Dodge RamCharger Central banner
1 - 20 of 21 Posts

·
Registered
Joined
·
53 Posts
Discussion Starter · #1 ·
Howdy, I just bought a '90 Ram 150, 318 o/d auto tranny, 4x4 and just took first long trip. I got about 7-8 mpg. Truck has 180k and runs alright. Changed plugs, wires, cap, rotor, filters and fluids. I am going to try new 195 degree thermostat recomended by others and get injectors (Throttle body) cleaned. Anything else? Thanks, Tim
 

·
Premium Member
Joined
·
5,548 Posts
Probably should check the codes by turning key on and off 3 times and leave the key on the last time. It will flash the codes on the check engine light.
 

·
Premium Member
Joined
·
16,239 Posts
If you want to shoot in the dark without pulling or figuring out the codes, replace the oxygen sensor and coolant temperature sensor. Run a bottle and a half of Lucas through it, too.

I average 12 mpg in my 90 RC, but I have a 3.21 rear end and no front differential, driveshaft, or drive axles.

Don't expect miracles. A 1990 4x4 truck is only supposed to get 11 city and 13 highway.....brand new.
 

·
Registered
Joined
·
1,894 Posts
Was the O.D. off? But as already said, I'd go for the O2 sensor, first.
Mike
 

·
Premium Member
Joined
·
16,239 Posts
AZ_RC_LUVER said:
Was the O.D. off? But as already said, I'd go for the O2 sensor, first.
Mike
Thinking of the O2 sensor, do you have a lot of black soot at the end of your tail pipe?
 

·
Registered
Joined
·
53 Posts
Discussion Starter · #8 ·
Yeah, I've heard O2 sensor also. It does smoke a little also, black smoke. O/D was on also. Fuel filter was changed already too. I might try to get o2 sensor next. Thanks. Tim
 

·
Registered
Joined
·
5,581 Posts
if the truck is running rich, test the coolant temp sensor as well. mine went out once, causing really bad gas mileage.

Duane
 

·
Premium Member
Joined
·
16,239 Posts
CLRracer said:
if the truck is running rich, test the coolant temp sensor as well. mine went out once, causing really bad gas mileage.

Duane
I never thanked you for suggestion this to me Duane. I changed mine and it helped with the mileage......thanks! ;D
 

·
Premium Member
Joined
·
16,239 Posts
13---are you sure it's not 12, you should get a 12 (normal)---13 deals with the signal from the MAP sensor

37---normal for your truck, means there is an open or short in the torque converter part throttle unlock circuit in trucks with A-999 or A-500 trannys (you have an A-518)

51---Lean Fuel/Air condition---Oxygen sensor indicates a lean F/A ratio condition

41---Alternator field circuit---An open or shorted condition detected in the alternator control circuit.

55---normal---means there are no more codes


I had a 51 (O2 sensor signal input indicates lean F/A ratio). With that code and the fact that I had a ton of soot on my tail pipe, I figured that the truck was running too rich all the time. I changed the O2 sensor and my mileage went up and the soot never came back.
 

·
Premium Member
Joined
·
8,998 Posts
Also try some Prestone fuel injector cleaner. I had low voltage codes in on my car (indicating lean), and ran some of that thru, the codes went way, and it is running great. I ran 1 bottle per tank for 2 successive tanks, then I will use it like every 5th tank or so.
 

·
Registered
Joined
·
53 Posts
Discussion Starter · #15 ·
Well, I did pick up an O2 sensor and temp sensor, just need time to put it in and pick up antiseize. I have soot on my tailpipe also. I'm sure that is the problem. Thanks. Tim
 

·
Registered
Joined
·
97 Posts
a100: i am having the same problems you are having with the gas milage and soot out the tail pipes. let me know if the 02 sensor and CTS works. hope you get it fixed, i had to park mine and bought another truck.
 

·
Registered
Joined
·
639 Posts
if you have a vacuum leak, your map sensor will cause the computer to use more fuel. I get about 14 mpg out of mine with 35's and 4.10's, but I drive 55. If I do 65 or so, i only get like 9 or 10. I guess those governement folks were on to something when they put the speed limit at 55 to save gas. who woulda thunk it?
 

·
Registered
Joined
·
53 Posts
Discussion Starter · #19 ·
I flushed coolant and put in new temp sensor last night. Probably try to put O2 sensor in tonight. I have regular tires and 3.55 gears. Also drive from 65-75 on roads, depending where. So that probably hurts a lot. I also ran 2 bottles of injector cleaner through a couple tanks. Might try another bottle. We'll see how the new O2 sensor works. Whats the best way to check for a vacuum leak? Thanks a lot, Tim
 
1 - 20 of 21 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top