Megasquirt XJ

I am in the process of megasquirting my '92 XJ 4.0L. I have done quite a bit of research and am starting on actual build. I am planning on using the stock crank and dizzy signals for ignition on my Megasquirt1-V3 board running MSnS code. I am in the process of documenting all of my progress on a crude (but operational) website:
http://www.squirtingxj.exofire.net/

I was wondering if anyone else has implemented the MS? Or if anyone has some starting fuel and ignition maps to use?

If anyone has any expertise in this area I would really like to here about your experiances. I would like to keep the correspondence on the forums (to help more people).

I had an ex-girlfriend who used to....oh, nevermind....

What the heck is a squirting XJ?

Skwerly said:

I had an ex-girlfriend who used to....oh, nevermind....

What the heck is a squirting XJ?

Click to expand...

I thought maybe this belonged in the Den...the title sounded messed up enough.

lol, no it isn't anything like that. . . .
Megasquirt is a DIY engine managment system. By installing megasquirt it gives the user full control of the amount of fuel injected and ignition timing. It allows the owner to tune! If you havent been exposed to this do a quick google search and you will see how truely powerful this engine management system is and the best part is that it is CHEAP!
So those of you thinking about throwing that turbo/supercharger on your XJ. . .this is for you! ALL engine performance modifications are maximized with a good engine tune.

Megasquirt also has the capability of controlling numerous other features.

I hope to throw some pictures of my MS unit on my website.

I've been thinking along these lines myself, so I'd love to see your notes.

"MegaSquirt", for the uninitiated, is a DIY fuel injection/engine management setup devised by Bruce Bowling & Al Grippo (automotive technical writers, I believe. They had an advice column for automotive matters somewhere.)

The MS controller may be bought as a kit from any of several vendors, and parts lists and PCB artwork are also available if you want to totally "roll your own" - and schematics are also available, if you want to do it on breadboard or wirewrap board. The base programme has been made available - with explanations, so it can be tuned.

I seem to recall that the MS can be made to work on any gasoline engine with one cylinder or more. I've been thinking of using it for forced induction on the AMC six - or as a replacement for OBD (you'd have a better understanding of how the thing works - even if you didn't design it, you have the opportunity to build it from the ground up.) I think the MS controller uses standard GM sensors - available pretty much anywhere.

Google <MegaSquirt> or <Bowling & Grippo> for more information. There is also a Yahoo! group devoted to the MS - there may be more, but I only know of the one (and it's fairly low-traffic.)

I thought you were talking about the rear washer hose connection! I got me a tailgater today with my mega squirter!

But on a more serious note, this is interesting and new ground for me so I will be reading and learning.

Have you looked into anyother managment systems? We run a Microtech Lt-8s in our auto-X RX-7. Just from what ive seen id rather go with that or a Haltech rather then an Megasquirt. Just wondering why you picked to go with a Megasquirt i guess.

all of the data from that yahoo group has been moved to tech articles and the megasquirt homepage I believe. As far as implementing MS on the AMC six there is a writeup somewhere online that details the build specifically on that motor (it does make a difference if you use stock ignition sensors)

Here is the link for the 4.0L AMC spirit (I think)

http://amccars.net/cgi/yabb2/YaBB.pl?num=1180803230/30

To elabourate - I was actually thinking about doing forced induction control in one of two ways - either with a MS unit setup for six-cylinder engines, or by adapting the GM 60-degree V6 DIS (3.1L/3.4L) mount to the AMC block. Since both the 60-degree V6 and inline six are "even fire" engines (60* between all firing events,) either approach should be able to work. And, since there is a great deal of flexibility in (re)programming the GM system, that would also allow the system to be built using entirely OTS parts - except little to no soldering and such.

Sadly, I've not had the time of late to work on either idea. But, I'd still love to see notes and such on the current AMC242/MS project, and I'd happily play "sounding board" if you get stuck!

I am actually looking into something like this for my stroker. Especially since I want to eventually have a badge that says 4.7Lturbo. Looks like a great way to do it.

very interested in this, keep up the updates
MS is big on big turbo applications

Headed to the junk yard this weekend. Going to pick up GM CLT temp sensor, Air intake sensor and hack apart some unsuspecting wiring harnesses for nice automotive grade connectors. I am going to make a seperate wiring harness for the MS so I am able to go back and forth quite easily from the stock setup to the MS setup.

As far as the big turbo applications. . .that is what I am leaning toward. But I know those setups get expensive fast. Right now I am going to consentrate on taking control of engine parameters (via MS) then I might throw a low pressure turbo setup (w/ water injection possibly) to keep extra piping to a minimum.

Mega Squirt gets two big thumbs up from me.
I have built and tested a Megasquirt 2 with version 3 PCB board. Its a good project to work on ones soldering skills. I have a classic SAAB900Turbo that its going into. I know a buch of guys on TSL(saab forum)That have been running squirts in a number of diferent Saabs for years now.

A very cost effective , and easy to tune system.(with a Wideband) Theres lots of support, and software programs to run different Fuel and Ignition programs. Its simple and in case of newer versions quite durable.

A must with a custom forced induction setup, Only pitfall is OBDII vechicles and Pass state inspection tests.

When you were wiring your MS did you create a whole new harness for the MS system? Or could did you splice most of the lines coming from the stock ECU/PCM? Did you use the existing relay/fuse circuitry or did you create your own seperate "fuse/relay box"? Im starting to plan the actual wiring and would like some feedback.

Alright, I think I have a pretty good handle on the wiring. My real concern was the triggering signals being dirty. I think I have found a solution tho. According to my website I am going to use a voltage follower op amp. After thinking about this a little bit I have decided to use a PNP transitor to keep the load low on the orignal signal line while producing a nice +5V squarewave (same as original signal) to my MS. The op amp circuit only gave values close to +5V and GND. I didn't want the little stray voltage to be decided by my microcontroller (not sure if it'll read a 0 or a 1 then).

If anyone has done this similar thing did it have good results? I am planning on building a mock circuit to try (simulating with a function generator) tomarrow at work.

I would go with an op amp / comparator and use some hysteresis to prevent false triggering.

MS is generally used on turbocharging non-factor turbo cars, but it would also be a SAWEEET way to get extra power of a budget built stroker motor. If you're gonna strap on a turbo, i'm guessing you've got a pretty fresh block though...but just for other ideas.

are you only concerned with needing to clean up the power because you are splicing off your ecm? Nobody I have talked too needed to do this. I was planning on completely replacing the jeep ecm with a megasquirt located in the cab. We got a thread about this going on horsepowerjunkies, and a guy local to me has been playing with this for a couple of years.

I have yet to install squirt in car, still got to build motor first. I am going to build a complete /non spliced harness. I like the megasquirt relay board, but I found useing a relay center out of some junkyard car allows more room to grow.
I built a extra relay center for my 00XJ using a relay center from a 96Xj/ZJ. Cannabalized a bunch of GM wiring connectors in various wire counts, and soldered all connections and pins so no splices were needed. I relayed lights and extra cooling fan. Still have room for four more circuts, plus mini and Maxi ato fuses. I sure same thing could be done with squirt.
Wolfgraj, are you going to try to run the Direct Ignition rail from a 00,01XJ. Saab has a similar DI rail.I am gioing this route. I have to fab up a crank pick up using a VR sensor off a Ford, and a custom CAM sensor (optical). I know of one saab owner who uses this setup. Has to fire all coils at same time(wasted spark) but I think you can make ignition firing squential.

I'd like to Squirt my 00XJ but still retain stock ECU for emmisions testing.