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kwik, think your idea is genius which I will definitely consider down the road but for right now I would need a quick fix. I have the same fuel pressure problems that you had, idles at 60 PSI but dumps down when you step on it. Being that you have a 550 I'm guessing that you have a metal aft rear axle tank like I have in my 450. I don't think that the thought came up to most people since everyone has plastic tanks, but Little bits of rust particles gets in the fuel and clogs the inlet screen on the pump. I was amazed at how much junk was in my fuel bowl, I'm surprised the pump still even works ! How much was the in tank fuel pump? Where the modifications that you had to do difficult? My only issue with that setup is you would probably need a pretty good filter on the in tank pump and would need to be cleaned every once in awhile which could be a pain compared to the racor and inline pump. Definitely a great idea, wish I had the time and resources to do it
Quoting again.....
You probably could just as easily install that Bosch 69430 pump in place of the factory pump and simply swap outlet fittings. The pickup screen is still present in the tank, so you won't be feeding the fuel pump any gravel, and it will be all that my setup will be, minus the benefit of having no air present in the fuel supply. I'm sure it will end up being 99% of what I did with 10% of the work.
You probably could just as easily install that Bosch 69430 pump in place of the factory pump and simply swap outlet fittings. The pickup screen is still present in the tank, so you won't be feeding the fuel pump any gravel, and it will be all that my setup will be, minus the benefit of having no air present in the fuel supply. I'm sure it will end up being 99% of what I did with 10% of the work.
well I installed my new pump and truck runs better but still losing 10 psi WOT. I thought for sure it was the pump. Glad I changed it but didn't solve my problem. Wish I would have got the 69430, but the own pump works good for most so I will continue looking for a problem. Going to rebuild fpr next, apparently there is a o ring that can go bad and cause my problem
A lot of guys in the Jeeping community just cut a piece out of the rear "bed" to get to the pump. I dropped the tank because its gasoline, then cut a hole in the bed. I drilled 4 holes and welded threaded bungs under the 4 corners of the bed of the Jeep. I can now just bolt a larger plate down to the bed. Easy access down the line and no need to drop tank.
The opening on our tank is huge, and it takes working room to remove the "Mason jar ring". An opening in the bed to get access to the tank would imply we need to get in there often, and the bed would be compromised by such a huge hole. Instead of a heavy cargo-carrying pickup, we'd have a fix-the-tank-mobile.
As for the pressure drop, a drop of only 10 PSI is really an improvement. What happens it you drop a hose from the pump inlet to a can of diesel and powerbrake it? A small fuel pressure drop could also be a sign of bad injector O-rings.
I'm with Rich on this. There is something else going on here and the different pump may have masked the problem a bit more, but would not have cured the problem. The OEM fuel pump is more than adequate to do anything you need it to.
As for the FPR o-ring, you are right.
Below is a link to Diesel O Rings fuel bowl rebuild instructions.
If you look at page 8 and 11, you will in fact see that there is are o-rings on/in the FPR housing. When I rebuilt my fuel bowl, I had one left over and Bob had to tell me where it went via email with a picture. The old one was square and looked like metal it was so brittle.
Here you can see them in the picture I sent to Bob.
Also, when I had the fuel bowl resealed and put back together, I didn't know that the return line in the FPR was clocked very slightly and was not all the way in the FPR. It was sealed and did not leak, but was allowing for the FP to build to near 100 PSI and when I would accelerate it would drop to around 70 and then back up. I took the truck back home and this was the first line/thing I checked and it was immediately clear the line was not seated all the way, even though it was not leaking.
I'm with Rich on this. There is something else going on here and the different pump may have masked the problem a bit more, but would not have cured the problem. The OEM fuel pump is more than adequate to do anything you need it to.
As for the FPR o-ring, you are right.
Below is a link to Diesel O Rings fuel bowl rebuild instructions.
If you look at page 8 and 11, you will in fact see that there is are o-rings on/in the FPR housing. When I rebuilt my fuel bowl, I had one left over and Bob had to tell me where it went via email with a picture. The old one was square and looked like metal it was so brittle.
Here you can see them in the picture I sent to Bob.
Also, when I had the fuel bowl resealed and put back together, I didn't know that the return line in the FPR was clocked very slightly and was not all the way in the FPR. It was sealed and did not leak, but was allowing for the FP to build to near 100 PSI and when I would accelerate it would drop to around 70 and then back up. I took the truck back home and this was the first line/thing I checked and it was immediately clear the line was not seated all the way, even though it was not leaking.
well I supposedly had a mechanic rebuild the fuel bowl but I think he probably only changed one o-ring fix a leak about a year ago. This is why I don't go to mechanic anymore. All I have right now is the fpr rebuild kit so I will try that first and go from there. I haven't really been able to find a diagram of how the O-rings are supposed to go in does anybody have one? Just worried once I take it apart things will fall out and not sure where they were supposed to go
No diagram really other than the instructions on Diesel-O-Rings that I linked above. If you look at how I have the FPR laid out on the table, that is how it goes back into the bowl housing. The spring and plunger separate from each other as well, but there is not much to it.
