Fluctuating Idle - Page 3

mtford · #31 (**permalink**) 07-10-2007, 12:41 AM

I have a similar sounding prob. but mine only does this hot. Idles a little high (900-950) and shakes like missing some cylinders. Also touchy throttle and blows soot/smoke much easier with less throttle. Pulled two codes 1211 and 0603. Ok cold. Oil changed 1000 miles ago running rotella synthectic. New napa 6637 filter 1500 miles ago. Just changed fuel filter and add some fuel additive two days 150 miles ago.

Loadre · #32 (**permalink**) 11-17-2007, 06:37 PM

Just changed the oil with Delo (which I had been using) and a new fuel filter yesterday. It sat overnight and was about 40* this morning, romped when I started it for the first time and I pressed the peddle and it went away. Went to work and came out 7 hours later and it did it again. Only thing I did different yesterday was actually drained the fuel bowl before removing the filter, I usually just let it spill out.

mtford · #33 (**permalink**) 11-18-2007, 12:35 AM

My rough running problem became a constant. Took it into a local diesel shop that said they thought o-rings but that it was rare at 55k. Then changed their tune and said oil press reg. for injection and replaced it which got the press. from 400-1200 psi to 500-1200 psi. Then said that the DME (main engine computer) which i believe is driver side fire wall area was bad. DME fixed it and its been ok for last 5k.

mastertech2002 · #34 (**permalink**) 05-10-2008, 06:32 AM

hello all ive come across the morning romp romp myself on a few of my ambulances 7.3 auto trans and found fuel leaks to be the cause...
Hear me out... IF the locks have been removed from the fuel lines they will start pumping back and forth on the hard line to the frame. This over time will collect dirt. and the dirt will eat the Orings in the fuel lines like sand paper..
sucking air into the system... Also you might wanna check your lift pump...
you can use a small mirror to look at the underside of the pump ...and as your humped over your engine place the mirror down into the valley and look up underneath the pump it has 2 small holes that start to leak ...if the pump fails
the upperhole will leak fuel the lower oil...

if it leak romp romp romp

Kwikkordead · #35 (**permalink**) 05-10-2008, 07:24 AM

Welcome to FTE Mastertech2002.
It sounds like you are talking about the older style engine in the 94.5-97 body style with the mechanical pump in the valley of the engine.
The 99-03's have a Bosch pump on the frame rail and your fuel connector o-ring theory would be a good one for that one too. Those quick connects will let a LOT of air into the system.

dief_167 · #36 (**permalink**) 11-19-2008, 01:41 PM

I my self are having that same idle problem with my 7.3. but i have also done my first oil change but i put a gal. or lucas could this cause the problem with the ruff idle.

bearman113 · #37 (**permalink**) 04-19-2009, 08:47 AM

Mine does it every time I start it until it warms up. Oil change every 3000, sensors replaced in December. Any other ideas will be helpful

megawatt00 · #38 (**permalink**) 04-19-2009, 08:55 AM

Quote:

Originally Posted by dief_167

I my self are having that same idle problem with my 7.3. but i have also done my first oil change but i put a gal. or lucas could this cause the problem with the ruff idle.

Quote:

Originally Posted by bearman113

Mine does it every time I start it until it warms up. Oil change every 3000, sensors replaced in December. Any other ideas will be helpful

The easiest cure for the romps is to use syn oil and not dino. When I was using Rotello Dino in my truck I would get the romps when it was cold in the morning. I switched over to Rotella Syn and the romps went away. The truck runs much quiter now also. Do not add any additives to the oil what so ever. I would drain that oil out as quickly as possible. Our trucks run on high pressuer oil to fire the injectors and adding additives is not good. Lucas actually foams up Take a look at this
What about Additives?

bearman113 · #39 (**permalink**) 04-19-2009, 08:58 AM

Thanks Jim, The only adds I put in her are in the fuel system over 200000 miles and not sure the injectors have been replaced. Those will probably be the next thing done.

megawatt00 · #40 (**permalink**) 04-19-2009, 09:16 AM

Your welcome Eric. The other poster had put the Lucas in. Try running Syn and see if that helps it out. If I used the block heater I wouldn't have the romps with dino either. But where your in the North Pole a combination of the block heater on a timer and Syn oil will help you out.

bearman113 · #41 (**permalink**) 04-19-2009, 10:10 AM

Don't use a timer, plug it in and leave it, never know when you have to go somewhere. Have been running synth also didn't start the romp romp till about a week ago.

megawatt00 · #42 (**permalink**) 04-19-2009, 10:20 AM

Here I use the timer the electric rates are some of the highest around! Make sure that your block heater is working also.They rarely fail but the cords on them do.

bearman113 · #43 (**permalink**) 04-19-2009, 10:22 AM

Check the cords in the fall b4 snow flies and several times during the winter. Just a little worried as the romp romp is a new thing for my truck