Okay guys, Got a truck acting up, trying to figure out the flow's and pressure on a 04.5 up truck which alldata isnt showing.

The truck is a 06. Factory LP/CP3.
Showing 10 PSI and 250mL of flow in 10 seconds (I feel thats too low)
No Start. Wont fire on roll off, Fires on eaither but wont stay running.

Went through complete diagnoses only 3 Items left are CP3, Rail pressure Relief , or Inadequate LP Flow.
My question is, Is the 250ML of flow low enough to cause a No start condition?
I'm going to put a Relief valve block plug in, There was fuel at the top of the relief but the truck should still start with a bad relief valve? Injectors show fine.

My thoughts on it not being lift pump is just because the truck died going down the road and instantly, will not restart. Most lift pump failures dont present themselves this way. No fuel in oil, Crank/Cam Signals good. Just no rail pressure.

 

when the lp died in the 03 it died and would not start at all. a rail pressure gauge would tell you better as far as if their is enough pressure to start the truck then a flow test. the flow test seems to work better to determin which injector is bad. If it will not run after firing on ether then odds are its the lp when i have had llow rail and low flow the truck still ran when started on ether. gone thru this with the 03 and 06

 

Thats What I'm thinking, I'm showing no rail pressure on the gauges. Or on the modis. Also , I'm doing a liftpump flow test. No need to do and injector return flow test till I get the truck running lol

 

Relief valve or the fca is faulty.

 

FCA voltage is fine, and unplugged still no start. I'm gonna pop it off and check it. No idle problems what so ever ran great until now

 

Any codes pop up??

 

Just codes I induced like a Rail Pressure high and a FCA code, Neither of which were on the truck when it arrived at the shop.
My real question being how much flow is needed at the CP3 to create enough rail pressure to start.

 

All I'm getting to mine is 8 psi and about 70gpm. No rail pressure is either a blown relief, CP3 is no good, or you got one or more washed injectors.

 

I just took the FCA out cleaned it, I'm going to polish it a bit but movement is fine, No trash in it. Spring is good.
I'm gonna put a RPR plug in it. I just dont see how a CP3 or injector failure can manifest it's self instantly. Truck running great to truck not running. No fuel in oil, no missing, no smoke , nothing that leads to injector failure.
70GPM is alot more than what this truck is getting, 03 trucks require 950mL in 10 seconds while this one is producing 250mL in about 10 seconds. I'm just curious if thats enough to cause a no start issue?

 

Bad injector maybe? my brother in law had the same issue and it would only start on ether. It had two or three bad injectors. Take it to your nearest injection shop, they can save you lots of money, we ended up changing the lift pump and the cp3 and we had no luck.

 

We're a full service shop. We've taken all the measures to check the return flow on injectors and they show fine. Generally when it will start and continue to run with either, that could be considered and injector failure but this truck will only fire on either which pretty much eliminates an injector leaking down. No fuel in the oil. Connector tubes good, Valve lash good. Resistance on the injector leads is fine. No cracks in injectors or bodies. So I'm thinking I've pretty much ruled out injectors. I did pull the FCA and find it to be hanging a bit, I disassmbled it cleaned it and went over it with some sand paper and diesel fuel and polished it back up. Seem to have better movement now. I'm thinking it's related to the lack of fuel supply or a rail pressure valve at this point.

Also , Cracked injector holder and or nozzles and bad barrel seals (most common CR injector failures) present them selves for the most part in a performance problem and mainly in trucks with added rail pressure or poor filtration. Water and debri (above 3 mic) can destroy these injectors.

This truck is stock, and I will say that fuel filtration has been comprimised and the filters not changed on correct intervals but a truck dying in mid stride dosent fit injector issues! I'm gonna get the other key for the truck and see if I can get it to fire. Could be a key issue!

 

Try running it with the fuel supply line in a bucket of fuel.The cp-3 does not need positive pressure to run.It can create its own pull to adequately supply the engine. The intank pump is said to be able to pass fuel when going out but many have experienced problems to disprove this.

As far as far as showing RP while cranking,my DiPricol shows nothing till its running.Not sure what your using to read RP?

And also if the relief valve is fully blown it will not crank.It will not allow the RP to come up high enough to fire the engine off.Best way to check it is to remove the return line on the top and gently push it off to the side.Dry the top of the valve out,put a bag or something on the return line to catch the fuel,unplug the fca and start the engine(with ether in your case)Only let it run for a couple of seconds because a disconnected fca will max the RP.The top of the relief valve should remain dry.Any leak is no good

 

DRB and Modis industrial edition on the RP. I've already flow tested the pump. Flow is well below suggested rate. Relief valve sealed to about 200PSI under air pressure but no way to check above that. But you did give me a ideal the truck just had a new bed put on, I wonder if I've got restriction due to a crimped fuel line. I've also checked flow from the cp3 (with open fuel line fuel from cp3 discharges at or near atmospheric pressure ) and flow is low there too!
I'm just not one of those throw parts at it guys.

 

DOH!! I just re-read your post and misunderstood what you were saying.
I dont know why i didnt think of that before. I've got a bucket system made out of a Fass 200 GPH setup on a 5 Gallon bucket....Like i said, I dont know why i didnt do that before!

 

10 psi is fine, the volume as you stated is to low. I would be looking for a fuel line restriction. Nice job on trying to solve the problem.