Hard start in morning, then good rest of day

[Liviniuk]

2001 6 speed. So here's the story. Lately when the truck sits over night it cranks 10 seconds if not more to start. Rest of the day is no issue. I've got 20psi to the vp44. I've parked nose down. I've checked every bolt and fuel line. I've checked and load tested the batteries. Batteries are a touch on the weak side but not bad. I cannot for the life of me figure it out. Fuel tubes and injectors were pulled and re o ringed ect. A year ago. Any ideas? I'm honestly down to replacing the vp44 check valve and the fuel heater on the canister o rings. I understand its losing prime somehow but I'm having a hell of a time finding where. Once it fires up its bump the key and it pops. I'm going to pull the LP fuse next and see what happens. If that dosent help I'll pinch off the return line before the tank and see what happens. Any insight would be great.

Vp44 is less than a year old. Wait to start light works as it should as per normal. No excessive smoke ect. Turn the key to on and LP kicks on for the split second as per. Truck runs / sounds as normal once it starts in the morning. Cannot figure this out. 

[Dieselfuture]

Sounds like you're on the right track to figure that out. Are all your fuel lines original or did you upgrade to 1/2 inch. What lift pump are you using, are you sucking from factory fuel basket( it has push lock connectors) did you put a draw straw in. Have you looked at the T at the back of the head where VP and injectors meet to return fuel.

[Stormin08]

Along with all the free fuel related checks...recently the IAT sensor has been mentioned as well.

 

 

mine has developed a hard start / longer crank on cool morning...all other fuel items replaced within a few miles....i am leaning towards trying the IAT sensor

 

[Liviniuk]

Ya I read somewhere that those IAT sensors can shoot up bad and cause all sorts of problems. I'll look into that for sure. I'll get on that sensor, check the vp check valve and check a few other things before I decide to pull injectors and tubes. Probably wouldn't hurt to go over all that jazz anyways.

[Mopar1973Man]

2 hours ago, Stormin08 said:

recently the IAT sensor has been mentioned as well.

 

Don't bother to replace IAT. Just hook up a live data tool like an OBDLink LX or similar. Then check the IAT temperature in the morning with the ECT temperature they should be the same. Sensors are fine then. 99% of the time IAT sensor is fine and doesn't need to be clean or even messed with.

 

Check the suction side of the pump. Suction side leaks never drip. Then continue to draw air in through the leak and drain the prime back off. This can happen between the lift pump and the tank for fitting or connections. 

 

Return lines. The return at the back of the could be weeping or at the tee on the return line. 

 

Look at the crossover tubes mating faces and the lines. If the faces are damaged or pitting its possibly to weep air in when shutdown.

 

How many miles on the injectors? 

[Liviniuk]

I cant say for certain how many km are on the injectors and tubes. That is quite possible also. That will be the next step in the process will be removing injectors and tubes if all else fails

Its roughly 3 to 4 celcius this morning I'm going to try and start it and count how many seconds to start

Ok something has changed since yesterday. 1 maybe 1.5 revolutions and it popped right off like as it should cold. WTS light on for 9 seconds before it popped off. Yesterday I took off all battery cables and cleaned every connection. Wasnt bad but wasnt perfect. I then cleaned up grid heater connections ect. I shoved my hand up under tank and pushed on the fuel lines to to make sure. I also left the fuel tank cap loose. So now I think I'm down to either 1. Something with the grid heater not working properly? 2. Tank vent clogged. At least I know it's not injectors and tubes

[Mopar1973Man]

About 160,000 kms (100,000 miles) those injectors are done. Just because it starts and runs good doesn't mean the injectors are good. Like I found I kept my stock injectors thinking they were good for spares if needed. Come to find out sent them int to be pop tested and sure enough, they all test very low in pop pressure about 260 bar stock should be 310 bar.

 

Now that the injectors are out you can visually look at the crossover tube socket on the injector for damage. Then look at both ends of the crossover tube. Now the tip of the high-pressure lines. Like here in Idaho DOT use a ton of salt I've already had to replace a set of injector lines. Weeping enough to drip diesel fuel also enough that a light hard start was happening in the morning. 

 

@dripley just had the o-rings on the injectors leaking where it was pumping diesel fuel into the head area. (Fuel in the oil).

 

Banjo bolt at the back of the head has two sealing washers. PITA to change but keeps it starting.

 

The return tee is a square cut o-rings and kind of spendy. Some just replace with normal compression tee or barbed tee with hose joints. Personally, I would keep the factory tee and o-rings.

 

Suction side leaks are common. The trick is pressurizing the fuel system at the fuel tank after the system has been fully primed up. Electric shop vacuum on blow should have enough pressure to push fuel out a leaking connection or joint. Be patient and have a second guy looking for wetness. If you need to use baby powder to check joints. 

