LA sequential fuel and spark EFI conversion

Fuel and Air Systems

  1. racerjoe

    racerjoe Well-Known Member

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    I thought I would share my “cost effective” fully sequential fuel and spark EFI conversion with everyone. I know I’m not the first one to convert an LA Mopar to EFI, but I haven’t been able to find a comprehensive thread on this specific topic, so I figured it would be nice to have all the information in one spot for anyone looking to make the switch.

    I want to preface with a few details.

    · I call this cost effective because in no way did I try to find the absolute cheapest way to do this, nor did I go at it with an endless budget. It can certainly be done for much less money, but my plan was to build a nice, reliable EFI system without spending $5K on something that still required modification to suit my needs.

    · I’m no expert, I learned as I went through this using knowledge from books and online success stories. If I say something you disagree with, I’m happy to listen.

    · I’ll list some prices that I remember, but some may have changed since I purchased them.

    Let’s get started. The basis of my build is a 408ci, with aluminum heads, and solid roller cam. I used this same engine for drag racing my car and it was pretty stout running 10.50s in an all steel car. Once I decided to quit racing and put the car back on the street, I detuned the motor by replacing the pistons (lower compression) and a much milder, 112 centerline cam. I had planned on using speed density EFI control, which means the engine needs to produce a vacuum signal. The old 106 centerline cam wouldn’t cut it, nor was it good on the street.

    After I educated myself enough, I started deciding on and procuring parts. I’ll separate all major parts in separate sections to make details easier to find.

    Intake Manifold

    Since I already had a Mopar M1 single plane intake, I decided to use that intake and have injector bungs welded into it. I sourced the bungs from ebay (approx. $30). I also sourced some Edelbrock EFI rails so my machinist would be able to get the spacing correct. The rails are designed for the Magnum motors and were about $100 at the time. Edelbrock also makes an intake manifold with the bungs casted into it. I think it is about $350.

    Throttle body

    Initially, I wanted to use a single, forward facing, LS style 92mm throttle body. I purchased a used one on ebay, along with an Edelbrock throttle body elbow. I like the look of this setup, but ultimately it wouldn’t work with an A/C compressor unless it was turned sideways. That ended up not being the look I was after either. So I sourced a 4 barrel throttle body off ebay. It was $159. There are tons of name brand 4 barrel throttle bodies out there. It’s absolutely absurd what these companies what for that product. I think the next lowest cost from the one I bought is $500. That’s plain stupid. It’s a chunk of aluminum with some throttle plates. I don’t get it.

    ECU

    I used the Megasquirt MS3X. I actually bought the kit and built the controller myself. This saves you a few bucks, but you will need to be pretty good at soldering small components. They have options to purchase them already built and even have new and improved ECUs with better connectors and a few more features. I may upgrade to that one day. Check out diyautotune.com for details and prices. Megasquirt gets a bad name in some respect since it is basically an open source product. They have gotten better over the years with support, but since every application is different, their tech support may not be as good as Holley since they sell cookie cutter systems. Megasquirt uses Tunerstudio for configurations. There is a free version, but for $60 all of the features are unlocked. It’s worth the money, get it.

    Sensors-

    Once you decide what sensors you are going to use, go to a junk yard and get a few sensors of the same type along with their connectors for when you are building your harness.



    · Fuel injectors – used take offs from an SRT-8 Hemi sourced from ebay. Find an online calculator to determine what size you will need for your motor. Be honest with yourself here. You don’t want to put that your engine makes 600HP if it really only makes 250HP. If you get injectors that are too big, idle tuning may be difficult.

    · Water temp- GM style, nothing fancy. Get them off a junkyard engine, or diyautotune sells them with the connectors.

    · Intake air temp- GM style, same as above, but I used something different. I’ll get to that further down.

    · MAP- most GM MAP sensors work, but I used something special for my setup, more soon.

    · TPS – The 4 barrel throttle body uses a TPS from an early 2000s Ford. I looked at a bunch of different ones at the JY and they all looked the same. I grabbed a few of them. The single 92mm throttle body uses pretty much any GM style TPS.

