ClassA4x4

At the last leg of my recent 2500-mile Baja adventure trip, my fuel pressure reading dropped to zero. Not knowing what the problem was and since the engine ran just fine, I continued driving home for maybe a few hundred difficult miles. After I replaced the fuel filter when I got home I tried to prime the fuel system using the lift pump's manual lever. The lever has no resistance and wouldn't prime. The lift pump is obviously toast, it amazes me that the engine continues to run with no noticeable difference. Maybe it helped that the fuel tank is right next to the transmission.

Nevertheless I went ahead and started the engine, on an empty fuel filter (I know I should have filled the filter with fuel, but I didnt). It started immediately then died after it used up the fuel in the pump/lines. I then tried to start it again but it wouldn't start. I then tried for the 3rd time, this time cranking it for over 5 seconds, it started rough but ran smooth after a few seconds.

Back to my question: How bad did I hurt my injection pump by running it with a dead lift pump for a few hundred difficult miles AND starting the engine unprimed the way i did?

jimbo486

You might be ok if you weren't heavy on the throttle at all after noticing no fuel pressure. Our IP's have a vane type pump themselves and have the ability to draw fuel on their own. However, if heavy throttle is applied, the demand for more fuel is needed. Thus, the vane pump can't supply the IP with enough fuel. That being said, if you were at a cruising speed and not accelerating heavily, it probably survived. There's nothing wrong with not filling the fuel filter. It only means it'll take longer to bleed the air from the system. The rough idle you got after changing the fuel filter was just air in the lines. The injectors eventually bled themselves and the idle smoothed out then.

ClassA4x4

By difficult miles, I mean real heavy on the throttle climbing the steep grades of Baja and the I-8, many times over 25 psi of boost, over 2500rpm and over 1100 EGTs. Do you think i hurt my IP bad? It runs as if it's normal. The only thing I notice is at cold starting - it has a lower-than-normal idle for one second then it climbs up to the normal 750 rpm. Maybe it helped that my fuel screw is turned past the collar.

ChrisLib

Volkswagen spec VE pumps don`t even use a lift pump so there is a good chance you`ll be fine...it aint no VP44 thats for sure.

rebal

you will be fine no harm I have seen trucks come in that no body knows how long the pump, was out a year or more, and there still running fine.

sshort

I ran mine for aprox six months pulling my 15k toy trailer before i found out the new pump i installed was broken inside Have had no trouble from IP

ClassA4x4

That's good to know. Thanks.

ClassA4x4

Thanks for all the comforting words guys.

dzl_damon

You're good to go. My boss's Volkswagens VE pump has no lift pump. It has over 300k on it.

ClassA4x4

Solved!

Since I have no intentions of using larger injectors or upgrading turbos at this time, I replaced the lift pump with a Delphi diapragm (stock) pump, rather than going piston lift pump as others have suggested. The fuel pressure before the lift pump is restored to the normal 5-8 psi as before.