What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Why EFI owners don't Program their own PROM's?

I've got tunerpro on my netbook, just need to get a cable and then I can really start learning about all this stuff. Is everyone just buying the USB cable on moates?


---
- Sent from my iPhone using Tapatalk
 
Last edited by a moderator:
That's the one I had too! Sold it with the Burn2 when I went up to AutoProm as it has an ALDL cable specific for it.

Moates must have one available? Is the one at ALDLCABLE that much cheaper? I just buy everything at Moates, couple extra bucks here and there with them is well worth the tech support they have given me and they are the inovators that keep us going.
 
I've burned TONS of chips for my 7747, but I don't do it anymore because I'm not making anything better. Dialing in the VE table is fine, but in TunerPro there are about 100 (100's?) of little values and tables you can mess with, but nobody seems to know what the hell they all do. My Blazer runs like crap in cold weather until it heats up. How do I fix that?

Heck, I don't even know which 7747 factory bin to start from. I've tried a bunch and some are really awful to begin with.

I'm an engineer for a living. What I want to get into tuning 7747 is a document that explains how the logic in the ECM works. What exactly is the equation that determines the pulsewidth sent to the injectors? If I understood that, maybe I could change some of these weird values and not just be hacking. I spent a couple years begging for basic info on Thirdgen and I just don't have the time or energy for it anymore.
 
There's so many that don't need to be touched!

If you go to the link in my signature and look in the photgallerey you will find a Super_$42_1227747.XDF that has quite a bit more information and comments. There's also a Super...ADX for data logging. Both have been contributed to by lots of people. this may help you.

Cold start issues and running can be outside the chip. My Suburban runs as good at 0 as it does at 100. Do you still have the heat riser valve to force hot air through intake when cold? It opens when hot! Do you still have the hot air tube from exhaust manifold to air cleaner? It opens when hot!

If you have a 5.7L 700R4 TBI engine stock to start I can send you an excellent starter BIN file...
 
Mastiff said:
I've burned TONS of chips for my 7747, but I don't do it anymore because I'm not making anything better. Dialing in the VE table is fine, but in TunerPro there are about 100 (100's?) of little values and tables you can mess with, but nobody seems to know what the hell they all do. My Blazer runs like crap in cold weather until it heats up. How do I fix that?

Heck, I don't even know which 7747 factory bin to start from. I've tried a bunch and some are really awful to begin with.

I'm an engineer for a living. What I want to get into tuning 7747 is a document that explains how the logic in the ECM works. What exactly is the equation that determines the pulsewidth sent to the injectors? If I understood that, maybe I could change some of these weird values and not just be hacking. I spent a couple years begging for basic info on Thirdgen and I just don't have the time or energy for it anymore.
Click to expand...

The main reason I help people switch to the newer TBI PCM (93 ~ 95) was for all the above reason. Check out my thread '7747 R.I.P. http://coloradok5.com/forums/showthread.php?t=270253

TunerPro V5 has excellent .xdf's (with formulas) for the newer TBI PCM's!!

dave w

Injector Fow Rate.jpg
 
eagle mark said:
There's so many that don't need to be touched!

If you go to the link in my signature and look in the photgallerey you will find a Super_$42_1227747.XDF that has quite a bit more information and comments. There's also a Super...ADX for data logging. Both have been contributed to by lots of people. this may help you.

Cold start issues and running can be outside the chip. My Suburban runs as good at 0 as it does at 100. Do you still have the heat riser valve to force hot air through intake when cold? It opens when hot! Do you still have the hot air tube from exhaust manifold to air cleaner? It opens when hot!

If you have a 5.7L 700R4 TBI engine stock to start I can send you an excellent starter BIN file...
Click to expand...

I had an open element air cleaner but I switched to a factory style one with the hot air duct. It didn't help. Don't know about the heat riser thing. My 83 never had that I don't think. My engine is stock-ish, but I don't have EGR, I have headers, no VSS, maybe a few other differences. It runs great hot.

Keep in mind I live in Tucson. Cold here is like 40 degrees, and that's all it takes for it to act up. It fires right up, but bogs hard when I step on the gas from a stop. Just coughing and sputtering until it gets moving. It's a hard thing to debug because I get one shot per day to reproduce the problem, and I'm normally on my way to work. :rolleyes:

It could be non-ECM related. I was thinking maybe some sort of air leak at the intake that squeezes shut when things get warm. That's just a wild guess though.
 
dave w said:
The main reason I help people switch to the newer TBI PCM (93 ~ 95) was for all the above reason. Check out my thread '7747 R.I.P. http://coloradok5.com/forums/showthread.php?t=270253

TunerPro V5 has excellent .xdf's (with formulas) for the newer TBI PCM's!!

dave w
Click to expand...

