zapo

Hi all. New guy needs help.

Here is the situation. Got a 89 Camaro with a 350 TPI swaped in where the 305 TPI was. The motor is basic with Just forged flat top pistons and a mild 212/212 @ .050 112LSA cam.

Right now with the stock 165 MAF computer It runs Ok on the road, idle is on the edge and usually stalls at idle in gear and/or stop signs. I have adjusted TPS and min air flow in different directions and found the best settings are still not good enough. The MAF sensor seems to come and go.

The car is supposed to be getting a Procharger, so i don't really want to buy an expensive MAF sensor and spend time fixing and tuning a 165 ECM. So to me a 749 or Megasquirt is the options.

I have used megasquirt on a completely DIY injection on my 473 CI mustang (yes ford...sorry). I know it works with enough tuning time and I am familiar with its tuning methods.

I have been reading here till my mind is exploding and am starting to get SOME idea of how's to tune 749 ECM. The ECM swap itself is not so much of a worry to me. Some rewiring on a stock harness after making one from scratch is not a problem.

So What do you think. I like the Megasquirt for being able to adjust fuel on a live table, a like the simple basic design. But I know how much work it takes to get OEM perfect starts and drivablity.

So what do I need to do for the 749 swap and beginning burning chips or flashing EPROMS?

THE LIST

ECM swap

-749 ECM and harness pigtail
-2 Bar Map sensor and plug
-Memcal from a 90 to 92 SD (730?)
-Knock Sensor from SD car (or a 4.0 ohm resistor bridged to ground on knock sensor circuit)

Tuning (this is the part I am more unsure of)

-If possible with the 749, a EPROM Emulation
-TunerPro

Any help will be much appreciated.

gta324

I use tunercat and xtronics romulator but there are several way to go.

For emulation
-Ostrich (moates)
-Autoprom (moates)
-Xtronics romulator

Program
- Tunercat
- Tunerpro

Sound like you have figured it all out....except that you can use a 1227730 ECM with the $58code, they are easier to find for less $$

/N.

zapo

Thanks for the response.

So anybody out there have experiance with Megasquirt and DIY Prom Burning/GM ECM tuning.

Trying to get a fair comparision, to help me make this decision.

89gta383

iTrader: (5)

There is nothing wrong with the 165 ecm, and I have a more radical combo than yours and it runs fine. I also ran the stock chip with the 383, crane 214-220 cam, headers and stock intake and it drove like stock. You have a mechanical problem somewhere. Maf sensors don't go bad once a month, so you shouldn't have to replace them more than once. The stalling sounds like not enough initial timing. I would check my basics first, it should run fine with the 165 ecm.

zapo

You may be right about the timing. This thing is back to almost Zero initial to keep the ping back on 94 octane fuel. But this to me is another reason to get some sort of programable EFI so that I can set idle timing to a proper level and take care of the ignition MAP separately.

The MAF sensor is pretty new right now, still has all the stickers on it (but from previous owner). I currently have a code 33 that comes up pretty consistantly. The car also runs very rich at warm up and idle. Once it goes into closed loop the computer corrects enough that gets rid of the extra fuel.

Tibo

iTrader: (15)

Mega Asquirted the Camaro since May. I love it. not as expensive and I think it is more user friendly than GM. However If you go the MS route, wait until MSII or Ultra MS come out soon.....

BMmonteSS

Just keep in mind the fact that your local autoparts store won't have any Mega squirts in stock when that gremlin under your hood decides to short out some wires going to your ecm. Luckily when that happened to me I was within walking distance of a parts store and I was easily able to pick up a replacement 747 ecm. Thats the big turnoff for any aftermarket ECM. Then again if your running somethin mean enough to outgrow what a 749 can do you'll probably have a trailer waiting near by.

zapo

It is true there are no megasquirts in stock at your local parts store. But when I fried the injector drivers in my Megasquirt with a Low impedence injector issue I did not have to spend $100 on a new ECM, but just a couple of bucks on some FET's at a local electronics repair shop. It is much more difficult to solder in a new Part than replace an ECM, but not a big deal to some.

But you are right in this case as the car is not my own and the customer lives 4 hours away from me, so it would be much wiser to use parts that they can come across easier.

Tibo

iTrader: (15)

If I am going to go too all of the trouble of building my own Mega Squirt and then writing my own code for it and learning all of it, I am going to know how to properly wire a car. Yes a 747 or 730 ecm can do this and that. Both have their own bells and whistles. If a person knows what they are doing though, Ultra Mega Squirt is a lot more fun and is cheaper. $200 for everything needed. VS GM's ECM+Tuning equipment+___=more than $200.

Grumpy

The first is, your opinion, and the second is figuring your time is worth nothing.

Tibo

iTrader: (15)

I am not good for nothing, I am good for free.

I do like GM 7730 though, I am going back to it for a while with an auto prom.

CAMp3RO

i myself am switching from carb to MS. i think i was intrigued by the idea that i can reprogram without having to burn new chips and the overall adaptability. the interface seems to be very easy to understand as well. i just need for it to be better weather out to get back working on it.

as for part availability, everything is available at a parts store except for the computer. seeing at the moment i will be using the tbi setup as a learning project. but how often does a computer die? as with all our projects, you dont go on a 200 mile trip 5 min after you throw in a cam, new intake, or new programming; you give it time to work out the bugs.

as for money vs. time, i've got a lot more time than i have money. it took me a few hours to solder the computer, relay board, and stim board. but with both setups, you're gonna have to datalog and spend time figuring whats the best setup for fuel, spark, etc. so neither one is better than the other in this department.

i guess it all depends on what you want.

esc

iTrader: (6)

What I like about Megasquirt is the ability to modify the base code (firmware). That way I can invent my own features.

I plan on using MegaSquirt and Spark Extra as a starting point so that it can control the fuel, ignition, N2O, water injection and a few other things.

As far as parts availability it won't change my situation any since I don't use factory injection anyway. (Projection 4)

BTW, my Megasquirt arrived yesterday. I'm soldering it together right now!