home to install new ADII

[jumpjg]

Moostang, I doubt you would have both an in-tank pump & a block-mounted pump. The dealer fix for a failed block-mounted pump was to install a new module in the fuel tank that had the in-tank pump. From all accounts it was an unsatisfactory fix. I'm inside my tank right now to fix a leak at the top of the in tank fuel module (http://forum.mopar1973man.com/threads/4049-Fixing-Fuel-Tank-Leak). My truck is a '99 like yours, and the module is much different than the one pictured earlier in this thread. I have taken some pictures but I haven't had a chance to download them from my camera - try to get that done soon. I have ordered a Draw Straw 1 as recommended by Vulcan Performance along with a big line kit (3/8"). Last fall I replaced the OEM Carter fuel pump with an Airtex unit, mounting it in the OEM location. With the big line kit comes all the hardware & electrical harness to move the mounting location of my Airtex down onto the frame next to the tank. The Draw Straw 1 will plug into the top of the existing tank module, keeping the fuel pick-up & return in the basket. Expecting delivery of the parts late on Friday. I'll update the Fixing the Fuel Tank Leak thread in the next couple days. Joe in St Louis

[dripley]

So its one or the other, not both?

that is correct. though i installed another pump on the frame rail when i found out how low a pressure the in tank put out.

[dripley]

satrted my install today. got the tank out, rebuilt the basket, reassembled the tank and it is ready to install. the intank pump is about double the size of a D cell battery. i know size aint every thing but it sure aint impressive, especially when compared to the AD. ther were 2 wires for power to the pump. they were connected with push on connecters. nothing in the instructions dealt with those wires so i just cut them off near the top on the basket where they could not short to anything or each other. they come from a relay mounted on the dash, drivers side. 2 other wire go to the ecm connector near the old pump location. a single wire fused to the battery. there is one more wire (O/R) that goes into the conduit along the frame rail towards the old pump location. if any one knows what that one is please let me know. i am hoping i can get rid of that relay. it looks like it was installed with the intank pump. looks like th new relay and harnes will take care of everything but that O/R. i will have to chase that down tomorrow. got everything else off and hopefully get it all back together tommorow helping hands are a little sparse right now. i took some pix and will post them later.

[dripley]

i got the ad installed and working today. the fuel basket i have is just like the one in AH64ID's photo, except mine did not have the fancy fittings at the top. i just reused the ones molded into the top. I connected everything back in the basket utilizing AD's kit. when i tried to bleed the system of air i got a good stream of fuel for 2 seconds and then got alot fuel air mix. i cycled the pump several times with the same results. i connected to the vp and tried to start the engine with no luck. could not get any fuel to the injectors. thats when i realized i had not installed one of the spring clamps on the fuel pick up properly:doh:. went back to one of my photos and it confirmed what i thought.figued it was sucking air. i had to take the fuel tank back off and install it properly. got it all back together, then it started raining and i had to wait until today to finish. i reinstalled the tank and connected every thing this morning and had the same problem while bleeding. figured i had around 5 or 6 gallons of fuel in the tank. but went and got 8 more just to see what happened. put 4 gallons inthe tank and got a good stream for about 5 or 6 seconds and mor fuel air mix. i put 4 more gallons in and got a steady stream of fuel. i reconnected to the vp and the engines statred on the second attempt. enough about the trials and tribulations of the install, a couple questions for you guys #1 with the ad pumpimg straight into a fuel can does it return any fuel to the tank? thought that could be a source for the air since possibly nothing is going back into the basket. #2 how much fuel does the engine return to the basket? this is another source for air since it returns no fuel if the engine is not running. i have got this 1/4 tank thing in my head and worrying that is my problem. i guess i'll just put a 5gallon can of diesel in the bed and drive and see what happens. i appreciate all of yalls input.

[jumpjg]

I don't have an Air Dog but I've studied it and all the tank pick-up stuff lately. I'll give your questions a try.

#1 with the ad pumpimg straight into a fuel can does it return any fuel to the tank? thought that could be a source for the air since possibly nothing is going back into the basket.

Not sure. There probably is some going back, but certainly not the full flow of the AD pump. if you dead-headed the flow out of the hose into the can, all the fuel the AD is pumping would return to the tank. What ever amount was coming out of your hose into the fuel can was having to be supplied by the tank through the basket. If the AD return is through a tee installed into the filler neck line, it may take some time for the fuel to get back to the basket. With a low tank it could lead to pump cavitation.

#2 how much fuel does the engine return to the basket? this is another source for air since it returns no fuel if the engine is not running.

