Bad IP?

[tjcsr]

last week I fixed the return lines, NO air in filter after sitting over night, truck starts the same when cold, sounds the same. Now lets say I start the truck, let it idle 5 mins, then drive it 2-3 miles into town, shut it down, hop into the store for 5 mins, come out to start it, fires up strong but then starts to "miss" terribly bad, 30seconds - 1 min later it levels out.
also, if I get after it and rev her up a bit in 2nd or 3rd to get into traffic then shift to 4th and let off the pedal it'll start "missing" but wont die, If it was a gasser, for sure it would die, thats how bad it sounds, Also when cruising home, 4th gear, (maybe 30mph, 3.54/285-75-16tires) barely pressure on the pedal the truck will rev up a little bit ans actas if to take off but flattens out after 5-6 seconds. Im thinking this has to have something to do with this IP advance or something in that nature, Truck sounds and runs great, same as it always has, I guess this missing when starting issue has creeped up on me slowly and I havent paid attention.

Before some tells me to look through the FAQ's or tech articles, please understand I work nights, and on sunday night when myfamily was in bed I sat her on Oilburners for 4 hours reading the 6.9/7.3 idi tech and FAQ's, I have so many things i need to do now, from 3g alt to headlight wiring ECT ECT ECT.

Just wondering if this sounds like IP going bad, from what I read I think some people have had similar issues before and that is the conclusion.

 

[79jasper]

Sounds like air to me. Lol

I mean could be the advance plunger.
But really sounds like air getting in somewhere.

Fuel level?
Have you fixed the shower heads?

What lift pump are you running?


Sent from my iPhone using Tapatalk

 

[icanfixall]

Whats the mileage on the injection pump is the first question to answer. Consider anything more than 125,000 miles and the pump is mostly worn out. Injectors about the same. What level are the fuel tanks when this happens. Most fuel tanks have the broken suction strainer so they run out of fuel with 1/4 left in the tanks they can't suck out. Easy fix for that. Is the valley pan wet onder the injection pump. Some times the plunger on the drivers side of the pump gets a leak that will drain the pump when it sits. Thats the advance plunger. See if that looks wet and report back.

 

[riotwarrior]

Could also be weak lift pump, what is your fuel pressure when running? Gotta cheap ass gauge to test? Just pull schrader valve test fuel pressure when running.

Lets wait on report back on mileage first ...

 

[mr_smith]

Does it act funny if you let it idle for 20 mins or so?

 

[tjcsr]

Mileage- around 70k miles, Bought truck from original owner. but ODO says 9k, think it doesnt work half the time.
Fuel level- anywhere. both tanks
Valley pan- dry

Fuel pressure. IDK, need to find/buy a gauge.

Just drove it home, 330 am, 40 degrees out, plugged it in at work, cant get it to act up when cold at all, ever. usually when plugged in it takes half a crank to fire, but lately its been 5-6 seconds. As stated in my sig, GP system is dead, i plug it in for 1st start of day. but GP's been dead for 9 months, this issue just started.
Tomorrow morning when i go out Ill pop fuel filter and check level.
In last week ive replaced return lines/orings,fuel filter and checked the water sep. system.

Looks like this weekend im going to have to buy some clear hose and start investigating for bubbles.

 

[mr_smith]

I would start by double checking your work. Make sure you don't have a leaky cap or something.

 

[riotwarrior]

FIX THE GLOW PLUG SYSTEM!!!!

 

[mr_smith]

There is a test you can do that involves pouring water on the IP.. I have heard about it but never done it, so look around. Or wait for someone more qualified than myself to chime in. You should fix the glow plug system, Im doing mine now, it is relatively easy, but read some threads on it because there are issues that can arise depending on the plugs that are in there now etc..

You are new here (as am I) so I will be the first to tell you only use quality glow plugs. Motorcraft/Bosch are commonly accepted around here. Stay far away from autolite/champion.. far away.

