No start hot turned to intermittent hard start

[onebadiditurbo]

Ok I previously had a no start issue, hadn't done injector return rebuild in awhile so I figured I'd go ahead and rule that out just to be sure, but with the help of you guys thinking it was the shower head in the fuel tank. Anyway got the kit installed for the injector return lines and it didn't help my hard start problem. After its hot it's more noticeable but it cranks alot longer almost to the point I need to give the starter a break. But while it's cranking about 5 seconds into it it begins to shake like it's picking up cylinders then bust of and purs like a kitten. Thinking heat soak but wanna get another opinion, this IP is only about 40k old.

 

[riotwarrior]

IP pour luke warm water on distribution area where lines come off to cool head down shrink tollerances....if starts....IP is toast or near toast

 

[onebadiditurbo]

Well I did the water trick and no noticeable change, it's almost got me stumped cause sometimes it will start just fine, and sometimes not but when it does start it doesn't spit, sputter, stall, hiccup, nothing...

 

[onebadiditurbo]

Is the return lines suppose to actually have diesel all the way to the tank?

 

[icanfixall]

yes the return line does have fuel in it all the way to the tanks. Where did you purchase the injection pump from? Any chance you may have replaced the seal from the lift pump to the filter head? That is a 3/8 olive in that brass fitting up there. Then on the filter outlet and inlet to the injection pump is a 5/16 seal called an olive. McMaster Carr sells them as dose any good injection pump repair shop.

 

[onebadiditurbo]

Reason I asked was I replaced the fuel return line coming off the T on the back of the engine to the hard return line and got just very little fuel out, and it probably wasn't 45 mins after I drove it.

 

[icanfixall]

Why change that to the hard line running down the drivers side of the intake manifold??? You were better off keeping the rubber hose return system. Reason I say this id the brass fitting you now have at the back of the drivers cylinder head has a rubber sel in it called an olive. Not sure if the seal is 3/8 or not. Most members have no idea that fitting has this seal and it does harden over time from the fuel and the heat in that area. Also remember there are 2 different size fitting for the 2 different size return lines. Any return line with a green clamp is the smaller 3/16. The larger return line with the red clamp is the 1/4 inch size.


DO NOT EVER MIX THESE SIZES ON THE SAME RETURN LINE SYSTEM....
You will end up with leaks.

 

[onebadiditurbo]

I can fix all that's what I did as far as replace with a rubber line, mine had the outer insulation split where it rubbed the lip of the firewall, you sat there's an olive on the back drivers side engine? Mine has a bracket that attaches with the last 2 intake bolts, it's a T that ties each bank together and connects to the return goin to the tank. Are we talking about the same thing?

 

[G. Mann]

Question:
Do you have the engine driven fuel pump? If you do.. how old is it? Sounds like you are having a no start because you don't have fuel.

I had this problem.. drove me nuts.. finally discovered the engine driven fuel pump had a pinhole leak in the pump diaphragm.. On shut down.. it would sometimes leak down the fuel prime to the IP and make a hard start.. or no start... sometimes.. it wouldn't.. engine hot seemed to open up the leak at the pump, and so hot starts were an issue..

Replaced fuel pump.. problem solved..

Might slave in an electric pump to check if it starts OK with known fuel supply first..

Just a suggestion.. mine gave me fits..

 

[Koch13351]

You need a new injection pump
I had swapped an injection pump I got from the junkyard onto my truck when I first got it as a troubleshooting effort to fix the smoking issue it had. It turned out to be a loose rocker arm, and I left the pump on it since it worked fine and I didn't want to go thru the process of changing it out again. It never did fire right up. Took about 8-10 seconds of cranking after 10 seconds of a manual glow plug cycle. When the weather got cold, it would have a hard time starting, so I assumed it was glow plugs. I never changed them out because I just plugged in the block heater an hour or so before I'd start it up. Once the weather started warming up, it still wouldn't want to fire up in the morning unless I gave it a slight dose of ether (manual glows - not used in cases of ether use). Then in early April, I started to get heat soak. SOB wouldn't start for NOTHING! Confirmed it by drenched rag placed on IP. Would eventually start, and run smooth so I know it wasn't air (plus I have clear lines on the return system so I can see what's going on inside). Finally got around to swapping the IP that originally came on the truck, and all problems were solved! Now it lights right up after a 10 second glow plug cycle on a cold morning start. No more heat soak issues. And one thing I forgot to mention: right before the heat soak started, I had two occasions of a misfire that occurred after sitting at a stop light for a minute. Would start driving and all of a sudden I thought my truck was going to die. Didn't get surging, just a rough running engine and severe loss of power. I pulled to the side and popped the hood and could hear the miss jumping around from cylinder to cylinder. It would go away above 2000-2400 rpm (by ear since my head was under the hood) and come back as it dropped back to idle. Held the throttle wide open for a couple seconds and it stopped. Very weird. Let's just say I think I got every possible bit of use out of that IP
I hope my ranting of my experiences help you out. I learned from it. Now I know the symptoms a dying injection pump from first hand experience. And I certainly experienced the majority of them.

 

[onebadiditurbo]

Appreciate it guys, I'll make a few repairs and see what happens.

 

[icanfixall]

At the end of the drivers side return hard line is a brass manifold with 3 nipples on it. One is for the drivers side returns. One is for the passenger side returns and the final nipple is the return to the tanks. That is the fitting I mentioned that has the olive seal in it. It will attach to the intake manifold just the same as the other return line fittings that do not have this olive seal in them. Those olive less fitting commonly are found on engines that do not have the hard line for the returns on the drivers side of the engine. Hope this clears up any misunderstanding.

 

[onebadiditurbo]

Well I don't have the olive anymore apparently, I guess mines been swapped with a hose barb.

 

[Koch13351]

At the end of the drivers side return hard line is a brass manifold with 3 nipples on it. One is for the drivers side returns. One is for the passenger side returns and the final nipple is the return to the tanks. That is the fitting I mentioned that has the olive seal in it. It will attach to the intake manifold just the same as the other return line fittings that do not have this olive seal in them. Those olive less fitting commonly are found on engines that do not have the hard line for the returns on the drivers side of the engine. Hope this clears up any misunderstanding.

I believe it was changed to the 3-way barb tee fitting on 7.3s. I've never seen a 6.9 with one. And snagged the one I have on my truck from a 7.3 I did a full olive delete and changed over to the 7.3 1/4" return system on my truck. Along with clear lines that are still holding up just fine after a few months of daily driving

 

[icanfixall]

Any 6.9 that has the hard steel line running to the return directly off the top of the injecton pump will have the manifold at cylinder 8 in back that is the 3 nipple brass return line manifold with the olive in it. My 89 came with a short piece of rubber hose off the top of the injection pump return to the 3/8 hard line running down the side of the intake manifold. I fixed that.... I even had the small return lines with the green clamps. So I purchased the rear brass manifold with 3 nipples from any late 7.3 and the large filter bleeder. Then changed over from small to large.. Never looked back either cause I got rid of some olives. May now change the oem line from the lift pump to the filter inlet to all rubber 3/8 hose. That gets rid of the olive fitting at the filter inlet. Eventually I will be rid of the filter to injection pump hard line with the 5/16 olives in both ends. Then engine will be olive free. This improvement involves replacing the oem filter head with a psd filter head. I can't wait for that to happen. Cheaper filters.. No olives...Or heaters to leak plus... Mush easier changing filters. Remove screw on cap. Pull out dirty filter. Drop in new clean filter. Screw on top... Done....
"Bob's your uncle"...