01 falls on face during acceleration

[tcwhitejr]

01 duramax sometimes seems to fall on its face when accelerating, usually when getting on the freeway or going over 60mph, it used to cutout when it would do it and the check engine light would come on then it won't go over 2000rpm?
Even if it is in park and you rev the engine it won't go over 2000rpm.
It is throwing a P0101 and a P0093, any suggestions?
I did replace the fuel filter a couple months ago and problem went away for a while.

[01 D_Max]

P0093 is a "fuel leak large" code. It triggers the DTC light, and sets the truck into "limp mode." Your fuel pump (CP3 pump) is not keeping up with the fuel required at the time. Some people have tried numerous things to fix it. The only thing I have seen "FIX" it perminently is replacing the CP3 pump.

The pump is old and weakening. When it needs to pump the high pressures commanded for that long of a time it just can't anymore. If you have a scanner that can read Rail Pressure, compare the Command vs Actual when this usually occurs.

[Bear9350]

Replace the fuel filter and cut this one open to see what it looks like inside. Where do you fuel up? It could be that you are getting bad fuel plugging your filter up.

[tcwhitejr]

Is it a mechanical or electrical fuel pump?

[01 D_Max]

Its gear driven. There is no pump in the tank. The pump is in the valley of the motor. It sucks the fuel from the tank by vaccume, and then pressurises it up to 23,000 psi to the injectors.

[tcwhitejr]

Thank you I will change it out and see.

[01 D_Max]

It's not cheap... But a new one should come with a new Fuel Pressure Regulator. And you can find a LB7 CP3 for $650, so dont pay the 800 bucks alot of websites are asking for.

[01 D_Max]

By the way P0101 is a dirty MAF sensor. Or dirty filter effecting the MAF sensor. Clean/change the filter and then clean the MAF sensor with MAF cleaner found at the local parts store. If you have a oiled filter the oil could be covering the sensor, and it may take a few cleanings.

[Bear9350]

Originally Posted by 01 D_Max

P0093 is a "fuel leak large" code. It triggers the DTC light, and sets the truck into "limp mode." Your fuel pump (CP3 pump) is not keeping up with the fuel required at the time. Some people have tried numerous things to fix it. The only thing I have seen "FIX" it perminently is replacing the CP3 pump.

The pump is old and weakening. When it needs to pump the high pressures commanded for that long of a time it just can't anymore. If you have a scanner that can read Rail Pressure, compare the Command vs Actual when this usually occurs.

Is it possible he has a dirty or gelled fuel filter? I had the same symptoms and the same code thrown when I first bought my truck. Clean fuel and a new fuel filter fixed it.

[01 D_Max]

Yes... And honestly I would start there too, but you already said it, so I didnt see the need to repeat you. It wouldnt hurt to inspect the quality of the fuel.

The fact that He has changed the filter and it helped for a short time, is another reason to inspect it now.

If he looks into the fuel quality, and does the rail pressure test before He buys a new one He will know if the CP3 is weak. It will climb in PSI then max out and drop, or never get above say 18k psi when it needs to be 21k psi.


But in the end, Im sure it's His CP3.