Another ITB Megasquirt and EDIS setup experience

[quaz]

Hey everyone, I want to post this information on ITB's, Megasquirt and EDIS so there is another thread to reference for DIY EFI. My 71 still had the Zeniths and Marelli dizzy on it up until last year. Although both of those components are good quality, finding parts and service for them are becoming very difficult. Not to mention with increased amounts of ethanol in our pump gas carbs tend to deteriorate just by sitting. As I came to find out through tuning the new EFI my old carbs and dizzy both had serious issues, but more on that later. So here is what I learned over the last 2 years.

First what manifold/throttle body/injection setup do you run. I kicked around the Tbizt kit, looked at buying throttle bodies and thought about making my own from scratch. Here are some links to the various out of the box options.
Borla-TWM Induction - Throttle Bodies (423) 979-4045
Kit: Porsche 911
PMO High Performance Porsche 911 Carburetion

Since I already had carbs all I needed was the actual throttles. I had manifolds and linkage. Then I stumbled upon this thread a few years ago and built my ITBs just like these.
Project ITBs: Part 1-parts arrive

One thing to keep in mind if you go the route of the ITBs is sizing. Every one thinks bigger is better, but everything I have read points to the same thing. If your ITBs are too large you will have a hell of a time tuning them in. There are unique challenges to tuning 6 throttles even when they are properly sized, but when they are too big it makes it that much harder to dial in. I setup my system for the 2.2t engine and went with GSXR600 throttles which are the same ID as the original Zenith carbs. If my calculations are correct I could run up to a 3.0l on this setup. Any more displacement and I would have to go up to 750 throttles. Here is some info on sizing and the GSXR throttles.
Sylva Mojo Build Diary
Jenvey Fuel Injection Throttle Bodies for motorsport
Final notes here, I used the stock injectors from the GSXR 600 throttles. They had enough flow for the 2.2 and should be good up to about 200hp. If you need more then that there are a lot of places that sell upgraded injectors for these ITBs for modded GSXRs. Otherwise you can fit Honda injectors in the bungs which have as many options available. Use an injector calculator to figure out the proper size of required injectors you will need. Like ITBs bigger is not necessarily better. Injectors too large will make tuning the fuel difficult.
Injector Size Calculator

I did consider the Tbitz kit and will keep my comments to a minimum here. I like the all in one package/support, but I would have had to go to a single manifold. Since I wanted to do ignition I would have been off the reservation from the word go. If you just want to add MS and do not want to do ignition and you already have the correct manifold this is a great setup. You are a search on this site away from great info about it.

Next on to ignition, all I can say is this. EDIS is EASY! If you have any hesitation about EDIS you don't need to worry. It was so simple to setup and get running. If anyone asks me what to do for ignition I am going to have only one answer EDIS and here is why.

Can you do direct ignition from Megasquirt? Yes you can. What do you need to do to get it working? Well it is as easy as first getting your trigger wheel installed, getting a VR/Hall sensor pointed at it, finding a coil pack that you know the dwell and resistance times on, modifying your MSII main board, set your sensor pots, make sure all the ignition setting in MSnS are correct, don't overhead your drivers, track down all the noise in the system, figure out why your trigger wheel isn't being read correctly, build new trigger wheels, figure out firing order of coil packs, try new VR sensors, email 47 people on 10 different lists, beg for help from anyone on the street………….

I gave up.
(Did I mention I killed my starter doing cranking tests trying to get this working? Oh well I needed to upgrade to a mini-starter anyway)

EDIS worries about all the crap above for you. Get a trigger wheel and sensor holder from here:
Blank
Or you can make your own trigger wheel and sensor holder. Not that hard to do, but premade is easier.
Get a complete EDIS 6 setup from Ebay or here:
Boost Engineering - Advanced Engine Management
Also get EDIS coil pack ends from boost engineering and just put them on the coil pack side of your stock wires.
You will need to study this page a bit and make sure you understand how to install it.
EDIS Ignition Control
Now a couple of notes on wiring EDIS. First I strongly suggest going to a junkyard and finding a Ford Explorer or Windstar with the EDIS 6 kit on it. Then pull the entire wiring harness off the engine, you can grab the entire setup at that time, but it won't be bench tested like the ones from BE or Ebay. Maybe pick them up as spares. Anyway, with the harness from the original car you will have way more lead wire than you need and all the colors will be correct and match. Now you can just trim your wires down to the lengths you need instead of having to splice in shielded wire in different colors. Everything will be as Ford intended it….LOL on your Porsche.

