Have to pump the throttle to start it?

[Pipeliner_86]

My old 86 had this problem, kinda. After I installed an electric pump, the air leak problem was "cured". By my truck always puffed white until it warmend up, a leaky valve seat or something of that nature. It would run on 7 cylinders untill it warmed up, and then all 8 would start popping.

 

[Agnem]

There is no carburator dash pot, so "pumping" the IP is only making your brain feel better. There would be less wear and tear if you were to just hold it to the floor.

 

[seawalkersee]

Not true. When I stopped pumping it, it would sound just like it was spinning (no ignition) and then I started pumping it again and it would sound like it was hitting on some of the cyls. Maybe it is coincidences(sp) and today will tell.

Where is the o-ring leaking from on the 7.3?

SWS

 

[Agnem]

It would be illogical if that were to work. All your foot does is turn a the metering valve, which doesn't "squirt" anything. As long as their is fuel presure and the cold advance is working, it's not tweaking the timing any either.

 

[Dsl_Dog_Treat]

Yup, just mash the go pedal to the floor and crank it till she fires.

 

[subway]

Where is the o-ring leaking from on the 7.3?

SWS

either the top or bottom of the filter, mine was actaully the top and not the bottom o-ring.

 

[FORDMAN41291]

what is a filter head valve are you talking about that return valve?

 

[subway]

there is a shrader (car tire valve) on the filter head at the engine. this is where you can blead the air out of the filter when you change it or have air intrusion problems.

 

[FORDMAN41291]

oh yeah thata one, so why we are talking about timed injection and what not, how do you time the injection pump?

 

[david85]

Not true. When I stopped pumping it, it would sound just like it was spinning (no ignition) and then I started pumping it again and it would sound like it was hitting on some of the cyls. Maybe it is coincidences(sp) and today will tell.

Where is the o-ring leaking from on the 7.3?

SWS

I noticed that with mine a long time ago too (before new injectors and a whole mess of other fine tuning). All the way to the floor wouldn't quite start it, released all the way was no good either, but by feeling the ideal position it would fire. By pumping you are probably finding that spot for long enough that it catches.

What I usually did was floor it until it would start to catch then gradually back off until the throttle position was right.

Maybe its a timing thing. Some of the timing is controlled by mechanical throttle position, right?

 

[FORDMAN41291]

I don't know about throttle position.....

 

[91f2504x4]

I don't know about throttle position.....

Seems like a pointless post?

 

[FORDMAN41291]

I put that than I forgot what I was gonna put after that

 

[seawalkersee]

Okay, so here is my update. I found a leak. It was in the return line on the second injector on the pass side. I swapped the o-rings from the previous set of injectors and the leak stopped. Now, I have another question. When I crank it, why am I supposed to put the pedal to the floor if there is not a dashpot per se? Also, it seems to hunt for idle as it has since I have had it running. If it does not use the pump screw while it is at idle normally, does it use this when the enrichment selonoid is activated?

SWS

 

[subway]

you only need to put it to the floor if you are trying to purge air out. you want to do this because although there is not a dashpot the injection pump is putting out the most fuel with it floored. the more fuel it puts out the faster the lines can purge the air.

not sure about idle, how long have you run it. might still be purging a little air out.