    · IAC – GM style I did learn there are two types, one with a brass cone shape valve tip and one with a rubber tip. The 4 barrel throttle body needs the one with the rubber tip. I believe it came on an early 2000s GM. Look on rock auto through the GM products. They have pics of the product on their site, which is helpful.

    · Crank position- I used a threaded body sensor from DIYautotune with their 36-1 trigger wheel. I had the hole in the trigger wheel bored to match the backside of the steel crank pulley, then put a couple tacks to hold it in place. Once installed on the engine, I drilled and pinned it to the damper so I can put it back into the same position if I ever have to remove it.

    · Cam position – The sensor is a 2004ish Jeep 4.0 cam position sensor. You will want to get this whole piece out the junkyard. You can get it all new, but why? I did end up buying a new sensor, but the drive piece is required. You will also need the adapter for this. SD Concepts sells them. I paid like $50 for it, but I think he has raised his price now. He also offers a complete kit for this now.

    · Coils – LS D585 coils. I think these come on 6.0 GM trucks or suburbans. They are the ones with the heat sink on the top. I read these were better, I don’t know why. They were the same price at the junk yard as the standard ones so I got them. Make sure to grab all the connectors when you get these.

    · TMAP- OK, this is what I used on the throttle body. It’s a MAP sensor and inlet air temp sensor in one. I loved the idea of combining the two for a more sanitary installation. I haven’t figured out what car they come on, I found them on a random website that sells sensors. I think it has a Bosch number on it. I’m sure I could take it to a parts store and have them cross it over.



    Fuel tank/pump/regulator

    If you haven’t heard of Tanks Inc. maybe you are living under a rock. The manufacture tanks for many makes and models and also offer EFI conversion tanks. Their tanks use a drop in style pump hat and the tank is baffled to keep the fuel around the pump. I used their pump (size according to your HP needs) and I also used the “corvette style” filter/regulator. This basically allows you to use your existing fuel line without having to run a return from the engine back to the tank. I’ve heard good and bad about these, but I haven’t had a problem yet.



    Wiring Harness

    You will have to build your own engine harness since no one makes a drop on harness for the LA Mopar engine- at least I don’t know of anyone that does. DIYautotune sells harnesses with one open end (it has the ECU connector on the other end) Get one of these. They have wiring diagrams on their website for basic wiring. I was able to find all the diagrams I needed to get started. I realize this is likely the most confusing part to some people, and I’m happy to answer any questions.
     
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    • racerjoe

      racerjoe Well-Known Member

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      Here are some pictures of my setup. You can see I made custom brackets for the coils. When the air cleaner is on it, most people don't even notice there is no distributor.
      I'll add more content soon. For now, enjoy and let me hear some questions...



      eng2.jpg eng3.jpg eng4.jpg
       
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      • 67Dart273

        67Dart273 FABO Gold Member FABO Gold Member

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        !!THANKS!!! We need more guys like you to give details of "whut 'cha done"
         
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        • TF360

          TF360 Well-Known Member

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          So it actually fires in sequence. Are the injectors close enough to spray the precise amount at just the right time. Looks great
           
        • racerjoe

          racerjoe Well-Known Member

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          Yes. For the fuel, the injectors can be batch fired or sequentially fired. In batch fire systems, the ECU usually limited outputs for the injectors. So you would likely group one side of the engine on one output and vise versa. This means fuel is sprayed onto a closed valve. This isn't a big deal since it is essentially what a carburetor does. Sequential means it sprays on the fueling event for that particular cylinder.
          For spark, there is wasted spark and sequential. It is essentially the same as the injector, only the plug is sparking in a cylinder that is already on the power stroke or exhaust stroke so the spark essentially does nothing. Sequential acts like a distributor. The cool thing about having individual coils for each cylinder is it negates the need for an external spark "enhancing" box like an MSD. The reason we use an MSD box is to charge the coil faster. With only one coil having to fire for every cylinder, sometimes it can't charge fast enough. Within tuner studio, the dwell time of the coil can be adjusted to increase the spark output of coil. It's pretty neat to see. There's also no need to purchase those high dollar aftermarket LS coils, the stock ones are fine. I've seen several people running 1500HP boosted applications on stock LS coils. Don't waste your money on that crap.
           
