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Old 07-08-2010, 11:50 AM   #16
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Re: Fuel Pressure Problem

Mike,
I had this problem with coated hose on the suction side. They are only for pressure and will suck closed after use.

Jim
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Old 07-08-2010, 12:04 PM   #17
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Re: Fuel Pressure Problem

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Originally Posted by PanozDuke View Post
Hope this helps others avoid the tail chasing I've been through
I've been having this issue on and off as well, and if it rears its head again, I'm coming back to this thread straight away. Thanks for the write-up.
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Old 07-08-2010, 01:32 PM   #18
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Re: Fuel Pressure Problem

After my problem I went to 3/8 hard pipe bent it to size and no more problems.

Jim
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Old 07-08-2010, 02:26 PM   #19
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Re: Fuel Pressure Problem

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After my problem I went to 3/8 hard pipe bent it to size and no more problems.

Jim

Yes this a problem w/tube liner breaking loose from the hose on suction applications as they get older. When I had this problem I just installed new 3/8" high nitrile hose w/a spring inside for support like the industrial guys do. Simple cheap and it works. If all else fails put some Viagra in your fuel cell.
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Old 07-08-2010, 07:26 PM   #20
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Re: Fuel Pressure Problem

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Yes this a problem w/tube liner breaking loose from the hose on suction applications as they get older. When I had this problem I just installed new 3/8" high nitrile hose w/a spring inside for support like the industrial guys do. Simple cheap and it works. If all else fails put some Viagra in your fuel cell.
Why not? I've tried everything else!!!

Mike
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Old 07-09-2010, 07:56 AM   #21
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Re: Fuel Pressure Problem

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I'm with Kevin on this one. My car (even on a good day) was all noise and no go with the injection fitted. Night and day with a carb on it, a cam and a set of heads. Go on chuck all that injection paraphenalia in the bin and give the car an extra 100hp

Kel.
Same problem Kevin is having..but no home track. Tracks are 300' alt. 499' alt. 4,000' alt. 4800'alt. so (4) sets of jets and dyno time at each alt. ? ..thanks for the imput Bill
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Old 07-24-2010, 11:34 AM   #22
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Re: Fuel Pressure Problem

"Fine, car. How'd you like to be turned into a deer lease vehicle or may be just a stand?"

Got it out on the track in 95 degree heat and it was great for about 10 laps, then it started to lay down corner off, PI alarm, fuel pressure fluctuating below 20 psi WOT, saw as low as 4 psi. Backed off and pressure and motor ran fine. This is an improvement over the three laps I got in 85 degree weather (before replacing the lines in suction). 30 gallons in the tank. Cockpit temp 125-130 degrees. Let it cool for 30-45 minutes after cleaning out the recently installed external fuel filter screen (there was some minor debris. Looked to be small blue cell foam particles and some black particles of unknown origin. In my opinion, not near enough to drop the pressure, but enough to reduce flow to a minor extent.). Same scenario on next run

The heat shielding in the fuel lines in the engine compartment is fine, no contact with any heat source. The metal lines running along the passenger side were almost too hot to keep a finger on after each run. This is a stock GTRA motor so I'm are not asking the pump, filter or lines to provide excessive fuel flow.

I am using (not by choice) 93 unleaded with 10% ethanol. I am thinking that the fuel line heat may be causing some vapor issues. It was filled fresh. Any thoughts on that? I am going to try putting heat shield sleeving on the metal lines and flat shielding on the enclosing metal channel that houses them. This in hopes of keeping the engine and passenger side exhaust heat away from these lines. I will also use the car pump to pump the cell dry and see what gets trapped in the screen and replace the canister filter.

I'll run it again next month and provide update.

Not ready to go carb, it has gotten personal now between me and this fuel system If Ford can get a smaller, wimpier system to go 100K miles with this motor, I think this system should be more than capable of a track session or enduro.

