MEGASQUIRT!, Need some info plz. Options

[lapuwali]

I beg to differ. The D-Jet wiring harness should be mostly usable. Certainly, you can use the air temp, CHT, and injector connections. The cold-start system can be left as is. The ECU connector would have to be chopped off.

It would be a better install if all new wiring was used, but we're talking minimum costs here.

[teen914]

if you want to learn about megasquirt, talk to my dad (dnhunt). we installed megasquirt on our car about three years ago, and it works well.

Gerry

[teen914]

i just realized that my dad had a website and it has a lot of information on megasquirt. here is the link

[JeffBowlsby]

I thought about this very approach sometime ago and agreed with the initial concept, but with all due respect and only after significant research, I don't see how it is all practical or reasonable to reuse any original D-Jet harness for any PEFI application for at least these considerations:

* Virtually all original D-Jet harnesses are at the end of their service life. The casing is hardened, cracked and brittle and internal wires have wire insulation that is typically hardened and cracked, wire terminals are corroded and loose. The possibility for internal shorts is great. Why go to all the effort of a new ECU/programming if the circuitry or connections are dubious?

* The harness circuitry is substantially differently for the D-Jet system than PEFI and would require extensive modifications to work. If it could be made to work at all, there would not be much more than a few wires remaining of the original harness. For instance, D-Jet injectors have only a 1-wire control circuit each, the second wire goes to ground internally within the harness. PEFI requires two wires for each injector from the ECU and if the stock low-impedance injectors are used, 2 wires are needed at the ECU for each injector. The injector ground wires in the harness do not go to the ECU location, they are internal to the harness, so 4 additional wires would be needed for the injector circuits at a minimum.

* The 4-wires for the MPS could be abandoned, thats ok. They are too early in the harness to be useful for another purpose unless they were extended.

* The 2 CSV wires could be abandoned, one of which goes internally to the TTS and the CSV and TTS will likely be abandoned too.

* The simplest AAR setup is to use the stock AAR valve and circuitry, both of which are external to the D-Jet FI harness. This approach works, but it seems most 91 4owners want to use a new solenoid or stepper motor which requires more and bigger wires.

* The 3 trigger point wires could be abandoned, or extended and reused, if shielding is not required.

* Using the stock D-Jet harness implies that the new ECU will be in the stock location because of the existing harness length. I support that personally, but the ECU mfrs recommend a dry, cooler location out of the engine bay, so at the very least the harness would need to be extended. This might require soldering or multipin connectors to extend the existing harness length.

* The single TS2 and two TS1 wires could be reused as they are, I concur.

* The 4 TPS wires could potentially be reused, standard potentiometer TPSs only need 3 wires, but shielding will likely be required.

* A shielded coil wire will probably need to be added, but that could be external. This circuitry will vary with the triggering device...optical, crankfire or....What I am hearing is that triggering off the coil for digital electronics is not recommended and is likely to be problematic. An optical trigger like the Crane is about the least costly solution.

BUT, there are more significant issues to address.

I have been working with 2 EEs to develop an aftermarket PEFI harness specifically for the 914. We are in process, but its not complete yet. Both have spent substantial time looking at the various systems including MS and others. Both have concluded that certain wires need to be larger gage than stock and other wires need to be shielded or twisted pair. Apparently digital electronics are significantly more sensitve to cross-talk between adjacent circuits than the D-Jet system. After much discussion and research, they have concluded that its best to physically separate certain branches of the harness which by definition requires a different configuration of the harness compared to stock D-Jet. Also it has become apparent that stock grounding configuration which carries the ground through the 3-prong ground lug at the back of the engine and then the tranny cable is not at all sufficient. An enhanced FI ground system is required to assure reliable service.

So I count only a few wires that might be reused and even then only if the wires are serviceable, the rest of the harness substantially modified or replaced. For the reasons above, I would not bother trying to reuse an existing D-Jet harness.

[toon1]

Jeff, thanks for the info. I am going to setup my MS system soon and was thinking that the stock D-jet wiire harness would work. After reading your post I am going to order the aftermarket wire kit. Thank's

[mightyohm]

If you don't want to spend a lot of time learning about fuel injection and messing with the configuration, Megasquirt is not right for you. I can say through personal experience that it is a lot of work to do right.

[ischmitz]

I agree with what most have said. Megasquirt and Megasquirt-II are very versatile and powerful systems when it comes to fuel injection and ignition control.

