411 PCM swap - Chevy Impala SS Forum
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post #1 of 11 (permalink) Old 10-03-2019, 10:16 AM Thread Starter
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411 PCM swap

I’ve been chasing a misfire for a couple weeks now. #3 is cold, plug is fouled and all signs are point to the optispark again.

I’ve been reading online about how the optispark can function in batch mode without high voltage parts (like vortec truck motors do) if connected to a 411 pcm. There is nothing on this forum about it, but there is some information on YouTube, fbody and corvette forums.

It supposedly requires repinning the (4) LT1 pcm connectors to the (2) 411 pcm connectors, but uses the existing LT1 Harness. You should then be able to log data and tune LT1 motor using EFILive or HPtuners using vortec 5.7 tune as foundation.

Ive pulled the wiring diagrams, bought the PCM and connectors for less than $100. Has anyone completed this conversion?
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post #2 of 11 (permalink) Old 10-03-2019, 12:11 PM
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I don't know anything about what you're speaking, but you might be confusing batch injector firing with spark plug firing.

You can batch fire fuel injectors, but shouldn't do it with spark plugs.
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post #3 of 11 (permalink) Old 10-03-2019, 01:24 PM Thread Starter
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Wouldn’t be the first time that I was confused.

How I understand it the 411 PCM works on a variety of late 90s and 00s gm vehicles. It also has capabilities to control timing in multiple ways depending on the tune.

I may have been wrong to use the word “batch fire” but using the optispark as a rotor only and control timing differently (with 411 ecm) may have some merits.

I’ll try it. If it doesn’t work I’ll either replace the optispark (I have an extra one on the shelf) and continue my frustrations. or drop in the ls motor that’s sitting on my garage floor.

Check it out for yourself and decide. Eficon ection.com selling the conversion kit. This guy has a bunch of videos of him converting and driving his LT1 around with a 411 ECM in it: https://youtu.be/nk3pvxJtYyU
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post #4 of 11 (permalink) Old 10-03-2019, 01:49 PM Thread Starter
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post #5 of 11 (permalink) Old 10-03-2019, 08:17 PM
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It is slightly more than a repin of the connectors. I also had to split a few sensor 5v wires into separate circuits and add the wires for all the coil connectors. I also went through my harness and cleaned out unused connectors and cleaned up a few other minor things.

I used the EFI Connection 24x kit. The trickier part is getting a good base file and then tuning everything.


'95 B4U LT1/T56 in Purple Pearl. 24x 355 with I believe most of the bolt-ons.
'63 C10 LT1/4L60E from B-Body. Rides like a Cadillac thanks to air bags.
'06 GTO LS2/T56 Torrid Red with CAI and Borla Cat-back thanks to the lady who rear ended me.
Still in Wichita.
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post #6 of 11 (permalink) Old 10-03-2019, 09:43 PM
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1) Batch fire is a fuel injector firing scheme. The injectors are fired together as a "batch". It doesn't care about specific cylinders. This is an older methodology than the modern sequential injection used by the B-Body (and newer cars), which fire each individual injector at specific times depending upon cam timing.

2) These videos are keeping the Optispark and using it solely to distribute the spark from the original single coil. They are bypassing the optical sensor and reluctor portion which was used to sense camshaft position.

3) The EFI Connection system completely removes the Optispark and replaces it with a 1X cam sprocket and sensor, and uses a 24X crank sensor. It uses individual coils for each plug. It basically turns the engine (electrically) into a LSx. It's not relevant to these videos.

This sort of setup could also be easily used on the '94-95 cars by swapping in a '96-97 timing cover, crank reluctor, and hub. The wires for the crank sensor would have to be added, too, of course.

Mike - '94 BBB SS (RIP 06/16) - '95 DGGM SS - '96 DCM SS - '92 BBB Wagon
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post #7 of 11 (permalink) Old 10-03-2019, 11:58 PM
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I have heard you can use the OPTI housing with just the crank sensor and then no OPTI problems. But haven't seen anyone but the YouTube guy do it.

Neil P.
1996 Federal hearse. CAI, Delphi 3.5 MAF, Aluminum elbow, airfoil, coolant bypass mod, 36lbs injectors, LE 223/231 110 LSA cam, Trickflow pushrods, Comp Cams rocker studs, Lunati 1.6 roller rockers,double spring kit and lifters, F-body heads, Cometic MLS .027 head gasket, Hooker headers, Cloyes timing chain, PowerBond balancer, EGR, air pump and AC delete. Solomon tune. CPT Pro-Race trans, 9.5 inch 3200 stall converter, 9.5 inch 14 bolt rear, 4.10 gear and TruTrac helix gear diff
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post #8 of 11 (permalink) Old 10-04-2019, 05:06 AM Thread Starter
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Thanks to All for the replies!
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post #9 of 11 (permalink) Old 10-08-2019, 08:09 PM Thread Starter
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Here is an update from one of the 411 PCM swap designers. The factory LT1 4x reluctor and the LS PCM in L31 vortec mode is possible but we would need to add a few internal connections to the PCM to cater to that kind of setup. The 4x L31 setup is really only compatible with 96/97 cars (it removes need for opti hi rez/low Rez)
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post #10 of 11 (permalink) Old 10-11-2019, 10:37 AM
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In case you didn't catch it? the first guy/video is using a rear-mounted distributor.
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