Hybrid TBI on my GW....and I need HELP!!!

[MjrWraith]

Ok so after a lot of thought and research, I have finally decided to convert my old '87 GW with a 360 out of an '85 GW to TBI. I am going to use the throttle body, a few sensors, ECU, and wiring harness from a junkyard donor vehicle. The majority of the sensors I am going to buy new. I'm looking at using the MegaSquirt II for a tuner. After doing some research on it though I was wondering, and this might be a stupid question but hey in my opinion the only stupid question is the one never asked, do you still need to run the ECU when you're using the MegaSquirt II or does the MegaSuirt II replace the ECU, and can you hook it up for just fuel with the ability to add ignition control later? I've looked everywhere I can think to look and can't find the answer to these. So any help would be greatly appreciated. I know a lot of you have some knowledge and experience with this. Anyways thanks for your time and I look forward to the responses.

[FSJ Guy]

A Megasquirt controller IS the ECU.

ECU stands for Engine Control Unit, also known as ECM, which is Engine Control Module.

And yes, that's DIFFERENT than a PCM, which is a POWER Control Module which controls the engine AND the transmission.

So, either way, you'll need some sort of ECU/ECM to take the info from the sensors and control the injectors, IAC and timing (if you desire.)

I would really recommend computer controlled timing. It's not that much more complicated and it eliminates the Duraspark ignition entirely. Not that Duraspark is inherently BAD, but original modules are old and the "remanufactured" ones aren't known for their longevity.

[Billygoat]

Since you already have the GM ECU I'd do the chip mod and get a tuning software/ship burner and run with that, plenty of info on the web for it (check out he GM sticky)

[MjrWraith]

Hey thanks for the info guys, but I guess I should've given a few more details. I understand the difference between and ECM/ECU and a PCM. I recently upgraded the fuel control system on my wife's '85 4-Runner, and the system came with just a computer and programmer. Everything was in the computer box and I didn't know if the MegaSuirt was the same way. I've looked at the MegaSquirt system and reprogramming the chip. The MegaSquirt just fits my needs a lot better. As far as the ignition control I just don't have the ability to set it up right now (no more money). Anyways just wanted to add this little bit of info. I'm not an amateur at this but by no means am I an expert and I appreciate all the help from those with more experience than me thanks.

[Bill USN-1]

Your spending more on the megasquirt for fuel only then you would to use the GM system with fuel and spark.
There is no difference in the system except you lock out the mech adv in the distr. So there is no additional cost involved. Unless you don't have a duraspark distr, then they are only $50 at AZ if you don't want a junkyard one.

I think you are just convincing yourself why you want to go MS.

[MjrWraith]

I just like the ability to set the fuel curves and all on the MegaSquirt. I'm not a fan of using chips cause from my understanding you can't program them on the fly like the MegaSquirt. As far as the ignition system I thought you also had to have like a hall sensor or some other form of crank position sensor for the ignition. Am I just confusing my wife's MPI system with the TBI system. I know on her's I had to install the hall sensor on the crankshaft pulley to control the ignition.

[Bill USN-1]

You are only half armed.
I would recommend reading some of the basic FAQ's at the link in my sig.

Nothing more then a stock magnetic pickup like the duraspark distr has, to allow timing control.

There are simple plug in devices that allow tuning on the fly. Then when done you just burn the chip and move on to the next project.

But they really arent needed, they are just a toy to play with.
Programming a chip takes about 5 seconds.

I log data and stop in a parking lot, make changes on my laptop and burn a chip right there. Then drive some more.
Unless you trust someone else to drive or make changes while you drive, it gets a little hectic and is as bad as texting while driving.
The laptop will end up on the floorboard when you slam on the brakes.

Been doing this stuff for 10yrs so I know what works and what's really needed vs what is just neat.

[PlasticBoob]

Originally Posted by MjrWraith

Ok so after a lot of thought and research, I have finally decided to convert my old '87 GW with a 360 out of an '85 GW to TBI. I am going to use the throttle body, a few sensors, ECU, and wiring harness from a junkyard donor vehicle. The majority of the sensors I am going to buy new. I'm looking at using the MegaSquirt II for a tuner. After doing some research on it though I was wondering, and this might be a stupid question but hey in my opinion the only stupid question is the one never asked, do you still need to run the ECU when you're using the MegaSquirt II or does the MegaSuirt II replace the ECU, and can you hook it up for just fuel with the ability to add ignition control later? I've looked everywhere I can think to look and can't find the answer to these. So any help would be greatly appreciated. I know a lot of you have some knowledge and experience with this. Anyways thanks for your time and I look forward to the responses.

