4% compression loss
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Tuned
Joined: Dec 2006
Posts: 337
Likes: 39
From: Shenandoah valley, Va
4% compression loss
Just got back from the dealership, thinking I'd just get the new flash to improve cold starts. My symptoms were:
2-3 second crank before starting (i thought this was normal)
7 second lag time before gauge showed any oil pressure
1st cold temp start of the day engine dies off after a few seconds, but will run if given a little throttle
Tech spends 1.5 hours going over the vehicle and reports a 4% compression loss in one cylinder. Also says that the high presure oil pump that was replaced at 4k miles may be cracked if not properly installed. Obviously this will all be warranted work, but will you techs please advise me as to what to expect as outcome from all this, anything to watch for, and will all be well after this repair? These symptoms are probably due to me being new to diesel and thinking thats how it was supposed to run.
2006 f-250 6.0 16,000 miles
2-3 second crank before starting (i thought this was normal)
7 second lag time before gauge showed any oil pressure
1st cold temp start of the day engine dies off after a few seconds, but will run if given a little throttle
Tech spends 1.5 hours going over the vehicle and reports a 4% compression loss in one cylinder. Also says that the high presure oil pump that was replaced at 4k miles may be cracked if not properly installed. Obviously this will all be warranted work, but will you techs please advise me as to what to expect as outcome from all this, anything to watch for, and will all be well after this repair? These symptoms are probably due to me being new to diesel and thinking thats how it was supposed to run.
2006 f-250 6.0 16,000 miles
Postmaster
Joined: Sep 2005
Posts: 2,725
Likes: 3
From: Florence,SC
everything sounds normal for what you stated. the 4% loss is way in spec, as we are talking about software not real numbers. plus it was probably on a cold engine. do you have a problem or are you just worried about normal-not normal.
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Tuned
Joined: Dec 2006
Posts: 337
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From: Shenandoah valley, Va
Truck was driven in to the shop today, so I assume a relatively warm engine
As for the 4% loss, I don't know what is acceptable. The tech says Ford only allows up to 2%.
I went in to the dealer only because of cold start issues. Truck seems to run great to me.
As for the 4% loss, I don't know what is acceptable. The tech says Ford only allows up to 2%.
I went in to the dealer only because of cold start issues. Truck seems to run great to me.
Elder User
Joined: Sep 2005
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I don't care much for relative compression tests unless there is a major driveability issue, and I'll just use it as a quick check before doing a real compression test. I once did a relative compression test with a glow plug removed, and it only showed a 15% lack of RC. I'd question why he even bothered to do a relative compression test, or feed you (what I think are) lines about a cracked HPOP.
Last edited by CanadaGuy; Feb 7, 2007 at 05:41 PM.
Thread Starter
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Tuned
Joined: Dec 2006
Posts: 337
Likes: 39
From: Shenandoah valley, Va
Originally Posted by CanadaGuy
I don't care much for relative compression tests unless there is a major driveability issue, and I'll just use it as a quick check before doing a real compression test. I once did a relative compression test with a glow plug removed, and it only showed a 15% lack of RC. I'd question why he even bothered to do a relative compression test, or feed you (what I think are) lines about a cracked HPOP.
Hopefully this day of service will repair what I thought was a simple problem, largely cold start issues. If you're not concerned about the 4% compression loss than neither am I. He states that truck will start up immediately after this service and cold start issue will be gone. Other dealer in the area doesn't seem to care much about servicing diesels so I'd like to stay on the good side of this one, at least they're thorough.
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Tuned
Joined: Dec 2006
Posts: 337
Likes: 39
From: Shenandoah valley, Va
Called the service mgr today to get more detail. Turns out it was a slow day in the shop and since they had never serviced this truck before, they did a complete checkover for any outstanding tsb's. They found a less than ideal oil pressure so they did a compression check amongst other things. Since the difficulty cold starting could've been due to a low oil pressure, they want to corect the low compression cylinder first. This somehow makes since to me, but please advise, Am I fortunate to have found such a thorough dealership or are they just playing around?
Postmaster
Joined: Sep 2005
Posts: 2,725
Likes: 3
From: Florence,SC
on this or any powerstroke, you could have down to 8 psi oil pressure and the truck still would run like a top. i give you my word, the 4% loss is perfectly fine. you probably need injectors and nothing more. i had a truck with around 6% loss and a manual check put the reading with 10psi of each of the other cylinders.
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