Compared to other systems you get a lot of performance and bang for the buck. I believe it is better than most 2000$ to 3000$ systems out there. Since MS and MS-II are not designed for a single application the first step is to understand what you really want to do with it. Applications range from a simple piggy-pack setup to richen up the mixture all the way to a crank-fired EDIS setup with boost-controlled water injection and sequential fuel injection. On top of that the CAN bus allows communication with other modules (O2-sensor, transmission control, etc) Welcome to the modern world of car electronics.

The first downside is that you do have to understand how fuel injection and engine management works. If you don't you have to be willing to learn. There are tons of resources out there to read up on. It'll save you costly mistakes.

Second, you need to have all the right tools. Without a wideband O2-meter I don't see a way to properly tune an A/F map. Best case you leave HP and drivability on the table. Worst case you burn or blow up your engine.

That being said if you are savvy with a soldering iron it is fun to build it yourself. I have done the work on Mike's 356. We have had the advantage of having a base motor that already had the fuel injection (CB Performance) installed. It was pretty easy to "throw in" the MS-II. I got it to idle with two days of work.

The tougher part is to tune the system properly. After we got the 356 to start and idle we did some driving with me running the laptop and Mike at the wheel. We had the wideband hooked up and had the system to autotune the A/F map. Sure enough we broke down right in front of the cops on the ocean front.... and the laptop battery was nearly dead. The car wouldn't start for almost half and hour. Turned out Mike handiwork allowed the main ignition cable to short to the braided oil line killing the spark. Meanwhile I had screwed up the tuning values thinking that we had a fuel issue.

Those are the things you have do deal with. However, it already runs nicer than it ever did with the old Delco ECU. Next is to convert to crank-fired EDIS and make sure it runs properly with boost dialed in.

ingo

[JPB]

i just realized that my dad had a website and it has a lot of information on megasquirt. here is the link

Great job on the link thank you for all of us.


(IMG:style_emoticons/default/smilie_pokal.gif)

[JPB]

Nice info fellas. I guess a brand new and improved harness is the ticket. Keep the info coming please.


(IMG:style_emoticons/default/beer.gif)

[Mueller]

The first downside is that you do have to understand how fuel injection and engine management works. If you don't you have to be willing to learn. There are tons of resources out there to read up on. It'll save you costly mistakes.
ingo

In my opinion, one needs to learn and have a basic understanding of FI and engine management no matter what system they purchase and install, even a $5,000 MoTec will be as useless as a brick if one does not have a basic of FI and how each sensor and component reacts and is used.

[Brad Roberts]

So. The question is Jeff... when? when will you have a ready harness for us? Something that plugs into the MS setup?

I totally agree the stock harness' are dying a slow death. I'm amazed they have last this long.


B

[DNHunt]

Brad

One of the problems with MS as a kit with harness is the very versitility of the thing in the first place. Unless everyone is custom configured you end up right back with other PEFI. The beauty of MS is it's DIY and you can set it up the way you want. But, to get what you want out of it you have to learn about it and put it together with the stuff you want.

I love my setup with EDIS and I'd love to help someone put one together. But, if anyone wanted to do it for some profit you'd end up right up with the systems on the market pricewise.

Dave

[JPB]

Friends, greatness has no price.; If the Megasq system is the ticket, we can all benefit from it. Perhaps someone can just fashion a specific part as the next individual can also and we all can be part of the price/profit game. Some can weld good intakes, some can solder wires, others just have the proper data to enter into the system for a quick trial without failand others just have the ability to make this conglomeration of equippment work on paper. The question is, what can you do to make this a possibility?

(IMG:style_emoticons/default/beer.gif) A couple of beers latter and we are all brothers.

[JeffBowlsby]

when will you have a ready harness for us?

We are making good progress on it, the initial engineering work is mostly done, but it will be a few more months at least for prototyping and testing.

My view of an FI system for an automobile is that it should be durable in the long term without overkill. Many of the custom wiring jobs I have seen are more of a temporary nature and not reliable long term. Anyone going to the trouble of a PEFI conversion should expect trouble-free service of the install measured in multiple years, even decades, not months. That level of quality costs more money initially, but keeps you on the road and gets you there faster.