When I was considering which ECU to use, I did months of thorough research and found MegaSquirt II to be a VASTLY superior system to these old hacked ECUs the GM boys are running. I was going to make a website listing all of the MegaSquirt advantages, but never got around to it, and now I can't remember them all exactly (maybe they're in my notes...) Anyway, I would not switch from MegaSquirt if you paid me; it's that good. The flexibility of the system is simply mind-blowing; it's the Linux of the EFI world. It requires more initial education, but if you do more research and compare the systems, I am sure you will come to that conclusion as well. However, if this is your daily driver, or you will allow someone else to fondle and fix your baby when something goes wrong, MegaSquirt isn't for you.

Going off of memory here: MegaSquirt consists of a physical box that contains the system board and the processor/integrated circuit/code. There are three versions of the board, and three processors. The MegaSquirt version is a combination of the system board and the processor/code. For example, MegaSquirt II implies a version 3 system board, but that isn't always the case - for example, you can plug a MegaSquirt III expansion board into the v3 system board, or plug a MSII IC into a v2.2 system board (some mods are necessary I believe).

Anyway, you will need to use the ECU. You will also need a MegaSquirt-specific wiring harness, which you can solder the sensor pigtails into. It is advisable to use a wideband oxygen sensor, and run without timing control at first to set up your fuel table. Once you get that dialed in, you can add timing control. This is the stage of the game I'm at, but lately life has prevented me from giving my Jeep much attention.

As far as I know, I was the first person around here to inject a 401 (407), so there was no data to borrow from anyone to use on a hacked GM system - I had to start from scratch... and since I was starting from scratch, I gave MegaSquirt a look, and fell hook, line, and sinker. It may be easier for you to go with a hacked GM ECU, since there are tons of TBI'd 360s floating around at this point, and sharing the programming will save you tons of work.

So basically, you need:

The ECU: http://www.diyautotune.com/catalog/m...ase-p-119.html

Harness: http://www.diyautotune.com/catalog/8...ady-p-477.html

Optionally - wideband oxygen sensor and controller: http://www.diyautotune.com/catalog/i...3769-p-41.html

The price for the LC-1 has jumped greatly in recent years, how unfortunate. It's a great investment, however, and for the time it has saved me in tuning I definitely don't consider it optional.

[Bill USN-1]

PB,
I think the flaw in your logic is you started out thinking your AMC was something special and you had to reinvent the wheel to install a system.

The fact is that the EFI system, no matter what it is, doesn't care what motor it is bolted to.

So you "could" have simply followed any TBI conversion and completed the same process on yours. It's been done regularly since about the early 90's.

You have a 407ci internal combustion, naturally aspirated engine. No more no less.

All an EFI system cares about is how far the throttle is open, how much change in manifold vacuum, and is the engine burning all the fuel that is injected.

So any system can be installed and tuned on any engine.

[PlasticBoob]

Originally Posted by MjrWraith

Hey thanks for the info guys, but I guess I should've given a few more details. I understand the difference between and ECM/ECU and a PCM. I recently upgraded the fuel control system on my wife's '85 4-Runner, and the system came with just a computer and programmer. Everything was in the computer box and I didn't know if the MegaSuirt was the same way. I've looked at the MegaSquirt system and reprogramming the chip. The MegaSquirt just fits my needs a lot better. As far as the ignition control I just don't have the ability to set it up right now (no more money). Anyways just wanted to add this little bit of info. I'm not an amateur at this but by no means am I an expert and I appreciate all the help from those with more experience than me thanks.

Oops, I didn't read this - you will need - GASP! - a laptop to tune MegaSquirt box/ECU - that's not asking much at all as we roll into 2012, lol. You can tune it as you're driving, if necessary (I've had to do this more than a few times and it's not as dramatic as Bill suggests). But usually, you turn datalogging on, drive, recalculate and modify parts of the maps if necessary, then repeat until everything is dialed in. It's pretty darn easy.

Acceleration Enrichment seems to be the biggest hurdle, as it's completely subjective. Some people like a nice, soft, easy tip-in, and others like snappy, aggressive acceleration (like me). This is where tuning from the driver's seat really helps, because it's hard to get it just right without going excessively rich. Like I said: log, drive, change, repeat.

[PlasticBoob]

Originally Posted by Bill USN-1

PB,
I think the flaw in your logic is you started out thinking your AMC was something special and you had to reinvent the wheel to install a system.

The fact is that the EFI system, no matter what it is, doesn't care what motor it is bolted to.

So you "could" have simply followed any TBI conversion and completed the same process on yours. It's been done regularly since about the early 90's.

