Duck Hunting Forum banner
1 - 20 of 34 Posts

·
Registered
Joined
·
392 Posts
Discussion Starter · #1 ·
01 Dodge Ram 1500 318 115K. Ran good for the first 45K miles that i owned and then last year, it started running rough. Missing, backfiring, "coughing," "spitting," if those help describe. The truck is also a 5 spd and has true dual exhaust with glass packs minus converters so it is pretty darn loud and the backfiring is very violent. Anyway, I changed the plugs and back to perfect. a couple months later, it starts the same ole crap. I havent checked to see what the plugs look like but i probably will tomorrow. What could be causing the plugs to go bad if in fact that is the problem. The new plugs dont even have 10K miles on them. Thanks in advance.
 

·
Registered
Joined
·
1,103 Posts
I'm no mechanic.
That said, if it isn't a factory exhaust, you may need to change a chip, or reprogram the computer, to compensate for the loss of back pressure.
 

·
Premium Member
Joined
·
6,203 Posts
True duels suck and suck gas as well.
 

·
Registered
Joined
·
1,744 Posts
Your problem isn't the exhaust. Less backpressure is generally speaking a good thing...pretty common misconception actually. What size exhaust tubing are you running, that play a bigger factor than the type of exhaust you are running.

If your plugs are continually getting fouled obviously something isn't right. Pull a few and compare them to this:

http://www.gnttype.org/techarea/engine/plugs.html

That should give you a pretty good idea of what is going on. If you're not sure post a pic of the plug(s).
 

·
Registered
Joined
·
1,744 Posts
smackaduck said:
True duels suck and suck gas as well.
That's not true. Freer flowing exhaust increases engine efficiency so technically mileage should increase. The reason that it doesn't 99% of the time is because people can't keep their foot out of the gas with a loud exhaust.
 

·
Registered
Joined
·
1,744 Posts
That should be about the right size for that motor then. Ideal size for a single pipe on the 318 is 3" and 2 pipes at 2" diameter each only has slightly less volumetric flow.

When is the last time you had 02 sensors replaced?
 

·
Registered
Joined
·
370 Posts
Im pretty sure your exhaust is not the problem. This sounds like spark timing. If you have a distributor with a solid state ignition then I would be checking to see if it has skipped a tooth on the gear. If you have DIS ignition then I would be checking the crank and cam positioning sensors. If you have access to a Fluke 98 or a Modis then I would use that to graph the signal from the sensors and you should see a digital signal(fully on or fully off nothing in between). If it looks a little funky then it may be the reluctor ring might have a gap plugged or it might be broken or the sensor could have some crap collecting on the end of it which will cause it to give an inaccurate reading. Since those sensors are magnetic, they can pick up alot of crap.

Thats my guess!
 

·
Registered
Joined
·
1,744 Posts
KCDuckMaster said:
Im pretty sure your exhaust is not the problem. This sounds like spark timing. If you have a distributor with a solid state ignition then I would be checking to see if it has skipped a tooth on the gear. If you have DIS ignition then I would be checking the crank and cam positioning sensors. If you have access to a Fluke 98 or a Modis then I would use that to graph the signal from the sensors and you should see a digital signal(fully on or fully off nothing in between). If it looks a little funky then it may be the reluctor ring might have a gap plugged or it might be broken or the sensor could have some crap collecting on the end of it which will cause it to give an inaccurate reading. Since those sensors are magnetic, they can pick up alot of crap.

Thats my guess!
Those are 2 things I never thought of, but could very easily be the culprit. Don't most motors only have a crank or cam position sensor, but not both?
 

·
Registered
Joined
·
370 Posts
Some do have both a Crank position sensor and a Camshaft position sensor, this is especially true on newer vehicles. However your also right because some have one or the other, it just depends.
 

·
Registered
Joined
·
392 Posts
Discussion Starter · #11 ·
ajmorell
I had forgot about the O2 sensors and that might be it also.

I also for got to mention that it isnt running like this all of the time. It might run great or run really bad or sometimes inbetween. Even so much that I might accelerate and it will run rough, come to a stop at light, accelerate and it run good.
 