        • brian6pac

          brian6pac Well-Known Member

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          Where is your crank trigger wheel ?
           
        • racerjoe

          racerjoe Well-Known Member

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          A6B6570E-5237-4BCF-B872-D209CCA9437D.jpeg
          I have it listed above under crankshaft position. It’s on the backside of the crank pulley. There are easier places to put the sensor if you don’t have AC and power steering. I actually had it on the other side but the AC belts came in contact with it.
          If you run a magnum engine, the crank sensor is on the flywheel side of the engine. I think the flexplate has holes in it for the sensor to pick up. I also think SD concepts makes a kit for this, but it’s really expensive.
           
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          • racerjoe

            racerjoe Well-Known Member

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            Sensor Wiring Details

            Fuel Injectors- they have two pins that are not polarity sensitive, meaning, it doesn’t matter which one is power and which one is ground. Megasquirt switches the ground for the injectors. They will require constant 12V power. I separated mine by bank. Cylinders 1,3,5,7 are on one fuse, cylinders 2,4,6,8 are on another.

            Water and air temperature- again, two wires. It’s a restive type sensor so it isn’t polarity sensitive.

            TPS- these are potentiometers. For those that don’t know what this is, it is a variable resistor. They will have 3 wires, 2 of the wires will be the total resistance of the resistor. The 3rd wire will be what is known as the wiper of the potentiometer. It basically moves along the resistor varying the resistance as it moves. Typically, voltage is applied to one side of the total resistance and ground is applied to the other side. The voltage out of the wiper is the signal fed back into the computer. I can elaborate on this more if needed, but I’m sure a simple internet search would result in some pictorial to help understand.

            Pic of TPS
            tps.jpg

            IAC- The GM style is a 4 wire stepper motor. It has 2 coils inside it, one to move the plunger in, one to move it out. The MegaManual shows there are two different configurations for the coils. One configuration has the coils on terminals A&D and the other on B&C. While the other configuration is A&B and C&D. My IAC is the later. You can determine your configuration by using an ohmmeter and “ringing” out the terminals. Now, I learned this can be wired one of 4 ways. Before I knew how the software worked while the engine was running, I thought it was working correctly. (There’s a test function in the software) I later learned it was operating backwards. It took 2 wiring changes before I got it right. 3rd time’s a charm!

            PIC of IAC
            iac.jpg

            Cam Position- I was able to find a diagram online for the Jeep cam position sensor. Luckily it was correct.

            upload_2019-4-24_9-32-33.png

            TMAP- this sensor came with a wiring diagram and connector when I bought it.


            tmap.jpg

            I'll also add that this throttle body didn't come with any hardware. Of course all the threaded holes are metric. I took it with me to the hardware store and spent some time figuring out what sizes I needed. Luckily they had everything I needed. You will also notice I had to use a spacer under the throttel body. As you can see the sensor hang down below the bottom of it and contacted the intake.
             
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            • racerjoe

              racerjoe Well-Known Member

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              Time for another update to this thread. Let's talk coils. Below is a wiring diagram for the LS coils. What makes these great for stand alone EFI controllers is they are "smart coils" meaning they have the igniters built into them. All they basically need is a signal to fire. The MS3X has 8 sequential outputs for coils.
              Just like the injectors, I separated the power for the coils from bank to bank. So one fuse for right side, another for left side.

              upload_2019-5-2_9-17-46.png

              If you are planning to use MS3X on a G# Hemi, you will need external igniters for the coils since those are not "smart coils".
               
            • Rolling_Thunder

              Rolling_Thunder Rolling Thunder

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              Not sure why Dodge didn't use coil mounted igniters but so be it... I am mocking up my MS3X for my 6.1L Hemi and am dealing with that now.

              Great build!
               
            • 67Dart273

              67Dart273 FABO Gold Member FABO Gold Member

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              THANK you!!! For this detailed info!!!
               
            • racerjoe

              racerjoe Well-Known Member

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              EFI Source has a ignitor module that would make it pretty easy.
               
            • racerjoe

              racerjoe Well-Known Member

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              No problem. Hit me with any questions you have. I’ll be happy to answer whatever I can.
               
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              • pishta

                pishta I know I'm right....

