REPLACE ECM 99 Mustang GT

[DrSpeed]

Problem started with no start condition that turned into the Ford returnless fuel pump nightmare... Changed out fuel pump to find bare wires (fuel pump harness @ tank) pinched and grounded to tank... I was thinking I found the problem but wrong again! To make a long story short I checked everything I knew but and even tested using a manual ground at the fuel pump module... The pump ran and car started... PLEASE NOTE IF YOU TRY THIS THE FUEL PRESSURE WILL KEEP BUILDING AND YOU WILL HAVE A HIGH PRESSURE GAS LEAK AT WEAKEST POINT... Now I'm replacing ECM just need to know if I can use the original backup to flash the replacement ECM... Listed info that is related below... I don't want to screw up so please include any threads that I need to study before beginning

1999 Mustang GT 4.6 2v 5 speed manual
Diablo U7146
NIB Reman Cardone 788484F ECM

[mikel]

No, you should restore the stock tune to the current pcm, have the new pne programmed, then use the tool on the new one.

[DrSpeed]

Restored stock tune to current (original) pcm and verified by checking last tune written... The car started then stalled after about 5 minutes so thinking the pcm is not grounding properly and fuel pump not turning fast enough to maintain required fuel pressure... Checked vin# displayed - ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff ANYONE able to translate?

What is the difference between taking to dealer to have the new one programed and using the Diablo to flash the pcm forcing the stock tune from backup?

[mikel]

the intune is not designed to program a PCM entirely, so its not the right way to do it here.

[DrSpeed]

Thank you for your response... I love to test things and push it to the limit! Going to try reprogramming the new pcm using the Diablo and the original backup... Nothing to loose! Will post results to inform forum users ASAP

[DrSpeed]

Did a search about VIN# displayed on Diablo tuner as ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff other forum members said this was a glitch in the tuner and was told to call Diablosport with the tuner connected and powered up and could walk you though it to fix the problem??? Anyone here have the same problem?

[garrett]

a lot of the mustangs back in the day did not have vin numbers programmed into them. If you were having an issue with the vin number, the solution would have been to go to the dealership for a flash. when trying to tune, does the tool ask you to input a vin number?

[DrSpeed]

It's a 99 Mustang GT using Diablo U7146 should the vin display or not? Someone at Diablo should be able to answer that question I hope! BTW it does not ask to input VIN#... Just trying to figure out if it's the pcm or a glitch in the programmer that is causing the tune to be corrupted... Have read at least 3 post from other forums that indicated same problem with vin# ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff.ff said they called Diablo with tool connected and walked through process to correct problem? I can not drive the car so will have to be towed to dealer then pay the fee to be flashed... Don't want to spend money unless there is no other solution!

[mikel]

No, as garrett mentioned, lots of 99-04 Mustangs never had a VIN in the pcm, so there is nothing to display.