Misfire under load
Thread Starter
|
New User
Joined: Sep 2004
Posts: 16
Likes: 0
Misfire under load
I've got an 87 6.9 with only 140k on it. Lately it's been missing and I can't figure it out. Feels like a dead cylinder, engine shakes and seems like its down on power a little. It's most noticeable under load. It's smooth while at a constant speed and just barely noticeable at idle.
I figured i had a bad injector so I cracked each line with it idling and all the cylinders caused the engine to slow when I had it cracked. Is there something that would keep the injector from working under load but work fine at idle or no load?
Black smoke under load, a little blue smoke at idle. It uses a quart of oil every hundred miles if that helps.
Thanks
I figured i had a bad injector so I cracked each line with it idling and all the cylinders caused the engine to slow when I had it cracked. Is there something that would keep the injector from working under load but work fine at idle or no load?
Black smoke under load, a little blue smoke at idle. It uses a quart of oil every hundred miles if that helps.
Thanks
Cargo Master
Joined: Feb 2008
Posts: 3,409
Likes: 1
From: back in SE Iowa
well you can try cleaning the cdr its a tuna can shaped thing behind the air cleaner.what you do is take it off soak it in gasoline then drain it then soak it again until it comes clean.then let it air dry and re-install.do not used compressed air to speed up the drying process it could rupture the diaphram inside.then you can take off the fuel filter drain the fuel out of it and fill it with diesel kleen fire it for about 10-15 seconds shut it down and let it sit for an hour or so,so that it cleans the injection pump.and also see if your air filter needs swapped out for a new one.and you can also try a new lift pump.you can do all that for around $50.i hope this helps
Post Fiend
Joined: Nov 2004
Posts: 5,638
Likes: 1
From: Manitoba
Here is a good post I saved.......by DD
DieselDon
Oil consumption, and the proper checking of the oil levels in Ford diesels comes up periodically. Ford dipsticks are calibrated for hot oil. The 10 quarts in the IDI engines expand about 1/2 to 3/4 of a quart as the oil heats up, and contracts the same amout after cooling. If you check the oil first thing in the morning ( which I grew up doing ) the engines will all indicate oils level below full, but when checked hot, will ( after a 10 minute drain time ) the oil level is usually at full. If you are checking the oil cold, and keeping the level at full, you are actually over filling the engine which will burn of the extra rapidly.
Suggestion: Check oil hot after 10 minute drain time.
Don't add until level reaches add line ( 2 quarts ).
In my days at Ford this often cured, or at least improved, the apparent oil consumption complaints.
DieselDon
Oil consumption, and the proper checking of the oil levels in Ford diesels comes up periodically. Ford dipsticks are calibrated for hot oil. The 10 quarts in the IDI engines expand about 1/2 to 3/4 of a quart as the oil heats up, and contracts the same amout after cooling. If you check the oil first thing in the morning ( which I grew up doing ) the engines will all indicate oils level below full, but when checked hot, will ( after a 10 minute drain time ) the oil level is usually at full. If you are checking the oil cold, and keeping the level at full, you are actually over filling the engine which will burn of the extra rapidly.
Suggestion: Check oil hot after 10 minute drain time.
Don't add until level reaches add line ( 2 quarts ).
In my days at Ford this often cured, or at least improved, the apparent oil consumption complaints.
Post Fiend
Joined: Nov 2003
Posts: 21,285
Likes: 16
From: Nutter Fort, WV
I think I would try the Diesel Kleen in the filter with a strong dose in the fuel tank you are currently running on first.
My guess about the miss is you have an injector that is getting weak.
The Diesel Kleen may clean out some deposits and fix the problem.
140K and the injectors are probably original, so they are due for replacement.
My guess about the miss is you have an injector that is getting weak.
The Diesel Kleen may clean out some deposits and fix the problem.
140K and the injectors are probably original, so they are due for replacement.
Thread
Thread Starter
Forum
Replies
Last Post
Macrobb
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
48
Mar 5, 2016 11:55 PM
vancouverpower
1999 - 2003 7.3L Power Stroke Diesel
13
Nov 23, 2004 08:29 PM
