First Post - 6.0 Crank Compression Test
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Tuned
Joined: May 2019
Posts: 279
Likes: 14
From: Brookings, SD
First Post - 6.0 Crank Compression Test
Hi all,
First post here. My truck is a 2005 F250, which I bought last year. Its got 150k miles on it, just studded by a shop in March of this year. When the head stud job was done, brand new heads were installed due to cracks in the valve seats. The shop quoted me 2200 bucks extra to put new injectors in during the job, but I refused, knowing that I can get remans from Tousley for 1400 bucks and put them in myself.
So, the truck has what I believe are the stock injectors. Now, since i've got the truck back, Ive begun to notice more and more of a tick or chuff. Its hard to explain. I'm not sure if its a valve train noise, injector noise, or leaky exhaust manifold noise. But its been worrying me more and more as time goes on. So I decided to perform a quick and crude crank compression test. If you aren't familiar with this test, Diesel Tech Ron did a video.
Any rate, I did this test on my truck, and the crank is nowhere near as consistent as in Ron's video.
What are your thoughts? And what should my next steps be? I was leaning towards putting new injectors in the truck in the near future, but now I'm wondering if i've got a whole different issue to address.
First post here. My truck is a 2005 F250, which I bought last year. Its got 150k miles on it, just studded by a shop in March of this year. When the head stud job was done, brand new heads were installed due to cracks in the valve seats. The shop quoted me 2200 bucks extra to put new injectors in during the job, but I refused, knowing that I can get remans from Tousley for 1400 bucks and put them in myself.
So, the truck has what I believe are the stock injectors. Now, since i've got the truck back, Ive begun to notice more and more of a tick or chuff. Its hard to explain. I'm not sure if its a valve train noise, injector noise, or leaky exhaust manifold noise. But its been worrying me more and more as time goes on. So I decided to perform a quick and crude crank compression test. If you aren't familiar with this test, Diesel Tech Ron did a video.
Any rate, I did this test on my truck, and the crank is nowhere near as consistent as in Ron's video.
What are your thoughts? And what should my next steps be? I was leaning towards putting new injectors in the truck in the near future, but now I'm wondering if i've got a whole different issue to address.
Fleet Owner
Joined: Apr 2012
Posts: 27,307
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From: Spanaway
Live data. Don't just throw parts at it. If you have someone that will run the uncompensated power contribution test on it that is where I would start.
The test can be run on FORscan or the VCM or VCM2 with the IDS software. Now Forscan you need the software that you can download and one
of the ELM devices to plug into your OBD2 port. The ELM device wil cost the least.
The test can be run on FORscan or the VCM or VCM2 with the IDS software. Now Forscan you need the software that you can download and one
of the ELM devices to plug into your OBD2 port. The ELM device wil cost the least.
Thread Starter
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Tuned
Joined: May 2019
Posts: 279
Likes: 14
From: Brookings, SD
I have a Bluetooth reader and forscan, but I've not been successful in getting the contribution test to work with it. Are you sure forscan is capable of doing it?
I have been able to do an injector buzz test with forscan, and the injectors all pass that test, so I've got forscan working.
I may have to take the truck in and have someone with a scan took run the test.
I have been able to do an injector buzz test with forscan, and the injectors all pass that test, so I've got forscan working.
I may have to take the truck in and have someone with a scan took run the test.
Fleet Owner
Joined: Apr 2012
Posts: 27,307
Likes: 549
From: Spanaway
I have not used Forscan as I have both a Snap-On and the VCM2. But what I have read points to the laptop version as to what is needed.
I think it may be a Pro version that runs on Windows (still FREE) and all you would need is BT or WiFI depending on the ELM device you have.
If you ask over in the (Link>>>) What did you do to your 6.0L today someone will likely have the answer you need.
I think it may be a Pro version that runs on Windows (still FREE) and all you would need is BT or WiFI depending on the ELM device you have.
If you ask over in the (Link>>>) What did you do to your 6.0L today someone will likely have the answer you need.
Thread Starter
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Tuned
Joined: May 2019
Posts: 279
Likes: 14
From: Brookings, SD
I have not used Forscan as I have both a Snap-On and the VCM2. But what I have read points to the laptop version as to what is needed.
I think it may be a Pro version that runs on Windows (still FREE) and all you would need is BT or WiFI depending on the ELM device you have.
If you ask over in the (Link>>>) What did you do to your 6.0L today someone will likely have the answer you need.
I think it may be a Pro version that runs on Windows (still FREE) and all you would need is BT or WiFI depending on the ELM device you have.
If you ask over in the (Link>>>) What did you do to your 6.0L today someone will likely have the answer you need.
Contribution test came back normal and all cylinders looked about equal. The tech was using a snapon scanner though, so he did not turn off the cylinder fuel compensation setting that the IDS scanner has.
The relative compression test, though, was not so consistent. See the attached image. There are some clear weak cylinders. The tech said he wouldn't worry about those results one bit and thinks everything is normal and that the truck runs good. I however, feel differently. Am I being overly cautious or is the tech full of beans?
Mountain Pass
Joined: Dec 2004
Posts: 195
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the first thing I would do is verify the batteries. the quick and dirty way I use is disconnect each battery, one at a time and crank for a few seconds on each battery to see that they have roughly equal cranking power, then if equal charge them over night. Your cranking sounded a little bit slow to me
Thread Starter
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Tuned
Joined: May 2019
Posts: 279
Likes: 14
From: Brookings, SD
Batteries are new as of January. I also have a load tester and each battery load tests good. Cranking may have been slightly slow. I did that crank test a few times before I took the video.
