Engine/Transmission (1998.5 - 2002) Low voltage V44 pump damage

[bmwcushman]

Last night 50 miles from home lost alternator. I kept driving, when voltage about 10 I shut lights off most of the time(full moon). buncha lights and dinging at the panel warning of bad stuff going on. I kept them off after flipping them on to meet a car and evidently the pump cranks tons of advance when voltage is about gone--clattterrrr!! Question--Can you damage a V44 pump if you run out of fuel? If something like this happens again, can you keep driving till it quits? Was my lift pump still pumping toward the end? Can something like this mess up the computer?

Lotsa engine noise coming through the throttle-stops with cruise engagement. Have looked for discussion about this but no can find so must not be common-driving me nuts!

Anyone know where I can find a good deal on trading my 4. 1posi Dana 80

rear for 3. 54? Buy gears?

My signature is incorrect now-Just got a '99 quad 3500 5-sp 183000 mi. Now the old 12v will just tear this new wimp up- have 4" exhaust, 275 inj, EZ Comp, pyro, boost, fuel press gauges ready for installation.

 

[tgee]

Considering the problems with the VP44, I'm suprised someone hasn't replyed Seems the VP44 doesnt like low fuel pressure, for it needs it to feed high psi to the injectors, also needs good flow to lubricate itself. I think the lift pump is pulsewidth controlled, not a steady voltage. If the voltage drops to the Cummins computer, the computer will shut down when voltage goes below a certian level, typically 9. 5 volts. A long way to say I dont think you hurt anything.

 

[Bob Wagner]

tgee nice to see you post I would agree

 

[bmwcushman]

I musta been close to 9. 5 as it lurched a couple times driving in the lane. . The green odometer was dead-wonder if the miles were adding up anyway... .

 

[tgee]

Good to hear you made it. One thing I've learned about 24 valve engines (electronic controlled fuel injection) is it is worth it to invest in a fuel pressure gauge. My old 96 12 valve Dodge, 100,000 miles on it, never any problems except the paint fading. Had to get an extended cab, the family version! Electronic stuff is great, just got to understand it.

 

[SnoKing]

I just installed a in cab fuel gauge and have noticed that the grid heaters will cause the fuel pressure to drop a few lbs when they are on. Probably not the best idea to keep driving when the voltage is taking a swan dive. SNOKING

 

[RACE427]

Computers

The ECMs are designed to shut down when system voltage drops to approximately 9 volts. They shut down to protect themselves from self destruction. I see this all the time on gasoline vehicles and they suffer no real damage from it. The ECM or PCM as they are called on today's cars will always protect the engine and not cause any mechanical damage. The manufacturer has also designed the PCM ro not leave the customer stranded if a sensor should fail. In fact the PCM will substitute a good known sensor value for a sensor that has gone bad, just to keep the engine running well and avoid causing the customer to get stuck with a car that will not run. Hope this helps.

 

[claykelly]

Only thing I'd be concerned about is the electrical system failing, engine dying, and then "coasting" the engine to a stop. With no power the lift pump is not running, no fuel is being supplied to the inj. pump, and the inj. pump is still spinning w/ no fuel being supplied to it for cooling or lubrication.

 

[2-ND TIME]

voltages on vp/44

If you are wanting to change your gearing and if ??????? maybe try changing tire ratio's. I went to 235's from 215's and yes it is still gutless with the 215's on. but no real change of power. These are 4. 78% larger.



Still looking for someone to explain the sign waves to the VP/44 for this has to explain the lack of performance!!!!!!!! :{ :{

 

[tgee]

Very good point!