If the engine is not running while the AD is pumping, a small portion of the flow is returning from the engine. If the engine is running there is a significant flow returning from the engine. MoparMan has a video of it here (http://mopar.mopar1973man.com/cummins/2ndgen24v/fuel-pressure/fuel-pressure.htm).

Since the AD is a positive displacement pump, it has to go somewhere; either to the VP or back to the tank from the AD return through the filler neck tee. The flow to the VP either gets sent to the injectors or back to the tank.

Hope this helps,

Joe in St Louis

[dripley]

I don't have an Air Dog but I've studied it and all the tank pick-up stuff lately. I'll give your questions a try.

#1 with the ad pumpimg straight into a fuel can does it return any fuel to the tank? thought that could be a source for the air since possibly nothing is going back into the basket.

Not sure. There probably is some going back, but certainly not the full flow of the AD pump. if you dead-headed the flow out of the hose into the can, all the fuel the AD is pumping would return to the tank. What ever amount was coming out of your hose into the fuel can was having to be supplied by the tank through the basket. If the AD return is through a tee installed into the filler neck line, it may take some time for the fuel to get back to the basket. With a low tank it could lead to pump cavitation.

#2 how much fuel does the engine return to the basket? this is another source for air since it returns no fuel if the engine is not running.

If the engine is not running while the AD is pumping, a small portion of the flow is returning from the engine. If the engine is running there is a significant flow returning from the engine. MoparMan has a video of it here (http://mopar.mopar1973man.com/cummins/2ndgen24v/fuel-pressure/fuel-pressure.htm).

Since the AD is a positive displacement pump, it has to go somewhere; either to the VP or back to the tank from the AD return through the filler neck tee. The flow to the VP either gets sent to the injectors or back to the tank.

Hope this helps,

Joe in St Louis

#1

i kinda figured the AD would have to have some resistance on the line to return fuel to the tank. withit pumping into the fuel can it seems there would be little resistance and return flow would have been minimal at best. my return line from the pump is fed straight into the basket thru the old supply outlet and not thru the filler neck. the engine return is thru the original return inlet. i would think AD did that to be sure there is always enough fuel in the basket to keep the pump fed.

#2

i did try and start the engine and never got any fuel to the injectors. i think it was not able to get enough fuel with out sucking air. i put 8 gallons of fuel with the 4 already in the tank, got a steady stream of fuel and it started on the 2nd try:hyper:. the new fuel pick up in the basket is a 2 piece nylon tube with the joint right at the top of the basket, could be another source for sucking air. wish i had done that differantly.

it is runnign fine right now and when the time is right i am going to see how low the tank wil go before running out. i have always been able to run my tank dry. i dont really want to end up with the 1/4 tank problems i have heard about.

thanks for the info.

by the way dou yu have any clue as to why installing this pump would have caused my engine to finally run at proper temp. i have battled my engine running between 165 and 170 for a long time. after the install my temp is right at 190 like it should be. tstat is new. been thru several trying to fis it.

[moostang]

I just replaced my VP44 and installed my AD 150. The vp44 was a piece of cake, the airdog gave me a little trouble. The problem wasn't with the AD, but the connections on top of the tank. The 150 came with the draw straw which seems to be fine, ran down to 1/8 tank. My problem is the return line into the top of the tank from the engine is rusted and i'm worried it may leak. Is there something I can replace it with? I was going to use the plastic fitting (aux. fuel inlet?) but its right under the bed frame rail and can't get a straight hose on it.Also, after install my EGT's dropped 200 deg. Is that from the vp44 working properly now?

[dripley]

I just replaced my VP44 and installed my AD 150. The vp44 was a piece of cake, the airdog gave me a little trouble. The problem wasn't with the AD, but the connections on top of the tank. The 150 came with the draw straw which seems to be fine, ran down to 1/8 tank. My problem is the return line into the top of the tank from the engine is rusted and i'm worried it may leak. Is there something I can replace it with? I was going to use the plastic fitting (aux. fuel inlet?) but its right under the bed frame rail and can't get a straight hose on it. Also, after install my EGT's dropped 200 deg. Is that from the vp44 working properly now?

my truck had the in tank pump with a differant basket from yours. all of my inlet and oulets were molded plastic. there was an unused capped opening that i used to install the fuel pickup line. had to drill it out. there is a thread on the 24 valve non power train titled "fising fuel tank leak" that should address your concerns. there is also a link in the thread to a write up about a slimilar problem with alot of pics. some of the guys here would be more knowledgable that i on the egt issue. i would think that one of the pumps could have helped with that i dont know enough to pass an informed opinion on. after install my ADII my egts remained pretyy much the same, but my fuel milage at higher highway speeds went up. hope some of this helps.