Once all the EDIS stuff is installed, two wires goes to Megasquirt, and one to your tach. The rest is all done by the EDIS controller. If you do run into a problem with the VR sensor and trying to get polarity correct here is how you sort it out. Put the sensor on something metal/magnetic and then pull the senor away with a multi meter on the ends. If you get negative voltage then you have the positive and negative leads on the multi meter correct. If you get positive voltage reverse leads and try again. You now know what is the positive and negative side of the VR sensor.
Once mine was wired correctly my car started on the first crank. Now makes sure you have all the megasquirt settings correct from here:
Configuring Megasquirt for a DIYAutotune.com trigger wheel
This Diagram is for EDIS in a dual plug setup, but ignore the second controller for a single plug setup:



As for the Megasquirt ECU I got if from DIYAutotune.com and would recommend them. At the very least get the MSII ecu, but the MSIIIs are out now. If you can pop for that do it. They were not out when I ordered mine, but I may upgrade to it. With EDIS you don't need any mods to MS. You will then need to order the following:
ECU
12' harness
4 and 6 pin weather packs (if you want to be neat)
Optional relay board (I didn't use it)
CLT/OIL/CHT sensor and harness
IAT sensor and harness
Wideband O2 sensor and bung (I got the LC1)
I did order some extra wire, but you really don't need it. The 12' harness is so long you will have plenty of extra.

Last is the fuel system. If you have CIS or a 71 and later car you already have to and from fuel lines to the tank. If you have a 70 or earlier with carbs you will need to run a return line through the body. All the lines I added were braided stainless with -6AN fittings. The fuel pump is a Walboro LPH255. I just got a generic adjustable FPR and gauge. Everything fuel related I ordered form Summitracing.com . One note on the fuel pumps, apparently there are fake Walboro pumps floating around. Order it from Summit and you won't have a problem. Order from Fleabay and more than likely it will be a cheap Chinese knockoff with plastic internals.

I think that covers everything you will need other than a laptop and Tunerstudio. So here is how my install went.

As noted above I built the ITBs from the GSXR assemblies and they already had a TPS and vacuum ports. All the vacuum ports on the ITBs are plumbed into one collector manifold and then one line goes to MS and one line goes to the FPR. I used the stock carb linkage but had to make custom brackets on the ITBs to mate up with it. It all looks pretty stock completed and adjusts like the factory carbs did for syncing.

For the CHT I used the GM CLT sensor, but secured it on one of the heads between the fins. So far it reads CHT very well, but I want some more miles on it before I say this is a good route to go. Others have used oil temp sensors or crankcase temp sensors. I think as long as you have your engine temp close to the block and reading whether it is warmed up or not you will be good. The IAT sensor just goes into one of your throttle assemblies and reads the incoming air temp.

As I was adding wires to the engine I unwrapped the entire stock harness and removed old unused wires. If you are anal like me and you still have an external regulated alternator you can get rid of more wiring by going to a newer internal regulated unit. I know some don't like these, but I got one from our host and pulled out all the old wiring I didn't need. Every connection I made was soldiered, shrink wrapped and then taped. I hate crimp connectors and didn't use a single one. From the engine to the car I used a couple of different weather packs to create removable connections when I drop the engine.

Continued in next post........

[quaz]

I think this process is very important. Take your time, make sure you have all your wiring diagrams out and available and don't guess. Check and double check everything. Tracking down wiring problems is a PITA. I only had one wire to flip and it was on the TPS which I guessed on.

Setting up the fuel system is time consuming and again don't be afraid to do something over if you don't like how it turned out the first time. I used a mix of hard and braided lines to make my fuel rail loop. I didn't use any claps and bought a flair kit to put ends on all the hard lines. Once everything is assembled check and double check for leaks. I had one leak because my fuel rail was not sitting right. It was a little scary to see fuel dripping on first test. Fixed that and now I seem to be dry. I am also still monitoring the car after every drive to make sure it stays this way.

