking power uphill.
« on: March 22, 2019, 07:17:38 PM »
I have a 2008 ford f650 with a c7 engine that we use to pull a 17000 lb toyhauler.  We use to pull a 20,000 lb living quarters horse trailer and although the we didn't race up hills we still could pull a long steep hill at about 50-55 mph.  Lately we can't pull a long steep hill at more then about 35-45 mph.  I know our wind resistance has gone up because the nose of the toyhauler is higher but we went down in pounds we are pulling so I feel like it should be pulling hills about the same.  We also have a service engine light that comes on right after starting it if it is cold out and /or above 2500 feet .
In May of 2018 we had the turbo replaced and the cat dealer did not have the right piping to replace the old piping so they pretty much jerry rigged it to get us to our next destination, which was Phoenix, az, at which time we took it in and had them replace the old piping with new stuff.
Everything was good until we went up to Heber, az. which has an elavation of about 6500 feet.  We shut the engine down and then when we restarted the engine the service engine light came on.  We let the engine warm up and shut it down and restarted and the light was off.  We went home to Colorado and took it to our local cat dealer and they could not find a cause for the light except to say that there might be an air leak but once it warms up it seals itself up and is not a problem. 

Fast forward to the present and the light still comes on if it is cold out or if we are above about 2500 feet.  It does still go off if you let the engine warm up and shut the engine down and restart  it.

We just took it into the cat dealer again and they said there are no active codes but there is a logged code of 520192-18 which has to do with the CGI valve.  We had the CGI cooler replaced two years ago.  In googling the code it says that there could be an air leak in the piping which cats says they have checked and can't find, or one of the three sensors in the CGI valve system could be bad.  Also when reading through this forum I have found that a bad sensor could be the cause of lack of power when climbing.

So any ideas on what our next step should be?  Cat wants us to take it to another shop that has a dyno to try recreate the lack of power when towing up hills problem which is fine but I think we are dealing with a sensor issue on both problems and that can fixed without spending a ton of money on a dyno test?



Offline David.e.atherton

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Re: 2008 ford f650 with cat c7 engine lacking power uphill.
« Reply #1 on: March 22, 2019, 11:46:53 PM »
Lonetreegh, going to answer your question first of all you do not have any problems.
Climbing long heavy grade at 35 / 45 mph is normal. ( be sure to keep Engine rpms
above 1600 rpms or higher. ) speeds at 1400 rpms or lower your Heui pump will not
Raise pressure or flat line, which canine injection Actuation pressure cannot increase.
Second part of question, low power at startup. Your engine ECM has what is called a
Cold mode which is a safety feature on engine ECM to prevent damage to engine with
Cold engine oil.the engine has to warm up without speeding up engine.which takes about
10 to 15 minutes depending how cold out side, durning engine in cold mode engine will
run rough, smoke , low power etc. when engine is at operating temperature will run normal.
The check engine light coming on climbing grade or driving down highway engine rpms
We’re at 1400  rpms or below. Which the engine Heui pump cannot in lug condition and
cannot increase pressure until lugging conditions go way. Ask Dave,  Dave Atherton Retired
Cat  Mechanic

Offline Lonetreeqh

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Re: 2008 ford f650 with cat c7 engine lacking power uphill.
« Reply #2 on: March 23, 2019, 09:33:56 AM »
Thanks Dave.