I would be more concerned about a leak than ripping it out. leaking gas/fumes/ sparks random stuff on the road.... cigs....

all kinds of bad things can happen with just the smallest leak, and if it leaks its going to spill all over the place.

I know a guy who junks and parts outs cars, and one day he was cutting something out with a torch a little too close a gas tank and it went up in flames, basically blew up in a ball of fire.... he had severe burn injuries. Took him two years to get back to being able to move around and work again.

thats just my two cents.......

no better thing than overkill when it comes to safety....


I have never seen a passenger vehicle with a tap on the bottom.... but doesnt mean they arent out there i guess.....

 

I know there aren't any that came from the factory with a fuel pickup in the bottom of the tank. But there's no other way to do it. It won't leak, that's what these fittings are made for, they use them in race cars and such. I wouldn't have done it if it wasn't safe. Only thing is catching it on stuff, but I'm making a skid plate to avoid that. And as far as inspection, the fuel pickup is the last thing that they're going to look at. Carb won't pass emissions, no cats won't pass emissions or safety, exhaust dumped under the cab won't pass safety. It's good for 2 years, and I'll find somebody to pass it when the time comes.

 

Oh yes there are other ways to do this.

1 Some of the factory fuel pump module have a aux pickup built right into them.
2 You could have removed the factory fuel pump and installed a pickup tube in it's place.
3 There are kit's made for the diesel trucks that go in the top of the tank.

So as it stands right now your truck won't pass a safety because of mods you have done........ hope you don't get into a accident as you might just be held liable for whatever.

Garden tractors, lawnmowers, chainsaws don't travel down the road so who cares what they do to them.

Edit: You better keep that tank at least half full, I see fuel starvation problems with anything less than that. It stalls at the worst time on you and that will be the end of things.

 

Okay I did not know this thread was here but I better chime in here as I was just alerted to its existence...

By early 2nd gen I mean 1996-1997 unless explicitly specified...

I did give him a lot of advice and tips on this like I have for several others. But that doesn't mean I suggested or recommended every single thing. There are some things that mccart has said that are incorrect but I simply cannot address them all here... Mccart not trying to be an a$$hole but I want people to have the right info for this and I know the details well. I pretty much had to figure out all this stuff on my own and spent many many DAYS doing what essentially is reverse engineering. Not trying to brag but you won't get all the info from anyone else...

If anyone comes across this thread wanting to do a carb conversion PM me and I'll be happy to walk you through the whole thing.

Umm the part about being more of a pain than it is worth to you is probably the only true statement there. You do NOT have to run a new fuel line. You only need a special line adapter readily available from Summit that converts the A/N quick coupler used AT the fuel rail connection toa threaded connector. Finding the hot wire for the pump is not difficult either. As far as the flow, the EFI pump will support a carb perfectly fine. Only when you start getting into extreme performance will it not provide enough fuel. But for most carb setups it will provide plenty of flow. There is a specially designed regulator for dropping the 50PSI down to 7PSI available from Holley. P/N available on request. It will NOT damage the EFI pump contrary to popular myth. It is not difficult to setup or install and is much easier than running a whole new pump system. It is also much safer. It simply costs a lot more and many people prefer to el cheapo out... Carbs do NOT, DO NOT need more flow than an EFI system. They need roughly the same fuel flow. Carb will need a little bit more but for God's sake not three times as much. Where in the world you got that from I do not have the slightest clue...

It wasn't my idea to put the fuel pickup line in that way. I recommended that he used the factory EFI pump. Otherwise I said to drop the line in from the top of the tank (and there is a way to do this safely as well). So don't credit me with the idea of the line through the bottom of the tank. Using the factory pump is by far the safest and easiest way although it is more expensive. It will prevent any issues with leakage or the possibility of ripping a line out. It will also retain the factory level of safety in the event of a collision in that it is significantly less likely to leak. As well it will still retain the vapor recycling system for the tank.

Also, as far as a carb not being as efficient, that is correct. However a properly tuned setup will yield excellent results. I just clocked 16.8MPG at a steady 65MPH with my carb seutp. Any other speed and fuel economy drops rapidly. EFI provides better MPG over a broader RPM. IMHO comparing carbs and EFI is somewhat like comparing apples to oranges. They are both fruit but very different. You see my point.

As well the carb will feel more powerful and act more responsive. There are factors to this though. The EFI system may not be tuned the way a user wants it to be. Having a carb enables them to do that so the feel will obviously feel better. Another factor is that the intake manifold ALWAYS is changed so that changes the whole game. It is also possible to run more timing with a carb than EFI (I'm running 15* or 17* advance base timing and 35* advance through the dizzy) and still stay on street gas. Granted I run 89 octane when towing in hot weather. I need to re-tune the engine though as the mountain air is different. And that is another inconvenience of most carbs. Most have no way to compensate for altitude.