Mike
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Old 07-24-2010, 06:17 PM   #23
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Re: Fuel Pressure Problem

Mike, have you replaced the fuel pump? I have a practically new walbro you can borrow or buy to try if not... Very bizarre! Have you replaced ALL the soft lines?
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Old 07-24-2010, 06:25 PM   #24
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Re: Fuel Pressure Problem

Disregard my last post, I see you replaced the pump already... It has GOT to be hoses collapsing due to heat and getting too hot.... I'd replace every bit of soft hose you can.
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Old 07-30-2010, 09:35 AM   #25
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Re: Fuel Pressure Problem

Hi Mike,

Did you ever resolve your fuel pressure problem?

We are having exactly the same issue!! checked the fuel cell, everything OK, removed the screen filter and replaced the pickup line, made sure it was proper length, added a filter
before the pump, replaced the fuel pump, also checked all the wiring and fuel lines. we are going to a test day at Mosport next week and hope we don't have the same problem

Let me know how your fixes turned out.

Thanks,

Bob
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Old 07-30-2010, 12:35 PM   #26
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Re: Fuel Pressure Problem

Bob,
I have been working on it and may (?) have hit on my problem. Won't know until I can get out on the track next month. I tried draining the cell using the existing pump and a jumper battery. It would barely pump fuel out. Tried two more pumps (Bosch 044's) I have collected and no difference. This pump is rated at 5 ltr. per min. free flow. I might have been getting 1 lpm. Thought it had to be something in the cell. Nope, it was all fine (foam, inlet, hoses...). Now I'm looking for a big hammer to calibrate the whole thing when I find that the wires going to the battery are very hot. These are 14 gage. The wires from the car harness are double 14 gage. I check out recommended wiring for fuel pump relays and the voltage feed wiring to the pump is supposed to be 10 gage. I checked my fuel pump relay and find a single 14 gage feed wire both from battery source and to pump. I haven't traced where or why it goes from a single 14 gage to double 14 gage, but I'm in the precess. I intend using 10 gage to the junction of the double 14 gage in the main loom and 10 gage from the battery source. Is this the smoking gun? I don't know, but if the amperage was restricted, it would reduce the pump performance and over heat it, further reducing it's performance. I have a feeling there was a poor pump relay wiring repair on the car at some point that only shows up when it gets really hot. I decided to put the hammer back in the tool box

I am also seriously thinking about installing a second identical external fuel pump in series to increase both flow and head pressure as an extra measure of buffer. It should never need this at anything less than 500 hp, but I am not really wanting to upgrade all the lines from AN-6 to -8 and I think this should be everything else short of that. It will require a separate relay and pump wiring. I happen to have lots of extra pumps, fittings and filters to make this work.

Mike
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Old 07-30-2010, 03:28 PM   #27
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Re: Fuel Pressure Problem

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Originally Posted by PanozDuke View Post
Bob,
I have been working on it and may (?) have hit on my problem. Won't know until I can get out on the track next month. I tried draining the cell using the existing pump and a jumper battery. It would barely pump fuel out. Tried two more pumps (Bosch 044's) I have collected and no difference. This pump is rated at 5 ltr. per min. free flow. I might have been getting 1 lpm. Thought it had to be something in the cell. Nope, it was all fine (foam, inlet, hoses...). Now I'm looking for a big hammer to calibrate the whole thing when I find that the wires going to the battery are very hot. These are 14 gage. The wires from the car harness are double 14 gage. I check out recommended wiring for fuel pump relays and the voltage feed wiring to the pump is supposed to be 10 gage. I checked my fuel pump relay and find a single 14 gage feed wire both from battery source and to pump. I haven't traced where or why it goes from a single 14 gage to double 14 gage, but I'm in the precess. I intend using 10 gage to the junction of the double 14 gage in the main loom and 10 gage from the battery source. Is this the smoking gun? I don't know, but if the amperage was restricted, it would reduce the pump performance and over heat it, further reducing it's performance. I have a feeling there was a poor pump relay wiring repair on the car at some point that only shows up when it gets really hot. I decided to put the hammer back in the tool box

I am also seriously thinking about installing a second identical external fuel pump in series to increase both flow and head pressure as an extra measure of buffer. It should never need this at anything less than 500 hp, but I am not really wanting to upgrade all the lines from AN-6 to -8 and I think this should be everything else short of that. It will require a separate relay and pump wiring. I happen to have lots of extra pumps, fittings and filters to make this work.

