Need help! Starts then dies

LSTTYPE

Active Member
Car ran fine when taken to my brothers to do a bunch of work. We installed a new Racetronx dual fuel pump system with new -8 and -6 fuel lines. Also installed new stock location intercooler, dual fans, transmission and intake reseal. Car will immediately start but only run for 2-5 seconds and die. It sounds smooth when it starts. I verified fuel pressure both running and key on to prime. Tried another known working ecm, map sensor, new plugs, and unplugged the maf to no avail. I did hot wire the fuel pump using the old jumper lead trick like when we drain our tanks. This made it to where I could crack the throttle constantly and keep the car running but the second I disconnected the jumper lead it died. Car is e85 and we added 5 gallons of fresh e85 to the tank. Any ideas appreciated
 

dank GN

BlackArts Automotive (661)993-8277
Okay when it comes to these cars they need 2 sensors to be set correctly and working . That is the cam sensor and the crank sensor. If the ecm doesn’t see them it will not allow the car to run or start . So double check the cam sensor is set correctly . Even if you have to take the sensor out and re set the sensor at the 25* ATDC . And I believe the crank sensor needs to be spaced out .025 from the reluctor ring .
 

dank GN

BlackArts Automotive (661)993-8277
Are you using a chip or a stand-alone ecm to control the flex fuel? It needs 30% more fuel to run correctly
 

LSTTYPE

Active Member
TT 6.1 chip with datalogger. 120s. Z06 maf, translater. Been on E85 for years. Car ran good when parked.
 

dank GN

BlackArts Automotive (661)993-8277
Okay well it doesn’t run good now so check out the cam and crank sensor
 

TexasT

Texas, Where are you from
The part where you directly power the pump(s) and then when you disconnect it dies has me thinking you have a poor connection in the power circuit to the pump. Are you sure of all the connections all the way to the pump(s)? Measured with a meter? What are you getting at the rear bumper connection for voltage, assuming you are using the stock stuff to trigger the hot wire?

You say you verified the pressure while running, What is it? Also what is the voltage back at the tank while running , then when it dies?
 

michael evans

Well-Known Member
Sounds to me it is the fuel pump relay by the MAP sensor or the oil pressure sensor that goes from key pre-start to after-start (controls relay).
 

LSTTYPE

Active Member
Ok found it. The maf was plugged in backwards somehow. Live in learn. I thought the previous poster meant he had the maf flow backwards
 
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