As for the gauges, well I really should do a write up on the whole converting to carb thing for those who wish to or want to know more about it. For 1994-1997 you can FOR SURE save and use your factory gauges. They do require that your PCM be functional as well as certain parts of the wiring harnesses. There are certain sensors that are required as well. If desired I can list them... From 1998-2002 Dodge introduced some updates including the 24 valve Cummins and for the gassers a new PCM. There are other changes as well including the interior. It may be possible to get the cluster to work but I cannot say 'it works FOR SURE' as I have never been able to walk someone through it and I don't have the newer 2nd gen truck to experiment with. There are certain other techincal difficulties that would take a bit longer to explain. Very briefly, the later 2nd gen cluster runs off of the CCD/CAN bus and is not directly connected to any of the sensors AFAIK. For those of you who are curious what the CCD bus is it stands for Chrysler Collision Detection bus. Before the event of CAN (Controller Area Network) bus Chrysler invented the CCD bus originally for communication between sensors, the PCM, and the airbag module (and in some vehicles {not Ram trucks} the body controller as well). Later when CAN came out Chrysler continued to use the CCD alongside CAN until 2004 when they along with most manufacturers went entirely CAN. In the 1998 and later 2nd gen Ram trucks the CCD bus provided a lot of other data than just the air bag system data. It is the first thing to be initialized in the bootup stack on the PCM, even before engine functions. Yes I have been into operating system/code level with the JTEC PCMs. I even have the raw binary microcode for the Mopar performance PCM from 1996 stashed away on a backup somewhere. In late 1996 and 1997 Ram trucks the CCD bus can be used to pass commands directly to the PCM. Edit: On SOME early 1996 trucks ONLY the PCM can be accessed via OBD1 AND OBD2. In all trucks with CCD it can be used to access the airbag module via the OBD2 port. I do not know for sure if the CCD bus exists on 1994 and 1995 Ram trucks but I suspect it does as CCD was in the early 1996 PCMs that shared a lot with the OBD1 PCMs found on 1994 and 1995 ram trucks.

The early 2nd gen cluster depends on the PCM for speedometer input and tach as well although after inspecting the cluster and PCM hardware it appears that the PCM simply passes on the CKPS signal to the tach without any modification (It may do some noise filtering but that is all). That is not the case with the speedometer.

There is simply a heck of a lot more about converting to carb than I can write in this reply. The PCM controls an awful lot more than meets the eye and in the case of the early 2nd gen 99% of the functionality can be retained. Beyond the little I know about the later 2nd gens I can only guess based upon the little information I have from various sources such as the FSM, and other sources. Much of the info for converting to carb is applicable to other engine conversions as well, and there are other scenarios where such information is very handy. To date I think I have walked 5 or 6 people through converting to carb. All are prior to 1998 and all retain the factory instrument cluster. Most chose to delete A/C or did not have it in the first place. Yes A/C is controlled by the little devil known as the PCM. So is cruise control and a host of other things.

But I better stop there else this will become the write up... Like I said there's a lot more.

 

I don't think it would be that difficult to convince the A/C to work on a carbed motor......

 

Not too difficult but a small technical problem.

Gotta run around the PCM. There is the high pressure sensor and the low pressure switch. These act as cutouts in case there isn't enough freon, the compressor or lines freeze or there is a blockage somewhere. You have to bypass the PCM. However the signal from the A/C selector on the blower control (inside the cab, you know turn fan speed control to left for A/C) appears to send 5 volts and that won't engage the relay and even if it does it will burn it up. The sensors are supposed to get 5 volts IIRC and I'm speaking from memory so don't quote me. However they can run 12 volts just fine. So you want to get 12 volts from the A/C selector, run it through both sensors, then to the A/C relay. That will bypass the PCM successfully. Note that this info is applicable to pre-98 2nd gens. I do not know about 98 and later. It is probably similar but they got a bunch of extra fancy stuff so I can't say for sure.

 

PCM just controls the relay. There is a pin on the heater control head that *suggests* to the PCM that you want A/C. PCM then pays attention to the circuit with the pressure switches, and if it sees a signal, activates the relay for the compressor. With a bit of rewiring, you could have the control head turn on the power for the pressure switch circuit, and in turn, have that circuit control the relay.

 

I know this is an old thread, but I just finished a carb swap on my 95. Its a 408 stroker motor and dealing with the obd1 computer was hell for years, the mopar performance pcm worked until I put higher flowing heads, m1 intake, big cam, and 30lb injectors in. So instead of swapping to obd2 and going back in forth for tuning I went for the carb swap. Everything is working for now except for 2 things, my tach no longer works, and the alt doesn't charge. I know I can use an external voltage regulator, but is there anyway to use the factory alt setup? and how can I get my tach to work again?

 

Tack works off the ecu along with the regulator. What are you using for ignition?

 

I figured the regulator circuit would be an issue since it uses so many sensors that I am no longer using. The tach is what I really would like to get to work.

I am using a msd 6a box and an msd billet distributor, worst case I can hook up a tach to the msd box. I am just trying to retain the factory gauges.