My 03 RAM 3500 has developed a few problems I’d like to figure out.


It has a stumble at idle. Not all the time but about every 5th or 6th time you come to a stop the idle fluctuates. Occasionally, it also stubbles when accelerating from a dead stop. I have changed the fuel filter. I have ran five tanks of ejector cleaner through it. I also noticed dark smoke coming out of the tailpipe today and it has a strong diesel smell. The truck has 162K miles on it.

Thanks

Vic

 

Verify your LP is working and see what kind of fuel pressure you have first. Have you changed fuel filter lately? Also could be the FCA on the back of the CP3 as they are notorious for causing some crazy symptoms. Try the key trick to check for any DTC's too.

 

Yes, I did change the fuel filter.

What's the LP?

What's the FCA and CP3?

Lastly, How do I preform the key trick? I was going to pay a visit to Auto Zone to have them pull my codes. Sounds like the key trick can get codes as well.

Thanks

 

LP....Lift Pump
CP3....High Pressure Pump that feeds the fuel rail
FCA...Fuel Control Actuator located on backside of CP3

The keytrick is turn key (rapidly) on/off on/off on and leave it...don't start it. Any codes should display in the odometer window.

 

Check your oil level to see if your engine is 'making oil'. This occurs when one or more injectors spray too much fuel and it washes down the cylinder walls and into your oil. Not good, as it dilutes your oil and allows that cylinder wall to get scored pretty bad in some cases.

You may have come to the end of the useful life of one or more of your injectors. If so, you can replace with all new for big $$ or send your's out to a company like F1 to test and rebuild as necessary. Contact one of F1's Distributors for more info.

 

Pulled the key code just now. P0700 Transmission Control System (MIL Request

I recently changed the Tranny fluid and filter.

 

Last night I read the fuel section of my service manual. I see it needs to be between 9 & 14 PSI at the lift pump but I cannot see where to hook up my gauge!!

Can someone tell me where the pressure gauge should be hook up at for a proper reading of lift pump pressure?

Thanks

 

I have mine where the fuel enters the CP3 using an adapter from Geno's. It isn't for a temporary setup though, it is for my gauge on the pillar. Since the pressure pickup is post filter, it will give you an indication of a plugged filter as well.

 

This won't give you any numbers but you can remove the filter from the housing and bump the starter to activate the pump....it should fill the canister relatively quick....if it takes very long at all you can bet the pump is getting weak.

Other than that, Like FMB said, the entrance to the CP3 will give you a good reading from your pump. That's how old setup was...I just used a longer banjo bolt with a banjo fitting (nipple) to attach my hose to. My current setup comes straight off the AirDog housing post filter.

 

mine was doing similar and I changed FCA and cured it. Just my experience

 

Update from my earlier post. I no longer think it is an off idle stumble as I previously stated. It is more of a surge than a stumble.

I removed the fuel filter and drained the bowl. I had someone turn the key while I observed the flow. It filled up pretty quick.

I didn’t see anything that resembled a lift pump. Perhaps my year truck did not have the lift pump. When I looked online for lift pumps I did see comments about some truck having a pump in the tank.

Any ideas?

Thanks
Vic

 

Yep, the LP is in the tank on your truck. I helped a friend of mine put an AirDog on his '07 and when we pulled the canister out of the tank we found out pretty quick why he was having low power and surging issues after driving any distance.....the pickup screen was almost completely stopped up with trash.....not a good design if you ask me. He was basically starving the engine of fuel.

 

I just ordered an FCA. We'll see what happens when it arrives.

 

The FCA fixed it. Runs like a top!

THanks for everyones input.

 

Glad to hear you got it fixed!!! Sensors can be a nightmare to track down sometimes.