Ran fine until it went to the dealer. They replaced the stock breather bottle with the setup that hangs off the back by the diff. so is it possible that in doing this they caused a vacuum leak. The lift pump was replaced as well. I just put a full tank in it to double check the mileage, but I got 350 miles on this tank of fuel, and with a 6spd HO, it seems to be sluggish in terms of how it drives. Is there something wrong with the turbo? the map sensor? a vacuum leak? I am new to these cummins so any advice would be helpful. I am going to get gauges A.S.A.P but until then I would like to figure out what is wrong. I don't think it is anything major, but something is def. stunting the power and killing the fuel mileage. Oh and filling my tank up from the empty light, it only held 23 gallons. I thought these things had 30gallon fuel tanks?

 

The warning light comes on when you get to an 1/8 of a tank so you've still got some fuel left in it. I've put 30 gallons in my truck before and I was sitting on the red line. Your tank should be a 34 gallon tank. Try cleaning your MAP and IAT sensor and see if that helps. If not, try changing your fuel filter.

 

sluggish? Are there any codes?

 

Better check that lift pump! My fuel economy went seriously south when the lift pump did.

 

Yes, There is a chime on the fuel guage at the 1/8 mark. I've been there a few times not much though. Less fuel in the tank the less coolant for the IP pump.

It not good to run the tank low on fuel. The fuel is a coolant for your (IP) Injection Pump named (VP44). The lift pump needs to pump at least 8 PSI at WOT. This is the amount of extra fuel used to cool the VP44.

Fuel pressure is very important on these trucks. It is life or death to the VP44!

As for the IAT sensor you need a 13/16 socket and a 6" extension to get it out. It is on the back of the engine on the intake side (of course). The MAP sensor is the larger of the two and just foreward of the IAT sensor.

Most here recommend using contact cleaner but carb. spray will do in a pinch...(Just don't make a habit of it!)

 

I checked the codes on BArams truck and there was none. I drove it and it did seem sluggish
I didnt know you could clean the map so we didnt mess with it. Im thinking the dealer screwed up the pump timing or caused a vacuum leak when they changed the breather route.
I never saw the breather bottle update that they did to BAs truck before but i will leave mine the way it is. From what BA said they did to make the update the intake was removed and injector pump.So im thinking they didnt put something back on right. I wish i would have known about the sensors we could have cleaned them. BA get them gauges and give me a call
If you dont haul it back to the dealer have your brother clean the sensors its the one i showed you on the back behind the fuel filter ,not sure where the other one is.


Jeff

 

This is another reason I did want to upgrade to the DC breather bottle kit... I wasn't to keen to the idea of having my VP44 messed with.

I hope you can find the cure to it...

As for the MAP it is a 3 wire sensor just before the IAT sensor which is a 2 wire sensor. You can see the MAP sensor easy compared to the IAT which is buried under the manifold.

I tend to rather do my own work on my vehicles. If I screw up it my fault and I got to fix it...

 

Moparman ,that is why my truck has a pvc tube running down the front . Works great. Ba didnt know he was going to have this problem or im sure he would have had them leave it alone.

 

Mine runs over the back... Of the engine to keep oil spillage to a minimum...Check sig for link.

Someone listed the TSB (???) and I was reading that they pull the VP44, and a few other parts to make the mod work. There were several people that are against the DC version because of the VP44 has to be remove to do the mod.

The Cummins mod is expensive but it looks like it might work well...

Once again I hope he can find the problem for being sluggish...

 

Yea I hope I can find the problem as well. Like TexasTurbo said he checked for codes with no luck. We put seafoam in the fuel filter housing and some kinda of fuel additive on a fuel tank. I haven't had a chance to get out and run it though. It will be interesting to see the mileage. If this doesn't work I am going to have my bro pull the MAP and AIT and clean them. The dealership who pulled that VP to do that breather mod wasn't worth a crap so I wouldn't doubt if they fubared it. What could they have done to the VP to cause it to be sluggish? How can I fix it? Anyone every heard of a plunger in the VP sticking?