Brad May

thats one thing i forgot to monitor but im fairly sure it stayed up, i guess if it zeros it possibly is a crank signal. I also checked my fuel cut overrun, its a new tps, but even calibrated reads a low % at cruise so i wondered if it is activating fuel cut

Hi guys, sorry no log yet, but just seeing if this rings a bell with anyone. Atom on LS1 semi sequential and waste spark. At cruise anywhere from 70-100km it will often cut fuel or spark for a second or three then come back on back to normal. The car is an auto, so its not cutting to stall the engine as it comes back in,but allows no throttle input during it and afrs go full lean. Can do it 3 times in 1 minute, then not at all for ten mins, and can be at different revs each time. Fuel press remains constant.

Yes currently true semi sequential . Have not started it like this, but that's how I had it wired previously. Thanks for the advice, I may look at doing that. Yea the iat was never accurate as before all the fuel was on top of the blower

Great thanks for that!

Thanks, yea I just thought adding a couple of injectors also running off the main fuel rail, so essentially running 10 injectors instead of 8, so they will add to the overall map. I also intend to add water/meth as well, but would prefer some fuel going through all the time.

I have a 6/71 blower with 8 port injectors running as semi sequential (only have an atom with 4 drives). I want to add 1 or two injectors above the blower to help cool it. Is my best option just splice into 1 or 2 of the port injectors? Thanks

quick question someone may be able to answer, at idle it sits around -40kpa on the fuel table, someone thought this was really low vacuum? Mechanical gauge shows around 12" vacuum. Bear in mind cam has overlap. cheers

I thought you might. It's only a half hour job to set carbs up on it, so I may just do that tonight to eliminate the ignition side etc since time is not on my side

Funny you ask that, its connected, but just hanging in the engine bay so sees some high temps, however I am sure it is currently disabled towards fuelling etc

Hi guys, can anyone offer any solutions to this? link Atom, LS1, 8 injectors on top of 6/71 blower, waste spark, semi sequential paired injectors. Cam have some overlap (not ideal for blower but sounds great) Have had a couple of tuners look at it, but its doing something really weird. Starts, run, idles. We start to tune the table then (seems to be as it gets hotter) the AFR leans right out (22:1), runs rough and stalls. It will start again, then a few moments later will do the same thing. When it does this it hasn't moved from its box on the fuel table. Fuel pressure remains constant (42psi) throughout. It seems this EFI on the roots blower might take some time to sort properly, so I may chuck a couple of carbs on tonight to get it ready for a holiday and revisit the EFI when I have more time. Any quick ideas?

Well it's going now, what I thought was an over rich mixture was severly lean, and ruined plugs. New plugs and 25% more fuel and it's running great again, well until a proper tune. Can't believe it was so simple

Im still getting trigger errors when cranking so I'm guessing its one of the listed problems like sheilding, grounding etc. As the Atom does not support scope for the triggers I may have to drag it into a shop to get checked out

Update.... New cam sensor in and nope that didn't fix it. Still trys to catch starting and exhaust backfires

Jeez I hope its the same. Cam sensor here tomorrow so will chuck it together and see how it goes. Might just have to chuck a distributor and carbs in it instead!

Yes changed the cam and never rechecked offset etc. Just in buying a new cam sensor now, might as well so I don't have to remove blower and intake again. I just "assumed" the sync would all be identical