Hey Guys!!! New to Forum...a lot of you have a lot of knowledge about these trucks!!
First off I have a 1994 ext cab with a 3.9, I only have one problem with this truck, it is about to turn 100,000 and the gas gauge doesn't work, I bought the truck this way, but it really sucks to have to rely on a dummy light to tell me when I'm low, any ideas what this might be?

Also Looking for an exhaust system that sounds good. Any of you taken off the factory and put something that sounds pretty good? Or even a dual setup? Let me know
Thanks for your time guys!!!!

 

As far as the gauge, I didn't know the dummy light would still go on even if the gauge didn't work. Anyways, if there is one thing that it seems all Dodge trucks (or, all their automobiles for that matter) have wrong with them, its gas gauges that crap out, and this is a widely known issue. I've read that Chevron puts out a fuel cleaner, called Techron, that is supposed to aid the problem. I ran a bottle of this last fillup, it was $9 at my local farm supply store (well, its got much more than farm stuff). It helped a little, but maybe a second treatment would help me. Aside from trying that: I don't know what year they made the switch, but I know on my 1996 Dakota it does not have a seperate fuel sending unit, on your '94 it might. You can check with a local autoparts store and see. If its NOT a seperate part, you have to buy the fuel pump assembly (which is: fuel pump, fuel pressure regulator, fuel sending unit, fuel filter). Whew...

As far as exhaust, I'll tell you, I don't have a modified one, so I'll just be telling what I have read around here. First off, its a V-6, so your not gonna get the V-8 sound. I've read the Flowmasters (40 series?) are good. Some people don't like the sound of the Magnaflow, some people do. IIRC, I've read people that said they recommend against running duals. For more information, you can always use the search feature, since everyone and their dad's siststers' husbands' cousins' dog's previous owners' wife has asked about exhaust.

Hope this clears some things up.

 

Thanks I really appreciate the info, yeah it really doesn't make sense with the light coming on and the gauge not working, for the price of a pump and all that 300 or so to get a working gauge seems a little steep. I got another gauge from a junk yard thinking that it would be just the gauge but didn't solve the problem.... thanks again for the info

 

I have got Glass packs on my truck and it actully sounds ok for a v6. They are not the cheap ones though like cherrybombs. It also helped with the gas milage and the performance when i opened it up.

 

I have a 92 with a 94 3.9 in it.

My fuel guage didnt work yet my dummy light did. What I found was when I pulled the whole fuel pump assemble out of the tank. Theres these two tabs that ride up and down on this scale. One of the tabs werent touching. So I gently bent the tab in so it touched and vuala, my guage works now. Seriously.

As far as the exhaust. I have one lesson I have learned:[sm=icon_guiness.gif]

Backpressure bad, Velocity is good.

Backpressure is caused by restrictions in the exhaust system. Stock mufflers are typically very restrictive devices. Most aftermarket mufflers have a smoother flow and relieve some of this backpressure. A high flow cat is always nice too.

Velocity is the rate at which the exhaust gasses leave the system. In our smaller displacement engines, velocity plays a big role in how our 3.9's perform. If you use a larger diameter tubing, you will loose some of this effect. The main thing you will notice is the "bottom end" of your power band has gone flat. Torque numbers take a huge dive and so on and so fourth.

I have had other 3.9 dakotas that I have put exhausts on. I have had dual setups, side setups, dump it after the axle setups. Although our stockers are 2-1/2" before the muffler, the best by far (that I have found) is to use a single exhaust with no larger the 2-1/4" tubing after the muffler. (unless you heavily modified your engine, or do like I have seen people perform before.....supercharge it) This will allow you to retain your bottom end which relies heavily on the velocity of the exhaust flow to create like a scavenging effect in the lower rpm range to exterminate the exhaust gasses in the combustion chamber. A dual set up may sound good, but you loose some of this effect due in part to the split. Right now I am running a flowmaster 40 series with a 2-1/4" tail section. It gives it a nice deep growl and alleviates most of the back pressure. I have noticed a gain in power, but most important to me and most of us, a 2-1/2-3 mpg gain in my fuel mileage. Honestly. granted I do alot of highway driving.

I would recommend that you use nice smooth mendrel bends to keep the velocity up, since crush bends seem add a small amount of turbulance/backpressure.


Hope this helps

 

DUDE THANK YOU SO MUCH!!!!!!!!!! Your a life saver. THANK YOU SO MUCH FOR THE INFO. Just seemed that I was getting nowhere, and now that I have tlaked to someone that has experienced the same thing, makes me feel a lot better knowing that i don't have to spend 300 on a fuel pump assembly. As for the exhaust I will check into getting th eexhaust the way that you have it setup on yours, I am looking for something that sounds good but yet doesn't hurt me on power.... ONCE AGAIN THANKS!!!!!!!!!

 

Not a problem. I'm glad I could help.