Hard starting after sitting over night, pretty sure air is getting in!

[Omnious]

Hello all,

So quick summary on the truck. 1994 F350 IDIT, factory turbo, auto, 2WD. Recent work done: New front fuel tank, rear tank drained and cleaned, new fuel selector valve, replace fuel filter, and upgrade to Conestoga Diesel fuel return line kit. This work was done because i got some kind of contaminate into my tanks, looked like orange juice when it came out. Did the return line kit because everything was apart.

So after the truck sits overnight or longer, i have to crank the truck for about 10 seconds and the truck will start. Ill have to hold some throttle for the next 5 to 10 seconds with white smoke coming out the tail pipe. After that the engine clears up it runs great, no stalling or hiccups of any kind. So after reading many threads on this site, to me it seems like i have air getting in some place. I inspected all fuel lines from the tanks to the injectors and see no wet spots.

So i am wondering if i am getting bleed down thru the stock lift pump which is causing my hard starting. Is that a possibility with what i described? I have not checked the pressure coming from the lift pump, yet. I am sure you will say i should replace the lift pump since it has 130k miles on it, and i do have one, but before i take the truck apart again i want to see if there is something else i should be focused on.

Thank you all in advance for input.

 

[Cubey]

Maybe the return line o-rings are already bad? My RV got new o-rings 2.5 years ago and it tends to be hard to start after sitting a week this summer. It didn't have that problem last year. It sat for months then started fine. Might be this higher altitude I've been in though in Utah, Wyoming, Idaho. Although it did it a couple times in low altitude Arizona and New Mexico too. I have an epump conversation last year and a new FSV this year.

 

[IDIBRONCO]

I'm not really thinking that air is getting into your fuel system. Air intrusion will cause issues all the time that your engine is running, like with a hesitation, or it will fell like it gains and loses power. A 10 second crank is longer than it should take to start, but it doesn't sound like fuel drain back. With that, usually, the engine will start up like normal and then die. You'll have to do quite a bit of cranking on the starter to get it to run again. You didn't mention any rough running, but fuel drain back will cause your engine to run roughly after it's running the second time until the air is worked out of the fuel system. You mentioned fuel system contamination and having the fuel tank cleaned, but did you do anything to clean your pump and injectors? Maybe there's some contamination inside the IP? I would try to run something like a bacteriaside and/or a fuel system cleaner like Diesel Kleen through your fuel system and see what that does.

 

[Omnious]

The return kit was just installed two weeks ago so I hope it’s not the o-rings already.

And once I get the truck running it runs great. It will idle great and run great down the road.

No I didn’t clean the injectors or IP. Have about a half tank of clean diesel ran thru the engine since the work was completed.

 

[Big Bart]

Also check your glow plugs, does your wait light in the truck go on for 5-10 seconds, or does it just flash for one second and go out. If just flashes for a second and goes out that might be your hard start issue.

If the glow plugs work I would check your return lines, fittings and o-rings. I find you usually can see diesel wetness where the leak is after a few weeks. But if a slow leak you might not. My truck used to leak back due to orings and do what you described above. Also check your fuel lines to the tank.(You mentioned some tank work.)

One clue would be if it does it on either tank then it’s between the tank selector and the injectors. Would not hurt to put on the new lift pump since you have it.

I would put a little Vaseline on them orings to help them slide on and seal.

 

[TahoeTom]

Did the return kit contain "olives"? They are like a short (1/4") length of fuel hose. There are olives at the hard line connections in several places, sort of like a compression fitting. Mcmaster Carr calls them vibrolock. The line from the fuel filter to the IP and I believe the fuel filter inlet line. If you have the hard line return from the IP to the rear of the engine there is one on each end also. The easy one to do would be the lines at the fuel filter. The return at the rear of the engine not so easy. I had air intrusion at the filter fitting and there was no wetness there, but checking the olives they were old and cracked, and replacing them solved the hard start issue.

 

[Omnious]

The image below is the kit i installed from Conestoga Diesel. I looked on McMaster Carr for Vibrolock and couldn't find anything on their site to compare to what your calling a Vibrolock.