I'll check it out. The newer ones use different sensors, right? Like a mass air flow? Never mind, I'll check the thread. :thumb:
 
Mastiff said:
I had an open element air cleaner but I switched to a factory style one with the hot air duct. It didn't help. Don't know about the heat riser thing. My 83 never had that I don't think. My engine is stock-ish, but I don't have EGR, I have headers, no VSS, maybe a few other differences. It runs great hot.

Keep in mind I live in Tucson. Cold here is like 40 degrees, and that's all it takes for it to act up. It fires right up, but bogs hard when I step on the gas from a stop. Just coughing and sputtering until it gets moving. It's a hard thing to debug because I get one shot per day to reproduce the problem, and I'm normally on my way to work. :rolleyes:

It could be non-ECM related. I was thinking maybe some sort of air leak at the intake that squeezes shut when things get warm. That's just a wild guess though.
Click to expand...
Headers means you do not have the heat riser crossover unless you installed one on the collector! Also means you probably need a heated O2 sensor but I did tune my 1990 Blazer with headers to run cold without. Took several days of cold starts.

Newer PCM Dave is talking about uses all same sensors but must have VSS. No MAF.

VSS also helps idle/cold. Park/Neutral switch also helps idle/cold and most people don't install either when doing a conversion.

Richen up your cold start a little or increase the ECM version of acelerator pump.
 
I do have the heated O2, but no VSS, no park/neutral and also no A/C indicator.
 
Like I said earlier post, look into the Super_$42_1227747.XDF and you will find many more choke choke settings then a stock $42. :waytogo:
 
So when my stuff gets here and i start burning chips, how do I know what to change and how to change it to correct for my bad idle caused by too big of a cam and such?
 
y5mgisi said:
So when my stuff gets here and i start burning chips, how do I know what to change and how to change it to correct for my bad idle caused by too big of a cam and such?
Click to expand...

It's just like a carburetor and HEI distributor, except the vacuum guage is in Kpa not inches of Mercury (Hg).

The VE table is for fuel.

The Spark table is for timing.

A PROM chip emulator lets you make changes while the engine is running.

I adjust the Spark table and VE table to get a good vacuum at idle. Usually the idle vacuum is 35 ~ 45 Kpa (if your lucky with a big cam). 35 Kpa is a better vacuum than 45 Kpa. If you can't get the idle Kpa below 55 Kpa throw the cam away, or get a professional chip tuner to help! 100 Kpa is wide open throttle. Usually the timing at idle is 18 ~ 25 degrees, and the VE table is anybody's best guess.

Each time you want to change the timing, burn a new chip. Each time you want to change the VE fuel table, burn a new chip. Each and every time you want to change anything, burn a new chip.
 
dave w said:
Each time you want to change the timing, burn a new chip. Each time you want to change the VE fuel table, burn a new chip. Each and every time you want to change anything, burn a new chip.
Click to expand...

Can you burn over a previous burn, or do you need a brand new chip each time?
 
Another tip to bigger cams is do your tuning open loop. Get it to idle with VE and Spark. Bigger cams want more spark at idle! But not neccesserely off idle. That where you need to watch your vaccum change in SA table and adjust back if you get imediate knock off idle.

Once I get good stable idle as low RPM as possible it is still so much easier to tune open loop and use the wide band O2 sensor. In the end go closed loop and check BLMs. Still may have to be an open loop idle in real big cams. I think yours will be fine closed loop.

Without Wide Band it's all in the data log in BLMs then adjusting the fuel tables.

Then you play with adding spark, finding knock and backing off where knock comes in.

I bought an AutoProm so I could do all these adjustments with owner driving me around. From my home we do a 60 miles trip over the mountain and through the flatlands and back. I save several data logs after each tune or section of road. Usually the tune is good when done but I go through logs, make adjustments, use smooth tools and burn the final chip.

First big cam took me 20 to 30 hours. Now I can do any engine in a driving car in 2 hours if I find no mechanical problems like not enough fuel at WOT high RPM.
 
I can never remember if open or closed means that it is using the o2. Would one of you mind clarifying the exact differences between open and closed? My understanding is that simply one mode uses the o2 and the other does not. I think there is a little more to it then that.
 
You must log in or register to reply here.

Latest Posts

Top Bottom