SDS provides a harness, a set of harnesses really, but its not complete in that the wires are not protected with casing and they do not provide the rubber D-Jet boots to weatherproof and provide stress relief to the connections and other issues encountered trying to adapt a universal harness to a specific car. I dont like how they install the injector resistors and other details, but it is probably the best beginning of any system on the market for a good harness.

The MS and Emerald harnesses are simply a bundle of wires pre-mounted to an ECU connector. They are not expensive but they also require lots of work to complete. Its not waterproof, not cased, not terminated with connectors and no consideration is given about how it mounts in the 914, because it is a universal harness. If the ECU is in the cabin, then the harness must penetrate through the firewall...so if the engine is dropped, one has to dismount every connection on the engine? It is an incomplete solution, there are better ways, but it only costs time and $.

The 914 PEFI harness I am developing will be durable and applicable to all or most aftermarket FI systems, and a solution specifically configured for the 914, with some degree of customization depending on owner preferences for triggering, cold air intake chices etc. They are more time consuming be overdone.

[Joe Bob]

That's next....I have the complete EDIS and just waiting on the machinework for the crank sensor and the plug for the dizzy hole.....

[lapuwali]

I'm sure Jeff's harness will be an excellent part, based on what I've seen of his work. However, I agree with Dave Hunt that the market, esp. for MS buyers, will be vanishingly small. MS is all about DIY and inexpensive. It's not about premium products. Jeff's stuff is very much premium quality, and priced accordingly. Nothing at all wrong with that, but it just doesn't mesh with the MS crowd.

SDS provides a harness, which also limits the market for a harness of any quality level.

If Emerald or others start to make inroads, perhaps there will be more of a market for these high-quality harnesses.

Now, one way to have more of a market would be to provide more of a complete turnkey system, with a pre-programmed MS in a good case (perhaps hidden inside a D-Jet case), with a good harness, so the whole thing was pretty close to plug-and-play. THAT would probably sell well, as the people who didn't want to DIY will nearly always pay more for an easy to install system.

[Mueller]

I'm sure Jeff's harness will be an excellent part, based on what I've seen of his work. However, I agree with Dave Hunt that the market, esp. for MS buyers, will be vanishingly small. MS is all about DIY and inexpensive. It's not about premium products. Jeff's stuff is very much premium quality, and priced accordingly. Nothing at all wrong with that, but it just doesn't mesh with the MS crowd.

LINK sells a complete and proper Type I/IV specific wiring harness, price is about $950 (IMG:style_emoticons/default/blink.gif) I bought the cheaper unfinished wiring loom for $150....the wiring harness is the hardest part of the install I'd say....

[yarin]

I did roughly the exact same conversion that you are comtemplating.

I had dual weber 40s, thankfully they are SOLD.

The entire conversion cost me a bit over $1000. I built it all myself. I ripped out the entire fuel system, tank, lines, and started from scratch. I'm sure it payed off, i found some stuff that makes me want to (IMG:style_emoticons/default/barf.gif) .. but anyway.. check out this link for pics of my install:
http://www.flickr.com/photos/infinitelydig...57594124768996/

I bought all 2.0 parts (TB, injectors, plenum, runners, fuel rail, fuel pump) for about $150.

Regardless of which system you go with you NEED an Innovative LC-1 wideband O2. I bought all of my MS stuff and the wideband from DIYautotune, hell of a guy over there.

I bought their 12' single ended harness, crimped a connector on, built all the other harnesses, check out the pics. I haven't had a single connection issue yet.

Best of luck!

[Joe Bob]

I've come to the same conclusion as well..my Innovate wide band is sitting on the desk at home waiting for the install.

Now if I can just find some dyno time someplace....

[crash914]

if you want to just replace either a stock system or upgrade, get one of the packaged units. SDS, Link, etc.

The MS system is for those that like to tinker and play, you will find that you flash your program just because there is an update. The nice thing about MS is that there is lots of support on the net and now with 914's. both stock and hot engines. I have had mine for about 4 years now. I still tinker with it. its for fun, and because I think that I can improve something. I have had some issues with getting the tuning just right. But then its a 80 by 103 big valve motor with soon to be lots of compression and not much vacuum at idle. Again I like to fool around with it. I also know that it is reliable enough to just drive if I want. it has never let me down.. The connectors are or could be an issue. I made one, then made another and I carry it with me just because if I don't , i might have a problem. both my ecu and relay box are inside under the passenger seat. if you like to work with electronics, don't have a big ego and don't mind asking questions, ms might be right for you.....