Compression Test on e450?
Posting Guru
Joined: Jul 2017
Posts: 1,236
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Okay, I performed the blow by test - kind of. The extension tube for the oil is at an angle, so you can't actually sit a cap on top. I placed my hand over the opening tightly and couldn't feel anything at all? I could see a tiny amount of what I assume to be the results of blow by wafting out of the hole when I first started it, but barely noticeable.
LOL the glow plugs, so run the compression test since you are in there anyway.
I say this more than half joking, far less than a serious comment.
On the serious side, why are you wanting to replace the injectors? And maybe I missed something earlier in this thread. If you are in that deep, you may as well replace the glow plugs, and therefore may as well do the compression test. And even them why replace the injectors?
Back up a bit, lets get some data from TorquePro or Forscan. Maybe I missed it above, but do you have a problem with the engine? The blow by test says the rings are fine, but is there an indication of a valve problem? What about the engine suggests you need to replace the injectors?
I'm at almost 288,000 miles on my 7.3, and i have no reason to do anything than an overdue oil change.
Are you just wanting to make sure there is no problem in the future? I can understand that, but these engines just run and run. You might be doing work that you won't need for another 100,000 miles.
I fully admit I am a cheapskate, I run vehicles into the ground getting every mile at as low a cost per mile as practical. My goal -- and I often exceed it -- is 10,000 miles for $1,000. Not including fuel, oil, or insurance. I'm at about $1 per mile on my truck, but may be getting ahead of the curve.
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New User
Joined: Apr 2018
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Thanks, I'll post more pictures today. We're in the Greensburg area, about an hour outside Pittsburgh.
Regarding why... the bus doesn't like starting unless plugged in - and when it will it runs pretty rough until it gets hot. Good battery, starter running well. Starts fine if it has been driven at all (oil temps up) All this including temps where the glow plugs shouldn't be a factor. I don't know for sure that they are all running, but the relay at least works. Plug it in and it'll start up no problem. Drive it for 5-10 minutes and it runs very well. Starts immediately the rest of the day.
Based on all the reading I've done, my conclusion was that the poppet valves are probably worn, with the reasons being that this is common at the mileage I'm at (214000) and that it perfectly explains the current symptoms.
I'd love to not have to do this though, so if you guys think that's a bad diagnosis, let me have it...
Regarding why... the bus doesn't like starting unless plugged in - and when it will it runs pretty rough until it gets hot. Good battery, starter running well. Starts fine if it has been driven at all (oil temps up) All this including temps where the glow plugs shouldn't be a factor. I don't know for sure that they are all running, but the relay at least works. Plug it in and it'll start up no problem. Drive it for 5-10 minutes and it runs very well. Starts immediately the rest of the day.
Based on all the reading I've done, my conclusion was that the poppet valves are probably worn, with the reasons being that this is common at the mileage I'm at (214000) and that it perfectly explains the current symptoms.
I'd love to not have to do this though, so if you guys think that's a bad diagnosis, let me have it...
Posting Guru
Joined: Jul 2017
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OK, I suppose it could be. But it could also be glow plugs.
Since it starts better when plugged in, that also points to glow plugs being a possibility. Or UVCHs.
Also, what is the outside temp when you have trouble starting and not plugged in? And what oil viscosity are you running?
Since glow plugs are easy to test, and much less expensive to replace, I would look at them carefully first.
With an ohmmeter, what is the resistance from the switched lug on the GPR to ground? A probably good reading is anywhere from 0.06 to 0.25 ohms. I say probably good since this measurement can miss serious faults. However, a measurement well outside the range is proof of a problem.
Then unplug the connector on each valve cover and measure the resistance from the front two and rear two pins in the valve cover connectors, each to engine ground.
Good glow plugs measure between 1/2 and 2 ohms each.
You might as well measure the resistance on the next pairs of pins on each connector while you are at it, those are the injectors. I forget what the good range is for them.
Since it starts better when plugged in, that also points to glow plugs being a possibility. Or UVCHs.
Also, what is the outside temp when you have trouble starting and not plugged in? And what oil viscosity are you running?
Since glow plugs are easy to test, and much less expensive to replace, I would look at them carefully first.
With an ohmmeter, what is the resistance from the switched lug on the GPR to ground? A probably good reading is anywhere from 0.06 to 0.25 ohms. I say probably good since this measurement can miss serious faults. However, a measurement well outside the range is proof of a problem.
Then unplug the connector on each valve cover and measure the resistance from the front two and rear two pins in the valve cover connectors, each to engine ground.
Good glow plugs measure between 1/2 and 2 ohms each.
You might as well measure the resistance on the next pairs of pins on each connector while you are at it, those are the injectors. I forget what the good range is for them.
