Nothin' But Air

rholl77 · 04-08-2010, 08:30 PM

I changed my fuel filter, filled the filter with fuel, and when I bleed it I only get air. Does this mean my lift pump is shot? I should also say that I did crank on the engine before I filled the filter. I took the filter back off , filled it up and tryed again but nothin'. Any help would be awesome, Thanks. I should also mention that this is on a 1995 4x4 not on the truck in my sig.

ykdave · 04-08-2010, 09:13 PM

highly doubt it. it takes a LONG time to refill the lines and filter!

The lift pump is actually 2 seperate pumps (one cam driven and the other is the hand primer), its very unlikely that both would fail at once.

rholl77 · 04-09-2010, 07:59 AM

Thanks YK. I'll keep plugging away at 'er!

WUTNOIZE · 04-09-2010, 10:44 AM

a quick check for leaks is if u have a spare fuel cap drill and tap it for a 1/4 pipe fitting and them pump the tank with 3psi and no more then 5 psi or u will waste ur tank and that will pressureize your system and if there is a leak u will find it ,, not to mention u could bleed your system with that method

rholl77 · 04-09-2010, 11:06 AM

ok, so I have fuel at the inlet banjo bolt on the side of the ip. When I crank the engine, the fuel pulses out of the fitting. I tightened the fitting back up and loosened all the outlet injector lines but have no fuel there. What could that be? The fuel shutoff solenoid seems to be working properly. I hope the ip isn't shot!!

illflem · 04-09-2010, 11:26 AM

If you crank the engine with air in the filter (not bled well) often the injection pump gets airlocked.
Usually if you crack open the lines at the first three injectors and crank it over till air free fuel shows up, tighten the lines back down and it will start.

rholl77 · 04-09-2010, 12:08 PM

How long should I expect to crank? Starter is newly rebuilt.

WUTNOIZE · 04-09-2010, 12:13 PM

its not like a gasser no ore then 5 second crancks and even less then that or your starter wont be new...hold the pedal to the floor until it fires and slowly come up to mid pedal as the motor smooths out

illflem · 04-09-2010, 12:14 PM

It shouldn't have to crank more than 30 seconds.
I keep the throttle floored while cranking and keep it floored till it starts running well.
It will run poorly the first few seconds after it starts firing but will pull out of it.

Grok · 04-10-2010, 04:06 AM

Loosen the banjo bold on the motor side of the IP. Don't take the bold all the way out there is a spring you don't want to chase down in there. get the fuel flowing out of that then crank it down. crack the first 3 injectors at the pump, get fuel there then tighten them and crack them at the injectors. Get fuel there, tighten them down and you should get some good noise shortly. Keep your batteries topped off through the process.

I had a really hard time getting prime. I had to put a cup of fuel on the head and run a hose from the jar to the inlet on the fuel pump to get started.

Good luck your almost there.

cordellh · 04-10-2010, 11:28 PM

There's a spring in that banjo bolt? i just did a plate and afc slide and pulled that line and bolt out - I did not see any spring. Is this the case for all P7100 pumps? Did it fall into pump?

Grok · 04-11-2010, 02:17 PM

Umm,

The line closest to the fender, from the fuel supply, fuel pump to filter to IP is not what I am talking about.

The line out of the IP that tees with the return line from the injectors and makes it's way back to the tank is your return line. This is on the motor side of the IP, a P-pump. The IP regulates its fuel pressure with a 25# spring on its return outlet. If that is missing you won't build pressure inside your IP. This will make it **very** hard to start your truck.

If we are talking about the same banjo bolt and you didn't see a spring then maybe its still in there or maybe its wedged between the IP and motor where you can't see it. If you go looking for the spring by taking that banjo bolt off again be careful and wedge a rag under it between the IP and motor. There is also a round disk or ball at the bottom of the outlet (I don't know with I never saw it).

I don't want to get you off track, I just want to see fuel come out the IP then see it out the injectors lines at the IP then out the lines at the injectors. 'Cause if your having problems take each step carefully.