6.5 runs without fuel pump?

[73k5blazer]

A few weeks ago when I got in my '97 with 6.5td, I noticed perhaps it was a bit weak on power, and when you really got on it, like entering freeway ramp, it would cut out for a split second. I thought mabey my filter was clogged even though I change it every 10,000mi. I also noticed a lack of the noise when you first turn the key and wait to start (fuel pump), but didn't think anything of it since the truck was running.
My wife has been driving it for the last couple of weeks, without problem (she never gets on the gas), this past weekend I went to change that filter, opened the purge valve on top after installation, turned the key and nothing, no usual little spurt from there. I immediately thought of that fuel pump noise, or lack of, got underneath, disconnected the leads and connected directly to the battery, nothing. Swapped it out, and she purged normally and fired right up.
I never thought the engine could run without a fuel pump. Is there small pump in the injector pump or something, or was it just running on suction?

 

[azblazor]

I have read on TDP that there is an internal pump in the DB2 and the DS4. Although depending on the condition of the Inj pump it may or may not perform properly or even start.

 

[cegusman]

The injector pump has just enough suction to run the motor, but it is not good for it to just run without a main pump.

 

[73k5blazer]

Could I have seriously damaged anything, like the injection pump, by this forced fuel starvation? I know it was two weeks ago when I drove it and noticed it cut out getting on the e-way, so it's been at least 2 weeks running that way, put about 1100mi on it in the last 2 weeks. Engine has about 172k on it. Injection pump was swapped out under warranty at about 70k.

 

[cegusman]

I really wouldn't worry about it.