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Help! I am having the following problem. My 1993 F-350, 7.3L Diesel started to run rough, and eventually started to miss. I cracked the lines and found #7 and #8 injectors needed to be replaced. So I took them all out and replaced them with new ones, because the old ones had been in the engine for 2 years. Also changed the CDR Value on back of intake. New air filter replacement. After reassembly, engine still has a slight miss, which tries to clear itself and run smooth, also, blue/black smoke is pouring form the exhaust pipe. Smells of diesel fuel. Only thing hasn't been changed is injector pump, which appears to be working fine. Help...
Have your rubber fuel return lines all be upgraded to ensure you don't have any air leaks into the fuel system? Old rubber lines typically harden and let air into the fuel system. Did you install new o-rings on the injector return connections?
Any fuel leaks around the injectors or injection pump connections?
Blue smoke it usually an indication of oil burning. Unburnt Diesel tends to be more white smoke. Since you worked on the CDR valve, any chance there is engine oil being pulled into the intake because the new valve is not working properly. Check you intake for the presence of oil.
Did you replace all the injectors or just the two that you thought were giving trouble?
I am not an IP pump expert but running new injectors with old injectors (especially ones that have a lot of miles on them) is probably not a good thing for the IP as they probably crack at different pressures which may be enough to upset the IP and cause the misses.
Given the cost of a new IP and injectors nowadays it probably is wisest to do it all in one shot (i.e. IP and injectors) to ensure a stable system.
Return lines, O-Rings, all new. CDR valve, checked, no oil present or being sucked into intake! Engine is not using any oil...
All of the injectors were purchased at the International dealer. It might be possible that although new, one injector might not be good. I droved the truck, about a mile, and came back, it is smoking less, but still has the slight engine miss. The smoke from the tailpipe, smells of diesel, not oil!
Any suggestions?
If you drove the truck for a mile then most likely all the air should have cleared out of the fuel system by then. You have taken care of all the common air leakage issues.
Can you isolate the cylinder that is missing now by cracking each injection line one at a time to see if there is a change in the way the engine runs or is the miss more random? If the miss is more random than it does point more toward the IP as you had originally suspected instead of an injector.
Depending on you milage, I would install eight new injectors to see if that will settle down the IP (or have all your injectors pop tested to check for craking pressure and leakage). Given how cheap new injectors are I think most folks nowadays don't bother with getting the old injectors tested because you just spent a bunch of money on the test that you could have put towards the cost of the new injectors.
Before you do anything it might be worthwhile to run the truck a little more and add some additive to see if the miss will settle down. Check the easy things such as a new fuel filter and new diesel in the tanks.
Best of luck,
The injectors have been replaced with new Standyne injectors. I am going to drive it this afternoon on the interstate and get it warmed up and see if the additive, Kleener, makes a difference, if not then in the morning I am taking the truck to a diesel repair shop to let them find out if it is the IP. Appreciate the help!
Sound like you have done all the right things sofar and in the right sequence.
Note, the cost of a new IP is not that bad anymore if it came to that. Purchase cost should be in the $400 to $450 range. Note sure what they would charge for the installation.
Just got back from Airline Diesel repair. while driving there engine leveled out and started to run like it was brand new. I poured a half bottle of Diesel Clean/Cetane boost in both tanks and it began to run smooth. Went on to the diesel shop anyway, compression test performed, OK. Injectors POP, OK. No Blowby. Still get a small puff of blue/gray smoke, and determination: Injector Pump! I have a spare 7.3L engine which has an injector pump on it, and I will take off tomorrow, and take it in to either get it rebuilt, or get a new one. anyone know what rebuild would cost, verses, new?
If so, anyone knows a good rebuilder in Baton Rouge, La?
Where can I check on a new IP, over the internet?
check with a International truck dealership they will have the best quality and price for reman and will warranty the IP. Do this before tearing things apart. Find out if the fuel you have gotten was the Ultra Low sulfur diesel fuel. A friend of mine got some from a station recently and noticed on his duramax that his power went down dramaticly. Got him to change stations and his power went back up to normal. he a diesel mechanic and the station didn't know they had gotten several loads of the ULSD. So he is switching stations until he has to switch. This might be your problem since the diesel kleen is a lubricant/cleaner. Hope this helps.
Last edited by bigredtruckmi; May 11, 2006 at 03:12 PM.
Going to an IH dealer won't get you the proper IP, most likley. All the IH versions were lower output than the Fords.
As for a problem with ULSD, well, I work in the fuel buisness, and about the only noticeable difference it is supposed to make is that you'll get less smoke. ULSD supposedly has lubricity additives, and is going to be better in that department than the current low sulfur fuel(.05%) we have. I know for a fact that there's no difference in power between high sulfur fuel and current low sulfur, just slightly more noise, and much less smoke.