I think I have a bad ignition module

[FSJ Guy]

Could the spark controll module be causing it? I tried unhooking the knock sensor to see if that effected it any, and it didnt. Could that module be bad and be telling the computer to retard timing?

I missed this part.

YES, if the computer is getting a "knock" signal, it will retard the timing.

I have bypassed my spark control by providing the 5V reference signal to the knock sensor input on the ECM. (Bin B7 on the '7747 ECM)

You could try to zero out the knock retard tables in the bin and if that makes a difference, you've found your problem.

Does the ECM log spark counts BEFORE it gets into Closed Loop mode? If so, see if there are any spark counts in the table via WinALDL.

[PlasticBoob]

You MUST datalog! The great thing about fuel injection is that we don't need to play the silly guessing games that the carb guys do; the logs instantly tell us just about everything if we know how to read them. And if it doesn't, it at least tells us where to look further.

Even a log of the sensors with the engine off can tell a great deal about what's going on and if something's broken. For example, it's a 78* day and you see the CTS reading -20*, you're at sea level yet the MAP is reading 60kPa, or you see the throttle being depressed without your foot on the gas.

[Billygoat]

You MUST datalog! The great thing about fuel injection is that we don't need to play the silly guessing games that the carb guys do; the logs instantly tell us just about everything if we know how to read them. And if it doesn't, it at least tells us where to look further.

Even a log of the sensors with the engine off can tell a great deal about what's going on and if something's broken. For example, it's a 78* day and you see the CTS reading -20*, you're at sea level yet the MAP is reading 60kPa, or you see the throttle being depressed without your foot on the gas.

I would love to see some "how to's" on using data logging for diagnosing problems, tuning I get, but unless the computer has an error code, I don't trust it (or possibly understand it) for more than that.

[JeepsAndGuns]

Well bad news, this problem is gonna have to be put on hold for a bit.
I just had a uncle in VA get killed, so I am leaving out tomorrow to be with the family for the weekend during the funeral.
Once I get back and get some time, I will report back.

[JeepsAndGuns]

Ok, made it back in this afternoon and had a little time to screw with it. I tried unhooking the spark module and there was no change in how it ran, so I hooked it back up and unhooked the battery to clear the codes.
I hooked up the autoprom and the aldl cable and hooked it to the port.
I couldnt get it to connect/work. I had the switches on the back of the autoprom in the correct spots, but tried changing them to no avail. Spent some more time in the help topics of tunerpro (witch suck) and tried changing some settings for how it connects for dataloging. I forget what they were called, but it supposed to use the autoprom as just a aldl cable with the switch on the back flipped. It didnt work, changed it to a diffrent setting to where it uses the autoprom to datalog and I got it to connect. I managed to get some list type thing pulled up that got it show some stuff.

Heres where it gets all screwy again. I had started it up earlyer a couple times before when trying to get it to datalog and it ran like it has been. When I finally got it to connect and (I think datalog?) it was showing some data or something on there, I tried to start it and it wouldnt start. Tried a few more times and it wont start. It cranks over, fuel pump works, it acts like it wants to fire as it will kinda hit and miss a bit. But just wont start.
I stopped the datalog, unplugged the cable, closed tunerpro and unhooked the battery on the jeep. After about a min I hooked the battery back up and tried to start it again, computer and tunerpro were not connected. Still wouldnt start. It will fire a cyl every now and then, kinda acting like it wants to start, but doesnt. I unhooked the timing bypass and theres no change, still wont start. Its like the computer or tunerpro magicly or suddenly fried something. I am just at a loss now.
Also, how do you record and or save datalogs? If what I was doing was even a datalog? How can I tell? The nice dash I see pictures of with the speedo and tach and other sensor data didnt come up, just a empty window.
This tuning is NOT user friendly

[FSJ Guy]

If you want nice BLM info, I'd recommend datalogging with WinALDL instead of TunerPro.

If you want to use the emulation feature of the AutoProm, THEN you want to datalog with TunerPro.

There are two switches on the back of the AutoProm. You are correct in saying that one position makes it act like a pass-through and it simply functions as an (expensive) ALDL cable. The other setting allows you to emulate AND datalog at the same time.

The SECOND switch simply changes the ALDL cable mode setting. IIRC, it's a 10K ohm setting versus open. You want it open.

When you have everything configured in WinALDL correctly, you will get a flashing "green" 20 in a little box in the main window.



I don't see how the link via the ALDL cable could have fried something. Mine was hooked up backwards (got it like that from Howell. :-/ ) and it didn't do anything bad to it.

[Billygoat]

So now it will not run, when you turn on the key does it run the prime on the fuel pump?
Does the check engine light flash then stay on solid?
Pull a plug wire or hook up a timing light and see if you are getting spark.

