03 Gt, New Motor No Fuel Pressure

Kurt G. · Nov 26, 2017

I just dropped in a crate motor after the original 4.6 was knocking. the swap took about 7 months due to health injury, I broke 3 ribs. Now motor in car and started and ran for about 10 seconds then died like ran out of fuel. I did all the test and seemed like fuel pump. Oh car has manual trans and about 110k on it. tested power at gas tank plug and on plug top right corner has battery voltage and on bottom row right side pin was about 5 volts and left side pin was abut 3.5 volts. changed fuel pump and ran for about 3 seconds but stalled. anybody have any suggestions on what to look for. Please help..

wmburns · Nov 27, 2017

Need to know IF there's is key on +12 at the trunk mounted IFS switch. Use a KNOWN good ground for testing. Test both sides of the switch. There MUST be key on power at the IFS switch. Do not continue until power has been confirmed.

Turn the key on but do NOT crank. Listen for the fuel pump to run (prime) each time the key is cycled. Using a buddy can help. IF the fuel pump does not prime STOP and find out why.

The fuel pump itself is powered via the RD/BK and BN/PK wires.

But honestly did the motor run before the job was done? If yes then it's reasonable to assume that if you can hear the fuel pump run then it's working.

Want more proof that the fuel pump is working at some level? Cycle the key on/pause/off several times without cranking. Now crank the motor. Did it start for a short time? IF so, then the fuel pump has to be working at some level.

Do you want an educated guess? The motor is quitting when the PCM switches from "open loop" to "closed loop". What could cause this? How about a problem with the MAF (under reporting). Or maybe a vacuum leak between the MAF and throttle body.

Does the check engine light go out during cranking? IF so that means the PCM is getting a good CKP signal. IF not, STOP and find out why.

Having an ODB2 scanner that is capable of monitoring operational PID's might might make short work of this problem. Here's some information on an affordable Windows based ODB2 scanner.

ForScan ODB2 scanner w ELM327 USB
https://www.stangnet.com/mustang-forums/resources/forscan-odb2-scanner-w-elm327-usb.57/

1996+ Crank with no start check list
http://www.allfordmustangs.com/forums/4-6l-tech/336452-1997-mustang-wont-ignite.html#2984838

Kurt G. · Nov 27, 2017

Motor doesn't run long enough to go from closed to open. No pump is heard to run. I can open fuel rail right after cycling key and no pressure, not even a little. SEL is off during crank. I need to check power at interia switch. So far all looks good except for no fuel. It did kind of run right after new pump (10 seconds or so) and key cycling then sounded like starving and dies. Theft light goes off 3 seconds after key is turned. I'm getting a HEI spark tester in the morning just to test and see. I used a Bosch scanner and all good code P1000, said I need to drive it with scanner hooked up to check more but no run makes that tough. My son connected the neg battery cable to the bolt/stud holding metal motor mount to block but I see no other place to bolt it. I do not smell gas and spark and intake is all connected with non open lines, but even that would not give zero pressure. I made sure new pump had lots of fuel to prime it. car has 3/4 tank right now so it would be tough dropping it again since it has the spring in base of fill tube.

Kurt G. · Nov 27, 2017

Update:::: I just checked interia for power and found none so I wonder does it break power or ground? I need to get to a reliable wiring diagram and check.

wmburns · Nov 28, 2017

OK. Some good information. With no power at the trunk IFS switch this could be:

blown fuel pump (F1.14) or PCM (F1.26) fuse. Best to check all fuses in the Battery Junction Box (BJB=F1 panel).
bad CCRM
bad CCRM ground. Did you read all of the "crank with no start" check list?
bad ignition switch.
wiring fault.

There MUST be key on power at the IFS switch. Do not continue until this problem has been resolved. Frankly with your report that the new fuel pump did run at first and then quit this opens up the possibility that the fuel pump fuse blew.

Note, I have helped more than one person with the problem of blowing a fuel pump fuse after a fuel pump replacement that turned out to be a wire pinched in the gas tank fuel pump hat.

