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go-west.., Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 1197
Experience:  Technican with 20 years experience focused on engines and electrical.
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5500: I'm working on a customer's 2013 5500 cab and chassis

Customer Question

I'm working on a customer's 2013 5500 cab and chassis with a 6.7 cummins. It appears to not be making enough fuel pressure to start once the engine is warmed up.
I have replaced the CP3, the relief valve on the rail and 3 injectors. Not really sure what else to do other than replace the other three injectors. All of these parts are expensive and I hate to just throw parts at it. Is it possible that the rail pressure sensor could be bad and only act up when it is hot?
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  go-west.. replied 1 year ago.
good morningyes the fuel pressure sensor is a possibilityalso the fuel regulator at the other side of the rail is a possibilty but i see you have done thatgood one to eliminate
Customer: replied 1 year ago.
I'll try a new sensor. What does the pressure have to be in order to start?
Expert:  go-west.. replied 1 year ago.
ill need your esn to answer that my friend
Customer: replied 1 year ago.
Expert:  go-west.. replied 1 year ago.
there is no proper publish spec on this but there is a flow test you can do with the high pressure pump Minimum flow: Engine Cranking (150 rpm) 70 ml [2.4 oz] in 30 seconds.that is the spec that pump needs to put out minimumlet me know how you do
Customer: replied 1 year ago.
Will do. Will be Monday before I can get back to it. Minimum cranking pressure must be around 2000. It won't crank at 1800. I can hit it with a little ether and it'll start right up. When the fuel is cool, it starts fine.

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