Fordtechnician Posted June 17, 2009 Share Posted June 17, 2009 We have a 1996 7.3 that keeps blowing fuel filter caps off. It has had some work done by the other tech in the shop such as a fuel psi regulator kit, fuel pump and fuel heater. The trucks owner was blaming us for overtightening the filter cap. When it came to us it had a aftermarket lid, we replaced it with a oe lid and it blows that off as well. Whats wrong? Tech put the regulator on wrong? Somehow getting compression back thru the filter? Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted June 17, 2009 Share Posted June 17, 2009 What's the fuel pressure measure? Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted June 17, 2009 Share Posted June 17, 2009 Wow, me and Bruce were just talking about this the other day. You didn't post this over at IATN did ya? Quote Link to comment Share on other sites More sharing options...
LARRY BRUDZYNSKI Posted June 17, 2009 Share Posted June 17, 2009 Check the pressure coming out of the transfer pump. I have seen them go bad and start pulsating and do some crazy shit. Blowing the filter caps off is one of them. Quote Link to comment Share on other sites More sharing options...
Fordtechnician Posted June 18, 2009 Author Share Posted June 18, 2009 I am not the tech working on it, another in my shop is. Anyway it came to us with lack of power while loaded. The truck came to us in the start with a aftermarket fuel filter with lid that was part of the filter. It was leaking. He replaced it with OE parts. He replaced the fuel pressure regulator kit and that didn't work either. He then replaced the mechanical fuel pump and then it worked fine. A week or so later we got a phone call that the lid blew off. Owner blamed the tech for overtightening the lid and stripping the threads. Owner replaced the cap and it also blew off. As I said, I am not the one working on it, I am just looking for advice. Quote Link to comment Share on other sites More sharing options...
GregKneupper Posted June 18, 2009 Share Posted June 18, 2009 Is it possible that maybe the injector orings are bad and allowing high pressure oil or compression gas to enter the fuel system? That seems like that would be the only way for enough pressure to build in the system to blow that cap off. That cap is a pretty solid piece of plastic and I do not think that someone could strip out the threads. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted June 19, 2009 Share Posted June 19, 2009 Quote: Owner replaced the cap and it also blew off When you make the above statement, do you mean the "o"-ring blew out the side between the lid and housing, or do you mean the lid physically blew off and bounced off the hood and hit the ground? 3.8L Mustangs and T-Birds were bad about "blowing" off the oil filter when the regulator in the oil pump housing would crap out, but really it would just blow the "o"-ring out. Quote Link to comment Share on other sites More sharing options...
LARRY BRUDZYNSKI Posted June 19, 2009 Share Posted June 19, 2009 Quote: He then replaced the mechanical fuel pump and then it worked fine. I think you should check the pressure again, new does not always mean good, how many 6.0 EGR valves bad off the shelf??? Quote Link to comment Share on other sites More sharing options...
Aaron Posted June 19, 2009 Share Posted June 19, 2009 EGR Valves? See my sig Quote Link to comment Share on other sites More sharing options...
2006 Posted June 19, 2009 Share Posted June 19, 2009 I remember having the same problem years ago on a 95 or 96 truck. The lid would blow off about once a week. I never really found the root cause of it, but the problem went away. First, there used to be a SSM about this. If it has dual tanks, there is a fuel selector valve on the frame rail. If there are any aftermarket devices connected to the power feed of this selector valve, it can cause the valve to shift when the engine or device is turned off. This causes the valve to block off any return flow from the fuel pump and causes a spike in fuel pressure which will blow the lid off. That SSM did not help me. I ended up removing the fuel filter restriction switch on the side of the fuel filter housing and installing a pressure gauge. This is the low pressure side of the lift pump. This will be the same pressure at the fuel filter. If I remember right, the service manual said it should be less than 10 psi. I was getting about 20 psi on high rpms on decel. I then put a fuel gauge on the return line to the fuel tank, it was close to 0 psi, so I did not have a return line restriction. The only other thing it could have been was the lift pump, a blockage in one of the passages in the filter housing or a sticking pressure regulator valve. I was also thinking that the fuel heater could have been stuck on. Since the truck was still under warranty at that time, I replaced them all. The pressure came down to about 10 psi. It was ok for about 3 years, then it happened again. The customer then sold it... Quote Link to comment Share on other sites More sharing options...
Fordtechnician Posted July 9, 2009 Author Share Posted July 9, 2009 The Ford tech hotline is having the teck replace the fuel check valves in the head. Where are they and does anyone have a visual picture? I also have this posted on the FMC boards. Someone there suggested iresealing the injectors. I can't understand this working. How can the seal be good, then all of a sudden fail to blow the cap off then return to being ok again. Quote Link to comment Share on other sites More sharing options...
Brad Clayton Posted July 9, 2009 Share Posted July 9, 2009 This truck is an oldy and has a return style fuel system, so there are no check valves in the head. Sounds like the college graduate at the cold line was thinking of a '99 up with the returnless system. As easy as it is to get those injectors out, I would just pop them out and give the things a good look over. You can't hurt anything by re-o-ringing them. Give the cups a good look also. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted July 9, 2009 Share Posted July 9, 2009 Brad's right about the check valves in the heads, they're only present on the Gen2 systems, and I can't see them being the problem even if it was a Gen2. (Hotline loses again.....) I could see leaking injector o-rings causing this on a longer shot. Is the FF lid OEM or aftermarket? Wix and others do make them. Is it an OE style FF or the fucking integrated lid/filter setup? So, back to my original question, has anyone driven this truck around with a FP gauge on it? Gen1's do have a lot of problems with the FP regulator and we've discussed this before. You said someone already was in there, but I don't know of a way to assemble it wrong to make the pressure too high (but I'm sure there is). Massive accumulations of crud in the regulator are common, and I've seen FP way too low, or way too high (100psi+) from debris in the wrong places. Here's a pic of a '97 FPR which was already uploaded, which is similar to your '96 except yours has a strainer cup on it: So, what's the fuel pressure? Does it jump up under heavy load? Quote Link to comment Share on other sites More sharing options...
