this is for a freind....so pls help if ya can....came out of nowhere... truck was running fine and starting fine then all of a sudden it starts to have longer cranks where i have to fool the pump and just knick the key to get the pump to push some fuel....and have to do that 4 or 5 times before it will start but even when it starts it cranks over prolly twice...?? it used to just not even turn over all the way and it would start.....im not sure about this but would have anything to do with the crank sensor??? would it not be picking up signal and sending it to the injection pump causing it not to fuel or what.....??? we was thinking lift pump but it will start and run and keep good fuel pressure...it just had a new vp put on it a few hundred mile back .....any help would be appreciated ....thanks in advance!!!

 

what's the truck??

 

I would bet money on your buddy having an air leak somewhere. Mine has a similar problem, waiting for time to fix it. Some days it starts right up others I have to bump the starter and make the pump cycle to push the air out.

 

Air and/or fuel leak.

 

right before my vp took a dump on me, it became very hard to start. It always started on first crank, then one day it took two, then three and so on. It didn't post any codes, no power loss, nothing. Then all of a sudden the truck shut off while cruising, and sure enough p1688 showed its ugly head saying "time for a new pump". Just something to think about.

Bryan

 

Check the valve on the return line on the inection pump. If its bad or has trash in it, you will lose prime. It is the large banjo bolt toward the front of the VP44. You can check to see if you are lossing prime, by cranking it and letting it warm up, then kill it wait 30 sec and restart, if it cranks right up you are lossing prime somewhere when it sits for a while. I went thru this a few weeks ago. Hope that helps.

 

I ended up with a new VP when it happenned to me.
There were no codes, but 30 second cranks to start.
I had to threaten Glendale dodge with a lawsuit (4 weeks before my warranty ran out way back when) before they were willing to cough up the new VP44 and LP. I believe (can't remember for sure) their service manual says you shouldn't crank more than 15 seconds or something at a time to start it...or damage could result...So that is where I caught them.
That fixed it..
But you better check for air leaks, etc., first. because that's always the first place to look.

 

When my overflow went bad, it would fire on 3 cylinders, then die for the next 3, and so on until it finally started, roughly 5 or 6 revs for it o fire. Only time my truck has never started was when it was doing this, -30 and had 15w40 oil in it.

 

Anyone got any photos of where that **** overflow valve is? I get a real lumpy start after the truck has been sitting for 6+ hours and ONLY if its below 30* or so. New batteries make her fire up without an issue, but it seems like it doesn't have the fuel at first. New fuel filter didn't solve it, no visible leaks. Gonna have to start searching for air leaks soon...

 

The OFV is the banjo bolt in the return line, which is the frontmost line. Supply line is the rear line. I don't have a picture, but its easy to see.

 

Is it right next the the line with the schrader valve in it?
Here's my truck. It usually starts ok when cold in the morning or after sitting until the motor cools off. Usually means it has been hard to start a few times in this condition.
Most of the time when the motor is hot or within 30 minutes after the motor has warmed it will not start until I have cranked it for 20 to 30 seconds. Sometimes I have had to pause and let the starter cool a minute or two before cranking again. It has always started but my new 29 series batteries are being challenged. For short trips I have to try and stretch the time out to charge the batteries.
I have tried bumping the lift pump and letting it run for 10 seconds before cranking but it doesn't seem to help much.

I have a question. Does anyone know if there is a valve in the injector pump that allows diesel to flow and build pressure to fire the injectors? It almost seems that the second that the engine gets fuel it fires up and runs fine. I have never once had the motor stumble or show signs of having air in the line. Not once.
So what I am asking is what stops the flow of high pressure fuel to the injectors when you turn the key off. I think that may be the key to whats causing my problem.

 

That may be your VP going out. Word has it that the heat expands the circuit board in the VP. When you shut it off hot, it doesn't make connection to get it fired. When it cools off, the board contracts and connection is restored.