Serious Loss of Power Dodge Diesel

[Duke Winch]

Looking for some help with my Dodge 6.7L
It has been dropping into Limp Mode a lot recently, even though I have a PFD and EGR delete on it, though it was still drivable.
And now it has lost so much power I cannot even drive it to work. Can barely go 40 MPH and even the slightest hill is a problem. Oddly enough on one run, I stopped and shut it down, restarted it and ran fine the rest of the way home but the next day went back to the barely 40 routine.
Looking for any and all suggestions as to what to try next. Haven't tried much of anything yet, (ITS COLD OUTSIDE!), besides re-flashing the computer with my Smarty JR and pulling the battery cables to reset the computer but to no avail.

I did drain the fuel filter believing H2O my be an issue, fuel but no water came out and didn't help. Next to try is replacing the throttle valve, which is disconnected for the PFD and may have loosened up and gone close, with a straight pipe. The weather has not let me install it yet.

So ... prior to shotgunning replacement parts, I'm looking for a more measured approach to hunting down the gremlins. I researched the internet and forums for ideas but found a hodgepodge of questionable info.
At this point I just want to get it running correctly long enough so I can sell it.

Duke

[frankstruwe]

Steve,

I've suffered engine derate issues on my GMC over several winters, and all were related to protecting the engine. The two I've had to deal with are IMAP sensor freezing and low fuel rail pressure in the high pressure side. The first is 'inlet manifold air pressure' sensor, and when that signal is detected to be 'wrong' (doesn't match other sensor readings), the engine will derate (limp home mode) to keep from getting into a situation that could result in screwing up either the air fuel ratio or the peak cylinder pressure in-cylinder. Thus protecting the engine. Similarly, the low rail pressure indication will derate to keep from damaging injectors if a large fuel demand was commanded (basically keeps end of injection from 'dry firing' at close). I believe the low rail pressure was due to fuel gelling, and it happened this year (for the first time) when we had the really cold days few weeks ago. I limped home, let the truck sit for a few hours and then it was fine (after I cleared the code).

I do know the idea of 'protecting the engine' is something we do with the yellow engines. As an engineer, I'm a fan since it minimizes broken stuff. As a consumer / customer, it pisses me off. I'd guess your derates are more about engine protection than related to emissions. And, clearly, related to the cold. Fuel or air pressure sensors or water temperature (coolant) could all be suspect.

Does your derate throw a code that you could read? Have you done that?

Not sure this helps or not. May be the same random crap you've found elsewhere.

- Frank

[Duke Winch]

Thanks for the input.

It's not throwing any codes. The overhead chimes in with "Catalyst Full Service Required". Since there is no catalyst and a programer that defeats all the associated nanny electronics I'm unclear as to what is throwing it into limp. I spent a great deal of time on the internet trying to identify what conditions trigger the alarm with no definitive luck. The general conscience was;

1. Low full pressure and to plug the rail relief valve, which was already completed.
2 Low air flow, or at least the engine believes there is low air flow. I was going to swap out the MFS but haven't done that yet.
3. The ECM hasn't experienced a regen for so long it decides there's a problem and drops into limp mode. There may be a kernel of truth to this one as the alarms I use to receive prior to the PFD would read " "Catalyst XX% Full Service Required" where XX= 70, 80, etc. If this is the case I may be f**ked as I have no way of clearing the alarm.
4. Fuel filter, which may make sense as it's been cold and there may be some jelling. Plan to replace it as well.

Once it warms up will start one item at a time.

Duke

[Matt Brown]

Steve, what software do you have loaded into the smarty jr? Any chance that you updated with the US software and not the ME software? When you plug the smarty in and it shows the file name what is it?

[Duke Winch]

Steve, what software do you have loaded into the smarty jr? Any chance that you updated with the US software and not the ME software? When you plug the smarty in and it shows the file name what is it?

I'll have to hook it up to look, but the Smarty JR I have is the ME (Middle East) version. I have tried the Standard, Economy, and Towing programs all with the same results. Could take it back to stock program and then re-install one of the others and see if that would clear it.

