Fordracer Posted December 8, 2009 Share Posted December 8, 2009 I have a wierd one here. A 1999 F-350 7.3 has 120,000 miles on it and it came in a few weeks ago with a stuck IPR. Replaced it and sent him on his way. Now he's back with a hard start cold and looses power and dies while driving. After some diag I checked the oil pressure and it was 12 psi at a hot idle but if you barely raised the rpm a little it would drop to 0 psi. I checked it on a cold start and it takes alot of cranking to get the oil pressure to come up. I did TSB 03-21-43 and the oil pressure is the same at the oil galley in the bottom of the block as it is on the top of the engine. I replaced the oil pump and the pressure regulator and I gained 10 psi at idle but it still goes down to 0 but not as fast as before. Also the owner said he's been running staight 30W because an aftermarket parts store told him that's what semis run. I changed the oil before I replace the pump and regulator and it didn't help. Has anybody seen this before? The next step is to pull the engine but any ideas to try before I do would be great. Quote Link to comment Share on other sites More sharing options...
LARRY BRUDZYNSKI Posted December 8, 2009 Share Posted December 8, 2009 Sound like low pressure pump. Better check the cover and the clearances on the gears. Quote Link to comment Share on other sites More sharing options...
Fordracer Posted December 8, 2009 Author Share Posted December 8, 2009 The pump and front cover checked out okay but I replaced the pump anyway and it didn't help. Quote Link to comment Share on other sites More sharing options...
Aaron Posted December 8, 2009 Share Posted December 8, 2009 Pickup cracked/leaking? Jam a few extra quarts in 'er and jack the ass end of the truck up in the air and see if that fixes 'er. Quote Link to comment Share on other sites More sharing options...
Fordracer Posted December 9, 2009 Author Share Posted December 9, 2009 I thought that was on older 7.3's but I decided to try it anyway. I put an extra 4 quarts in it and jacked the back way up and it still does it. Quote Link to comment Share on other sites More sharing options...
mrbudge Posted December 9, 2009 Share Posted December 9, 2009 Has someone replaced the oil pan yet? Sounds like the pickup tube is plugged with silicone. Some people are "generous" with the silicone gun. And yes, I have seen this, on many different engines that use RTV for oil pan sealant. You get ok oil pressure at idle but as soon as the demand for oil increases with RPM the pressure drops off. Quote Link to comment Share on other sites More sharing options...
Fordracer Posted December 9, 2009 Author Share Posted December 9, 2009 Oil pan looks like it still has the factory silicone. Quote Link to comment Share on other sites More sharing options...
LARRY BRUDZYNSKI Posted December 9, 2009 Share Posted December 9, 2009 Yank the filter and check the bypass plug, see it its working its way loose. What was the IPR plugged up with? Have you cut the old filter apart and inspected it? Running 30W oil can't be good for the bearings, maybe worn bearings causing low oil pressure? Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted December 9, 2009 Share Posted December 9, 2009 Is the bottom of the pan pushed in? The only time I've seen RPM go up and oil pressure go down the pickup screen is starved, blocked, or the pan is crushed in. Good Luck! Quote Link to comment Share on other sites More sharing options...
cbriggs Posted December 9, 2009 Share Posted December 9, 2009 I wonder if an oil sample (from the lp) would show aeration if pickup was restricted? Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted December 9, 2009 Share Posted December 9, 2009 I wonder if a borescope or other visual tool could be used to check the pickup through the drainplug hole...... Quote Link to comment Share on other sites More sharing options...
mrbudge Posted December 9, 2009 Share Posted December 9, 2009 WOW, a 99 7.3 that the oil pan hasn't rusted out yet. I guess in Kansas they go easy on the salt. Quote Link to comment Share on other sites More sharing options...
Aaron Posted December 9, 2009 Share Posted December 9, 2009 ^^^ LOL! Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted December 10, 2009 Share Posted December 10, 2009 Shit, in South Carolina, if we had the original pan off to get in the bottom end, the pan got the goo cleaned off it and spackled with new goop and put right back on. One of the perks of working in Vermont now, I dont have to clean the pan off. It gets tossed in the garbage and a new one put on. Quote Link to comment Share on other sites More sharing options...
