Engine/Transmission (1998.5 - 2002) Vapor Locked??

[JGoss]

I looked at a 98. 5 today with 166k miles. Overall it's in really good condition. The guy told me he has had zero problems except for last week. He said it started fine but died. He said his mechanic told him to pull start it because it was vapor locked. After he did that he said it's been running fine. I know a gas engine can, but can a ctd?? I thought it might be the lift pump. There's probably not enough info. but maybe someone can chime in. I don't think it will be for sale much longer though. Thanks.

 

[2-ND TIME]

engine dies after starting

Sounds more like there is a leak in the fuel line before the injector pump. Might there be any signs of fuel misting around the pump and lines? THey are easy to reprime. Loosen #'s 1,2,4 nut to hold down the injector . Spin the engine and very shortly the fuel should come out, close them down so to do one cylinder's injector at a time to bleed the system. ( the air horn is in the way for # 3 I think ) IT will want to start at this time if it isn't the vp44 if it doesn't start it is likely the vp and this is why the gent sold it.

 

[Cummins724]

98. 5 models mostly had 53 blocks in them. I would check the engine for a 53 before anything else. It does sound like a fuel problem... . check for codes before guessing. Just my $. 02

 

[JGoss]

Thanks guys. There were no codes, and no fuel leaks that I could see. I also figured the lift pump or vp is going out. I'll look closer tomorrow.

 

[JGoss]

cummins724, what is a 53 block??

 

[Cummins724]

cummins724, what is a 53 block??

Do a search on 53 block... . lots of info there, but it is casting that was made in Brazil which is prone to cracking along the passenger side of the engine right below the freeze plugs. Don't buy one... trust me!

 

[2-ND TIME]

Vapor locked

Yes my 53 has been leaking coolant out the crack since November. It goes through about two gallons of coolant on my 960 km trip to work. Just waiting till spring to order a new truck. On the drivers side I think there is a number cast in to the block check to see what the number is you may need a flashlight. Don't touch it if it is a 53. Costing out mine, to be replaced was going to be about $13,000 for a long block. I have some quotes in my alum can at work on options they gave me.

 

[Mundgyver]

VAPOR LOCK Hmmmmm, me thinks and would like to know how much fuel was in the tank when they tried to start it and was it on a hill with the nose pointed up hill.



The 2nd gen trucks with the 24valve and VP-44 will sometimes not want to start with a fuel tank is is below 1/4 full and the nose slightly up hill.



Why you ask. Experience has shown that with a low tank and the nose pointed up hill the return line in the tank from the VP and the head is exposed to air. Gravity does its thing with liquid pulling it down out of the return line, particulary if the VP-44 ball regulator at the VP's inlet is not seated, meaning that maybe it has a piece of grit or the ball seat has a very small scratch so it does not seal. The fuel in the return line starts to drain back into the tank like a siphon and then the VP winds up with a little air in the inlet section.



On older trucks this is a valid problem. It never seem to happen with a tank above 1/2 full or with the nose pointed down hill or on level ground.



Food for thought with this problem. Been the and suffered that

 

[WestTN]

There will be no vapor lock with diesel. Diesel has way too high a vaporization point. Now if it was full of gasoline and it was REALLY super hot outside... .

 

[DCreed]

anyone check codes?

 

[JGoss]

It did have a 53 block, but the truck ended up selling. I thought $7200. 00 was pretty cheap for a 2500, 4x4 reg. cab. long bed with nv4500, but guess it was meant to be. It was going to be my new farm truck to replace my 89'.

 

[SAndreasen]

particulary if the VP-44 ball regulator at the VP's inlet is not seated,"

where is the valve in question? my 01 is suffering from a hard start condition i have replaced the fuel from the tank and the rubber lines from the lift pump to the filter and from the filter to the vp44 piece of **** still wont start ! although my problem also ocurs with the tank clear full but this valve may be sumthing to check? thanks and sorry for stealing this thread

 

[Mundgyver]

Look at the VP-44 and find the inlet fuel line. You will notice that there is another fuel line attached near it, but the line takes off and runs to the back of the engine and connects with a "T" to the return line from the injectors and then heads back to the tank. This is called the overflow valve.



That is where you should find your overflow valve at the second fitting. It is designed to open up at 14 psi so you don't overpressure the VP-44.



It is one of the reason I went to a larger fuel line for volumn of flow but keep my fuel pressure at 15 psi. Plenty of fuel for the VP-44 with out doing a hydraulic lock to it.



This information is right out of the BOSH Distributor-Type Diesel Fuel-Injection Pumps Manual, page 73. The manual is dated 2003 and covers a System overview, Helix-and -portcontrolled distributor injections pumps, Axial-Piston Pump (VP29, VP30) and Radial-Pistion Pumps (VP44)



The ISBN number is ISBN-3-934584-65-9.



Look for (The Bosh Yellow Jackets Edition 2003 Diesel-Engine Management). This manual is well worth buying and should be considered a Diesel Information Requirement for anybody that owns a Dodge right along with the Factroy Maintenance Manuals.



I have 200,000 on my original VP-44 and it shows no signs of weakness or problems.

 

[Mundgyver]

Here is the manual and page I was talking about.

 

[Mundgyver]

Here is what the book says;



Overflow valve

In order to vent and, in particular, cool the

distributor injection pump, excess fuel flows

back to the fuel tank through the overflow

valve (Fig. 3) screwed to the pump housing.

The overflow valve is connected to the

overflow valve (4). Inside the valve body (1),

there is a spring-loaded ball valve (3) which

allows fuel to escape when the pressure exceeds

a preset opening pressure.

In the overflow channel to the ball valve,

there is a bore that is connected to the pump

overflow via a very small throttle bore (5).

Since the overflow valve is mounted on top

of the pump housing, the throttle bore facilitates

automatic venting of the fuel-injection

pump.

The entire low-pressure stage of the fuelinjection

pump is precisely coordinated to

allow a defined quantity of fuel to escape

through the overflow valve and return to

the fuel tank.



So there you have it. If this valves sticks open, you can find yourself venting the lowpressure feed side of the VP-44. This is another reason why if you park on a hill, put the nose of rig down hill, that way if you do have a slight leak, any air in the overflow line with vent to the tank and not the VP.



Food for thought guys.

 

[Cummins724]

It did have a 53 block, but the truck ended up selling. I thought $7200. 00 was pretty cheap for a 2500, 4x4 reg. cab. long bed with nv4500, but guess it was meant to be. It was going to be my new farm truck to replace my 89'.

I would try to find a old 12v truck for a farm vehicle. The vp44 is expensive if it should crap out.