Fordtechnician Posted July 9, 2009 Author Share Posted July 9, 2009 We put the 9k061 parts in it. Are the parts contained in the 9150 kit also necessary? Does the 9150 kit also include the 9k061 parts? Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted July 9, 2009 Share Posted July 9, 2009 Dunno. Larry? Quote Link to comment Share on other sites More sharing options...
Fordtechnician Posted July 14, 2009 Author Share Posted July 14, 2009 We just got the f6tz-9150-ba kit in. There is no shuttle ball valve in the kit. Is our kit bagged wrong? Or do you just install new seals on the old ball valve? What is in the f6tz-9150-aa kit? Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted July 14, 2009 Share Posted July 14, 2009 I took a pic of the back of the 9150-BA bag when I bought it, too. It contains the Brillo pad, large and small o-rings, and large snap ring. IIRC, you cannot buy the shuttle ball separately, you have to buy the complete regulator and/or housing assy. I'd defer to Larry for accuracy on this, though. Is your shuttle ball screwed up? I've never seen a bad one, just guys losing them. Quote Link to comment Share on other sites More sharing options...
Fordtechnician Posted July 15, 2009 Author Share Posted July 15, 2009 I am not the tech working on it. It is in my shop. It has not been taken apart yet. I was looking for tips ideas to cure this POS. Quote Link to comment Share on other sites More sharing options...
LARRY BRUDZYNSKI Posted July 15, 2009 Share Posted July 15, 2009 The kit your after is the 2C3Z9157AA. I thought we had been thru this before. Quote Link to comment Share on other sites More sharing options...
Fordtechnician Posted July 17, 2009 Author Share Posted July 17, 2009 Well......so far this truck now has the 2C3Z-9157-AA kit, the F6TZ-9150-BA kit, the fuel pressure regulator kit, a new fuel pump, all new fuel pump hoses, new fuel filter, numerous fuel filter lids (Ford). It still blows lid off. We have NEVER seen the lid blowe off. It happens whenever??? Last time it came off it took a trip from Pa to Michigan till it let go. Here are the exact comments to the coldline from the tech "Quote"...took fuel pressure readings and at light throttle fuel pressure is very erratic, goes from 30-75psi rapidly. WOT its around 45-50psi. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted July 17, 2009 Share Posted July 17, 2009 Here are the exact comments to the coldline from the tech "Quote"...took fuel pressure readings and at light throttle fuel pressure is very erratic, goes from 30-75psi rapidly. WOT its around 45-50psi. Wild pressure fluctuations in the older mechanical pump system are normal. I suggest using a long hose on your FP gauge filled with air to dampen the pulsations so you can get an average reading. If you're using a standard style Snappy or Mac gauge, drain the hose out and do not open the bleed valve. The air present in the hose should dampen the reading sufficiently to read accurately. I know you're not working on this truck, and I've never seen this problem before. Are the threads worn in the aluminum housing from repeated lids blowing off? It this is not the problem, I still think there is a small possibility of injectors bypassing combustion pressure into the fuel system as the root source of your problem. Unfortunately, we need a fuel pressure reading at all times to determine what direction to go, or throw a FF housing at it as a guess. The FF housing is on the low pressure side of the system and should only be seeing 4-6PSI. The high pressure is developed after the pump secondary where final pressure is delivered to the heads. If this were in my bay, I'd take an old lid and drill/tap it for a fitting to check FP in the filter housing in the bay. If it exceeds several PSI, there is a restriction in the system or the FP regulator is assembled incorrectly. I have not done this and don't know what spec to give you other than "several" PSI. According to FMC, the housing should only see 4-6 PSI, IIRC. Gen 2 7.3's run full pressure in the housing. I would also interrogate the driver about exactly what was happening when the lids blows off- as if he is at WOT, which would increase the possibility of injector leakage. Has he complained about any intermittent misfire, or does the engine run perfectly? There is a small screen built into the side of the FF housing under the regulator. Was it checked for blockage when the regulator is off? It is very common to block with white fibers from aftermarket FF coming apart. Good Luck! Quote Link to comment Share on other sites More sharing options...
Fordtechnician Posted July 17, 2009 Author Share Posted July 17, 2009 Pressure is somewhere between 8 and 10 in the hsg. We teed in the diesel gauge to the hp fitting on the hsg and see the pressure is 50+ psi at wot not moving. I even bled out the air in the hose. I can fel the pump pumping in the plastic hose. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted July 17, 2009 Share Posted July 17, 2009 Go for a RT with the gauge on the housing and beat the snot out of it. See if the housing pressure changes at any time during WOT. No performance complaints from the driver? Good Luck! Quote Link to comment Share on other sites More sharing options...
Fordtechnician Posted July 20, 2009 Author Share Posted July 20, 2009 No performance complaints from the driver. I meant to say he installed a fitting in the filter lid. Quote Link to comment Share on other sites More sharing options...
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