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A new one on me! 6.5 very very hard to start.

countryboy69

countryboy69

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Location
Marengo,IN
Ok this is a new trick that years of 6.x trucks hasnt done to me.

Friday I drove up north in my 01 6.5 db2 truck. 2.5 hour drive one way. run like a top all the way to Indy. Was in the trade show for about 8 hours and it was a little hard to start. Chocked it up to being cold and run hard coming up. Ran fine coming back south. Stopped at an old friends before going home. Went to leave and it wouldn't start. Lost prime is how its acting. Kept bleeding the filter and cranking it until she finally fired. Ran fine coming home.

Next morning took a little extra time to get it started. Still runs fine but if you let off throttle too quick it will die. Fires right back up.

Went home and changed filter, checked glow plugs, hunted for leaks in the fuel lines that might let air in. Nothing!

It started sunday with a little bit of work. That evening it wouldn't even start. Gave up. Jumped it and got it running this morning.

Longer it sets the harder it is to start. Have to prime system every time. Electric pump is working and has decent flow but I dont know actual pressure. Fuel filter gets air in it. Bleeder on the crossover has air too for a few seconds. Lines are all fairly new and DB2 pump has about 2000 miles since brand new from Stanadyne. Not a reman it is brand new. It also started having a fuel knock occasionally. I have checked all the obvious but experience has me thinking injector. But it runs perfect when its running. Any suggestions?
 
Ya know I was considering that sock too. Here's why.....It still has the electric gas fuel pump in the tank I think! I dont remember taking it out when I built the truck! And my fuel I filled up with before the trip was questionable too.
I may have to take a day off work to fix it. Only wheels right now.
 
So you built a 6.5 truck from a gasser?
What DB2 do you have? 4911 and a couple others had a head and or rotor problem that would cause hot start issues, but your seems to do it when cold?
 
4911 and yep! was a stolen/recovery 2500 ext cab 4wd. The 6.0 gasser was missing. Had a 95 I bought that was ugly but low mileage. Pulled and didnt want to wire it for DS4. Had the new 4911 that I fell into on a trade! Rest is history.....or sitting outside knowing its not gonna start in the AM!
 
I'd pull the filter can and look at the o-rings on the wif sensor... pretty common.
air in the filter and lines is getting in somewhere.
if you are pulling through a tank sock and pump assembly from a gasser... yeah... um. pull that.
 
Sorry to say, but I don't know how the 6.0 is set up to run, but ar'int the pumps for 6.0 like 30 or more PSI on them? Im also not sure if those pumps will hold up to diesel fuel. I do know diesel will turn a non diesel rated hose to gum.
Also you said you checked GPs might want to confirm that again.

Any up dates
 
I am running a stock 6.5 pump and lines. I talked to those who was there when I did it and they said I dropped the tank and connected the sock(a new one) to the line above the pump. My memory sucks! So basically I made my own diesel pick up inside the tank.

The glow plugs are fine. The IP is new with only about 2500 miles on it. Not ruling it out though. I have checked orings and fuel filter in the manager but not the sensor. Its definitely getting air in. I pressurized the tank and lines hunting for a line leak and no luck. But I can bleed manager first then shoot the bleed by the crossover and it will fire right up. I usually delete fuel manger and go with a race filter. I may do that tomorrow. I think I have it narrowed to either manager or IP.
 
have you tried leaving the fuel cap loose or off. A vacuum in the system will pull air thru something that won't leak under pressure
 
Did you use a 6.5 sock with check valve in it or a gassser sock, it makes a difference, also does your former gasser tank have the baffle in it to keep from air being sucked into the fuel system in a turn with low level in tank sloshing over to one side?
 
Another thought, if usings a factory style lift pump, trash in the outlet check of it could possibly let fuel drain back to the tank and maybe lose prime and your modified in tank pickup sucking air at low fuel level ?
 
Your stalling may be a misadjusted idle or bad injectors. 650 hot idle. Worse is the metering valve or governor sticking closed. Is your fuel heater working?

Sock may be plugged from bad fuel or waxing from the wrong fuel. Run a prefilter or a walbro with a built in screen. No reason to leave a sock in the tank. Cold fuel can wax and plug the sock. Any restriction like a kinked hose can boil diesel from the vacuum in the lines and look like air. Bad injectors may let air in, but, the hard starting would be hit once and then stall. I had a pinhole in a fuel heater letting air in through the wires. It was dripping diesel from the wires.

Clear return line on the IP is useful...
 
WarWagon said:
. I had a pinhole in a fuel heater letting air in through the wires. It was dripping diesel from the wires.

...
Click to expand...

Had a customer call me yesterday and we were tring to figure out why his FFM was allways wet? I suggested the same thing. He thought I was crazy.
Seen it on transmissions bulkheads too!
 
Yall are great! I cant remember what I done in the tank. But this came on kinda sudden over the coarse of a long trip. So I am ruling out the pick up on this simply because it rocked before.

I do wonder about the check valve in the lift pump. But......Today I tried to rebuild the FFM. Had it all good and dropped back on and still had same issue. Kinda ticked I pulled it off and switched to the setup off the dually since its down yet. Bleed and running and still same.

I can feel a small miss, very faint. Also if it dies warm it cranks and cranks before starting back up. Never losing pressure from the lift pump before restarting. So I did an old school trick for me. I had it idling and cracked inj lines loose one at a time. Each one would almost kill it as soon as the seal was broken.Except one! It still makes a difference but not as much and only drops rpm about 50.

Could this injector be letting air in? Or draining pressure from the IP causing the trouble making it all build up every time? I drove a customers FedEx 6.5 truck home tonight. I cant afford to throw 8 new injectors in this thing. But I have tons of extra used ones in the storage trailer. Tomorrow I am swapping out that inj. There is an obvious problem there anyway. Maybe it will fix it! I can dream right?!
 
you could always swap cylinders on the suspect injector and one that does not seem bad and see if the problem moves or not.
 
changed injector and replaced the rubber lines around. It does run better and doesn't die when I let off quick. But still has to prime to start. Thinking maybe that new IP is the suspect.
 
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