Also you don't need to disconnect the battery to kill the system, you wired in 2 connections to battery power, 1 is for the fuel pump, the other is the computer, pretty sure Chevy uses a weather pack on that wire, if you left it in place you can just unplug it, I wired a switch into mine now so I can just turn it off when I change chips (and rest the BLM), plus make a nice theft deterrent feature.

[PlasticBoob]

[content deleted - I no longer support MS]

[PlasticBoob]

Billygoat, it is hard to understand at first. That's why I always warn anyone thinking about fuel injection that they're going to eventually have to learn a little (ok, sometimes a LOT) of theory. Once you understand how it works, and know what things SHOULD be versus what you are seeing in the logs, you've reached another plane of existence.

You would have to trust the data you see, since the computer will be trusting the same numbers and injecting fuel accordingly. In other words, if the computer shows you wacky sensor readings, trust that they're wacky (unless the ECM itself is the problem - oh boy, that's not even fun to think about ).

The key is to use our human brain and see if it makes sense with what SHOULD be. Like I said, let's say you know you're living on a mountain, and the MAP is showing 120kPA with the engine off, you know something's wrong (sea level is around 100kPA). The computer trusts that number and will then enrichen the fuel map accordingly. It's a thought process; that darn engine light doesn't always tell us every little bit of info we need, especially since it's OBD-1 on GM TBI, right?

[JeepsAndGuns]

So now it will not run, when you turn on the key does it run the prime on the fuel pump?
Does the check engine light flash then stay on solid?

Yes the fuel pump primes and I watched my guage and confirmed I am getting fuel pressure. It will kinda hit a lick every so often like its wanting to try and start, but wont. So I am getting some type of spark, but something screwy now.
Never paid enough attention to see if the light flashes, but it does come on when I turn on the key and stays on untill I crank it. Before when it would start, there was no light.

FSJ Guy, the paper that came with the autoprom says the outer switch is is for standalone datalogging. Your place the switch in the outer "away from usb port" position. When in this mode I can not get it to work.
It says the other switch will give 10k resistance across pins A-B, or open across pins A-B. If I am not mistaken I had it in the 10k mode when I got it to spit the (I think) log data. But ever since then, it wont start. I thought I read somewhere that pins A-B have to be connected to place the ecm into ALDL mode so you can datalog. Is that not right?

Plasticboob, when you say my box sounds screwy, are you talking about my laptop/tunerpro, or talking about the ECM?

[FSJ Guy]

FSJ Guy, the paper that came with the autoprom says the outer switch is is for standalone datalogging. Your place the switch in the outer "away from usb port" position. When in this mode I can not get it to work.

The "away from USB port" position is for use with WinALDL. The other position is for use with TunerPro and other programs that offer emulation

It says the other switch will give 10k resistance across pins A-B, or open across pins A-B. If I am not mistaken I had it in the 10k mode when I got it to spit the (I think) log data. But ever since then, it wont start. I thought I read somewhere that pins A-B have to be connected to place the ecm into ALDL mode so you can datalog. Is that not right?

On my 1227747 ECM, putting the switch into 10K (ohm) mode opens the IAC all the way. On mine, I leave the switch "off".

You should be able to see the "green 20" in WinALDL with the key on, engine not running. That will tell you that you have everything set up correctly. I had to play around with the baud and com port settings before I got that "green 20". Yes, it was annoying trying the different combinations.

Once you get that set, let us know and we'll go from there.

[Billygoat]

PlasticBoob - Discounting the forum, if my truck was running bad from day 1 the datalog would be useless because I would not know what the numbers typically SHOULD be, I have several logs I saved now so if something goes wonky I can compare to old logs and look for numbers out of wack, that is a not an option JeepsandGuns has, granted he can post up and pull from everyone here.

I really suspect a timing issue, and I would be curious how that would show in the log, maybe the rpm's would be crazy....

JeepsandGuns - What program are you using to datalog? I have not tried tunerpro yet, with mine the instructions say to put the inner switch toward the usb cable, that turns on the resistor and puts the computer in ALDL mode.
ALL the programs I have are set to add 8* of spark in ALDL mode, and IIRC shuts off the knock retard feature.
That added spark would cause it not to start if you have an ignition timming issue.
You stated that after if did not start trying to log that you unhooked the cable and rest the computer...that should have cleared the ALDL mode, and it should run it's bad way again, so I am at a loss.

[FSJ Guy]

You do NOT NEED to be in ALDL mode (10K switch) to datalog with any program. It is ECM dependent. Some need it. Some don't.

[Billygoat]

You do NOT NEED to be in ALDL mode (10K switch) to datalog with any program. It is ECM dependent. Some need it. Some don't.

Just saying that is what the Turnerpro set up says...circled in red

[FSJ Guy]

Just saying that is what the Turnerpro set up says...circled in red

Dunno... With my 1227747 ECM, if I do that, it goes into ALDL mode and completely opens the IAC valve. (shows 145 on the display)

I have a screaming high idle when I accidentally move this switch. That's why it is now covered up.