 

IAT only turns on the grid heater for intake heat. Timing doesn't come into play till the engine started and running. Once running then the IAT controls the timing and below +80°F (26°C) then the timing jumps an extra +4° advancement. Has no bearing at startup.

 

 

[Liviniuk]

Roger that moparman. I also have a P0380 code, it's been there for quite a while but has never affected anything. I can get injectors fairly cheap which is no prob, probably the only good thing about vp44 24vs lol. New injectors and tubes. In the injectors and tubes were out last year and they looked good but weren't bench tested. I know I know...

New washers o rings ect. Truck started and ran flawlessly. Still runs flawlessly just this damn 15 cranks every morning. Except this morning Haha. Next step will be the shop vac in the tank and see what happens. I appreciate the help fellas!!

[dripley]

3 minutes ago, Mopar1973Man said:

 

@dripley just had the o-rings on the injectors leaking where it was pumping diesel fuel into the head area. (Fuel in the oil).

This was also causeing hard start issues for me. Severe at times. Occasionally it would bust right off, but not for the most. Replacing them and the crossover tube orings stopped the issues completely. It does not take much of a leak in the high pressure or return side of things to cause hard starts. 

[Liviniuk]

100% agreed. Just wishful thinking it's something less. But...with unknown idea of how many km are on injectors and tubes it very well could be as well. As moparman said, could get some bigger injectors i want anyway and swap em out and bench test the old ones. If they are good then they can be backups

[Mopar1973Man]

7 minutes ago, Liviniuk said:

I also have a P0380 code, it's been there for quite a while but has never affected anything.

 

Typically either the small wires to the grid heater solenoids or the solenoid has failed. might help with cold start issues if the compression is low. 

 

10 minutes ago, Liviniuk said:

Next step will be the shop vac in the tank and see what happens.

 

Remember air molecules are much smaller than a diesel molecule which is why you have to patient for it to show. Air can leak in easier then diesel can be pushed out. 

[Liviniuk]

You betcha sir. I've got all day and baby powder ha. I'd like to rule out low compression but I cant speculate without do a test. Wishful thinking again!

I wonder if cleaning up the batteries and all connections made a difference. I almost wonder if the motor wasnt spinning fast enough when cold to start it immediately 

[Mopar1973Man]

10 minutes ago, Liviniuk said:

I'd like to rule out low compression but I cant speculate without do a test. Wishful thinking again!

 

You could do a poor man blow by. Start the engine. Then unscrew the oil cap. place it in the hole. Does it just sit there?

 

Actual blowby test is hooking out manometer and measuring the amount of water column. 

 

Best way to go is get your hands on a compression tester and all the cylinders when the injectors are removed. (425 to 450 PSI typically tight engine)

 

Be aware blowby test will not catch a broken piston. An old member here fought a misfire problem for a long time and spent a huge amount of money. Never done a compression test. Did tons of blowby test which always pass the test but he had a cracked piston that leaked more when the engine got hot. But never failed the blowby test. 

 

As long as this isn't happening I won't worry much...

Edited May 8, 2019 by Mopar1973Man

[Liviniuk]

I've done the poor boy test and it's good. I guess when I R&R the injectors I'll do a proper test as well since I'm already there. 

[dripley]

I currently have 467k on my cross over tubes. I know things wear out, but that is some seriously hard steel they are made of, on the late models anyway. 

 

This last time I went thru it if it did not start in in a couple seconds I let off the key and let the lift pump run a cycle then hit it again. Repated if necessary. Not sure the truck started any quicker but figured it was easier on the starter.

Edited May 8, 2019 by dripley

[Liviniuk]

Ya that's an option if its losing prime but isnt fixing the problem unfortunately. I'm gonna do the moparman route and check for leaks and probably wind up pulling injectors and tubes just for reassurance. 

[dripley]

28 minutes ago, Liviniuk said:

Ya that's an option if its losing prime but isnt fixing the problem unfortunately. I'm gonna do the moparman route and check for leaks and probably wind up pulling injectors and tubes just for reassurance. 

That did not fix my issue either, it just got me by untill I could find the problem. With what you have already done my money is on the return line on the back of the head or the tee below it. It does not take much of a leak to cause hard starts and they are not always visible. Thats where my first hard start issue came from. Simple parts but a pain to get to. Not knocking @Mopar1973Man suggestions in the least.

Edited May 8, 2019 by dripley

[Liviniuk]

I know these trucks are voltage/amp sensitive and if it dosent have adequate juice that will also produce bad starts. I'm sure the dirty terminals and connections didnt help anything. 

Ya. The banjo on the back of the head was cleaned and installed with new washers and tee has been checked. I could always change the push on o ring for what its worth. 

[dripley]

Damn, just lost my bet. 

[Mopar1973Man]

Computer wise you only need 8 Volts minimum to start and run. Learned this driving around with my blown up PCM and burned up alternator. 

 

This is where all the mods come to play.