| mattfromthepier |
04-25-18 11:26 AM |
Too rich to start? N/A T2 swap Walbro
The car is an 88 gtu with a T2 swap, rtek 1.8, 4x750cc RC injectors, walbro 255lph fuel pump, 4x bur9eqp NGK plugs, and safc2 hooked up to the pressure sensor instead of throttle position. The car ran so well for years it was miraculous until recently, when I installed a msd 6aL onto the leading coil and it sputtered around the 3k rpm range. This is when the multi spark discharge should kick in so i looked into it, concluded it was faulty, and rewired the leading coil to its factory arrangement. I started the car and it fired right up and ran smooth for my neighborhood warm up cruise, when I got to the nearest highway i gave it a bit of throttle to build some boost and it sputtered and shut right off and wouldn't start again so I towed it home with the trusty toyota corolla. I noticed when i got it home that my fuel pressure gauge was reading zero PSI so i checked voltage at the pump and there was none.
SO... I wired a 4 pin relay and fancy toggle switch below the dash and have the fuel pump (255lph Walbro) connected directly to the battery from the relay/switch and there is battery voltage at the pump, but the car hasn't started since. So is it possible I am dumping a ton of fuel, too much for the start map on the factory t2 ecu? I ran the battery out and after letting it charge a while (jumpered with the trusty corolla), it was fully juiced and perhaps the starter spun fast enough to skip the start map causing it to fire up but run terribly, is this scenario possible? At this point i should have messed with the safc2 to see if it could help improve idle/ low rmp but it ran so boggy i wanted to scream and cry so instead I let it sputter out. I know the T2 has a fuel pump relay for low and high load, but this t2 engine is in a NA shell so was i not running full voltage to the fuel pump anyway? Other symptoms the exhaust smells like gas and is a little smokey and it occasionally backfires while trying to start. I'm searching high and low for vacuum leaks. I have removed all emissions so there's not much too search. I checked resistance in both leading and trailinig coils and they both were within FSM specified values (0.4 ohm exactly). I pulled the almost brand new spark plugs and they were dark with carbon and had droplets of unburnt gas on them. Is having the fuel pump wired like this causing a "too rich to start" condition? What could cause the fuel pump to see no voltage so suddenly while driving? Is this somehow a result of the faulty MSD unit? I have a spare set of bur9eqp NGK's which I am currently running in both leading and trailing positions. I want to to try to start it with the new plugs but if its so rich why foul them? Right? Thanks for reading and any helpful input is much appreciated!
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