Engine/Transmission (1998.5 - 2002) Fuel pressure starting

[IdahoJim]

OK, guys.....here's where I am on my starting problem. Like Pappy, I have to run the lift pump, and then crank for 15 seconds to get it to start.....obviously losing prime. I changed the injection pump and
injectors in October. New 0-rings on tubes at that time. Truck ran great until about 3 weeks ago, when the hard starting issue began. I put in a new overflow valve the other day. New drain valve on filter
canister. Good fuel pressure 12-13 at injection pump. I did notice, today, slight leakage on cylinder #4 where the hp line connects to the crossover tube. Tightening did not help. The o-rings I was sent were
orange, or red (color blind)...LOL. When the truck finally starts, it runs great immediately...no missing, etc. It acts like the problem is in the low pressure system, but what do I know?
I need some help.
Jim

 

[phantomusa]

Start with the obvious #4....then try a little magic
I also had a problem with my #4 injector line I had to replace it and my problem is fixed
Pappy

 

[DavidC]

Two trucks with # 4 line problems, what are the odds of that. If it is seeping it seems logical when shut off it will suck air.

Dave

 

[KATOOM]

Just to make sure.....none of these hard start problems you guys are talking about are with a HOT (operating temp) engine, right?

 

[IdahoJim]

Nope, Katoom....at least in my case. The truck is in my shop, plugged in, but the shop is about 20* in the morning. The condition persists in both hot engine, and cold engine starts...usually if it sits for
more than an hour. It is odd that both Pappy and I have had the problem on the #4 line. Coincidences do happen, however.
Jim

 

[phantomusa]

Jim hopefully if you need a #4 injector line your dealer will have one in Stock mine didn't but they had a crate motor they borrowed the line from until they get another new line

 

[Joe Mc]

Guys, I didn't read the whole thread - 1st page all of it and a few on page 3 so, figured I'd share what I experienced years back. The fuel tank top module supply line to the LP/VP metal elbow had a rusty spot on it, after further investigation I found a pin hole in the elbow = lost prime overnight - hard to start. Fix Vulcan Draw Straw. You can check top of tank sitting on the ground under the truck with an inspection mirror and flashlight, it's a tight fit between the exhaust and drive shaft but not as tight as between the shaft and tank, might be able to get an eye on top of tank from between the bed and frame rail? Worth a look see...

 

[IdahoJim]

Pappy, I'm in the process of pulling the #4 line right now. My local dealer doesn't carry squat.....I'll probably order one from Genos. From what I can see of the end, it doesn't look good. I'm going to try and
clean it up, but probably won't have much luck. Wish I could chuck it in the lathe...LOL
Joe, I moved the flatbed back far enough to get to the tank module. Lines looked good.
Jim

 

[IdahoJim]

OK....the line end looks fine. Smooth, and no scratches. I pulled the tube, and the o-ring had a gap in it. Looks like the line leaked, and the high-pressure fuel chewed the o-ring up. I can't buy the o-rings
locally. I have an o-ring kit, and the rings are Buna N BG715 Nitrile 70 Shore. Will that type of o-ring work?
Jim

 

[IdahoJim]

I did some more digging, and apparently you need Viton o-rings on the connector tubes. So, I ordered some from DAP.
Jim

 

[IdahoJim]

The prices charged for these o-rings are crazy....$3.00 each in lots of 5, or 10? So, I did some measuring, and looked around the internet, and the size you want is 7/16" ID x 9/16" OD x .070", or roughly
1/16" thick. Both Buna N, and Viton are excellent for diesel fuel, but Viton is what you want...it handles temps to 400 degrees vs only 250 for Buna N. You can get the O-rings at the O-Ring Store here: Item
# GV75013. As long as you buy at least 5, they cost $.12 each
http://www.theoringstore.com/index.php?main_page=index&cPath=367_2038_2035

 

[DavidC]

The prices charged for these o-rings are crazy....$3.00 each in lots of 5, or 10? So, I did some measuring, and looked around the internet, and the size you want is 7/16" ID x 9/16" OD x .070", or roughly
1/16" thick. Both Buna N, and Viton are excellent for diesel fuel, but Viton is what you want...it handles temps to 400 degrees vs only 250 for Buna N. You can get the O-rings at the O-Ring Store here: Item
# GV75013. As long as you buy at least 5, they cost $.12 each
http://www.theoringstore.com/index.php?main_page=index&cPath=367_2038_2035

Nice find. I think the same with Banjo washers but I am getting old and everything looks expensive.

Dave

 

[Bob4x4]

The prices charged for these o-rings are crazy....$3.00 each in lots of 5, or 10? So, I did some measuring, and looked around the internet, and the size you want is 7/16" ID x 9/16" OD x .070", or roughly
1/16" thick. Both Buna N, and Viton are excellent for diesel fuel, but Viton is what you want...it handles temps to 400 degrees vs only 250 for Buna N. You can get the O-rings at the O-Ring Store here: Item
# GV75013. As long as you buy at least 5, they cost $.12 each
http://www.theoringstore.com/index.php?main_page=index&cPath=367_2038_2035

How did you come up with the fractional sizing,everything I have come across in bosch systems for the cummins has been metric ?

 

[IdahoJim]

That's what the o-ring measured, as close as I could tell, Bob. I'm going to order some of the fractional rings, and will compare them to the ones I get from DAP.
After re-measuring, I guess they could be 11 x 15mm, but that would be a bigger disparity than the actual diameter of the seat.
Here's the actual size chart from the O-Ring store.

Jim
http://www.theoringstore.com/index.php?main_page=page_2

 

[IdahoJim]

Bob, after doing some more research, it's apparent that when you look at the actual sizes, there's very little difference between the metric 1.78mm x 10.82mm o-ring, and the 1/16" x 71/6" x 9 1/6" o-ring. The difference is within the manufacturing tolerance. I checked the bore on my engine and it measures .561". The compression of the o-ring is about .010". I'll know more when mine arrive tomorrow, and I can put one on the tube and measure it.
Jim

 

[KATOOM]

Many vendors have the o-rings, or simply look for the nearest Cummins store and have them send you some. I got mine from Cummins West (cause I'm located on the "west") and they were about $2 each. Dont put whatever you think will work in there.....

 

[SAndreasen]

Had a crossover tube o ring leak on my 01 wouldn't start took it to the shop they diagnosed it and charged me 96 cents for the o ring and diagnostic time truck started like it should after that end of story

 

[IdahoJim]

I installed a new o-ring,on #4 cylinder, and got it back together yesterday. I've let it sit all night, and will try and start it this morning and see if it fires up quickly. If it does, I'm good to go. If it doesn't, it's more diagnosing.
Jim

 

[IdahoJim]

Nope....still have the same issue. Looks like I'm going to have to pull all the lines, and tubes to check the o-rings. Not much else to check. I'm about at my wit's end on this.
Jim

 

[DavidC]

Needle in a haystack

Dave