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OK, so I've been battling some random issues with my 6.7L Megacab.... Basically it just dies, sometimes when idling around town, once in a while it happens while going down the highway. Sometimes it just 'shudders' but then never completly dies. Sometimes it dies completely (thankfully never on the expressway,) but then it will always restart right away. Sometimes the dash lights up like a xmas tree, and sometimes nothing. When the dash does light up, sometimes there are fuel pressure related codes. Also, a couple of times the overhead has shown 'cat full, maintenance required'. (It skips over the 'cat full, read the manual' message.) However, after driving it for a while then cycling the key the cat full message goes away...

A little bird told me to take it to the dealer and have them flow test the lift pump. (I'm still under warranty...) He explained that low flow from the lift pump may cause problems with regen, because it's not meeting the extra fuel requirements of the 'power' stroke and the 'regen' stroke... So the computer is not 'satisfied' that the burn is going right, so it starts leaving the injectors open longer during the 'regen' stroke, which results in a crappy regen, and burns more fuel..
He said that the lift pump fuel flow test should be a minimum of 600 ml in 10 seconds.
So I took it to the dealer. (They're already stumped, they're open to suggestions at this point...) They tested the pump and it came back 510, 540, 570, etc... So I said 'great, so I get a new lift pump right?' They said 'No'.... They told me star center said the spec is 500 ml in 10 seconds, and that my pump is within spec...
So now I'm really baffled. What's the actual spec? I actually trust my 'source' more than I trust the dealer, but I'm hoping someone who has a copy of the manual or access to Star can let me know what the fuel flow spec should be for a '07.5 6.7L
 

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318 Posts
Lift Pump Pressure

Fuel Pump Module
Part Numbers:
68003875A$
68003876A$
Issue Description:
Before replacing the fuel lift pump for a check engine light or engine performance issues, perform the DealerCONNECT In-Tank Fuel Lift Pump Flow/Diagnostic Test Procedure


Use the special tool #8979 Gas & Diesel Fuel/Pressure Decay Tester to perform the test.


The average fuel flow rate specification with this tool is:

5.9L - 520ml in 10 seconds.

6.7L - 500ml in 10 seconds.

Charlie
 

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OK, so I've been battling some random issues with my 6.7L Megacab.... Basically it just dies, sometimes when idling around town, once in a while it happens while going down the highway. Sometimes it just 'shudders' but then never completly dies. Sometimes it dies completely (thankfully never on the expressway,) but then it will always restart right away. Sometimes the dash lights up like a xmas tree, and sometimes nothing. When the dash does light up, sometimes there are fuel pressure related codes. Also, a couple of times the overhead has shown 'cat full, maintenance required'. (It skips over the 'cat full, read the manual' message.) However, after driving it for a while then cycling the key the cat full message goes away...

A little bird told me to take it to the dealer and have them flow test the lift pump. (I'm still under warranty...) He explained that low flow from the lift pump may cause problems with regen, because it's not meeting the extra fuel requirements of the 'power' stroke and the 'regen' stroke... So the computer is not 'satisfied' that the burn is going right, so it starts leaving the injectors open longer during the 'regen' stroke, which results in a crappy regen, and burns more fuel..
He said that the lift pump fuel flow test should be a minimum of 600 ml in 10 seconds.
So I took it to the dealer. (They're already stumped, they're open to suggestions at this point...) They tested the pump and it came back 510, 540, 570, etc... So I said 'great, so I get a new lift pump right?' They said 'No'.... They told me star center said the spec is 500 ml in 10 seconds, and that my pump is within spec...
So now I'm really baffled. What's the actual spec? I actually trust my 'source' more than I trust the dealer, but I'm hoping someone who has a copy of the manual or access to Star can let me know what the fuel flow spec should be for a '07.5 6.7L
It sounds like you have a electrical problem. Maybe a grounding issue to the ECU. One thing that happened to me was I left the Grounding Terminal loose on the Driver side battery. That made my dash light up like a christmas tree. truck would just turn over, no startie. Talked to my Diesel guy from the dealer and (which I found the problem at this point) he said that the ECU grounds off of that battery. But if power fails to the lift pump first then yeah you could get a lift pump code. But I think you got a electrical issue.
 
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