Which one is better? (long)

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rbkt65

rbkt65

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1971 dart. putting a 96 5.9 magnum in it. Going to use the factory EFI, wiring, fuse box and as much as possible. It will have a 904 in it. I need a new gas tank. Mine has the 1 nipple above the sending unit for a return (vent). Would the tank with the 4 nipples be a better choice? I could then have a return and vent for gas tank. Thought about piggybacking the tank vent to the return line but it might be a smell/leak hazard.
 
Your 5.9 came with a 904 ? Gas tank wise. To do it properly and safely will cost you $500-$700 to either convert a new standard tank to EFI or for a new complete tank and pump new and built for EFI.
Fuel system is nothing to shortcut. Do it safely/correctly.
Many companys with new products to convert the early Mopars to EFI.
Replace all fuel system hard lines, braided for any flw line connections, steel fuel filter and F.I. rated clamps/connectors.
 
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rbkt65 said:
1971 dart. putting a 96 5.9 magnum in it. Going to use the factory EFI, wiring, fuse box and as much as possible. It will have a 904 in it. I need a new gas tank. Mine has the 1 nipple above the sending unit for a return (vent). Would the tank with the 4 nipples be a better choice? I could then have a return and vent for gas tank. Thought about piggybacking the tank vent to the return line but it might be a smell/leak hazard.
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This is going to depend on a number of things.
Do you plan on running the charcoal cannister from the '96?
Does the '96 use a fuel return line or is it a returnless system? (Mopar used both over the course of the Magnum's life- I don't remember offhand which was being used in '96)
Does your Dart currently have a tank vent in the filler tube?
Are you planning on running a stock tank with the Holley or Spectra conversion pump/sending unit module, run an external pump, or get a complete tank/pump replacement from a vendor like Tanks Inc.?
 
I am putting a 904 in it because i am not going to cut up the floor for the a500/518. I will be using a Walbro fuel pump hooked to a 3/8 sending unit. I have braided line to replace the stock 5/16 line. I won't be using any emission stuff. The 96 truck this came out of is a return system. I have both filler necks, 1 with nipple and 1 w/o nipple. Fuel filter will be inline type. I thought it might be easier to use the 4 nipple tank so that i would not have to piggyback a vent on top of the return line. I guess that if i use the filler neck with the nipple, I could put the "t" in the fuel return high enough to connect with the filler neck nipple.
 
rbkt65 said:
I am putting a 904 in it because i am not going to cut up the floor for the a500/518. I will be using a Walbro fuel pump hooked to a 3/8 sending unit. I have braided line to replace the stock 5/16 line. I won't be using any emission stuff. The 96 truck this came out of is a return system. I have both filler necks, 1 with nipple and 1 w/o nipple. Fuel filter will be inline type. I thought it might be easier to use the 4 nipple tank so that i would not have to piggyback a vent on top of the return line. I guess that if i use the filler neck with the nipple, I could put the "t" in the fuel return high enough to connect with the filler neck nipple.
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Are you sure the truck was a return style fuel system? It has a fuel pressure regulator on the rail and 2 connections?

I am pretty sure that after about ‘93, all the Dodge trucks went to a single line returnless fuel system. The Jeep GC carried the return style setup the longest, but I thought even they went returnless by ‘96.
 
rbkt65 said:
I am putting a 904 in it because i am not going to cut up the floor for the a500/518. I will be using a Walbro fuel pump hooked to a 3/8 sending unit. I have braided line to replace the stock 5/16 line. I won't be using any emission stuff. The 96 truck this came out of is a return system. I have both filler necks, 1 with nipple and 1 w/o nipple. Fuel filter will be inline type. I thought it might be easier to use the 4 nipple tank so that i would not have to piggyback a vent on top of the return line. I guess that if i use the filler neck with the nipple, I could put the "t" in the fuel return high enough to connect with the filler neck nipple.
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The fuel neck vent does not get piggybacked into the fuel return, that would defeat it's venting ability and cause fuel delivery issues. The vent (when no charcoal cannister is used) is just open to atmosphere; from the neck it loops upward into the C pillar area and then follows the filler tube back down through the trunk, terminating inside the driver's side frame rail.
If the sending unit you intend to use also has a return fitting, then your tank will not require any additional nipples. If not, then your tank will require the extra nipple. There is no reason for a 4 nipple tank since you're not running a charcoal cannister or any other type of emission equipment, you will just end up capping them- more sources for future leaks.
Just make sure your system truly is a return style system, as DionR said. This affects your part selection and choices.
Your controller may need to be reflashed to ignore the lack of a transmission signal with a 904, and the lack of emission controls; which will generate fault signals and cause your CEL to be constantly on and possibly keep you in a "limp mode" all the time...
A 904 bellhousing will need to be cut to make clearance for your crank sensor.
 
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Why would you need to cut the floor for an a727 which most of them came with ? The 904 is not an o/d trans.
Make sure that the tank is supposed to be vented. Most factory FI cars will throw a code if the gas cap is loose. That indicates a non vented system.
Also if using a factory ecu you may have to add various sensors to your engine as well as O2 sensors.

Are you trying to use all the factory stuff to make it look like it is stock or trying to save a few $ ?
You might be a little unhappy with the performance of a totaly stock setup as the 5.9 was only available in trucks and as such is not a performance setup.
Aftermarket FI systems are much more user friendly and can be tuned. The factory setup really can't.
I might rethink this before you start to buy things.
 