The relative compression test shows certain cylinders that are low.
The relative compression test shows certain cylinders that are low.
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Fleet Owner
Joined: Apr 2012
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From: Spanaway
the first thing I would do is verify the batteries. the quick and dirty way I use is disconnect each battery, one at a time and crank for a few seconds on each battery to see that they have roughly equal cranking power, then if equal charge them over night. Your cranking sounded a little bit slow to me
Fleet Owner
Joined: Apr 2012
Posts: 27,307
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From: Spanaway
Something is going on between 4 & 6 and if my paper on the screen
has it right it looks to be near 10% down.
I think for me I might get a compression tester or a leak down tester
and see what is going on. With my preference being the leak down tester.
You really want to see what the uncompensated power balance looks like.
Not sure if it's worth doing it or not but it's free other than a little time on your part.
A bubble test would show if you have combustion gasses coming back through
an injector.
Jack what do you think?
has it right it looks to be near 10% down.
I think for me I might get a compression tester or a leak down tester
and see what is going on. With my preference being the leak down tester.
You really want to see what the uncompensated power balance looks like.
Not sure if it's worth doing it or not but it's free other than a little time on your part.
A bubble test would show if you have combustion gasses coming back through
an injector.
Jack what do you think?
Thread Starter
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Tuned
Joined: May 2019
Posts: 279
Likes: 14
From: Brookings, SD
Something is going on between 4 & 6 and if my paper on the screen
has it right it looks to be near 10% down.
I think for me I might get a compression tester or a leak down tester
and see what is going on. With my preference being the leak down tester.
You really want to see what the uncompensated power balance looks like.
has it right it looks to be near 10% down.
I think for me I might get a compression tester or a leak down tester
and see what is going on. With my preference being the leak down tester.
You really want to see what the uncompensated power balance looks like.
I put my photo in an online webplot digitizer that let's you pick data points off a photo, and I came up with the following relative percentages:
1 98.0
2 98.7
7 99.7
3 99.7
4 96.3
5 98.8
6 97.2
8 100
So 4 and 6 according to that method are 4 and 3% down, respectively.
Uncompensated Power balance I wish I had, but the shop I went to couldn't perform that test. I'll have to see if the shop who did my studs can do that test when they dig into it. Fingers crossed that whatever they find they cover under their workmanship warranty.
I'll see if I can find some time to do a bubble test as well. That certainly can't hurt. The more I know before I take the truck back to the shop for a hopeful warranty, the better I'll feel.
Mountain Pass
Joined: Dec 2004
Posts: 195
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it looks to me that the lowest cylinder is about 95%, while 5% down may not be ideal, in my opinion that should not be enough to cause a running issue, at this point anyway. Some of the others are in the middle of 95 and 100 so that further supports an agreement that this should not be a contributor to uneven running, This of course is not an accurate test and probably it might be most useful for a gross compression issue, which it looks like you may not have?
oops! I see you already looked at this.
oops! I see you already looked at this.
Hotshot
Joined: Dec 2014
Posts: 17,827
Likes: 3,111
From: Jersey Shore
I'd like to see it with a more familiar tool, like the IDS that gives a direct percentage.
A hard number leak down or compression gauge test would be ideal and the next steps. The problem with the relative compression test is that a 5 or 7% value means the cylinder is toast and can show a much higher percentage at actual or leak down. But it's quick, easy, and tells you if you need to go farther.
I really think with the end of warranty coming up its time for the shop that did the work to get involved. You can stake the claim, and if there are a few days of free time, get someone with more meaningful equipment to document the problem better. the shop will only rely on its own tests, so you might want to temper the costs of additional documentation.
A hard number leak down or compression gauge test would be ideal and the next steps. The problem with the relative compression test is that a 5 or 7% value means the cylinder is toast and can show a much higher percentage at actual or leak down. But it's quick, easy, and tells you if you need to go farther.
I really think with the end of warranty coming up its time for the shop that did the work to get involved. You can stake the claim, and if there are a few days of free time, get someone with more meaningful equipment to document the problem better. the shop will only rely on its own tests, so you might want to temper the costs of additional documentation.
Thread Starter
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Tuned
Joined: May 2019
Posts: 279
Likes: 14
From: Brookings, SD
I really think with the end of warranty coming up its time for the shop that did the work to get involved. You can stake the claim, and if there are a few days of free time, get someone with more meaningful equipment to document the problem better. the shop will only rely on its own tests, so you might want to temper the costs of additional documentation.
At this point, I'm just looking to understand the severity of the issue. I was going to take my truck on a 500 mile round trip this weekend, but now I'm not so sure that's a good idea, based on what I'm reading.
Fleet Owner
Joined: Apr 2012
Posts: 27,307
Likes: 549
From: Spanaway
You might check in your states local chapter to see if one of the members
has a VCM/VCM2 that would be willing to run the tests for you.
Stop in to there part of the forum and ask. You never know. IDS will give you the best info.
has a VCM/VCM2 that would be willing to run the tests for you.
Stop in to there part of the forum and ask. You never know. IDS will give you the best info.