As I mentioned earlier install the EDIS and crank wheel and wire them into MS. The Tach output from MS will drive a 74+ tach with no adapter. I bought an SC tach for my 71 and swapped over the needle to keep it looking stock. Hollywood speedo can also rebuild an older tach with newer internals if you want to retain your original gauge. While you are in there you could go to LED dash lights?????? I didn't but it is now on my list of todos. My tach works perfect and I don't have the floaty bouncy tach I was used to with the old system.

I ended up putting the coil pack where the original dizzy was, the EDIS where the old ignition module was and my fuse block where the old alternator regulator was. The old wiring harness and new MS wires were merged into one new wiring harness and taped back together. It looks like the original factory harness did.

Next time I pull the motor I will get a bit more picky about how some things are routed, but until then I am happy with this setup.

Here are some pics of my finished setup:





Once I had EDIS installed and got a base file from someone on the Tbitz list it started up right away. However it ran for crap. This is where you need to do a lot of learning. I read the MegaManual over and over again. Read this thread: EFI Kicks A$$ - the ST goes electric and this site Tuning ITBs - 77e21.info over and over again. With Tunerstudio you can to a certain degree just turn on autotune and let the car tune itself. However you still have to understand what you are tuning and be very careful. I just about have my car done, but still need to dial in the acceleration enrichment. I put the car way for the winter, but next spring I should be able to dial that in with a couple more drives and some logs. Don't get discouraged here, you are 90% done with the process and just need to get it dialed in. If you have a 2.7 or 3.0 there are enough starter files floating around here you should be close out of the box. If you need a 2.2 starter file PM me and I can get you started.

Some notes about code. I am an IT consultant by trade so I have years of loading code, debugging and analyzing dump files under my belt. For me this is the fun part because I just do what I do on a daily basis. If you are not a computer programmer or engineer you may get a bit frustrated doing firmware upgrades and analyzing log files. Just keep at it and ask questions on this forum: Megasquirt MSEXTRA and MS3EFI support forum • Index page

Currently I am running the 3.0.3v code and just noticed 3.0.3x code got released. Megasquirt MSEXTRA and MS3EFI support forum • View forum - MS2/Extra Development This is considered beta, but enough people are running it that it is very stable. My car runs the best so far on this code stream. Also the 3.0.3 code for MS2/Extra has ITB mode for tuning. This eliminates the need for blended tables and mixing alph-n/baro maps. Once I got this setup my car has run better and better the more I drive it.

Last note on tuning fuel before I turn to ignition. Idle is a tricky beast and don't rely on autotune to get it correct. You will have to get some log files and run it through Megalogviewer or manually adjust based on your AFR and RPM. Look at your tail pipe, if you see smoke and your idle is rough you are too rich, dial back the fuel and look at your acceleration enrichment threshold. Once I got this correct it instantly made driving the car much better because you don't have to worry about it killing every time you come to a stop.

Oh yeah and if you have ever setup carbs you know that balancing your banks/cylinders is also crucial. I have mine just about perfect but will probably tweak them one more time. I could never get my old carbs balance and suspected they needed a complete tear down and rebuild. After dialing in the ITBs I confirmed that suspicion because I was able to get them all very close to each other in about 10 minutes.

On to ignition, part of my beef with my car pre efi was I could never get the ignition working correctly. In hindsight I know now my advance on the Marelli dizzy was not working correctly. If I set the base timing where it was supposed to be the car ran great to 4K rpms, but then felt like crap. If I advanced it 10 degrees it drove greak 3-6K rpms, but missed at idle and had no low end power. Since I had no ignition map to go from I used this diagram of the stock curve:



From that I built a static map and have only started to tweak it up and down for drivability. I don't plan to go out of factory specs, but I think there is some additional power/drivability to be had in a couple of spots. For the 2.7s and 3.0s I have seen some maps floating around and if you search/ask you should be able to find them. Here is what I am running right now:



What I have left is acceleration enrichment for full throttle and some final tuning for gas mileage. Also full throttle mixture tuning for power. Hopefully by end of early spring I can get the laptop out of the car and just start to drive it. At that point I will probably even pull out the wideband and activate the narrow band for cruising. Next year there are supposed to be some versions of Tunerstudio released for Droid or Iphone. That will allow in car logging without a big laptop. Hopefully that code will come along.