Fleet Mechanic
Joined: Jul 2003
Posts: 1,614
Likes: 22
From: Springfield, PA
How the heck did you figure out he lives in PA? Just cause the bus is Eagles green and white?
To the OP, if you haven't already, look up threads on getting either (or both) Torque Pro and Forscan running on your truck. I have a OBDLink MX Bluetooth OBD-II adapter; Torque Pro is $5, Forscan for Windows is free. TP lets you monitor things while driving and is good for on the road troubleshooting if necessary, while Forscan is a great shop tool and if your laptop has Bluetooth it's great. The info from either of these will really help you pinpoint what's going on and save you a lot of wrenching around.
To the OP, if you haven't already, look up threads on getting either (or both) Torque Pro and Forscan running on your truck. I have a OBDLink MX Bluetooth OBD-II adapter; Torque Pro is $5, Forscan for Windows is free. TP lets you monitor things while driving and is good for on the road troubleshooting if necessary, while Forscan is a great shop tool and if your laptop has Bluetooth it's great. The info from either of these will really help you pinpoint what's going on and save you a lot of wrenching around.
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New User
Joined: Apr 2018
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The Eagles have nothing to do with the color - the availability of rustoleum at Lowe’s does LOL the paint job was done w/ rustoleum and a hardener from tractor supply.
I will definitely check the glow plugs. My guess is that at least some are bad too. Starting is near impossible up to the 60s and then becomes possible, improving as you increase and if in the sun. My thinking with the injectors being part of the problem is that the glow plugs would explain the rough running after it actually starts. Maybe I’m wrong there.
Ill definitely get it scanned. I have a WiFi obd2 thing already, I just forgot to run the scan when I had it on for the blow by.
Walleye - any chance you have the resonator box still? It’s a plastic box that sits at the top of the engine connecting in to the air pipe before the turbo. I have it plugged now but would like to test the noise difference with the box. And before someone jumps in - yes, I know how much people hate that box - I’m just curious.
I will definitely check the glow plugs. My guess is that at least some are bad too. Starting is near impossible up to the 60s and then becomes possible, improving as you increase and if in the sun. My thinking with the injectors being part of the problem is that the glow plugs would explain the rough running after it actually starts. Maybe I’m wrong there.
Ill definitely get it scanned. I have a WiFi obd2 thing already, I just forgot to run the scan when I had it on for the blow by.
Walleye - any chance you have the resonator box still? It’s a plastic box that sits at the top of the engine connecting in to the air pipe before the turbo. I have it plugged now but would like to test the noise difference with the box. And before someone jumps in - yes, I know how much people hate that box - I’m just curious.
Hotshot
Joined: Mar 2014
Posts: 10,750
Likes: 1,065
From: Douglassville, PA
# 1 He has PA listed in his profile, many put it there but not on their sleeve like we do.
I might have the resonator, is it a weird dead end box with something like one 2 1/2" inlet? I have that and it's still good, most of the other intake stuff was all broken up. If that describes it I can snap a pic to make sure.
I might have the resonator, is it a weird dead end box with something like one 2 1/2" inlet? I have that and it's still good, most of the other intake stuff was all broken up. If that describes it I can snap a pic to make sure.
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Posting Guru
Joined: Jul 2017
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If your E450 has a GPCM instead of a GPR, then skip ahead to measuring each of the glow plugs individually; I don't think you can measure the set as a whole if they are connected to a GPCM.
I looked up the injector coil resistance to refresh my memory, nominal stock injectors are 2.9 ohms.
If you do measure your glow plugs and injectors at the valve cover connectors, please post your findings.
I looked up the injector coil resistance to refresh my memory, nominal stock injectors are 2.9 ohms.
If you do measure your glow plugs and injectors at the valve cover connectors, please post your findings.
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New User
Joined: Apr 2018
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Yes! I tried to send a PM but the site won’t let me? I’m on mobile right now so I’m not sure what’s wrong. I’ll try again later on a computer.
And I will definitely check everything being suggested and will report back. I haven’t had enough time to actually dig in yet. I’m hoping to tomorrow.
And I will definitely check everything being suggested and will report back. I haven’t had enough time to actually dig in yet. I’m hoping to tomorrow.
Hotshot
Joined: Mar 2014
Posts: 10,750
Likes: 1,065
From: Douglassville, PA
Yes! I tried to send a PM but the site won’t let me? I’m on mobile right now so I’m not sure what’s wrong. I’ll try again later on a computer.
And I will definitely check everything being suggested and will report back. I haven’t had enough time to actually dig in yet. I’m hoping to tomorrow.
And I will definitely check everything being suggested and will report back. I haven’t had enough time to actually dig in yet. I’m hoping to tomorrow.
