hey all I have a 14 foot trailer that I tow my mowers on weighs in around 2000 lbs and now I get 5 MPG my Dakota is a 93 and I heard in 94 they did something different with the EFI system to boost power is there a way I can swap out my injector system for one out of a 94 or 95 with out any major mods?

 

92-93 had more power than the other years from the factory. iirc, to swap out the inector system you would have to swap pcms too.

i'm sure some one else will chime in too.

 

5.2L TBFI 170HP 265 1991
5.2L MPFI 230HP 290TQ 1992-1993
5.2L MPFI 220HP 280TQ 1994-1995

What they actually did in '94 is drop down to a 2.5" exhaust from 3". All Magnum engines have the multiport fuel injection, which may be what you are talking about.

Replace your oxygen sensor, change out your plugs and wires, and put synthetic fluid in your driveline. This will help...

I too will wait for expert-er people, but I have done a lot of research on this. Here are the changes I have made to improve mileage and responsiveness (and performance):
* MSD multispark box to MSD coil to brass cap and rotor through STI plug wires to Autolite 3923 plugs.
* ATF flush with high quality fluid.
* Higher pressure in the tires.
* 180deg thermostat.
* Edelbrock hot-air intake and breather.
* Dynomax ultra-flo exhaust.
I still have to switch to synthetics in the driveline, but I have already noticed an improvement. I am running a 4wd V8 in town only and getting well over 15mpg average. And I don't baby it at all...

 

What is your fuel mileage when not towing? My truck is a 4x4 v8 auto trans with 185k miles and was only getting 10mpg with 33" tires and 12.5mpg on stock tires. A bottle of seafoam through the brake booster line and suddenly i got 20mpg with the big tires during my next all highway trip. If you have the time, pull the heads and soak them in a parts washer to get all the carbon off. With seafoam, it all goes out the exhaust and could clog up the cat.

oxygen sensor and correctly gapped spark plugs will be another huge improvement if they are bad. At only 5 mpg, you may have a bad fuel injector (or more than one) that is just constantly dumping extra fuel in.

 

a bad cat can cause bad fuel economy too but usually causes other problems at the same time. just something to check out

 

You have to have something wrong. I got 15 MPG in my Dakota with a 5.9, automatic, AC on, OD off, towing a 3000+ lb mini-van from AZ to CA but I was doing 55 mph. '92-'93 Dakota's have more horse power due to larger exhaust manifolds and larger exhaust. In '94 Chrysler switched to a returnless fuel system for evaporative emission only. There is no power gain. I had a returnless system in my '94 but swapped to a return system because I installed a 5.9 and needed a way to up the fuel pressure so I could run the 5.9 with the 5.2 computer. I needed to increase fuel pressure and was able to do that with the return system because I could manipulate the fuel pressure regulator to get the extra fuel pressure I needed.

 

I did the typical sparkplug wires, cap, rotor, plugs, air filter.
But I also replaced my breather, PVC valve and hoses. Those all helped.

I also took out my Cat, replaced my o2 sensor and thermal sensor.

BUT the thing that gave me the biggest towing boost was my recent replacement of my u-joints and support bearing. Now I have no issues towing.

 

well nothing is wrong with my truck I think am getting better mpg now cause I am easier on it lol how ever I get 11-12 mpg on its own with 31 inch A/Ts I will try a few other things you guys suggested and I am shocked with the drop in HP in 94 I do not have a Cat on mine and still single exhaust the O2 sensor I think I will try that as well as dual 3 inch exhaust and sea foam in the booster is a neat idea I do plan on buying another truck for my business to tow my trailer I like to think outside the box with upgrades and save money too lol I have NGK platinum plugs coming too then of course thinking of cap rotor wires and coil H.O. MSD any more Ideas let me know
thanks

 

and of course you will get better MPG with a 5.9 than a 5.2 when towing and I am doing city driving all day in Port Huron Michigan so :-P to you lol

 

Combo city/highway driving not towing with AC on full blast in Phoenix I get 13 mpg. :-P