You have a 407ci internal combustion, naturally aspirated engine. No more no less.

All an EFI system cares about is how far the throttle is open, how much change in manifold vacuum, and is the engine burning all the fuel that is injected.

So any system can be installed and tuned on any engine.

No, I am and was aware of that. I did not really start out wanting to tinker with EFI - I wanted to go with a GM system, borrow a map from someone, and lead-foot from there. When I quickly realized (like so many others) that I couldn't just slap it on, load a borrowed map, and go on my merry way, I decided to look at the other systems out there, and MegaSquirt won me over with its openness, hardware superiority, adaptability and flexibility. I started researching all of this in 2004/2005 I believe, and the state of things was very different back then.

[Bill USN-1]

Originally Posted by PlasticBoob

Oops, I didn't read this - you will need - GASP! - a laptop to tune MegaSquirt box/ECU - that's not asking much at all as we roll into 2012, lol. You can tune it as you're driving, if necessary (I've had to do this more than a few times and it's not as dramatic as Bill suggests). But usually, you turn datalogging on, drive, recalculate and modify parts of the maps if necessary, then repeat until everything is dialed in. It's pretty darn easy.

Acceleration Enrichment seems to be the biggest hurdle, as it's completely subjective. Some people like a nice, soft, easy tip-in, and others like snappy, aggressive acceleration (like me). This is where tuning from the driver's seat really helps, because it's hard to get it just right without going excessively rich. Like I said: log, drive, change, repeat.

I find your AE process a little flawed.

Tuning is tuning and AE tuning is the same.
If you are using a wideband O2 then you would be watching the real time data and tuning the AE until there is no dip or rise as you tip in the throttle.

If it is lean it will have a hesitation depending on how much.
If it's rich then it will cause a bog like a quadrajet.
So there is only one way to properly tune it.

Timing would have more effect on the accelleration then the AE.

But it's all part of learning how to tune and learning what your engine really wants.

[PlasticBoob]

Originally Posted by Bill USN-1

I find your AE process a little flawed.

Tuning is tuning and AE tuning is the same.
If you are using a wideband O2 then you would be watching the real time data and tuning the AE until there is no dip or rise as you tip in the throttle.

If it is lean it will have a hesitation depending on how much.
If it's rich then it will cause a bog like a quadrajet.
So there is only one way to properly tune it.

Timing would have more effect on the accelleration then the AE.

But it's all part of learning how to tune and learning what your engine really wants.

You're right, I have been desperately wanting to get timing control working because I did realize that I need more advance for the acceleration feel that I want. Unfortunately, running a business and going for a second degree has kept me out of the loop for a couple of years.

I think I partially disagree with what you said regarding there being one way to tune AE - I understand the goal is to keep the AFR the same as we apply AE, but I have found that I can have a nice, soft, linear acceleration (on the leaner side of things but still below 14.7), or have a very responsive, agressive, "barking" acceleration (the 'correct' way I guess) - it's hard to explain, but I can definitely get two different tip-in "feels", and I don't think that there is only one proper way to set it - sure mathematically there is, but as far as "seat of the pants" goes, it's whatever the driver wants. It reminds me of pressing the Sport Mode button on my M3 - it's a noticeable difference. Ok, bad analogy since the M3's six throttle bodies are drive-by-wire. So, put another way, it's kind of like changing accelerator pump cams on a Holley - I went through just about all of them on my Truck Avenger, and got the same varying results. My goal is "barking without bogging", I guess, as I usually drive aggressively. There are some days when I just feel like cruising, and the touchiness of the throttle tip-in can annoying. There are about 8 different AE variables in MegaSquirt, including MAP-based, TPS-based, or any combination of the two, so it is hard to dial in to exactly what I want.

[Bill USN-1]

Keep in mind that the TPS based is for the initial tip in and that the map based if for the duration of the pump shot.

Were getting off topic but another thing that comes into play is PE-power enrichment. This is applied anytime the pedal is opened above a preset limit. Then 14.7 is ignored and it will go richer based on the PE tables. So it could be anywhere from 12.0-14.7 based on rpm/map/tps.

PS: I just retired from the Navy, finished my degree and started my business. So I think I understand.

[PlasticBoob]

Originally Posted by Bill USN-1

PB,
I think the flaw in your logic is you started out thinking your AMC was something special and you had to reinvent the wheel to install a system.

The fact is that the EFI system, no matter what it is, doesn't care what motor it is bolted to.

