RamJet 502 not pulsing injectors
06-30-2010, 05:39 PM
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Engine: RamJet 502
Transmission: Turbo 400 withTransbrake
Axle/Gears: Ford 9" with 4.10 Spool
RamJet 502 not pulsing injectors
Hello,
I have a RamJet 502 that I am now having problems with getting it started after doing some head work. It cranks but will not start, not even cough/stumble. It appears to be that the MEFIa controller is not providing pulses to the fuel injectors. If I squirt fuel through the throttle body, the motor will briefly run and then die. I checked the #1 fuel injection wiring with a NOID light but did not receive any flash/pulse. Verified that 12 volts was present at the “pink” wire of the fuel injector wiring harness.
Fuel pressure is present at the fuel rail and flowing through the return line to the fuel cell. I ran this motor all last racing season without any issues, so it was a known functional fuel and ignition system. Midway through the season, I added an MSD 72AL with the Dual Coil harness (PN 8876) with no issues.
I reflashed my MEFI controller and verified that it was responding/updating TP angle and ECT values.
Based on my troubleshooting so far, I believe that it could be a bad wire within the harness that provides the distributer reference pulse to the MEFIa controller indicating that the motor is running. I have seen better wiring diagrams in a Chilton manual that what the RamJet 502 Service Manual (PN 88962724) provides, but I think that connection J1-14 on the MEFI controller appears to the reference pulse input.
I have also looked at the MSD Harness Specification (PN 251013) and it lists J1-14 as “TACH”, but I don’t think that means output for a tach since it also shows J1-7 “RPM/CHG” which routes to L4 “Lead - Tach Signal”
My other question is regarding the distributer that came with the RamJet 502, (PN 104060). The distributer has two plug connectors but only one connection is used to connect to the stock coil (PN 1115491) which also has two plugs. The ECM wiring harness plugs into the other coil plug which has two wires, I assume one is for power and the other is for the RPM reference signal and ground must be through the body of the coil and distributer housing.
Any information that you might have regarding the distributer reference signal, the distributer and coil plug wiring would be greatly appreciated.
Thanks in advance.
I have a RamJet 502 that I am now having problems with getting it started after doing some head work. It cranks but will not start, not even cough/stumble. It appears to be that the MEFIa controller is not providing pulses to the fuel injectors. If I squirt fuel through the throttle body, the motor will briefly run and then die. I checked the #1 fuel injection wiring with a NOID light but did not receive any flash/pulse. Verified that 12 volts was present at the “pink” wire of the fuel injector wiring harness.
Fuel pressure is present at the fuel rail and flowing through the return line to the fuel cell. I ran this motor all last racing season without any issues, so it was a known functional fuel and ignition system. Midway through the season, I added an MSD 72AL with the Dual Coil harness (PN 8876) with no issues.
I reflashed my MEFI controller and verified that it was responding/updating TP angle and ECT values.
Based on my troubleshooting so far, I believe that it could be a bad wire within the harness that provides the distributer reference pulse to the MEFIa controller indicating that the motor is running. I have seen better wiring diagrams in a Chilton manual that what the RamJet 502 Service Manual (PN 88962724) provides, but I think that connection J1-14 on the MEFI controller appears to the reference pulse input.
I have also looked at the MSD Harness Specification (PN 251013) and it lists J1-14 as “TACH”, but I don’t think that means output for a tach since it also shows J1-7 “RPM/CHG” which routes to L4 “Lead - Tach Signal”
My other question is regarding the distributer that came with the RamJet 502, (PN 104060). The distributer has two plug connectors but only one connection is used to connect to the stock coil (PN 1115491) which also has two plugs. The ECM wiring harness plugs into the other coil plug which has two wires, I assume one is for power and the other is for the RPM reference signal and ground must be through the body of the coil and distributer housing.
Any information that you might have regarding the distributer reference signal, the distributer and coil plug wiring would be greatly appreciated.
Thanks in advance.
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