CAM LOBE SEP & EFI??

[Vettepilot]

Ok, thanks guys.

Anyone have anything to say about the FITECH offerings? Budget is a really tough consideration here, and the much vaunted Holley systems are so expensive.

A while back, I actually bought a "Stimulator" kit, which is the first step in getting your feet wet with Megasquirt. Have not built it yet.

Then, I suppose, there's the option of a modified OEM GM system.

I don't need nor want a system that makes me breakfast and tucks me in at night. Just something as simple and inexpensive as possible.

Can GM OBD1 be easily set up for tuneability, or is that stuff not available anymore?

Thanks for the encouragement!

Vettepilot

[Vettepilot]

Separate question.

There's "I need a touch more "accelerator pump" and want to fatten up the midrange a touch."

Then there's "I'll adjust VE and change some Bins and tweak the trims."

I'm WAY in the first camp. Is that gonna fly??

Note: I'm not totally "cave man." I have a wideband AFR setup.

Vettepilot

[steveo]

you can adjust whatever you want. if you don't adjust the VE table or other airflow parameters what's going to happen is the ECM will just trim the fuel to be correct. edit: when i say correct, i mean roughly correct.

adjusting VE is not a scary thing

all it is, is a grid of numbers. higher number more fuel. lower number less fuel.

one axis of the grid is load. one is engine speed.

so if you increase the number by 5% at a certain load and speed in this table, you get 5% more fuel there.

it's not only more precise than tuning a carb, it's way way easier.

also the old TBI ecms are great for caveman tuning. the VE tables are tiny and imprecise, but they work.

if you have a wideband and you learn to log it, adjusting your VE table so all your fueling is correct will be a very very simple and quick task

[steveo]

Ok, thanks guys.

Anyone have anything to say about the FITECH offerings? Budget is a really tough consideration here, and the much vaunted Holley systems are so expensive

if these are the parameters:

- throttle body type injection
- budget conscious
- good learning project
- fairly easy to tune
- guys on this forum help you

you want a modified OEM GM system FOR SURE.

what you want for a TBI system is an ECM that has 8192 baud data logging. the older 160 baud ones might frustrate you a bit.

of course with ECMs of that age on a budget, you are going to have to open them, pop chips in and out, and program them.

that said, megasquirt is totally great too.

try to stick with stuff made by hobbyists. holley, fitech, those commercial guys, if you buy into them, you rely on them for support, and a lot of them are business men rather than basement car hackers whereas

[Vettepilot]

So, how easy is it to burn your own chips?? The little reading I did on it made it seem rather daunting to get set up for that...

Then, converting OBD1 to being programmable. Again, over my head.

Sorry guys.

Vettepilot

[steveo]

stop being sorry. i was in the place you are in once and so was everyone else here. that's why you're here.
burning a chip is super easy. you buy a prom programmer on ebay or whatever they are cheap. you put the chip in it and read it modify the bin and then write it back. if you have enough computer skills to post on this forum you have enough computer skills to program a chip.
if you replace the chip with a larger one you have to 'offset' the program. this is also pretty easy.

[steveo]

oh and really old chips are this really cool thing called 'uv erase'
so if you have one of those chips you take the sticker off the 'uv window' and leave it hanging around on your window sill for a while and put the sticker back on
i tuned tons of cars with those UV chips

[Vettepilot]

Well, ok. Let's say that at least for one of my vehicles, I stay with it's original OBD1 TBI system, but want to tune it for a better cam, heads, and exhaust. It's a 1994 GMC K1500 5.7 4x4. I already rebuilt the throttle body, and did all the mods to the throttle body itself to improve it for performance. Use will be mild everyday with about 10% offroad. What, exactly do I need to tune it and where do I start?

Second vehicle. 1987 Corvette. I am installing a hot 454 big block, and would like TBI. Big cam, many other engine mods. How to TBI/EFI that one??

Note: I do have an ALDL cable, a laptop, a tablet, and TunerPro and "ALDLDroid".

Also, yesterday I scored a "7427" ECM along with it's wiring connectors. Useful? Also, out of the Vette, I will have it's original ECM multiport 'puter once the engine swap happens.

So many decisions!!

:~(

Vettepilot

[steveo]

tune your truck first

you should be able to open the ecm, pop the chip out, and put it in a chip reader if you wanted to pull the stock calibration off, then tune it with tunerpro, and write the program back to the chip.

it's not the most elegant way like newer flash or realtime ecms but it will get the job done cheap

im pretty sure your truck would already have a 7427 ecm so now you have a spare if you really mess something up

i will tell you tuning trucks that are no longer being used as a truck (i.e. not hauling yards of gravel or towing big trailers) can be very rewarding. the stock tunes are very very limp in terms of both spark and fuel, because if you're driving up a big hill with a ton of stuff in tow, they don't want it to blow up. there is TONS of power on the table.

so a tune for a truck like that would be something like:

- drive around and get a datalog with your aldl cable and tunerpro, maybe bring a wideband with you too. you can use the logs to see how close the stock fueling tables are, and how much you'll need to change them.

- make a first attempt to correct fueling by making some small changes to your VE table, so when you load your new tune you can datalog again and probably get it close to good on the second try.

