I told the customer at the beginning that this was an experiment, and if it didn't work then I wouldn't charge him for the DIS install and that's exactly what happened! Now to be fair, I was trying to fire a high compression motor with a 200 shot of nitrous with a single MSD coil and no CDI box! If we had a 6AL Digital box on here it may have worked, but it would not have fixed the sequential issue. The final blow to the Optispark was when we went to the track and the car would fall flat on its face when the nitrous triggered - even though it would make 600 ft lbs on the dyno! It was just running out of spark. I definitely wasn't going to be happy until it was running sequential. It ran great N/A in batch fire mode, but there was actually a power loss over the stock programmed ECU at high rpm and the fuel economy- even targeting 15:1 AFR on cruise went into the toilet. First, I wanted to run this in sequential fuel injection mode for a cleaner idle on the cammed motor and it would always glitch at high rpm in sequential and the startup sync was annoyingly long during cranking. So did the sensor fix all the problems? No. OEM and Aftermarket LED crank/cam sensors side by side- only difference is the Hitachi marking: Maybe a good add-on feature in the future? I know the Holley has filter settings for the VR sensors but not for Hall-Effect and LED. Now the strange thing is that the offshore sensor works just fine on an OEM ECU, but I think they have a lot more internal filtering than the Holley. So after I double checked all my wiring I found an OEM Hitachi sensor, and this resolved the flickering crank signal. Lane Culver said that he has seen this before on the aftermarket Chinese sensors (and I have seen the issue with offshore LS cam and crank sensors). Just with the ignition on here's what the System Log looked like: This was a huge mistake! I installed the disc into the distributor and it fit perfectly:īUT - as soon as I connected to the ECU, the RPM was flickering like crazy. I didn't have one so we ordered a new aftermarket piece: So as I mentioned before, Culver's Optispark disc does not fit into the MSD Optispark Distributor (which happens to be in my opinion, one of the nicest designed things that MSD has ever made). Here are the 4 wire colors from the Holley MPFI to the OEM IAC plug:Īnd here are the 3 wires from the Holley harness to the late model TPS sensor plug: I went this route, and if I were to do it again I think I would just buy the 558-101 and extend anything that didn't reach. There are two different harnesses that kind of work on the LT1- depending on your year- according to the Tech at Holley, the 558-101 (TPI/Stealth Ram harness) had all the right connectors for this 1996 Impala SS But the 558-104 (universal MPFI) harness would be a better fitment and I would have to change the early model TPS and IAC connectors from my OEM harness. If not, the car would always stumble on when it was shut off, or just keep running! Well it can't just be a "different circuit", there has to be a mechanical cut between these two circuits- IE: a relay.
So it took some time to pull the harness out and separate the old ECM/TCM harness from everything leftover, then wire in the speedometer & warning lights (the original Check Engine light is now the Nitrous Armed light!)Īlso, a note on wiring - they say "install the IGN +12V for the 4L60E harness (solid red wire) on a "different circuit" than the IGN +12V for the engine harness. The customer wanted the car 'stock appearing' and all gauges to function as original. Small block Chevy crank trigger kit 556-110 Ign Harness 558-306 (universal to wire in 8x/1x Culver disc and MSD box)Īnd for easy reference here are the Ignition part numbers I ordered later when the Opticrap wasn't reliable: Tune port harness TPI- 558-101 (late LT need to change the IAC and TPS connectors) "OE" Optispark distributor to fit the disc (Culver's disc does not fit into the MSD Optispark, more on that later. Culver 8x/1x Optispark disc from Lane Culver Here are the part numbers I initially ordered: My intention for this customer was to install a Dominator to control the LT1Įngine using the OE Ignition system (Optispark), Trans control on the 4L60E and a single stage progressive 200 HP Nitrous system. Finally have a forced day off and time to post this up.
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