Confirm IF there is key on power into and out of fuse F2.34, F2.2, and F2.8. Use a KNOWN good ground.

IF there is no power into fuse F2.34 suspect an ignition switch problem.

IF there is no power into fuse F2.2 and F2.8 then suspect a CCRM problem.

1999-2004 BJB CJB fuse panel layout:
http://www.allfordmustangs.com/foru...r-swap-wont-fire-please-help.html#post2669271

If you are interested in getting a full copy of the Ford service manual and wiring diagrams for your car I maybe able to help. PM if interested.

Kurt G. · Nov 28, 2017

Going to get spark test because I don't have one and probably should anyways. I will get back to all this later today if possible but work will keep me tied up about 12 hrs today so not much will get tested. but thank you for info and will post more as I find out.

Kurt G. · Nov 28, 2017

Update, I was testing fuses again fuse box under dash passed at least the ones mentioned but this time the BJB had one that didnt pass this time found one in front corner 20A was bad. I checked it before and it passed but anyway bought fuses on way to work. I will update tonight.

Kurt G. · Nov 29, 2017

Okay so after work I got the fuse changed and can hear the fuel pump cycle for about 3 seconds but still no fuel at fuel rail. I sucked on the line and there was gas right there but it did not make it to fuel rail.

wmburns · Nov 29, 2017

I'm assuming this means that the fuel pump fuse (F1.14) was blown?

Does the fuel pump "prime" each and every time the key is cycled on/pause/off? In my experience it may take several key on/pause/off cycles to build enough fuel pressure to start the motor from an empty system.

Are you certain that the replacement fuel pump is correct for the application? The 1999-2004 Mustang uses a fuel pump driver module (FPDM) in a return-less system and is a different FP from one used in a return style system.

Regarding the new fuel pump. Is it a Ford Factory unit or an after market unit? I'm interested to know if it was necessary to splice electrical wires to install the fuel pump. Why is this important? Because IF the wires are installed backwards then the fuel pump will run backwards. This results in noise but no fuel pressure.

Bottom line. IF there is key on power at the trunk IFS and the fuel pump primes at each key cycle and there still is no fuel pressure I'm afraid that the fuel tank is going to need to come back down because something is wrong on the inside.

Kurt G. · Nov 29, 2017

Aftermarket pump and no matter how much I cycle key pump do want to push fuel. The wires had new harness with 2 different size spade connectors. I will have to drop tank just to check again. I might even put old pump in and see if it ca n work while t Ann is dropped. At this point I'm trying to learn what going on besides just fix it, however I will be happy when it is fixed.

Kurt G. · Dec 2, 2017

Okay, so after more diagnosis I have a pump that sounds like it's working but it's not pushing any fuel. I have opened fuel line removed filter turned key and nothing but noise. Tomorrow drop the tank again and maybe see if old pump works.

wmburns · Dec 2, 2017

Be on the look for other "possible" causes. For example holes in the flexible suction line which would destroy the ability of the pump to move fuel. This could explain how it is possible to have the same symptom with two different pumps.

Kurt G. · Dec 3, 2017

Anything else you can think of, remember car has 108K on odo. I'm going to look at all possibilities.

Kurt G. · Dec 3, 2017

Okay when I dropped the tank I found an issue with flex line in tank. I fixed that then started and ran motor but I'm lots of water on the ground behind tight rear tailpipe. The car has sat for long time but new motor should not be blowing that much I'm thinking especially since driver side has none. Any thoughts on this, the water did not smell/feel or taste like anti-freeze. could condisation cause a misting spot about 12 to 16 inches diameter.

General karthief · Dec 4, 2017

Yes, unusual for one side, should go away after warm up

Kurt G. · Dec 6, 2017

Okay so car seems to be working fine, to recap Changed Fuel pump, then had to change fuses and discovered in tank flex line had problem. I now have SEL but when I ran the codes said rear O2 senors so those will be next.

03 Gt, New Motor No Fuel Pressure

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General karthief

wonder how much it would cost to ship you a pair

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03 Gt, New Motor No Fuel Pressure

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wonder how much it would cost to ship you a pair

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