I could use a 727, as i have several. I am using a lockup 904 because this will be just a cruiser. I already have a race car. I plan on using as much of the 96 wiring and stuff as possible. Car will also have a stock width dana 60 in it. I have a wiring harness relay box from a guy on FB that removes unnecessary wiring and makes the harness plug and play. This will be our 4th car that we are building. We have a 37 Chrysler, a 49 Plymouth, a 52 Dodge and now my 71 Dart. As far as buying things, i have most of stuff now. Was not planning on buying a gas tank but cleaning it did not help it. I will probably send the PCM out to be programmed or get a stick shift PCM. It will also be OBD 2. I will be putting O2 sensors in it and what ever it takes to make it a good driver. Thanks for all the replies so far. They have given me a few more ideas and things to ponder.
 
If the new fuel pickup/pump doesn't have a return nipple already in it, there should be plenty of room on the flat face of it to drill a hole and solder or tig a nipple in it. I'm doing basically the same thing to an 88 D100 long bed pickup. Truck is already fuel injected, but I have to figure out the pump also because the throttle body pump doesn't put out enough pressure. There's a bunch of videos on You Tube about wiring a complete factory harness to make it run. I'm gonna run a 518 (46RH) in my truck with 3.91 gears. If you have any contact info for your wiring guy besides Facebook, send it to me in a PM. Good luck with it!

:thumbsup:
 
MoparLeo said:
Why would you need to cut the floor for an a727 which most of them came with ?
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He didn't say he'd need to cut the floor for a 727. He said he didn't want to cut for an A500/518.
MoparLeo said:
Most factory FI cars will throw a code if the gas cap is loose. That indicates a non vented system.
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Since he's not running any emission controls, he'll need to get the pcm reflashed anyway. That code will not be valid in that case.
MoparLeo said:
Also if using a factory ecu you may have to add various sensors to your engine as well as O2 sensors.
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He already has all the sensors, as he's swapping in a complete '96 5.9.
MoparLeo said:
Aftermarket FI systems are much more user friendly and can be tuned. The factory setup really can't.
I might rethink this before you start to buy things.
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The factory PCMs (JTEC- OBDII) can be easily reflashed by any place that has HPTuners software, and other common software suites. The parameters of the factory PCM limit their use in max HP builds, but are easily adaptable for street or street/strip use.
 
No, we are not the same person. But I would like to thank him and all for the input, so far. If I knew 10% of what you all forgot, I would be really somewhat good. Even though I spent 47 years as a mechanic. Retired in 2016. Thanks to all.
 
Let me throw another thing out here for discussion. My 71 dart has a nipple above the sending unit. I stripped out a 70 318 car that also has a bad gas tank. That fuel tank DOES NOT have a nipple above the sending unit. It has a nipple on the filler neck, very close to where the neck is screwed to the quarter panel. Also the filler neck on the 71, without the nipple is approx 3-4 inches longer than the 70 filler neck. Look up in factory parts book only says w/wo ecs. What am i missing here? I have a 71 fsm but not a 70.
 
JDMopar said:
Truck is already fuel injected, but I have to figure out the pump also because the throttle body pump doesn't put out enough pressure.
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I am running a TBI pump in my ‘91 Dakota after swapping the 5.9 into it. It’s the same pump as used in the ‘92-95 SMPI motored Dakotas so when I swapped the 5.9 in I just left it. Pressure is controlled by the FPR.

Not saying your earlier TBI pump will work, only that it might. Just a thought.
 
I'm hoping it might work, but not holding my breath....lol. If it doesn't, maybe I can get lucky and find a new pump for a 93 D100 with a Magnum motor. I looked on Rock Auto a while back and they showed them in stock. Whether it fits my existing tank is yet to be seen.
 
I have experience with that concern, JDMOPAR. The 88-90 D series trucks is a low pressure system, approx 14.5 psi avg. Magnum is 45-50 psi, approx. The magnum fuel tank is different where the pump goes in the tank. Clamp vs screw top. So you will have to get a 91-93 tank or cut a top out of 1 and adapt it to your tank. I just switched tanks. The biggest problem is finding the 91-93 fuel pump plug for the wiring harness. It is not reproduced. But if you get a tank, just cut the plug back about 12 inches.
 
Just figured out the difference in 70 to 71 tanks and filler tube. 70 is 18 gal and 71 up is 16 gal.
 
rbkt65 said:
Let me throw another thing out here for discussion. My 71 dart has a nipple above the sending unit. I stripped out a 70 318 car that also has a bad gas tank. That fuel tank DOES NOT have a nipple above the sending unit. It has a nipple on the filler neck, very close to where the neck is screwed to the quarter panel. Also the filler neck on the 71, without the nipple is approx 3-4 inches longer than the 70 filler neck. Look up in factory parts book only says w/wo ecs. What am i missing here? I have a 71 fsm but not a 70.
Click to expand...
ECS is emission control systems. To the best of my knowledge Federal spec cars generally came without ECS, California spec. came with. The extra tank nipple was for vapor return, and was used in conjunction with a charcoal cannister- with a charcoal cannister the tank is not directly vented, the venting occurs through the ECS system. Thus the two different style tanks and vented & non vented filler necks.
 
Thanks Professor Fate. I went and looked over both my filler necks and see the the 71 has a divider in the center and has a set of "louvers", so to speak, on the top. That, as you said, is the vent. Thanks a bunch. I think that now, I can use the single nipple tank and use the nipple for the fuel return to tank.
 
Update on my j7nk. Ordered tank for 72 dart, 16 gallon with single nipple above sending unit. Will fit pump/wiring to sender when it arrives. Thanks too all.
 
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