The only other problem that haunts me is fuel pressure and I am debating on what to do about it. When the tank is less than 1/2 full I get some variation in fuel pressure because of swirling in the tank. I am debating putting in a second fuel pump and accumulator tank somewhere. It isn't a problem with a full tank down to 1/2. Otherwise I may swap out for a later gas tank. Over the winter I will research both options a bit more and figure out which one makes more sense.

I am kicking around the idea of putting together a DIY kit with MSII, EDIS and some directions and starter files. However I would want some feedback whether anyone would want it and if anyone would be willing to help beta the setup on various cars. There are already great ITB kits and docs on DIY floating around that I won't go there.

Ask away with questions and I will dump my brain out as much as I can. Part of this thread is to preserve what I have done so others can reference it and I can look back on it over time myself and remember what I did.

[mholbrook38]

This is terrific information with lots of links to look at. You guys up in the frozen north have long winters to work on these modifications. It is great to benefit from your experiences. That engine compartment is about as sanitary as you can get one. Down the road I want to lose my CIS and go to FI and a better ignition. I don't really need more power but want as close to total reliability as possible. You have done a great job there.

[hawaiipcar]

Thanks quaz excellent write up with usefull info.

[mytoy]

quaz

What perfect timing and what a thorough write up!!!!! I am debating the cis/efi scenario right now as well. That EDIS/MS kit would be a welcomed addition to the Porsche modifiers world. If you don't mind me asking how much did this whole system cost you?

Thanks for the great insight

[psalt]

Does your spark advance table read less advance at lower load ? Is "Ign load %", kPa from the MAP sensor ?

[quaz]

The load on that table is a bit misleading because it is a blended kpa/tps table. There is an imaginary diagonal line in that table where the switch from kpa to tps occurs. Some of the values on the lower right will never actually be hit and are just place holders. Other values are lower for throttle off decel. That table is a work in progress, but it is where I am at today. I am trying to start very conservative on that table and dial in advance where I can. Also remember this is not a boosted car. So 100% load is full throttle zero boost. If I were to add boost the top half of the table would all be dialed back significantly and the scale would be changed.

As for cost I really would rather not total everything up, but here is a swag.
ITBs, boots and rails ~$350
Megasquirt, sensors and wiring ~$600
Fuel pump, fittings, lines ~$600
EDIS, plug ends, crank trigger wheel (most of the cost) ~$600

I am sure there are other odds and ends in there, but figure I have somewhere between $2000-2500 in this setup. Some stuff I over bought on, some things I never used or repurchased because I found better solutions.

[psalt]

A load based table of a properly tuned engine would show much more advance at part throttle cruise. If you are really only running 17 degree at low load cruise, you are leaving at lot on the table in terms of efficiency.

[quaz]

Paul, I have never tuned an ignition table before so I started with a static map based on the original dizzy curve and I am adding advance where I can from that. You are correct in that every ignition map I looked at to this point has more advance at part throttle. When I get it back out next year I am going to work on that. If you have something I could reference to dial it in quicker it would be very helpful. Ignition maps are the one resource I couldn't find much documentation on.

[psalt]

Kevin,

Plenty of discussion on this site about programming EFI and factory ignition maps, search and you will find the Carrera map and comments. I have over 12 years experience in EFI conversions and here are a few comments. It is a good idea to copy the distributor advance curve with the understanding of the period and the factory fuel octane spec . If you go back before the 68 emissions laws, you will find vacuum advances that add +10 degrees of advance under low load cruise. When the curb idle HC test came in, the vac advance was replaced by retard for emissions only, mpg issues came later. The last distributors in the SC had both, after the fuel embargo. The mechanical advance is the full load timing the engine can handle without detonation. Efficiency at part throttle will improve out to 45-50 BTDC. When you study the later maps, you need to understand that the factory was raising compression and retarding timing because of the mandated unleaded fuel spec.

[luvndasun]

What do you think about using one EDIS controller and two coil packs for a Twing Plug engine?

I have bulk 8mm ignition wire and have to install the ends. Did you need any special tools for the assembling of the ignition wires? On the EDIS coil pack end, its seems like you only need to crimp the ends, and the spark plug ends are screw on. is that right?

Did you have the engine out of the car for your install?