 

[Zaggnutt]

Okay, just want to mention two things... If you did the return line kit and your fuel filter is staying full overnight then you do not have air intrusion from filter head to ip or lines. If you crank the engine and the filter drains then you have air / blockage pre filter head.

Second. The surging when driving with even pedal pressure is another sign that your problem lies before the fuel filter head. I had a similar surging issue that was caused by a malfunctioning FSV (fuel tank selector valve) BUT, I also had the same surging issue when I got down to 1/4 tank because my "shower heads" were gone. Also found a hole in the fuel line where it comes out of the lift pump and rides along the pass side fender well.

I agree with icanfixall and riot. Fix the glow plug system, get a fuel pressure guage (Harbor Freight sells cheapies) check for leaks at the lift pump, along the fuel lines, the tanks, and the FSV. No leaks rules out nothing, but its quick, easy, free, and you can learn a bit about the fuel system in the process. By leaks I do not necessarily mean wet spots on the road. Look for wetness where it shouldn't be.

 

[tjcsr]

Ive been over my return lines over and over. no leaks anywhere.

If you guys think Its gotta be air then its gotta be air. Ill just keep looking testing and smashing my head against the wall.

As for the gps...
1st week i had the truck the GP relay decided to weld it self closed. me not ever having a diesel before didnt think anything of the "glow plugs" light being on for 3 days, I thought it was something it did...."?" Well it cooked all the GP's.
I deleted the GP controller, Bypassed to manual switch. For some reason the NEW relay decided to stick closed the very 1st time I flipped the switch in the cab, and cooked 8 Beru's.
As I was installing the relay I tested that it would open and close 100+ times seriously. IT worked perfectly.
Relay, wiring, switch. all was brand new,

After it cooked the Beru's I tested it. and the relay was still stuck closed, like it had welded itself together, I was PISSED, $100 down the tube in under 30 seconds, when I was barely working 30 hours a week at the time,
after 20 mins i tested everything again but this time, the relay had "opened back up.

Ive checked the GP harness for splits, or cuts, I have the relay hooked up like it is supposed to be, Everything is like all the diagrams say, I have no clue why the relay is staying closed, and I dont have $100000000 to spend on GP's

 

[riotwarrior]

Ok sounds to me if a hammer can't fix it...it's an electrical problem

Now fuel molecules are larger than air and thus you can have air leaking where fuel won't...unusual but can happen.

If it's not already replaced I would suggest replacing the rubber fuel line from the steel line on the frame that then goes to the stock lift pump. A small hole/crack what have you could be the issue. Also if that line breaks down inside it could cause problems with intermittent blockage. It is short piece of fuel line, not expensive to replace. This short bit of rubber fuel line has been the bane of quite a few people, and lots posted here about it.

Have you got well past 1/4 tank of fuel in both or at least ONE tank? If so run from that tank only.

Has timing been checked/verified?

I'd encourage you to get GP system running, yes, it's maybe not as easy as you first thought, however the stock system when working correctly works quite well actually.

So, in summery,

Check fuel pressure while running,
Check/replace line from main steel line on frame to lift pump
Check/verify timing of IP
get gp working to ease starting of engine.

JM2CW at this point

 

[tjcsr]

checked lower line into lift pump. looks clean, ill replace this weekend,.

On another note, Filter is half empty.
Should there be fuel in the steel line from lift pump to filter housing? Fuel all the way to the top? I just popped that and there was no fuel up there.

All hoses up top, and a check valve in the works for this weekend, along with fuel hose to lift pump.

Thanks guys for hearing me out on this, You all know alot more about these beasts then I do.

 

[tjcsr]

Replaced Lift pump and hose from frame to pump.
Seems to have fixed it so far. Took a little drive to the store, went in for 10 mins n came out expecting it to shudder n miss like before.
Half a crank and she fired. No missing.
Seems to have woke up the beast a little too.

 

[icanfixall]

Glad you appear to have fixed it. Replacing that rubber hose is about the best idea. They take lots of bending from the engine movement all the time. a leak in that hose and your sucking air no matter what you do seeing its before the lift pump suction.