2800 rpm and fuel cut off ...

[fxr]

When engine rpm rise up 2800, fuel injectors cut off and rpm come down. If I try hold rpm hi, rpm go up to 2800 then fall down, go up and down and so on. That happen every time.

Rpm never rise more than 2800.

- Pulse Width Modulated – Returnless system

- all handheld dash data looks fine.

- no any errors.





Engine is sbc 350 cid (Boss Hoss 355 hp).

Distributor is Mallory Promaster 8360M.

Coil is Mallory 8207M.



Atomic tach signal is connect to coil -.

Handheld dash setting are check many times, everytihing be correct.



Need help!

[msdtechsupport3]

What has the rev-limiter in the Atomic been set to.

It sounds like you're hitting the limiter.

[fxr]

I was try many rev-limiter sets (5500, 7000, 14000 or so), nothing help.

- when I test it rev-limitter become active only if set is 3000.

[xcarguy]

Fxr,




Are you using an MSD ignition box? And what tachometer are you using?





I'm just wondering if you may need an MSD tach adaptor.

[fxr]

- No MSD ignition box, no place where install it.

- Tachometer is Autometer Pro Cycle.



What is MSD tach adapter P/N ?

[xcarguy]

Fxr,



Autometer tachs do not require a tach adaptor (as I understand it, tach adaptors are needed for certain tachs when using an MSD ignition box). However, the injectors need an isolated 12 volt square wave signal to trigger the injectors. This may be your problem. Here's an excerpt from page 1 of the install manual:





Note: The Atomic EFI requires an isolated 12 volt square wave signal to trigger the injection. An MSD The Atomic EFI requires an isolated 12 volt square wave signal to trigger the injection. An MSD Ready-to-Run Distributor (with tach output lead) or a CD ignition such as an MSD 6 Series Ignition Control.

[fxr]

Thank you xcarguy,



Very good notice.



but ...



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What RPM inputs are accepted?
A magnetic, points or standard coil negative will work, but not a hall-effect 5V signal. The signal out of any MSD distributor or MSD Ignition Control Unit will suffice to supply an RPM signal for the Atomic. NOTE: An Ignition Control Unit is required with most applications.



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If I am understand right, Mallory Promaster 8360M have magnetic pickup.

Is it true that it don't work with Atomic Efi?

[fxr]

NOTE: An Ignition Control Unit is required with most applications



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Do that mean that 6 series ignition module is only way with Mallory distributor?



Have MSD any small distributor what can use without ignition module?

[xcarguy]

I can't answer any questions knowledgably about the Mallory distributor. All my components are MSD product. As for an ignition box; it doesn't necessarily have to be placed in the engine bay. All this said, I still think you should discuss the situation further with tech.

[msdtechsupport3]

fxr wrote:



- No MSD ignition box, no place where install it.

- Tachometer is Autometer Pro Cycle.



What is MSD tach adapter P/N ?





The tach adapter is only needed when installing some tachs with an MSD Ignition box. It would not be used for the Atomic.



The MSD ignition box is really only required if the Atomic is going to control timing.