No Spark, No Fuel, No Tach
As the title says, fuel pump doesnt turn on, injectors dont fire, tach doesn't move, and there is no spark. I'm just about out of ideas on how to get this thing to work.
First, the background info: '86 NA, MT, manual steering, no A/C Engine blew an apex seal, replaced with an S5 keg and intake. All electronics are from the S4 motor except for the rear iron temp sensor. Vacuum rack, air pump, EGR, and cold start system were removed during the install according to the directions on Rotary Ressurection. Short list of attempted fixes/diagnostics: (I may have forgot some) Engine diagnostic light Change CAS Change coil packs Change ECU Check all fuses Check ECU voltage Check coil voltage Check Main Relay Check coil impeedance Check CAS impeedance Check all ground point impeedances Scrub grounds Replace battery cables Check continuity between ECU and coils, ECU and CAS Remove RPM Switch Disconnect MAF Check clutch switch continuity Check neutral switch continuity Now the story: First Startup attempt: The rear upper fuel injector began leaking profusely due to a pinched o-ring. Ring was replaced, and I tried it again. Second startup attempt: Engine has spark, unsure of fuel and tach. Engine does not start Third attempt:No spark, no fuel, no tach. Diagnostics begin Change CAS - No effect Check all fuses - Good Check coil voltage - 12V at the check bullet by the trailing coils Check Main Relay - same as coil voltage Check coil impeedance - within range Check CAS impeedance - within range Check all ground point impeedances - varried, 0.5-4.5 ohm Check continuity between ECU and coils, ECU and CAS - 0.5 ohm all around Check clutch switch continuity - 30-inf ohm depending on position Check neutral switch continuity - .5 ohm Changed the CAS, no effect. Went home. Next day: Hooked up engine diagnostic lights - Both lights flashed once quickly as the key was turned on, and remained off. Both flash quickly again when the key is turned off. Lights illuminate and stay lit while cranking. Doesnt match any of the diagnostic codes in the manual Replaced ECU - No change Replaced Coils - Spark! The plugs sparked, injectors worked, tach worked. Put the plugs back in, and everything reverted to where it was before changing the coils. no spark, no fuel, no tach. Tried some more, with jiggling wires, and the entire car shut down, as if the battery had been disconnected. Replaced Battery Cables - Car turned on, but still no spark, no fuel, no tach Cleaned all grounds - Scrubbed all the grounds with wire brush and carb cleaner. got battery grounds to chassis and engine, ECU brackets, coil brackets, wires going to chassis... checked all continuities, nothing more than 2 ohm. still no change Removed RPM switch - I read that this worked for somebody. no effect for me Disconnect MAF - same story as RPM switch I'm running out of ideas, anybody know what causes this? Thanks |
Re: No Spark, No Fuel, No Tach
ECU ground wire blends in with the main harness, and attached under the intake manifold. Reconnecting that fixed the problem. Do not confuse the strap from the back of the rear rotor to the firewall for the ECU ground.
http://www.aaroncake.net/RX-7/grounding.htm |
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