Replacing injector O rings

Reply Subscribe

Thread Tools

Search this Thread

Dec 12, 2003 | 05:46 PM

F350Bandit

Thread Starter

Freshman User

Joined: Nov 2003

Posts: 35

Likes: 0

From: Springfield

Replacing injector O rings

2000 F350 PSD 300,000 plus miles, would like to know what advantage to replacing the O rings; and is it needed? It has a hard time starting in the cold temperatures, checked all glow plugs and relays and they are ok, I was told to replace the O rings and it would help. High pressure oil pump does leak down about an inch in reservoir after setting 12 hours or more. Any suggestions on items to check for cold weather starting?

Dec 12, 2003 | 07:42 PM

International Tech

Senior User

Joined: Jan 2003

Posts: 371

Likes: 0

From: West Columbia, SC

I would only change the o-rings if they are bad. When they go bad they either puts oil in your fuel system or makes it EXTREMELY hard to start-up. How long is it taking to get it running? How cold is it where you live? How many times are you cycling the glow plugs? You can pressurize the high pressure oil rails and injectors in each head (to isolate the bank of injectors) with shop air and listen for air underneath the valve cover. You do this by taking the lines loose from the pump or at each head and hooking a blow gun w/ rubber tip (is easiest way) to them and listen. Im sure you know that the lines at the head are special fittings(special tool) and need to depress the spring inside to release.

Last edited by International Tech; Dec 12, 2003 at 07:49 PM.

Dec 13, 2003 | 09:00 AM

F350Bandit

Thread Starter

Freshman User

Joined: Nov 2003

Posts: 35

Likes: 0

From: Springfield

Back again! 28 degrees this morning , 6" of new snow. Cycled glowplugs one time, hit starter, cranked for about 10-15 sec. no luck. Recycled glowplugs tried again, fired off but missed real bad. ( Forgot to plug it in. ) No evidence of white smoke or excessive black, just the normal. This is normally the way it starts. Something has got to be wrong. After it starts and warms up it's ok. Any suggestions?

Dec 13, 2003 | 09:15 AM

Quadzilla

Postmaster

Joined: Feb 2002

Posts: 2,773

Likes: 0

From: Bonney Lake, WA

I would suspect that you might be losing pressure in your high pressure oil pump, and you'd then need to crank it for a while to get the pressure back up enough to fire the injectors.
Let's see if International Tech comes back for his diagnosis.

Dec 13, 2003 | 10:26 AM

International Tech

Senior User

Joined: Jan 2003

Posts: 371

Likes: 0

From: West Columbia, SC

ok, when you go to start her up again and it does this check the oil resevoir and see if there is any oil in it. If it is low you are losing the "prime" for the high pressure oil system and the high pressure pump (like Quadzilla stated) is the likely culprit. If it were the O-rings or injectors it would be skipping badly after it cranks and runs hot or cold.

Dec 13, 2003 | 10:02 PM

F350Bandit

Thread Starter

Freshman User

Joined: Nov 2003

Posts: 35

Likes: 0

From: Springfield

Thanks for the reply. I thought that it might be the high pressure oil pump because it does loose some oil in the reservoir. Just hate to spend the money to replace it if that is not the problem. I did replace the #8 injector after having a diagnostic test at a International Dealership, they said it was showing defective. Did make a lot of difference but still not right. Still looking for the problem. I will check out the oil pump.

Feb 18, 2006 | 04:37 PM

jessejames88

Junior User

Joined: Dec 2005

Posts: 65

Likes: 0

i know this is an old post but it might be my problem... mine takes forever to start unplugged if at all and has a bad miss for at least a half hour run time. here's what i've done so far new batteries, 8 new gp, gp relay,rotella 5-40 syn, fuel filter, seem to remember the old one being black. after sitting for 2 days checked the hpop res. it was at least 2" from the top last week after a good 40-50 mile ride pulled in and brought the rpms up to 1500 and was blowing blue smoke... what do you think injector o-rings, pump or both??? it misses more on humid and cold days always the first start of the day. oh it has a 138,000 and its a 99