it cranks quite a bit longer then normal, it will start everytime just takes awhile, letting it sit for a couple days doesn't effect how long it cranks to start, we rebuilt the fuel filter head, one thing I noticed before and after the filter rebuild is that the primer pump never hardens up, any suggestions?
LLY: truck cranks for like 5-6 before it will start issue, WHY?
- Thread starter kvw4x4
- Start date
You might try a new filter head. I think mine cracked or something rebuilding it never helped. Lift pump would help it start if that the case too. It’s just going to leak fuel until you replace the filter head.
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I'd buy a new filter head before I even thought about replacing injectors. Is it something that just happened within a couple of days or been gradually getting worse over a year ?
If just started happening I'd bet filter housing has a problem.
If just started happening I'd bet filter housing has a problem.
A clear piece of fuel line between the filter housing and the test port would give you your answer real quick if the filter head is an issue or not. I would moreso expect a start than stall from a cracked filter head though.
Install a piece of clear fuel line between the fuel filter and the T block that goes to the test port. If it is the filter housing leaking, you'll see an air pocket form in the clear line. If no air bubble/pocket forms, then theres no air leak. You can normally pickup clear vinyl tubing at a hardware store for a $1 a foot.
Also check the frp reading during cracking and while running if access to a scan tool any codes? Commanded vs actual? More info the better for diag.
Probly injectors returning too much, I’d do the filter head first then pull the injectors and have them tested, 300 bucks usually to test. Cheaper than injector/s you may not need.
Fwiw Just something to think about there is a thread on here that is related to fprv on the lb7. it can cause low rail pressure during start up hot or cold ppe makes a plug to address the concern it is associated with a p0087 and may set a p1093 it's cheaper than a $700 gm fuel junction block as well as a filter head from the dealer if its not leaking. If high injector return rates are the culprit the only way to address that is overhaul of injectors if bodies pass inspection and flow test or r and r injectors. keep us updated curious as to what is found
I would like to bump this up a bit. Adding if Truck is plugged in overnight it starts a lot faster. Not perfect but faster. The truck was at dealer. Fuel holds pressure to filter seems to have an issue on high pressure side. There were a couple injectors that were close to
+\- 4, dealer wrote still has long crank high psi side only ramps to 11,000 psi, checked pressure relief valve that was ok.
Attached is notes from dealer. Including balance rates
+\- 4, dealer wrote still has long crank high psi side only ramps to 11,000 psi, checked pressure relief valve that was ok.
Attached is notes from dealer. Including balance rates
Attachments
Sounds like high return rates on the injectors.
It start better when plugged in because it is cranking over faster so the CP3 pump is spinning faster.
New battery's, fresh starter, lift pump, will all help aid starting and act as a band aid. But more then likely it won't start good until you replace the injectors.
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It start better when plugged in because it is cranking over faster so the CP3 pump is spinning faster.
New battery's, fresh starter, lift pump, will all help aid starting and act as a band aid. But more then likely it won't start good until you replace the injectors.
Sent from my iPhone using Tapatalk Pro
