long cranking after AIRDOG INSTALL

[jasvan10]

so there is nothing else that I can look at that may cause the hard cranking if you all agree that the AD pump is working like it should ,the longer cranking occurrs durning the 2nd pump cycle then this maybe the VP ? can bad injectors be a issue ? I dont have a problem driving it down the road it runs good its only the hard starting . my long cranking durning most of the time seems to be around 15 psi sometimes lower

[dripley]

The only time you experiance the hard starting is if you bump the starter and and try to start it while tha pump is running. If thats true just dont bump the starter. Get in turn the key and start it. The only time I use the lift pump for that 25 second run is to reprime the fuel system after changing filters, servicing the fuel system, or any time I have to open the fuel system for any reason. Another thing to try would be to turn your pressure down and see if that makes a differance. The ADII has a pressure regulater on it. It should be at the return line on the frame of the the pump. It is a nut with a threaded shaft and a slot in it for adjustment. Loosen the nut and turn the screw until the pressure lowers and them tighten the lock nut. If this is your oe VP it is likely it is on the way out from way to low of pressure from the oe lift pump for so long. I would not think your injectors are bad since the engine is running good while it is running. Try filling out your signature again.

[jasvan10]

last nite I took it out and it was about a 3 second crank I have tryied all different combinations of starting it and all have given a relitifly faster start and a long crank it has been sporadic and diverse on all sometimes I do get in and just turn the key and it starts fairly good not like it did prior to AD Sometimes I wait till the pump goes through all the motions and it fires up again quicker then majority oif the time I am starting to loose faith in the VP,I will go out and make a adjustment today and see if this will help. Even my pressures while cranking has been inconsistant now I have seen 7-8 - 10 -15 psi is there any Validity in what Hex says in the overflow valve ?

[dripley]

I am not sure the overflow would cause hard starting unless it was letting all the fuel by and not letting the pump have any fuel to run the engine. It is fairly easy to to test.http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/25-fuel-system/49-fuel-pressure-specification-for-bosch-vp44-injection-pumps. Ibelieve they are pretty cheap and easy to replace. Is this your oe VP? If so it has had a long life ont the oe lift pump system. How many oe lift pumps have you had? Nice to see the signature.

[jasvan10]

Yes it is the Original VP , I wonder how accessible gaskets are for replacement of that valve

[dripley]

I would think that anyone who carries the over flow would have the sealing washers used on it. If you just want to check out the operation of the valve you shoul be able to reuse the old ones and replace them later if they have gotten hard.

[jasvan10]

this AD is the 4thn lift pump. I had to post 20 or more times before it would let me create a signiture

[dripley]

Were the others oe carters and intank pumps?

[jasvan10]

two were mounted on the engine block and the 3rd was intank and now the AD

[hex0rz]

two were mounted on the engine block and the 3rd was intank and now the AD

...Is this in tank unit still in the tank? If this in tank lift pump is still in the tank and you don't have a drawstraw or a modified basket, this is your problem! The AD is not gonna be able to suck nearly enough through a burned out in tank pump. Imagine trying to draw a soda cans worth of soda through a coffee straw all at once. Not gonna happen. IIRC, you had the work done. You need to check your invoice, etc. for what work was performed.

[jasvan10]

Sorry ,but I could not reply on this site it would not let me, the box would not show ,any way the old in-tank pump was removed I have it in the Garage ,the truck would not start at all yesterday It just crank till the batteries were low . today it cranked over after 3-4 seconds, it runs good on the road I take it for rides watch the new fuel gauge it drops to 14.5 in 2nd and 3rd gear then back up to 16 -17 psi I dont dare stop anywhere but at home .I talked to a guy in Bay City Michigan that said they were the first to have a BOSCH 815 test bench in Michigan he told me to take a air hose before I do anything else and pressurize my fuel tank to check for fuel line leaks ,he also said they rebuild lots of injection pumps for Farmers and anything that has a injection pump warrenties it for 12 months and puts a new pcm along with several other new parts. I have 3 new 1/2 inch lines coming from my AD 1 return line, 1 suction line , and 1 feed line , I read somewhere on this site that the fuel going to the VP 70% of it is returned back to the tank I think it said its for cooling the VP where on the VP is the return line coming from the VP going back to the tank ?

[dripley]

It is just to the left of the supply line. It has a line running to the rear of the engine.

[jasvan10]

is this supposed to be hooked up to what ,Just looked at that and it does not have a line hooked up to it should it?

[dripley]

is this supposed to be hooked up to what ,Just looked at that and it does not have a line hooked up to it should it?

Yes. it should be connected with a fuel line towards the rear of the engine where it joins into a tee that connects the return line from the cylinder head and then goes to the fuel tank return line,http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/25-fuel-system/88-bosch-vp44-injection-pump-overflow-valve. the first picture shows both the in take and the return line. the banjo fitting underneath the label should have a hard fuel line that goes towards the rear of the engine.

[hex0rz]

Can you take a picture of the vp44 like mike did in the article dripley provided?

[jasvan10]

OK ,I now see a line that looks like it goes down to a tee ,I have to get under the truck to see where it goes from there so if it goes back to the tank there should be a hookup into the fuel module along with the AD return line and the suction line frome the AD also learning alot here I have to thank you guys for helping I am going to borrow a aircompressor this weekend and see if I can pressurize the tank and check fuel lines for leaks then check the return valve , then IF those too check out I will have to surrender and buy a new VP

[dripley]

Did the tee look wet at all? Mine was leaking at the tee and at the back of the head. The line coming out of the top of the tee goes to a fitting on the back of the head. Those washers will get hard and can let air into the fuel system. That would cause a hard start issue ususally if the truck is parked in an uphill position and is hard to see. There just does not seem to be any rhyme or reason to your hard starting other than the VP. I dont want to recomend spending 1k to find out, but i dont know what else it could be.

[jasvan10]

I seen the te it did not appear wet I have not looked behind the head where it leads to I will di that sunday, today SAturday I dropped the fuel tank ,pulled all the lines off and pulled the fuel module out I found that when they did the install they broke the plastic clip that holds the sending unit on and pieced it back together also when they installed the fuel pickup elbow onto the top of the module it was loose I removed it and found 4 little raised plastic nubs that the inner washer was up against so I ground them down smooth and installed another rubber washer and tighten back on it has a better seal and its tight also the extra holes that were supposed to be 1/2" to 9/16" were only a 1/4".

I put it all back together and went to start it up and it cranked slowly ,now my Batteries are dead ,WHEN WILL IT END< I also pulled the return valve of and tried the air test just didnt seam to work I put a very small wood dowel into the end an was lightly pushing in on the check valve It seamto move very easily ,so Sunday I will go buy new batteries and try to start it ,If this does not work I will surrender and buy a new pump unless there is something else that I might be over looking.:banghead:

[hex0rz]

Ugh.. that why I try and do all the work myself! I avoid taking my truck to the shops as much as possible!

[jasvan10]

Well ,I agree sometimes I dont feel that I can do something without it taking to long and thats why I took it to a so called professional ,Man was I wronge ,and its winter and very cold and no garage or pole barn to do the work and I end up climbing under the truck drop the tank full of fuel and find this shotty workmenship , I am starting to believe that they delibertly sabotaged my truck to bring in more money and played me for a fool and wanted me to let them fix it right then ,they were Quick on the trigger to diagnose the problem and quote a price in the same Breath I will not condone anyone to bring there truck to this guy . I guess my next step is to start the dissassembly of the parts that will be in my way to access the VP, the weather is getting warmer this week.