Mike
Mike, Your problem sounds the same as mine was and it was not the wire or the pumps it was the inlet line inside the fuel cell. I had to replace it twice before I found a good section of high nitrile hose. Make sure the hose has no kinks cut the foam and feed the hose thru the hose to the pick up can. Make the hose as short as possible. If all else fails put a spring inside the hose to support it like noted before. Remember this is pressure hose not suction so approach it that way. Its a pia but simple.
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Old 07-30-2010, 04:22 PM   #28
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Re: Fuel Pressure Problem

Hey Mike,

I did not mention the wiring, but again, your situation is identical to ours
The wire going to the pump gets very hot. We pulled off the outer wrap
between the fuel pump and where it comes in from the frame rail, there are some after-market crimp connectors that do not look like Ford OEM.
We spliced in #10 wire at this point going to the pump, but like you have seen, the 2 small gauge wires come directly from the fuel relay.

We will give this a try next week.

If the original problem is still with us, we have wired up a stand alone power / ground harness, with #10 wire, it will have a fused off/on switch, this will eliminate the computer fuel pump relay, so the pump will be operated manually, from a switched 12v source.

P.S. We replaced the fuel pickup with #8 push-lock hose, very
rugged stuff, don't think the pump is strong enough to collapse it.

Thanks for all the info.

Bob
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Old 08-01-2010, 07:06 PM   #29
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Re: Fuel Pressure Problem

Jim,
I did have the hose collapse problem. I replaced the in tank fuel lines with steel braided teflon hose that is rated for fuel emersion and so stiff that it would take pliers to collapse it. I replaced the outer flex lines with new Aeroquip steel braided line with new fittings and a positive inner clamping seal to prevent inner and outer hose separation at the ends. This helped in that I got 10 laps before fuel pressure fluctuations. This was an increase from the prior situation of failure after three laps (at 10 degrees lower ambient temperature).

Bob,
I think I have proved the issue of wiring fault due to poor splices and or inadequate wiring gage. I disconnected the pump harness and placed the fuel output line in an empty container. I jumped the pump directly from a separate fully charged battery. First with 10 gage wires and it pumped normally with the strong flow beginning within less than a second. I jumped it with 14 gage wire and it flowed barely a trickle and took several seconds to begin any flow. I then jumped it with 16 gage wire and the pump operated, but failed to produce any output since it was unable to generate the necessary head pressure to suck the fuel up the internal feed line in the cell. The 10 gage wires remained room temperature after 15 seconds pumping. The 14 gage wires were warm to the touch and the 16 gage wires were very warm to the touch, both after similar pumping times. While the pump motor sounded similar on each trial, with the 10 gage wire it had a lower pitch that I interpreted as the muffling effects of the full flow of fuel passed through the pump body.

My plan now is what you have decided upon, to provide a stand alone pump circuit with 30 amp relay and 10 gage power feed from the battery source to the pump. I am going to retain the original circuit because it provides a signal to the ECU that the pump is receiving power. The actual wires to the pump will be left unconnected and taped to the harness. I will actuate the new pump circuit using the same ignition switch source as the original and the relays will be collocated near the ECU.

Mike
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Old 08-07-2010, 10:16 AM   #30
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Re: Fuel Pressure Problem

Hi all,

We were at a regional test day at Mosport yesterday and the car STILL
is loosing fuel pressure after a few laps!!!
We tried 3 different wiring methods, but the problem was still happening.
tried high/low fuel pressure settings, still happening.
The fuel pump gets extremely noisey after a few laps, when we come back into the pits it is howling, the pump body is cool and the wiring is
not hot.
Quickly removed the return line to the cell and ran the car after a session, seems to be a steady full flow.
The first few laps before this problem happens the car runs fantastic, it always starts and idles perfectly.
None of the fuel lines are getting hot, all are insulted.
It almost sounds like the pump is cavitating, this was a brand new pump.
I have to assume these pumps are "suckers" and do not need a positve inlet pressure. (Bosch #044 )
We are running out of things to try, we need the car ready for Watkins Glen next month, and I would hate to have to convert to a carb
Just don't know what to do now.

Bob
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