sixturbosix Posted October 13, 2010 Share Posted October 13, 2010 I got a 99 f550 7.3l in our shop yesterday.Customer just bought truck and drove truck 1100 miles and it has used 11-12 gallons of oil.It only has a small oil leak at one of the high pressure fittings but it it is very small.No signs of a large leak when looking under the truck either.The truck runs great and not smoking from exhaust.My first thought was injector o rings because I have seen these engines use alot of oil past an o ring and not show signs of smoke.Turbo looks good as far as bearings no oil visible.I have pulled all 8 injectors and it has new o rings already.Holes look good.It also has 3 new injectors and new uvc harnesses.It looks like someone else has been looking for the same problem previous to me.My question is where else can a 7.3l use this much oil.It obviously is not leaking this much it has to be burning it. Quote Link to comment Share on other sites More sharing options...
Jeff_E Posted October 13, 2010 Share Posted October 13, 2010 There are internal injector failures that can cause oil to be injected as fuel. We discussed it recently in this thread: CLICK HERE Quote Link to comment Share on other sites More sharing options...
sixturbosix Posted October 13, 2010 Author Share Posted October 13, 2010 All injectors have been tested with OTC 310-141/1.Sorry I did not list that I had done this test but I tested each one after I pulled all of them.I have also done a compression test which all cyl. passed no problem. Quote Link to comment Share on other sites More sharing options...
cbriggs Posted October 14, 2010 Share Posted October 14, 2010 Run a crankcase pressure test, if you can find the addapters. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted October 14, 2010 Share Posted October 14, 2010 Took the words right outa my mouth... but before he puts the GPs back in, a wet compression test may help rule out some stuff as well. Now... a GALLON of oil in 100 miles? Not to be the doubting Thomas, but I would have to think that driving behind this truck would be "unique". The inside of the CAC would look "interesting, maybe... I'd want to at least attempt to verify part of that statement. What kind of miles on the truck? Turbo dusted? Does it have the "world famous CCV mod"? Quote Link to comment Share on other sites More sharing options...
blown99 Posted October 15, 2010 Share Posted October 15, 2010 I wouldn't trust the otc tool. 2500 psi is a lot different than 25"hg. How many times have we been tricked working with an A/C system. Vac gauge doesn't drop off, must be no leaks right? wrong. Same thing goes for this tool. If the engine runs good, no skip, turbo is good, blow bye test is good, then replace all the injectors. You will never see the smoke from an internal injector o-ring leak. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted October 15, 2010 Share Posted October 15, 2010 It's a '99? Early one, maybe? Does the air cleaner housing say "Intercooled" on top of it? If so, the motor is commonly junk. The early housing sucked their air from the wheelwell rather than the grill. '99 was a BAD year for PSD's- lots of dusted motors. Get your compression tester out. The crankcase pressure adapter is easily made, I have the dimensions in my notes (.407" orifice IIRC). The spec was revised from 4 to 6" H20, I think. Let me know if you need the info. Tell us more- build date? Early, late? Does it have Perdels in scan data? Even if compression was low, a gallon/100 mi seems high. I'd be looking at the turbo and whether the fuel was black and oily. Injector o-rings are common, and internal leaks in the injector like Keith said, that allow HEUI oil to bleed into the fuel rail (or inside the injector) to be burned. With that much oil going through I might pull the fuel plugs from the heads, install 2 Schraders (Napa PN 90-290, plus a 45* street elbow, $4 each head), and take samples from both heads after it's been running, That would tell you if one injector o-ring on one side is bleeding oil into the fuel rail. I've also seen a few times where the injector o-ring has actually worn a groove into the cast iron head, mimicking a bad o-ring, even when it's new. This can bleed engine oil into the fuel rail to be burned in the engine. Put several bottles of UV dye in the oil and test the fuel from each head's Schrader with a UV light after it's hot. Good Luck! Quote Link to comment Share on other sites More sharing options...
sixturbosix Posted October 15, 2010 Author Share Posted October 15, 2010 Thanks guys.The customer just bought the truck in Oklahoma and drove it back to here in N.C. and said it used almost 12 gallons of oil on the trip here.This is a very nice crew cab with 190,000miles with a flatbed.No scratches and nice interior.Looks like whoever owned it didnt use the flatbed very often.Customer nabbed it for $4,000.From the amount of parts that have been thrown at it,the previously owner must have known it had a problem and spent alot of money and never got it fixed.It is blowing my because someone must have previously cleaned the cac hoses because there is not a spec of oil in them.I pulled back the down pipe from turbo and it doesnt have hardly any soot in it.Tailpipe has soot but no signs of wetness.Customer called this morning and said he wanted all 8 injectors replaced regardless if it fixed it or not.I will get some pics and post results after injectors replaced.Thanks. Quote Link to comment Share on other sites More sharing options...
sixturbosix Posted October 15, 2010 Author Share Posted October 15, 2010 By the way I checked fuel in filter housing and it was clean fuel only.Turbo is slightly dusted but not bad.Tips are not rounded just shinny and a slight bit worn.We have the crankcase pressure tools but I figured if it had alot of blow by I would see signs of it where the crankcase vents into the air intake tube.It was missing the oil fill spout on the bottom that seals against the valve cover and no signs of oil vapor escaping there either. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted October 15, 2010 Share Posted October 15, 2010 Run your fingers in the injector holes looking for wear ridges from the o-rings while they're out. Good Luck! Quote Link to comment Share on other sites More sharing options...
sixturbosix Posted October 19, 2010 Author Share Posted October 19, 2010 Got the new injectors today.Lets put them in and see what happens.Hope it fixes this thing or customer just threw away some big bucks.It was his decision. Quote Link to comment Share on other sites More sharing options...
sixturbosix Posted November 3, 2010 Author Share Posted November 3, 2010 It has been several weeks since I put all 8 injectors in the truck.I got an update from the customer today and was told all is well.The engine has not shown any signs of oil use since the injector replacement. Quote Link to comment Share on other sites More sharing options...
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