One more thing... you make it sound so easy - but say you are a kid new to EFI, have a base map for a Chevy 350, and are injecting a 401 with a completely different aftermarket cam, and you DON'T have a wideband O2 sensor: you are going to run into big trouble, and possibly melted pistons, as you try to tune the upper end of your fuel map. Unless you take your car to a dyno shop, you're never going to be 100% accurate in those cells, and a narrowband oxygen sensor is useless at high RPM and load, especially if the cells are that far off. What do you do, guess? Become a physics major and calculate each cell by hand? Trust an online GIGO calculator? You have to reinvent the wheel. And that's when you start looking at a wideband oxygen sensor, and then the other systems out there (MegaSquirt).

[PlasticBoob]

Originally Posted by Bill USN-1

Keep in mind that the TPS based is for the initial tip in and that the map based if for the duration of the pump shot.

Were getting off topic but another thing that comes into play is PE-power enrichment. This is applied anytime the pedal is opened above a preset limit. Then 14.7 is ignored and it will go richer based on the PE tables. So it could be anywhere from 12.0-14.7 based on rpm/map/tps.

PS: I just retired from the Navy, finished my degree and started my business. So I think I understand.

I agree, I hate getting off topic but have an annoying tendency to do so. Best of luck with your business, by the way!

I don't think there's a PE equivalent in MegaSquirt - everything feeds off of the Volumetric Efficiency table, and the system corrects it based on a customizable AFR table and wideband feedback (within ranges you proscribe). If anything, you have motivated me to get back in the game, so I think I should start hitting the EFI books again!

[PlasticBoob]

To get back on topic, there is no additional cost going from fuel-only to timing control on MegaSquirt II; everything you need is there already, and can be disabled while you're setting up your fuel tables with mechanical timing. When you decide to make the move to MegaSquirt-controlled timing, you have many choices: you can purchase a GM 7-pin timing-control distributor module as the GM guys do (I'm not sure if they caught up to controlling the coil directly from the ECU), or you can completely do away with this and let the MegaSquirt ECU perform its function (one less module and one more advantage of MegaSquirt in my opinion). Be aware that some of these choices may require you to change some things on the board (requiring de-soldering, moving things around, and re-soldering), but if you make the right choices as you're assembling your kit, changes will be minimal, if at all.

For the tachometer signal (the most important part of the whole deal): you can trigger the ECU with the stock Hall Effect sensor in the Ford distributor, the VR sensor in an HEI distributor, a crank trigger wheel and Hall Effect sensor, or points. Yes, even points will trigger MegaSquirt. You will need this regardless of whether or not you are running fuel-only, or fuel+timing control. I have been triggering with a 4-pin HEI module, but will be moving to a crank trigger and Hall Effect sensor, as I am getting noise from either the HEI coil, the PWM injector drivers, or both. I'm also going to add a separate Peak & Hold injector driver board inside the MegaSquirt box to eliminate PWM as it's an inelegant solution. ( http://www.jbperf.com/p&h_board/ ). Note that many people have used PWM successfully.

[MjrWraith]

Ok thanks for the debate guys...lol. It was actually quite helpful. I'm still a ways away from getting everything done, but I figured if I start researching and all now when the time comes to get it all installed I'll be going into it with as much knowledge as possible. So if anybody has anymore advice or bits of information please share.

[FSJ Guy]

RE changing tunes "on the fly": That is really only super useful if you have someone ELSE drive the vehicle and YOU adjust the bin.

Otherwise, you're going to have to STOP the vehicle and edit data anyway. It takes me less than a minute to burn a new EEPROM (including verifying) and I'm ready to drive around again.

Also, depending on what ECM you use, Moates offers bin switchers which allow you to instantly change what bin your computer is running off of. This allows you a "valet" mode (limit RPM and speed) as well as a towing/power mode and an econo mode. (quit laughing)

If you buy the AutoProm, you can have real time emulation, but again, you only need it if there are two people in the vehicle, one to drive and one to adjust the bin.

As always, different strokes for different folks. Some people like the autotuning feature, others like the security of being based on common GM parts and other people want a turnkey system that they can "set it and forget it".

[MjrWraith]

Originally Posted by FSJ Guy

Also, depending on what ECM you use, Moates offers bin switchers which allow you to instantly change what bin your computer is running off of. This allows you a "valet" mode (limit RPM and speed) as well as a towing/power mode and an econo mode. (quit laughing)

I'm checking out Moates right now and I am really intrigued. I thought chips took a lot more time and all to re-program but after looking at the Moates website it really seems to be about equal to the MegaSquirt. Just a different method to the same end. Anyways FSJ Guy I was wondering what all you're running on your system as far as things you got from Moates and all. Thanks.

P.s. You're comment on "econo mode" was great. I couldn't help but laugh.