Help Needed changed glow plugs now rough idle at startup

[AKTIVE1]

hello i just replaced my glow plugs 5 out of 8 were bad. was not to hard of a job. i also drained fuel filter assembly pit/c@@k in case there was water but forgot to purge the system before starting. my question is did i cause air to get into the fuel system and that is why the truck barley idles at startup unless i touch the gas slightly then it sounds a little better but still not right. it ran perfect brfore i changed the glow plugs, just hard starting. i hope i did not cause a bigger problem by not purging it first. it sounds like its only running on 3 cylinders at start up. any help or info would be great, thanks and happy new year!

 

[DaveBen]

Drive it hard. Get on it and the air will come put in half a tank full. You NEVER want to introduce air into the injection system on any diesel.

Dave

 

[JLDickmon]

Dave is correct..
take it out and drive it like you stole it.
7.3's use a return-less system, so any air stays trapped..

 

[AKTIVE1]

thanks i was hoping it was a simple fix, i'll be trying it later today , have to plow snow with it, while im at it, i want to change the oil in hpop pump, the video on you-tube says to do a qt at a time why wouldn't you get as much out as possible each time? does it only hold 1 qt? now for the mystery question, when i was all finished with the glow plugs change, i noticed a 2-pole plug laying in the valley with a clip lock like the injectors have. i looked to see where it hooks up and couln't find a spot it. is this a scan plug? or am i not looking close enough. thanks for the help. we just had a new baby dec 23 and i'm about as stressed as one could be!

 

[iracemine]

I ust made a thread about the hpop oil change the the whole comunity here seems to think its BS. dont wast your time.

 

[AKTIVE1]

WELL, i'm at the shop now and the problem is getting worse, now it wont start at all. and if it does it will not stay running.

 

[Tail_Gunner]

Are you getting good fuel pressure? You can check by opening the fuel bowl drain and turning the key on & checking for fuel coming out the drain under pressure vs just gravity flow.

If not, how much fuel is in the tank? less than 1/4 maybe???

 

[AKTIVE1]

i added 5 gallons more just in case, it was reading a little less than a qtr before i added the 5 gallons. i will try opening the drain in the morning to see if its pushing fuel or not....but..i did notice that when its pressurizing the injector system the fuel pump under the drivers side floor is now making a girgling sound after about 10 seconds and i do not remember it running as long before. i counted after turning the key and it ran about 15 seconds then made the girgling sound. when i try to start the truck now, it runs for about 15 seconds then shuts off, and runs terrible. start it again and same thing but does not run as long. the third try in the series, its starts for a second then thats it. if i wait a few minutes it will repeat the same cycle. i wonder if the fuel pump is going under the drives floor, is this common?

 

[Tail_Gunner]

i wonder if the fuel pump is going under the drives floor, is this common?

I think they all do sooner or later.

I had proof mine was going bad after installing an in-cab fuel pressure gauge. My fuel pressure was fine at idle. But when towing a trailer, my pressure would drop off some, maybe 15 to 20 psi. When I floored it, the fuel pressure would drop off down to about 15 psi.

One problem with the stock fuel system is there is no filter upstream of the fuel pump. There is only a screen in the pickup snout inside the tank. So anything small enough to get thru the screen will get to the pump. The whole pickup assembly have been a bundle of headaches for a lot of people. The biggest one being sucking air instead of fuel when the level in the tank gets low enough. (Hence my previous question about having less than 1/4 tank) The fix for that has been the ever famous "Hutch in Augusta" mod.

When I replaced my fuel pump (they ain't cheap), I also added a fuel filter/water separator for pump protection.

 

[AKTIVE1]

i am trying to get a game plan for the morning, i cannot understand why it ran fine 24hrs ago and jst had glow plug trouble fixed. now thats fixed and somethin else is wrong somwhere. i am going to change the fuel filter in the morning and buy a fuel pump just in case. is it possible to bleed air from this system.