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Thread: Looking for Help with Atomic EFI settings

  1. #31

    Default Looking for Help with Atomic EFI settings

    I would start by suggesting you don't waste any more time with that distributor. This system was NOT in any way designed to control timing on that distributor. Get a ready to run and an adjustable rotor, set it 15 degrees against rotation, set your balancer back to TDC, drop the locked out distributor back in with the rotor now phased correctly pointing back to the number 1 plug and start er up. Set the handheld to locked out under the timing and set the engine to 15 degrees at the balancer. Exit from the locked out screen and enjoy the performance.

    Play time is for behind the wheel, not under the hood.

  2. #32

    Default Looking for Help with Atomic EFI settings

    I agree, but gotta get it right before you play, or you're gonna pay by breaking something. For now I set the timing at about 9 to 10 degrees at idle at about 850ish rpm, and I disabled the atomic's timing control.. Haven't hooked up the vacuum advance yet. The engine is running really good though. Just got a couple more questions, which vacuum pry should I use on the atomic's base, and shouldn't the break booster line be hooked into the atomic and not the valve cover port? Just noticed it the other day. For now I'm saving up 400 big ones to get the msd distributor stuff and the extension cable for the handheld. I'll put up an update video to share with you all soon. Thank you again for all the feedback, support, help, and for everyone being so friendly to a since like me. Quick question, is close to 80psi oil pressure in a 383 normal on a cold start? Drops to below 40 once warm, bumps up close or a little past 60 under acceleration. Still trying to learn what's normal for this engine.

  3. #33

    Default Looking for Help with Atomic EFI settings

    To your oil question, assuming you are using a thick oil here that would be normal. If it is only a 10w40 or 30 it might be showing a bit high at cold start.

    Sounds like your engine is running correctly now with the right settings. I would hold off on the vacuum advance. Since the Atomic does not need it anyway. When the atomic controls timing it will make the vacuum adjustments digitally. There is no vacuum line needed.

    For the brake booster question, I always have mine to direct manifold vacuum. If it is connected to the valve cover, there is something wrong.

  4. #34

    Default Looking for Help with Atomic EFI settings

    Fantastic, Terry another thing that makes me wonder if the mechanic did everything right, good mechanics who are honest are so hard to find, is the manifold pry the big center port in the front?

  5. #35

    Default Looking for Help with Atomic EFI settings

    Done a little more driving and tweaking, the car is running much smoother, but there are a couple more things I have questions on. I recently dropped AFR from 13.8 down to 13.5, the car was running good on 13.8, however as the engine got warmer, and driven longer, there is a noticable drop in power and response, as well as the engine bucking, dropping the AFR down to 13.5 seems to have smoothed out the idle, as well as consistant driving habits from the engine. I'm wondering though, could this be due to the fact that the new 383 engine is pumping out crap tons of heat (usually sits around 190~195 operating temp at a sit still idle) and is roasting everything under the hood, including inlet air temp? Been wondering if I should look into plumbing intake ports or something to give the intake some fresh air from outside the engine bay. Another question is what would be a good low idle for the engine, I'm thinking 750 would be acceptable, and I am assuming that if I drop the target idle that I will need to readjust the IAC screws, if I am wrong please correct me. Lastly, I am looking to move my brake boost line off of the vacuum port from the valve cover how the mechanic put it to the Atomic ports, which port should be used for which, keep in mind I may be putting vacuum advance back to the HEI distributor till I can afford the MSD setup distributor, not even certain which port to use for that. I'll give a video update as soon as I can, as for the HEI Distributor's behavior, ever since I adjusted everything and turned off the Atomic's timing control function, it's been fantastic, no spark jumping as far as I can hear, feel, or tell, and throttle response is smooth and quick, only thing I can't figure out is why if you give a good idle stand still rev to the engine, it'll hesitate a moment to come back down and then idle drops down slowly, a small tap up to about 1500 rpm comes back down quick and nicely, but a rev and blip of the throttle up to about 2500 rpm has the engine stick for a moment and then slowly comes back down. Something else I am not sure about as well that has come up, is first start is fine, run the car a bit, park and come back after running into a store, start it and the engine revs up to about maybe 2500 it sounds like, holds there for a moment and then slowly drops rpm down to the target idle.

  6. #36

    Default Looking for Help with Atomic EFI settings

    I've had my first bad encounter, really bad I suppose. I was attempting to take my car through inspection, bumped the AFR back up to 13.8, planned on dropping it back to 13.5 after passing, while waiting in line (I can only assume) I started hearing a groaning noise from the back right, which is where my fuel pump is located, it did this a couple times, and after each time the idle became more and more unstable, bogging and lowering, till finally the engine stalled completely and would not crank back over, each attempt was a very slow crank. Checking the handheld unit, it listed two ERROR H codes on the last two diagnostics, W something and FP something I believe it is, what are these errors? Also, after letting the car sit for about 5 to 10 minutes while attempting to find someone to jump me, I tuned the AFR back down to 13.5, attempted again for giggles, and the car cranked twice very very slowly, before cranking faster and then kicking over like nothing had happened. I have no clue what's going on here.

  7. #37

    Default Looking for Help with Atomic EFI settings

    You have just experienced fuel pump cavitation. The fuel in the fuel line got hot enough to boil and produce bubbles in the supply. This causes the pump to run dry for a short period and not produce fuel pressure, hence why it did not start.

    A return line will typically cure this issue.

    How hot was it when this happened? How long is the supply line between the pump and the fuel tank and where is the pump mounted?

  8. #38

    Default Looking for Help with Atomic EFI settings

    The pump is mounted about a foot, maybe two at the most from the fuel tank on the side of the sub-frame connector, the engine was running about 195 or less, outside temp was maybe around high 80's, no higher than 92 degrees if I had to guess. I was really afraid that I broke something, that groaning noise really caught me off guard. I am surprised though, why would is suddenly do this when I raise up the AFR to get it to pass inspection, but when I lower the AFR down to run richer, it's perfectly fine?

  9. #39

    Default Looking for Help with Atomic EFI settings

    I think it was just a coincidence. The AFR setting should not effect the pump. It could however be that your fuel level had dropped down to lower the pressure in the feed line enough and the idle time and low fuel flow into the pump (this effects cooling) could have allowed enough raise in line temps to allow the fuel to start to boil and cause cavitation. In any case a return line/regulator would help this.

    I don't think this running condition (temps and such) should be outside the requirements of PWM returnless but in my experience a full tank of gas works better than half or less and although I typically don't run below half a tank there are times when I would need to so I ran a return and dropped my pump in the tank. No more issues with heat and I can drive it dry.

  10. #40

    Default Looking for Help with Atomic EFI settings

    I agree with Allan, I believe it was just coincidence that it happened at that time.

    I'm concerned that you have to run it so rich, the O2 sensor may be fouled out by now.

    What does the A/F reading show on the handheld while it is running? Does the feedback from the O2 sensor (DASH display) show the commanded A/F or does it show lean?

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