Fordracer Posted December 10, 2009 Author Share Posted December 10, 2009 I'm sorry I haven't been answering your questions. We had a snow storm come through and all the schools were closed so I had to stay home with my son yesterday and our wireless internet is not working because of the weather I assume. As for Larry, I replaced the oil pressure regulator witch comes in the oil filter housing so it has a new bypass but the old one was still in the old housing. I didn't see what was in the old IPR and the old oil filter is long gone. I had to wait for over a week to get an oil pump so the truck has been here a while. Bruce, the bottom of the oil pan looks fine. I remember back in the '80s the 302's would sludge up and plug the pickup tube and cause the pressure to drop when going down the highway. I'm thinking the tube screen has to be plugged with something. I have Snapon's new borescope and I looked inside the oil pan but I can't get it to bend sharp enough to see the pickup tube screen. Everything inside the pan looked clean, ie... pistons, pickup tube, main caps. As far as rusting oil pans, I've worked at this dealership for 26 years and I replaced my first rusted oil pan on a 7.3 this year on an Excursion and I think it must of lived most if it's life elsewhere. Thank's for all the ideas guys. I guess I'll see if this guy wants us to pull the engine and take a look inside. i'll keep you posted. Quote Link to comment Share on other sites More sharing options...
Fordracer Posted December 18, 2009 Author Share Posted December 18, 2009 Problem found. After talking to the hotline a few times, they said to try a high pressure pump. They said on the 6.0's they have seen the low side of the pump leak and cause a problem. After I put the pump on the pressure held better but still not right. The pressure was still at 50 psi cold but you had to rev it up to 2,500 rpm to get it to go to 0 psi, before it would go to 0 at 1,000 rpm. When I used my Snap On borescope to look inside the oil pan everything was spotless so I didn't think the pickup would be plugged but the only thing left to do was pull the motor and take a look inside. As soon as I pulled the pan I say big sections of paint on the inside of the pan missing and the pickup tube was plugged with it. I don't know if this guy used some engine flush at one time or what caused it to happen. We are still waiting to here from him to see if he had flushed somewhere. Has anyone else seen this happen? Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted December 18, 2009 Share Posted December 18, 2009 I have actually, but didn't think of it til you just said something. Mine was a little diferent though. The pan had got stuffed with paper by some disgruntaled individual. But mine would suck the paper up and starve the motor of oil at any engine speed. I let it run at idle and it would start to backfire from the lifters bleeding down. Pulled motor (it was an E-bag) and removed pan, cleaned everything up, reinstalled pan, and engine, and it ran mint forever on. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted December 18, 2009 Share Posted December 18, 2009 Problem found. After talking to the hotline a few times, they said to try a high pressure pump. They said on the 6.0's they have seen the low side of the pump leak and cause a problem. Probably the ball blowing out of the side on the early HPOPs. I just had one last week- low base oil pressure. After I put the pump on the pressure held better but still not right. The pressure was still at 50 psi cold but you had to rev it up to 2,500 rpm to get it to go to 0 psi, before it would go to 0 at 1,000 rpm. When I used my Snap On borescope to look inside the oil pan everything was spotless so I didn't think the pickup would be plugged but the only thing left to do was pull the motor and take a look inside. As soon as I pulled the pan I say big sections of paint on the inside of the pan missing and the pickup tube was plugged with it. I don't know if this guy used some engine flush at one time or what caused it to happen. We are still waiting to here from him to see if he had flushed somewhere. I wonder if the pans are coated by the same supplier that does fuel tanks? Has anyone else seen this happen? Yes, many times, usually by sludge and valve seals back in the '70s and '80s. Not so much lately. I wonder if this is why Ford uses such large mesh screen on their HEUI's? Quote Link to comment Share on other sites More sharing options...
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