Aerated fuel, Ingection pump, waste gate, codes P1214 P1656

[ewilliams]

My Truck:
1996 Chevy 3500 HD, 6.5 turbo diesel, manual trans

Some history:
For the last 2-3 years, lots of black smoke exits the tailpipe when I’m over approx 1/3 into the throttle. The amount of smoke is consistent and doesn’t change if im at half or full throttle.
For a long time the power hasn’t been all that it should be but, it has been running smooth, I’m not really into the throttle more than 1/3 anyway, and it gets about 17 mpg in the city so I have just lived with the black smoke and little power.

Here is my recent issue:
Last week the truck started bucking (did this three times) accelerating from a stop, while in second gear approx 1/3 throttle. The first two times I just babied it… the third time I put the pedal to the floor until it stopped (all 3 times, probably lasted for 4 to 5 seconds or so). An amazing thing happened after the 3rd time, It stopped smoking! There was a difference though… I noticed that even if I put my foot to the floor and there is no smoke and it seemed like it was governed… you know it just wouldn’t rev up over about low 1,000’s RPM. So I drove it that way for the next 2 days. During that time, it stalled a few times at inconsistent intervals similar to issues with and I assumed it must be the PMD, even though it’s relatively new as stated above. Eventually it stalled for the last time and I had to be towed to the mechanic shop.

My mechanic said:
1. Fuel gauge very low, fuel was aerated, need to put fuel in tank, need to prime system. (My fuel gauge doesn’t work and is on E all the time… actually, the tank is about ¾ full)
2. Found error codes P1214 and P1656.
3. He said needs new injection pump and waste gate solenoid.

Any advise/suggestions would be greatly appreciated as I’m trying to wrap my head around this issue before moving forward with installing a new injection pump. Something tells me that most mechanics may jump to conclusion regarding the injection pump because of the known issues. I’m concerned that if I move forward with replacing the pump without identifying the cause of Aerated fuel and Possibility of PMD issue, I may set the stage for another pump failure.

 

[3500GMC]

First thoughts it's starving for fuel. I would suspect a Lift Pump or associated wiring/relay/switch to be the problem. Your lift pump is located inside the driver side frame rail about in the area of the driver seat. It should 'rattle' or pulse rapidly when working. You can jumper it with 12 volts engine off to confirm if it works or not. Observe polarity.

Most likely your Injection pump is fine. (there is a difference between lift & injection pumps, totally different parts)

 

[ak diesel driver]

just because the LP rattles doesn't mean it's putting out fuel. check fuel flow at the drain T. if the LP has been dead for awhile it could have taken out the IP, definetly check the cheap stuff first tho

 

[NVW]

x2 on the above, your low power and smoking is a boost issue. Check for vacuum at the vac pump and before and after the waste gate sol. Check the vac lines for leaks.

 

[WarWagon]

Aerated fuel isn't going to work with a old or brand new IP. You can't compress fuel, but, you can compress air.

If this was my truck I would drop the tank. Then remove and throw away the tank sock. Check the pickup assy for pinhole leaks. Then replace the INOP fuel sender with the new design one from Leroy Diesel. Then I would replace the lift pump with a Walbro, also from Leroy, that has a easy to get to screen in it. I would also pull and inspect the fuel filter. P1214 is timing offset code and can be caused by air in fuel as air would case retard of timing before it compresses enough to move fuel. FIX AIR FIRST!!! Then worry about expensive parts. (Quite frankly find another mechanic that knows diesel engines or at least what air in fuel does to em!)

Then we move on to the black smoke that is covered above. P1656 is waste gate solenoid fault. Myself I would throw away the vac pump and factory turbo and add a tune with a larger non-wastegate turbo.