For the FPR, there are only 2 o-rings (I think...). One for the housing mating to the bowl surface, then one around that collar piece with the yellow arrow pointing to it. That is the one I thought was steel and had to ask advice from Bob about.
I cleaned the plunger up with very light emory cloth sanding and brake cleaner. Just be sure that the spring is in the middle of the perches when you re-install it. You will see what I mean when you get it apart and in your hands. Another thing to be sure of is getting all of the sleeve seal off the tube. I had to use a 90 degree dental pick type tool on some of them, others came off in one piece with needle nose pliers. Again, you will see what I mean when it is in your hand.
Really quite an easy job, just take your time and be prepared to set the pieces someplace not on the radiator so that you can lay them out and see how they go together.
When I rebuilt my fuel bowl, I had one left over and Bob had to tell me where it went via email with a picture. The old one was square and looked like metal it was so brittle.
I have that O ring floating around in the shop somewhere, I figured it was for something that wasn't on my truck, you know, a one kit fits-all type of thing.
No diagram really other than the instructions on Diesel-O-Rings that I linked above. If you look at how I have the FPR laid out on the table, that is how it goes back into the bowl housing. The spring and plunger separate from each other as well, but there is not much to it.
For the FPR, there are only 2 o-rings (I think...). One for the housing mating to the bowl surface, then one around that collar piece with the yellow arrow pointing to it. That is the one I thought was steel and had to ask advice from Bob about.
I cleaned the plunger up with very light emory cloth sanding and brake cleaner. Just be sure that the spring is in the middle of the perches when you re-install it. You will see what I mean when you get it apart and in your hands. Another thing to be sure of is getting all of the sleeve seal off the tube. I had to use a 90 degree dental pick type tool on some of them, others came off in one piece with needle nose pliers. Again, you will see what I mean when it is in your hand.
Really quite an easy job, just take your time and be prepared to set the pieces someplace not on the radiator so that you can lay them out and see how they go together.
thanks sous, I rebuilt the fpr with a new plunger spring and O-rings. It is now idling around 70 PSI and I'm still losing a bunch of pressure at wot. Now I think the fpr might not be operating properly. Aarrrrhhh
The opening on our tank is huge, and it takes working room to remove the "Mason jar ring". An opening in the bed to get access to the tank would imply we need to get in there often, and the bed would be compromised by such a huge hole. Instead of a heavy cargo-carrying pickup, we'd have a fix-the-tank-mobile.
As for the pressure drop, a drop of only 10 PSI is really an improvement. What happens it you drop a hose from the pump inlet to a can of diesel and powerbrake it? A small fuel pressure drop could also be a sign of bad injector O-rings.
Originally Posted by Chevota_72
Rich is saying to bypass the tank all together by running a hose to a can full of diesel and see what your numbers do.
ok gotcha, i don't think my brakes would hold to be honest and i don't see any kind of actual drop in psi unless im under load. would this test just be to eliminate air getting in from the tank side of pump ?
The powerbraking would put a load on the fuel pump, but not a great one... it's just a test to learn something about the truck.
If your brakes can't hold a stock engine back... maybe we'd better segue to another topic here.
yes I know it's just never ending with my truck. I'm just waiting for the day my wife gives me the ultimatum, the truck or her........lol. although I will say with all the help of you guys on FTE my truck is running a thousand percent better then it was when I got it. Took it to several mechanics when I first got the truck and they basically told me that's just how the truck runs and that's what you get. Really goes to show what they know
So I ordered the fuel bowl rebuild kit from diesel O-rings and we'll see how that turns out. The viton sleeve on the return fuel line is very corroded and not sure how it is not leaking, probably because it's not under a great deal of pressure but I'm wondering if this is causing any of my problems, especially on the 3/8 line going into the fuel bowl. I'm sure that the inlet sleeve looks the same but it is not leaking either. I'm also wondering if I have a small fuel leak where I can't see, maybe that passenger side fuel line. I have an oil leak that seems to be getting worse as I am fixing the fuel system but thinking maybe it is fuel dripping down the block mixing with oil before it hits the ground and it just looks like an oil leak. Is it possible that once the fuel mixes with the oil that it won't have the diesel smell? Dripping right down over the starter and I've heard that there is a fuel line that will leak and drip right over the starter. Just can't understand why it doesn't smell like diesel
so to recap, im losing 10-12 psi on hard acceleration. Hutch mod complete with racor, all new fuel lines to the pump, Fpr rebuilt, bowl filter changed. I am seeing like 1 air bubble in the racor but it just floats around for a while and then gets sucked through the filter, after a while another one will show up but hardly anything that would cause my problem. no more air bubbles come in at 2000 rpms or 650 rpms. I talked to bob from diesel o rings today and he was kinda stumped too. He mentioned maybe running a temperary line from fuel pump to the bowl to see if there might be a blockage in that section . anyone know how i could adapt to the inlet of the bowl? Any other suggestions? I havent tried the 5 gallon of deisel to the pump because i need to be under a hard load. power braking wont work. Im at a loss, seems like ive done everything other than replace pump to bowl line
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