·
Registered
Joined
·
4,560 Posts
I'm not much on dodges. but it could it possible be a vacuum line?
 

·
Registered
Joined
·
55 Posts
This truck has both cam and crank sensors.You many whant to check the coil, if the fines are spliting apart and rusted the coil maybe bad and somtimes you can see small sparks between the fines. Also ck under the distributor cap and spark plug towers for corrosoin. If you have the cap off remove the rotor and the cam sensor to ck the metal piece they come loose sometimes. do you any way to ck fuel pressure? If you can the fuel spec 49.2 +/- 5 psi. Any more info you need on a dodge let me know I will try to help.
 

·
Registered
Joined
·
392 Posts
Discussion Starter · #14 ·
that brings up another problem, if it is the vacuum lines causing this problem (or maybe both). not knowing too awful much about vehicles i only figure this problem is the vacuum lines. back in the summer, i was movin my brother to cincy and was haulin a stock trailer full of furniture. we noticed the A/C was actin up and it has done this ever since then (even with the heat). the fan will be up and blowing but when i accelerate nothing comes out and when i decelerate or have the throttle at a constant position, it will blow out air. you still hear the fan blowing when accelerating but nothing comes out.
 

·
Registered
Joined
·
55 Posts
I think you are talking about two problem. For the a/c problem there is a ck valve in line. Try to follow the line that come out of the fire wall where the a/c line go through and follow back to the engine there should by a round piece that the line plugs into, it may be on the right side of the engine on the intake. If you can blow through both way it bad replaced it . I do n ot thinks it a vac problem.
 

·
Registered
Joined
·
370 Posts
A vacuum leak wouldn't cause a misfiring and back firing. It would only cause a high idle, poor fuel mileage, and your check engine light would come on for lean 02 sensors.

About your a/c there will never be a check valve in an A/C system because there is no need for one. Maybe sea duck is talking about the orifice tube or expansion valve (only one of the other, not both and most likely the orifice tube). When the problem occurs do you have it set to blow out the vents or the floor? Because the diverter door is probably operated off engine vacuum and the default position is to blow out the defrost so when vacuum is lost the door automatically closes and the air is blown out the defrost so maybe check your defrost vents the next time it happens.This happens when you get into the gas engine vacuum falls and when your cruising with the trailer your engine load is higher and when ever engine load increases manifold vacuum decreases. So my guess on that would be you have a diverter door vacuum solenoid that is leaking. If I were you and if that is the problem I would live with it because I can guarantee you that will not be fun, if you must have it fixed I would highly, highly recommend that you take it to a shop.
 

·
Registered
Joined
·
1,744 Posts
KCDuckMaster said:
A vacuum leak wouldn't cause a misfiring and back firing. It would only cause a high idle, poor fuel mileage, and your check engine light would come on for lean 02 sensors.

About your a/c there will never be a check valve in an A/C system because there is no need for one. Maybe sea duck is talking about the orifice tube or expansion valve (only one of the other, not both and most likely the orifice tube). When the problem occurs do you have it set to blow out the vents or the floor? Because the diverter door is probably operated off engine vacuum and the default position is to blow out the defrost so when vacuum is lost the door automatically closes and the air is blown out the defrost so maybe check your defrost vents the next time it happens.This happens when you get into the gas engine vacuum falls and when your cruising with the trailer your engine load is higher and when ever engine load increases manifold vacuum decreases. So my guess on that would be you have a diverter door vacuum solenoid that is leaking. If I were you and if that is the problem I would live with it because I can guarantee you that will not be fun, if you must have it fixed I would highly, highly recommend that you take it to a shop.
I'm not sure you're right on that check valve. I know for a fact that the defrost default due to vacuum pressure drop is common on Jeeps such as mine, and the fix to the problem is to install a check valve.....I read this straight from the TSB.
 

·
Registered
Joined
·
1,720 Posts
May be dumb but: my 03 F-150 was doing the same thing whenever it got damp/humid out. Starter coil was shorting out.
 

·
Registered
Joined
·
1,103 Posts
WOW
I'm still no mechanic, but I'm now enlightened.
It's great that we have so many guys willing to help a fellow hunter out.
Bravo to you all.
 
1 - 20 of 34 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