[quaz]

The only reason why I see using 2 EDIS controllers would be for correct dwell time? However if they both had independent 12v sources the controller closes the ground to charge the coil, which should be the same dwell time for both packs. Let me think about that one, or maybe someone else could chime in.

As for the plug wires I just crimped the EDIS ends on the coil side of the stock plug wires. I didn't use any special tool, just a small needle nose pliers. So I didn't even mess with the spark plug end.

For the install I did a partial engine drop in the back to get the crank wheel on. For this I had to remove the rear bumper, exhaust and remove the rear engine support. At the same time I welded an O2 sensor bung into both headers. The rest of the install was done with the car back together. I could see working space being a bit tight with the stock CIS manifold, but with ITBs I had plenty of room to work.

[luvndasun]

I guess I'll go ahead and get a second controller. They arent that expensive and it gives me a back up if one of them fails. Even if it is not absolutly needed, it seems like good cheap insurance.
Thanks

[coilbox]

Wow, nice info here. Thanks!

One question about the rev counter, does the tacho signal from EDIS go straight to the cluster?

[quaz]

Yes pin 2 on the EDIS harness goes right to the back of the tacho. Mine was a purple wire with a black stripe. I think that same color code goes all the way through the SCs. I pulled that wire out of the factory harness in the engine bay and spliced it into the EDIS harness. Works perfect!

[jpnovak]

Hey, I don't know how I missed this one. Great work! I am glad to see someone else using the MC - ITB system. I still have mine and they are reserved for an upcoming build. Almost super secret.

Here is a timing curve for the 89 US Carrera. Thanks to Sal C for posting these in a previous thread. You can build your timing curve based on these numbers.

First, the WOT line is your 100kPa. Then you can scale the rest based on your idle and cruise load points. The load % can be correlated to MAP readings at different engine conditions. There is not a direct scaling factor but you can have a good idea of how they relate. Notice the high advance under lower load conditions in the mid-rpm range.

Also keep in mind that your peak TQ and HP rpm locations will be different than a Carrera due to the cams. You can look at the general trends for timing based upon published values for peak TQ and peak HP. Notice the subtle ramps and drops relative to these two reference points.



If you have a knock sensor installed you can make some fine adjustments to this curve.

[quaz]

Jamie, I have to thank you for your write up on how to build the ITBs. I built mine to the T based on your thread. I was studying pictures for weeks making sure I knew what I was doing when I built them. I have to say out of all the setups I looked at that was the cheapest to aquire, assemble and tune. The linkage was even easy to adapt. Being able to separate the throttles and having the plastic boots to mount them makes it the perfect setup. Hopefully there are enough threads now for some really good blueprints on how to do this.

Also thanks for that ignition map. I am going to take a good look at that this weekend and try to extrapolate a map for the 2.2 from it. Unfortunately I won't get to try it out until next spring, but hopefully by then it will be ready to go.

[psalt]

The Carrera map show higher advance under part throttle light load, the opposite of your spark table. It shows 41 BTDC advance at typical highway cruise load and rpm, where your map is decreasing advance and shows 17 -19 at similar load. The puzzling part is the below 10% load figures, which is probably an emission test driven exception.

[quaz]

OK, now that I have some time to really look over that Carrera map I see what all that advance is for. All the places where the advance is really high is under deceleration which makes sense. When decelerating you want resistance on the engine to slow it down. By firing before the compression stroke is finished you create force in the opposite direction of the engine rotation further slowing it. Since there is very little fuel there isn't much chance of doing damage.

For example look at the idle map on Carrera. How do you get to 4000rpms at zero throttle? Easy you accelerate to 4000rpms and then let off the gas. Once you let off the gas you advance the timing to slow the motor. It is the opposite of starting the car where you retard the ignition to help on power strokes. That map also corresponds with my fuel map where I decelerate.

The map I created is based on the curve of the T dizzy. From what I have read the head design of the 2.2 combined with the lower compression resists knock better than the later heads. Also why the 2.2s motors didn't need dual plugs to achieve higher HP, but have less advance at high RPMs.

Anyway, here is that Carrera map with some notes on it. I will post my fuel map tomorrow when I get time and you will see the correlation. I probably need to add some of those advance numbers to help on deceleration. I am learning a lot here.

[mppickett]

Kevin,
Super write-up and beautiful work! This is one of those threads that folks will learn from for years.
Cheers and best of luck.