By the way where do I find the replaceable fuel filter gizmo?

[vlucdog]

How long has it been since you replaced the fuel filter. I ask because your asking where it's at, or is there more than 1 fuel filter.

On my 6.7 the filter is on the drivers side of the block, between the air horn to the intake and the back of the engine. It's almost as low as the frame rail.

[vlucdog]

A friend of mine drives a service truck for Altorfer (Cat engines) when asked about the problems he sees in the field , the answer is "I replace a lot of sensors"

[Matt Brown]

I'll have to hook it up to look, but the Smarty JR I have is the ME (Middle East) version. I have tried the Standard, Economy, and Towing programs all with the same results. Could take it back to stock program and then re-install one of the others and see if that would clear it.

By the way where do I find the replaceable fuel filter gizmo?

Um... I got mine in late 2009 when I was changing it for the 3rd time. So if you filter has been changed since then it should be the new style housing with the replaceable filter. I get Napa Gold to put in mine, they are the good Wix filters. When you do change it, it has a 1/2" square drive on the bottom of the filter housing. Best I have found is a 1/2" x 3/8" adapter then a 3/8" swivel, then enough extension to get down far enough for a ratchet. You do not want to use a filter wrench on it as you will crack the housing.

[vlucdog]

Well my bad. I reread the first post , aparently the gizmo is something I don't know squat about. So sorry about the filter location.

I am courious when the last time the filter was changed. And, how long the same fuel has been in the tank? Is it possible alge has grown in the tank? This could plug the filter possibly quicker than normal. You might want to cut the old filter apart and have a look.

[Duke Winch]

The program is correct.

[W_A_Watson_II]

Duke,

I don't remember what year your truck is, but if the display is still reading that the "Catalyst Full Service Required" the truck has either had the custom DPF Delete tune corrupted, or it's been lost from the trucks memory for some reason. You might have to restore the factory tune then re-flash it with the custom tune to clear this issue if this is the case.

[matt4wheels]

I would start with the fuel filter. Several winters back when still living in Peoria I was forced to change mine out at Thortons there off of 116 as my power went to crap and to the point of "I need to get this off the road". The temp was -15F or so. Popped the new filter in which I happened to have with me and it was good as new. Would be an even more likely scenario if it's been a while since you've changed it. No codes were thrown but from startup to filter change that morning was probably only 30 minutes of run time.

[Duke Winch]

I tried to get the filter off but was afraid I was going to bust it in the process. Now the weather is improving I'll go after it again this week.

[Matt Brown]

I get Napa Gold to put in mine, they are the good Wix filters. When you do change it, it has a 1/2" square drive on the bottom of the filter housing. Best I have found is a 1/2" x 3/8" adapter then a 3/8" swivel, then enough extension to get down far enough for a ratchet. You do not want to use a filter wrench on it as you will crack the housing.

Follow this, just be sure to unplug the water sensor before you start spinning it. Before you spin it loose, drain it. When you think you have drained enough out to not spill any, drain it some more.

[Matt Brown]

OK, I may be way out in left field here, but I had a thought about this... I know scary isn't it. When you drop the DFP and the Cat, you put the o2 sensor back into the pipe and leave the other two pressure sensors hanging in open air correct? My guess is that the sensors that measure the pressure difference across what was the DPF have something up with them. That should be the only way that the DPF will show full.

[Duke Winch]

Got the truck running! The fuel filter collapsed. I haven't driven it enough to determine if the cat full issue has also been resolved. With the nicer weather I'll get it out on the road and check it out. Didn't want to get stuck in BFE with the sever cold.

Thanks to all for the ideas.

Duke

[vlucdog]

So are you still selling it?

[Duke Winch]

So are you still selling it?

Yes ... Getting it to the detailers tonight to get it shined up. Asking 25900 OBO

[matt4wheels]

How many miles out of curiosity.

[Duke Winch]

16500 miles driven by a little old lady only to and from church on Sundays.

[CLBJeep]

Injector Time!!!

[Fraser]

times 10