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Can you disable a single injector?

10K views 12 replies 4 participants last post by  Mudguts 
#1 ·
I purchased a 2002 f350 w/7.3 about six months ago and everything was good for the first few months but has gotten bad lately. There is a long story here that is still unfolding as I plan to do some under-valve-cover testing this weekend, but the short version of the story is that I possibly have low compression in number 8 causing a miss and causing the engine to blow white smoke out of the tailpipe. It is possible that I have a dusted engine. The engine still has plenty of power and i can live with the miss, but what I dont like is how I smoke people out at stoplights. The smell from the smoke is not a pleasant thing and i feel bad for the people around me. I have had some people tell me that since it still has good power that I should just drive it till it dies (which could be many miles down the road) and I am inclined to follow their advice to try and get some moneys worth out of the truck before I spend thousands on a rebuild. What I need to know is if I can disable the number 8 injector without causing any major problems. That way I wont be dumping fuel into a cylinder that isnt fireing. And if i can disable it without messing up my engine, then what is the best way to go about doing it? Can you disable it in the computer system using something like the AE tool. Can you just unplug it underneath the valve cover without causing any problems? Or clip the wire on the outside of the valve cover? Any advice would be greatly appreciated.

PS. Great forums! I have learned quite a bit about diesels in the past few weeks by reading posts here. Lets just say my bookmark list has grown quite a bit!
 
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#2 ·
I think I may have just gotten the answer to my question. Just got done talking to a diesel mechanic and he informed me that the fuel also acts as a lubricant for the top of the piston so disabling the injector would cause that cylinder to burn up fairly quickly. Bummer for me and the people around me at stoplights! :shrug:
 
#6 ·
Great! I will throw a quart in on my next fill-up and let ya know! It will probably be after the new year before I get a chance to try it. The truck wont be driven much with the holidays coming up. Like you say, its definitely worth a try at $3. Thanks again!
 
#8 ·
Just did one this weekend. Only did the drivers side because when I had a contribution test done, it showed the #8 as being the problem cylinder. The compression test showed the 2,4, and 6 at 400 psi and the number 8 at 150. Ouch. Someone said it could be stuck rings so I am trying some engine treatment that is supposed to help stuck rings if that is the problem. The number eight is the source of my miss and smoke though. At that low of compression, i am sure I am sending a ton of unburnt fuel down the tailpipe. While I had the valve cover off I unplugged the #8 injector and started the engine and no smoke. Then plugged it back in and started it and the smoke was back. I just bought this truck six months ago and cringe at the thought of having to rebuild this motor or put a new motor in, so I plan on just driving this engine till it quits. It still has plenty of power, my main concern is the smoke when I come to a stop. I just dont like smoking people out at stoplights. Just trying to figure out how to make it smoke less. Someone said that it might help if I install a catalytic converter in the exhaust as this truck did not come with one. He says it might help burn off some of what is getting through.
 
#9 ·
You can't disable a single injector but you can disable the IDM for an individual injector and prevent it from firing. You should ONLY do that for diagnostic purposes, though. If you are going to add any additive, I would suggest Rev-X. It may not help much, but MANY 6.0 guys swear by it. I know you have a 7.3, but it has done wonders for injector stiction on the 6.0 injectors where tolerances are MUCH tighter.
 
#10 ·
I have just pulled my #8 on my 01. I had it and the ICM (injector control module) replaced not too long ago at a FORD dealership. $2300 It was smoking white smoke that smelled like unburned diesel when I brought it in. Short version is it started doing it again last week after changing the oil. (went to R.T. synthetic) I am sure the dealership is going to try to say I caused it somehow. This is the very short version. I have paid them over $2000 in just labor since I got the truck in September. The injector was $450 for a reman. I am not going to bring it back to them. I am going to ask for a replacement injector since I have it out. I was curious if they had actually done it or put in a regular one where this one is supposed to be a long lead. It was LL. Whether it is the problem or not is yet to be known. I checked all of the connections and they appear to be making good contact. I started it with the injector in and it was squirting oil into the valve cover at a pretty good rate. I figured it was an o-ring and pulled it. The o-rings seem fine but they do not look like they have only been in a couple months. I have worked on gasoline engines for 30 years, this is my first diesel. I am beginning to think I have made a big mistake purchasing this truck. It is an xl single cab work truck. As of now I have around 12k in it and I am getting close to calling it quits. The odometer is showing 148k, I bought it from a lot that has been around for a few years(no warranty) The other part of the story is the dealership has already put a trans and tourque converter in it because it started slipping after I had done all of the paperwork and was on the way home. I guess there is some kind of lesson here for me. I have always liked Fords and have owned several that have been good, dependable vehicles. I may end up selling this one and taking a loss I'm sure if things don't stop going wrong with it. I didn't want to have to work on it all the time and shell out a lot of money continually. It is a great truck when its running.....
 
#11 ·
Hey wanted to let you all know what I did today. After sleeping on it and getting a fresh start this morning I read how to tell which injector is smoking in a service manual on cd I had ordered. It said to pull the exhaust manifold and start the engine. The smoker will be obvious, duh. So I did and now it's not smoking anymore. It was a different injector than the number 8. It was the front one on the driver side. The bottom o-ring was broken. Stuck another one on and presto, no smoke. I think I am still going to try to trade it for something else that is gas and gets better mileage. What I really want is a classic car or truck that is in good shape or has been restored. My passion is old Mustangs. I would trade for one in a heartbeat.. Meanwhile, I have to go put it back together now. Ya'll take care now.
 
#12 ·
Good info on how to see what injector is causing the smoking issue. Quick question though. Is that service manual on cd that you have like the actual service manuals that the mechanics use and if so, where did you get it? I have the hanes manual for my truck but it just doesnt have the same amount of info that a factory service manual will have. Thanks!
 
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