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                Sequential is only truly useful under about 2000 rpm as the valve events start to move faster than the duty cycle of the injectors and they end up spraying on a closed valve anyway at upper RPM's. It was really developed for low speed emissions. After 2K your actually fogging the intake runner and letting the valve take it in when it can. I can save you some coin on the injector rail: Just grab one off a Magnum beer barrel intake. Im building a MS2.2 based controller along your same lines but using a Edelbrock Pro-flow system minus its closed source controller. I chose a 3-BAR MAP off a supercharged Olds for a turbo future. Most of the Edelbrock stuff is rebranded GM or Ford sensors anyway. You can also take a triple crank pulley and notch the unused pulley to make it an integrated 36-1 wheel. My aerospace machineist friend did that to a slant 6 damper I had and made the inner edge the trigger wheel. I learned later that wasn't the best idea as the outer ring of a balancer may wander a bit under varying RPM's. I used an EDIS-6 coil pack on the slant. The MS controls the retard only and the EDIS module controls the rest, timing is directly received by the reluctor wheel pick up. you can also grind 7 of the 8 teeth off an electronic distributor reluctor wheel for a sequential cam sensor. That is a nice tidy build.
                 
              • racerjoe

                racerjoe Well-Known Member

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                You are correct about the sequential FI. If I toggle between batch and sequential at idle, there's a noticeable difference.

                I actually started with a Magnum fuel rail, and it would have certainly worked from a functionality standpoint, but I decided the Edelbrock rail was a better solution for the look I was after.

                I spent way too much time overthinking the whole trigger wheel setup on this. It seems easy to just put it behind the pulley, but that won't work on a SBM. First, my damper is 1/2" thicker than stock so that pushes all the accessories out. I didn't really want them being pushed out another 1/8". That didn't matter anyway because the wheel would come in contact with the bottom of the water pump if I were to just bolt it to the face of the damper. Not owning a lathe also presented another problem, but I finally came up with what I have. I'd love to see others' solutions for this.
                 
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                • racerjoe

                  racerjoe Well-Known Member

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                  Who wants to talk about tuning? I understand lots of people are scared of it, which I really don't know why. If you know how an engine works, and have some computer competency, it's possible to learn.
                   
                • tanis4457

                  tanis4457 Well-Known Member

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                  What would like to talk about it in particular?

                  I'm currently running the Holley Sniper TBI EFI on my 360 in my 67 Dart and use their PC based tuning software to adjust that, I've been getting pretty comfortable and proficient with it.

                  I'm very close to also starting my batch fired multi-port EFI system on my 440 in my 76 Ramcharger using the DIY Speeduino EMS which uses Tuner Studio as the software, a lot of the features look similar to the Holley software so there's lot of overlap in the setup. I'm planning on doing a write up on my 440 EFI install once I get it up and running/tested...etc...
                   
                • racerjoe

                  racerjoe Well-Known Member

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                  Nothing in particular. Just throwing it out there in case someone has questions about it. Again, I'm no pro, but I can offer advice on what I've done so far.
                  I've never used the Holley system. How do you like it compared to Tuner Studio. I know you said it was similar, but do you think one is better than the other? Is the Sniper software different than the software they use for the direct port systems? I paid for the upgraded tuner studio and also Megalog viewer. Honestly, I don't think you will be able to dial in the tune without megalog viewer. I went for a ride to datalog several parameters and made a map with the data mimicking my VE table, only instead of VE values in the table (Z data point) I populated the cells with AFR. I then calculated how far off it was from my desired AFR and adjusted the VE value with the respective percentage. It was practically dead nuts after doing that. After I get everything close, I'll turn on AFR correction and let the computer do the fine tuning. It did a pretty good job prior, but was still jumping around a little since my table was so far off in some spots. It's nice actually seeing a steady AFR when driving.
                   