- spend some time on your spark table. if you have a different cam than stock, you want the 'under load' part of your spark table to be a bit different. timing should advance towards the torque peak of the cam then level off, well, you have a different cam. you can also add quite a bit of timing advance everywhere on the table in general if your fuel quality is good and you aren't towing.

- tune power enrichment fuel. for something not hauling heavy loads, with consistent fuel, you will find peak power near 13:1. new tuner probably target like 12.5:1 or 12.8:1 or something. the wideband will really help with that.

- load your new tune and go and data log again. this time you're checking not just for fuel trims (to see how your fueling is doing) but also watching your wideband to make sure when you floor it, your AFR stays in the safe zone. you're also watching for knock to see places where you might have gone too far on your timing table

- now go back and make a few more changes based on what you see in the logs

analyzing logs can be a bit daunting, i have written software that helps A LOT, can teach you to use it. trimalyzer is pretty good for a beginner, i wrote it because i was kinda tired of teaching new tuners how to analyze logs.

[Vettepilot]

Ok, got it. Except for the chip reader and writer. What exactly do I need to do that?

I would love to be able to tune this. Buying a chip for several hundred dollars that might work ok, and would need changed (and bought!) yet again if I change something on the engine, never seemed like a good process to me.

Is it worth getting into whatever the setup is that programs to the computer in real time, whatever that's called??

Thanks for your info and patience with me. Outside of EFI, it's usually me that does the helping in various forums!

;~)

Vettepilot

[1project2many]

Separate question.

There's "I need a touch more "accelerator pump" and want to fatten up the midrange a touch."

Then there's "I'll adjust VE and change some Bins and tweak the trims."

I'm WAY in the first camp. Is that gonna fly??

Note: I'm not totally "cave man." I have a wideband AFR setup.

Vettepilot

Before Megasquirt existed, I met Bruce Bowling at a get together in Ohio. Bruce is a really sharp guy. We were talking about using tuning software. I told Bruce that the biggest hurdle for folks coming from the hotrod world was turning jet changes and accelerator pump shot into VE tables and AE duration. Tools that represent the hotrod way of tuning might be helpful... an "everywhere" fuel adjustment could represents jet changes, a dial for idle mixture, a choke spring tension adjustment for cold starts, a pair of accelerator pump sliders to tailor pump shot, would really help transition between mechanical things and digital bits. I'd even said that it would be really cool to be able to click on pictures of a digital carburetor and distributor to select the changes you want to make. I've never used MS but I believe their software has some of that functionality built in.

I came from the world of carburetors and distributors, and I started modifying EFI when people outside GM had very little clue how GM's software worked. We've had folks here in their '80s learning how to tune and swap efi bits successfully. I think you can get this. I wonder if coming from "I can do this easily with a carb" is going to be a big source of frustration? But maybe this is more like learning a new language. And the new language has more words to describe things so you will be able to understand what the engine wants much better.

So, how easy is it to burn your own chips?? The little reading I did on it made it seem rather daunting to get set up for that...

Then, converting OBD1 to being programmable. Again, over my head.

More detail to go with steveo's posts.

OBD1 is already programmable. Remember when we would tape over the small hole on the back of a cassette so we could put our music there instead of some craptistic band? This is the same thing. There's a chip inside the ecm that's programmed with lounge music. You can change the tune.

Tools you will need:
Eprom burner with software
Eprom eraser

You will also want a way to talk with the ecm to see how the engine is doing. The ecm is able to provide clues to what the engine wants and what it likes. You need software that can interpret the ecm's communication. Most folks use Tunerpro.

You will also want a tool to view and edit the data in the chip. Again, Tunerpro can do the job.

This is the bare minimum. Upgrades can include switching from EPROM to electronically erasable chips, adapters to allow quick and easy chip removal, and an emulator so you can make changes to your calibration while you're driving.

You have a '94 truck already? Automatic equipped trucks have a 7427 or similar ecm already. Those are a great choice for an EFI project. I agree with steveo. Start tuning the '94 to get used to the tools.

[steveo]

as a poor man i bought a cheap Chinese chip programmer
its tuned hundreds of chips now no problem
the sun can function as a free uv eraser in a pinch. it puts out tons of uv

[steveo]

open the lid on that 7427 you bought and have a look

[Vettepilot]

That was me using improper language when I said "programmable". I know it's actually programmable via the chip. What I meant was actually programming in real time using an emulator. But maybe I should take "baby steps"...

Ok, back to burning chips. Do you have a recommendation on what to buy to erase and burn chips, and where to get it?? If it's truly only UV to erase, I could rig up a "black light" in a reflective box if that would work/suffice. I do my daily work on Android tablets. However I do have a laptop computer with Windows 7, TunerPro, and an ALDL to USB cable.

Actually, just for looking, I also have ALDLDroid to read the data stream on my tablet too, though I've not yet used that.

My truck is a 1994 Z71, but I believe the ECM is not 7427. I'll check when I get home tomorrow night. In any case, I'll have an extra chip to play with, right?

Vettepilot

[1project2many]

I have a Willem GQ-4X that seems to work well.

Eprom erase frequency is 253.7nm. You'll want a light that produces UV-C for best results.