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www.cumminsforum.com > ... > 3rd Gen. Powertrain Jun 5, 2010 - 9 posts - 7 authors
I have an 06 Dodge 5.9L that has a light white smoke and rough idle when first ... 2006Ram 2500 QCSB 4x4, 3" Carli coils w/ 1" Daystar spacer, ... Still ran good tho, dispite the exact conditions you describe on Cold Start up.
FIRST CHECK YOUR FUEL PUMP TO ENSURE IT IS WORKING PROPERLY, THEN DO A FUEL PRESSURE TEST. AN AVERAGE READING WILL READ BETWEEN 15 AND 30 LBS. THEN YOU NEED TO BE MORE SPECIFIC IS IT GAS OR DIESEL IF IT IS A DIESEL THEN YOU NEED TO LOOK INTO INJECTOR PRESSURE THE AVERAGE CUMMINS COMMON RAIL PRESSURE AVERAGES AROUND 5,000 TO 8,000 PSI ANYTHING LESS THAN 5,000 PSI THE TRUCK WILL NOT START OR WILL BE HARD TO START.
You need 3 things.
Compression
Good hot blue spark to all plugs.
Good gasoline and proper fuel pressure. 63-64 lbs.
If you have all 3 then move on to injector pulse to all injectors.
I think each injector is on a separate driver on that one.
Check for pulse to all of them.
You may be weak on fuel pressure . Even a couple of lbs low on a cold start will cause a no start. Double check cold start cranking fuel pressure. If under 63-62 lbs you have problems.one test is to give it a squirt of carb cleaner not starting fluid. If you get a intake or engine full of starting fluid it can blow things. Carb cleaner will start it if it is a fuel problem and lot safer. Also in the good old days when i was a kid, i used to get a couple of cans of
starting fluid and get in the back and have a good starting fluid
spraying contest. Good for a big blast if someone lights a match. If it starts then you have a fuel pressure problem. Run the full fuel pressure test and post back pressures.
Here is the guide lines on testing.
Hard to start cold.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure. V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel. Do not leave home without it.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
The 75-85 is only a check on the capable full pressure of fuel pump.
If you can not find the rubber return line check full pressure by
plugging return line or just or the true full pressure can be taken
direct at the end fuel filter.
What are the pressure readings that you have done.
What are your cold start pressure readings?
may be a check valve letting warm expanded fuel to slowly leak back to the tank causing hard start. When starting cold its harder to move the cold thick fluid. Check into it. Good luck..
what about injector return flow
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