                • tanis4457

                  tanis4457 Well-Known Member

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                  I actually like the Holley system better, it's very intuitive once you figure out a few things. I do know the Holley Sniper version of the software is a little tamer than the full blown Holley EMS system as that has a more options for customization. I like how in the Holley EMS anything fuel related is in it's own side bar grouping as well as anything timing related and a few other parameters like system settings. With the Holley system you can look over your base tune and the learn table in seperate tabs and you don't have to apply the learn table until your ready, so I find that handy to be able to compare settings. I haven't played a ton with the datalogs as I was having issues getting them to save through the PC software, I had to re-attach the handheld to be able to send a tune to Holley to troubleshoot my 02 sensor (it went bad somehow).

                  Tunerstudio has a similar feel and finding things is pretty easy based off of the row of buttons across the top and the sub-menus associated with each one. I paid for the upgraded version of Tuner Studio to be able to use the auto-tune function, I would like to try out the Megalog feature as viewing and using datalogs can be quite handy. I've just gotten use to making changes on the fly and figuring what to do but would like to expand my capabilities a little. I'll have to try something similar to what you did.

                  Might be fun to start sharing tunes and seeing what everyone is using for settings or for fine tuning. I'm no bracket racer or anything so I don't care who looks at what I have going on. I'm in the middle of optimizing my tune again after the 02 sensor replacement and that can't happen til I get my valve body back in my transmission.
                   
                • racerjoe

                  racerjoe Well-Known Member

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                  I was trying it without the megalog viewer, but some things aren't noticeable enough changes for the human eye or ear to pick up. Also, there are way too many parameters to keep track of without it. I really wanted to dial in my idle and the megalog viewer really helped with that. There are some finite controls for idle timing so it helps to look at those values close up when trying to smooth out the idle.
                  I have no problem sharing my tune if someone wants to duplicate the components I have. Obviously there are several variables that will change the VE and timing table, but at least the basic setpoints can get someone started if they need help.
                   
                • BigBlockMopar

                  BigBlockMopar BigBlockMember

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                  I'm also using a MSX3 but controlling timing only on my 360ci.
                   
                • tanis4457

                  tanis4457 Well-Known Member

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                  What's the specs of your cam and are you using an auto or a manual? I'm a running a .040 over 360 around 9.8 compression with a cam of 241int/247exh, 532int/473exh lift center of 108, into a 904 with a 3200 stall converter.

                  I've been noticing that from cold through warmup I can get the idle to be stable but once I've been out driving around and I'm sitting at a stoplight in drive or in any gear I'll notice my vacuum gauge is lower and the engine is running a little rougher, I haven't really troubleshot it yet but I'm wondering if it has something to do with heat build up.
                   
                • racerjoe

                  racerjoe Well-Known Member

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                  How much vacuum do you have at idle with that 108CL cam? Does AF change when it gets rougher? And when you say rougher, do you mean it surges a little? Is the Sniper system running on speed density? Can the Sniper control your timing?
                  One thing I did to smooth out the idle is finite timing control. As you know, changes in timing affect RPM much faster than moving an idle valve. Therefore, when the RPM increased I retarded timing slightly. When RPM dropped, I advanced. This is on a finite scale now. I'm talking tenths of a degree and maybe a hundred RPM.

                  My engine is slightly more aggressive. 408ci, indybrock heads, solid roller -.594 lift, 278in/286ex, 112 LSA, 9.5:1, Tremec TKO500. I have about 13" of vacuum at idle. I had a much more aggressive cam prior to efi (106LSA) It was way to aggressive for a manual trans as it would make the car "jerky" at cruising speed. I never measured the vacuum with that cam, but I doubt it would have had enough to operate on speed density.
                   
                • tanis4457

                  tanis4457 Well-Known Member

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                  Yes it’s a speed density based system. At idle in park roughly 10” with it in gear in idle around 5”. The aft turns lean actually from what I remember so I might have to run it richer in that area of the fuel map. Yes the sniper is controlling timing. I have the car on jack stands right now due to me messing with the valve body. I noticed when I put it in gear the load of the trans and converter was enough to affect it similar to driving around so I’m going to play with it while the tires are off the ground and see what I can improve.
                   
                • tanis4457

                  tanis4457 Well-Known Member

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                  Took my dart out for a spin today after messing with the tune, ended up pulling some timing out at idle to around 24 and upped the afr just a tad, but the biggest plus was upping the idle rpm by 100 to 1100 seemed to help with my in gear vacuum.
                   
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