Since i owned the truck, the wait to start light will come on until the glow plug solenoid starts clicking then go out. I usually wait till the solenoid stops then start to crank. I have checked all of the fuel lines from the engine to where the lines disappear on top of the tanks and cannot see any wetness which is why i was thinking the fuel is draining back thru the lift pump.

I do have a new glow plug solenoid, glow plugs, and Classic Diesel Design glow plug harness. Was just waiting to do this after i finished fuel updates and didn't want to include another possible issue. Before my fuel issue, the truck never had this issue so that is why i was focused on the fuel issue and not glow plug system. It would start up with just a few seconds of cranking and no smoke. I never had any kind of issue until temps got down to about 50 where i would have to crank longer.

If we are thinking it is more related to the glow plug system then i will start that upgrade this weekend.

Also, thanks for all the feedback so far.

 

[TahoeTom]

It looks like there are some olives in the picture of the kit. Mel would include the better viton o-rings so those should be good. Here is what I bought at McMaster:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[Big Bart]

The image below is the kit i installed from Conestoga Diesel. I looked on McMaster Carr for Vibrolock and couldn't find anything on their site to compare to what your calling a Vibrolock.

Since i owned the truck, the wait to start light will come on until the glow plug solenoid starts clicking then go out. I usually wait till the solenoid stops then start to crank. I have checked all of the fuel lines from the engine to where the lines disappear on top of the tanks and cannot see any wetness which is why i was thinking the fuel is draining back thru the lift pump.

I do have a new glow plug solenoid, glow plugs, and Classic Diesel Design glow plug harness. Was just waiting to do this after i finished fuel updates and didn't want to include another possible issue. Before my fuel issue, the truck never had this issue so that is why i was focused on the fuel issue and not glow plug system. It would start up with just a few seconds of cranking and no smoke. I never had any kind of issue until temps got down to about 50 where i would have to crank longer.

If we are thinking it is more related to the glow plug system then i will start that upgrade this weekend.

Also, thanks for all the feedback so far.

Just wanted to confirm your wait to start light was on more than 1-2 seconds, when it does that its because the glow plug contoller senses a problem. But if it goes on for 4-15 seconds it is working. But the issue you mention is simliar to when your glow plugs do not work. You crank and crank and build up diesel in the cylinders, then it starts and runs on a few cylinders, then as the heat comes up, and it runs on all cylinders. So rough start, lots of smoke, and somtimes a big race up of the engine for 1-3 seconds.

So your fuel lines will not necessarily leak, there is no pressure in the fuel lines between the lift pump and tank, it is vacuum that pulls the diesel out of the tank to the lift pump.

If it was me I would redo the the injector return lines. Not buy a new kit per say, just pull the hard lines, pull the plastic caps, check the orings (You will see if the o-ring got dirty, cut, or bent/bound upon putting them on.) lube the orings with vasoline (Helps them slide on and seal, many say ATF but that will not do much to seal.), confirm a click as the o-ring seats, and just double check your work. This is not rocket science but those orings are not bullet proof going on. (Dirt, rough injector, plastic cap issue at manufacture, pinched o-ring, etc.) 95% of the time the job goes as planned, but there is room for error.

Then look pull and inspect the fuel filter and all the lines going to the filter holder. Then go back and look at the work done on the fuel tanks. Also replace the lift pump since you have one and that is now the weak link in the chain. If any of these items has a pinhole leak or a loose hose your fuel can drain back. Then you are waiting for the system to fill and build pressure.

Your challenge is you did several things at one time. So its not like you can say, hum, all I did was the return lines. So must be them! So now you have to go upgrade to upgrade till you find your leak, and/or keep in mind this is even a brand new problem. Maybe you just bumped the diesel filter heater, now that o-ring is leaking. Maybe that lift pump hose was bumped and now leaks. ETC. ETC. ETC. The beauty of 30 year old trucks!

But if you go step by step you will find it and fix it. That is what makes these trucks so user friendly. They are pretty simple/basic so you do not need a Snap On tool truck of tools to diagnose or fix them. (Maybe part of the Snap On truck, but not the whole truck!)

 

[Omnious]

Thanks. I’ll start that Saturday and see what I can find before starting the CDD glow plug harness. I’ll get back to you all.
Thanks again.