Low Res mode and batch injection
Thread Starter
Staging Lane
Joined: Mar 2009
Posts: 94
Likes: 0
From: Perth Australia
Low Res mode and batch injection Hi all,
1: Have a query about batch firing injectors on ls1 411 pcm. If i disconnect the cam sensor will that force to batch fire since its not receiving a signal? I am setting up a throttle body injection combo. I expect a fault code will be present and may turn over for longer before firing?
2: also running a 411 pcm off a distributor motor not coil on plug ignition with no crank or cam sensor. Do I just change it to low res mode in the options, have the appropriate tune and the distributor will fire each plug Or is there more to it?
Cheers for any advice, just havent found solid info yet.
1: Have a query about batch firing injectors on ls1 411 pcm. If i disconnect the cam sensor will that force to batch fire since its not receiving a signal? I am setting up a throttle body injection combo. I expect a fault code will be present and may turn over for longer before firing?
2: also running a 411 pcm off a distributor motor not coil on plug ignition with no crank or cam sensor. Do I just change it to low res mode in the options, have the appropriate tune and the distributor will fire each plug Or is there more to it?
Cheers for any advice, just havent found solid info yet.
On The Tree
Joined: Aug 2004
Posts: 104
Likes: 2
From: Central, IL
I have noticed that with only a crank sensor, that the injectors will still fire in sequence and not go into batch mode. I know this sounds wrong, but I have verified it with an oscilloscope and a 411 PCM using a bench harness. Now, I have thought about how to hook up a 411 to my old TBI 350. I believe that having the injectors still wanting to shoot sequentially is a good thing. Not sure exactly how you are wanting to use the 411 for your TBI combo.
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
Likes: 3,616
From: Central Cal.
ALL the cam sensor is for is to tell the ECM which, stroke the engine is on when starting.
That's why it cranks longer if the cam sensor is not working as the ECM figures it out on its own.
That's why it cranks longer if the cam sensor is not working as the ECM figures it out on its own.
Thread Starter
Staging Lane
Joined: Mar 2009
Posts: 94
Likes: 0
From: Perth Australia
Ok I will Elaborate a bit for context.
I have an old carburated V8 in an old classic.
The Distributor I have sourced for this experiment is out of a later model which is a 4 wire, IGN, GND, 1 Pulse per distributor rotation and an 8 Pulse per distributor rotation signal.
I have a 411 PCM, EFI live software, access to the base tune data base, so should be able to track down the Express Cal file.
I am capable of knocking up a harness to suit what is required,
I'm trying to put the jigsaw pieces together to run this motor on my 411 PCM and how it all ties together to make it work.
So the Cam sensor thing won't work as I thought.
Sounds like that Express tune with low res and Batch is what I am after. I will check it out.
What is the express tune expecting to see in relation to engine position?
I have an old carburated V8 in an old classic.
The Distributor I have sourced for this experiment is out of a later model which is a 4 wire, IGN, GND, 1 Pulse per distributor rotation and an 8 Pulse per distributor rotation signal.
I have a 411 PCM, EFI live software, access to the base tune data base, so should be able to track down the Express Cal file.
I am capable of knocking up a harness to suit what is required,
I'm trying to put the jigsaw pieces together to run this motor on my 411 PCM and how it all ties together to make it work.
So the Cam sensor thing won't work as I thought.
Sounds like that Express tune with low res and Batch is what I am after. I will check it out.
What is the express tune expecting to see in relation to engine position?
Thread Starter
Staging Lane
Joined: Mar 2009
Posts: 94
Likes: 0
From: Perth Australia
What I have tried:
Stock ls1 with standalone harness,
Single plane intake, 8 injector plate below a 4 barrel throttle body.
When I started this up I noticed the idle chased around the injectors as it was still running sequential and probably cycling a lean condition as each injector fired. So had a real Idle surge. Tried a few things with the tune to settle it out and never got to a good point.
This is what lead me down the Batch injection path initially, and how could I convert from the normal port injection to TBI.
So I have 2 things on the go at the moment really. Get the LS1 running batch fire. Then getting the old engine to run a 411 pcm.
None of this is typical ideal scenario, I have run multiple boosted ls combos in different chassis's, this i just learning now.
Stock ls1 with standalone harness,
Single plane intake, 8 injector plate below a 4 barrel throttle body.
When I started this up I noticed the idle chased around the injectors as it was still running sequential and probably cycling a lean condition as each injector fired. So had a real Idle surge. Tried a few things with the tune to settle it out and never got to a good point.
This is what lead me down the Batch injection path initially, and how could I convert from the normal port injection to TBI.
So I have 2 things on the go at the moment really. Get the LS1 running batch fire. Then getting the old engine to run a 411 pcm.
None of this is typical ideal scenario, I have run multiple boosted ls combos in different chassis's, this i just learning now.
What I have tried:
Stock ls1 with standalone harness,
Single plane intake, 8 injector plate below a 4 barrel throttle body.
When I started this up I noticed the idle chased around the injectors as it was still running sequential and probably cycling a lean condition as each injector fired. So had a real Idle surge. Tried a few things with the tune to settle it out and never got to a good point.
This is what lead me down the Batch injection path initially, and how could I convert from the normal port injection to TBI.
So I have 2 things on the go at the moment really. Get the LS1 running batch fire. Then getting the old engine to run a 411 pcm.
None of this is typical ideal scenario, I have run multiple boosted ls combos in different chassis's, this i just learning now.
Stock ls1 with standalone harness,
Single plane intake, 8 injector plate below a 4 barrel throttle body.
When I started this up I noticed the idle chased around the injectors as it was still running sequential and probably cycling a lean condition as each injector fired. So had a real Idle surge. Tried a few things with the tune to settle it out and never got to a good point.
This is what lead me down the Batch injection path initially, and how could I convert from the normal port injection to TBI.
So I have 2 things on the go at the moment really. Get the LS1 running batch fire. Then getting the old engine to run a 411 pcm.
None of this is typical ideal scenario, I have run multiple boosted ls combos in different chassis's, this i just learning now.
