Well I am introducing myself as well as posting my first question . I am new to diesels but not to mechanic work and I have found a bunch of info lurking around here for a few days, but on to the problem! 91 F250 4x4 ( free truck customer bought it for the 7.3 engine the overdrive tranny was junk gave me the remnants) being the smart guy that I am I decide to put in a 85 model 6.9 with a C-6 tranny (oh let the fun begin) finally got everything bolted in except driveshafts (did I mention its not a straight up swap like I was led to believe) and I cant get it to start!!

It seems like I cant get the air out of the system if you crank the crap out of it it will eventually start to pump fuel to the injectors but by the time it starts to hit the batteries are going down and then it has to sit and charge and I loose all the fuel that I had built up. I have changed the fuel pump and the injector pump it acts the same way. I guess the next step is to replace all the rubber lines and O-rings? Also there is a nipple on the side of the filter housing that runs to the return lines on the injectors that will shoot a steady stream of diesel out after I quit cranking is that supposed to be a one way fitting? sorry this was so long but I am frustrated

 

It takes a time to get the injectors bled out, but you should get an attempt for the engine to start. Unless the timing is out. Look where the injection pump mounts to the tower, there is a timing mark at the drivers side about 10 o clock position. Line up the marks and give it a try. If that doesnt help, I would venture the pump was removed at one time and the drive gears are out of sinc. You did mention there is fuel coming to the injectors? Get back.

 

Yeah I am gettin an attempt to start after a while but it takes so long to get fuel to the injectors that the batteries are down by the time fuel gets there and then I am back to the starting point.

I think the problem is air keeps getting into the system and I believe the nipple on the fuel filter is supposed to be a one way deal? (could be wrong) thanks for the reply

 

If you had the fuel and then after sitting a while its gone you may have either leaky return lines or check valve in lift pump is bad. Or maybe the pump you put on isn't up to par. Where did you get it and how sure are you that it was any good? Are there any leaks under the rear of the pump.

 

No leaks from pump, there is always fuel at the top of the line from the lift pump(where it goes into the filter housing) I am thinking leaky return lines and bad check valve. thanks for the replys please keep em coming and I will post any updates

 

A little more info on my check valve theory this nipple in the side of the filter housing is supposed to be a one way valve. according to another site this nipple has a rubber line on it that runs to the injector bypass lines that eventually runs back to the tank (if I am right) if it is bleeding fuel out of the filter while its sitting waiting for the batteries to charge when I try to start it again it shoots another big shot of air to the injector pump and here we go again

Yes?No?Mabye?

 

There is no check valve. Sounds like your getting air with your fuel. You can plug the hose if you think it's your problem. Take a small ball bearing and pop it in the hose and put it back on. I guess you could just pinch the hose too.

 

Update.... it runs replaced all the injector o-rings, rubber return lines, capped off return line to the filter, burned up one starter ,cranked the crap out of it and finally she fired off!!

when the truck is hot even luke warm she will fire up like nobodys business but after it sits all night I really got to crank it to start it up. But I am going to get the timing set and replace the fuel filter housing and see if that helps.

 

Spectramac I was down at the FORD house looking at thier computer parts breakdown it showed a spring and ball bearing inside the filter housing behind the nipple I was refering to was I looking at the wrong part???

If I was please let me know I may be chasing something that isnt even there.

 

For cold starting both batteries must be in good shape,if its not cranking fast enough it will be hard starting.Most places will check them out free of charge.Also have you gone through the glo plug system to see if it is up to par? When the temps drop you should use the block heater(great save on your new starter),i have mine on a timer set to come on 3 hours before i need to start. More info on your truck would help....year, model,etc.

 

91 F250 4x4, engine is a 6.9 from an 85 F250 replaced all the glow plugs, bypassed the glow plug controller, (glow plug system is from 91 7.3) new batteries,starter. Truck sits in garage all night the first start of the day takes forever then will fire up in like a second and a half for the rest of the day. Its got to be getting air in the system overnight!!! also replaced all the rubber return lines and injector o-rings. I think I will replace the fuel filter housing and see if that helps

 

Just out of curiosity why dont you plug in the block heater for a night and see how she reacts that morning? It would eliminate your glo plugs if its still hard starting. Just a thought.

 

I like the idea of plugging the truck in for one nite. Another theroy is air getting in some were or the lift pump/ transfer pump is bad. This is the pump on the side of the engine that draws fuel from the tanks then pushes up to the injection pump thro the ffuel filter housing. One way to elimate some guess work is clamp off the return lines and the supply line at nite. Unclamp rite before you go to start in the morning. If it starts rite up probally abd pump or bad lines/connection. If it does not start rite up id check the fuel filter housing. Another source for air leak is the bleed off valve on thefuelk filter housing. looks like a tire valve stem and has threads. mine was leaking air in and did the same thing you describe. Good lcuk!

 

There is a connector that plugs in at the top of the filter assy (electrical) I am not sure what that does but I saw some fuel bubbling out of it so I think that is one of the problems but I will check that bleed valve. Thanks

 

Thay connector is the fuel heater. I am on mt 3rd diesel and have yet seen one work. If its working the top of the housing will get warm. I think it also has something to do with temp as to whether or not it comse on.If its leaking when running it will be sucking air when shut down.