ALDL Software and a 3100

[thor124]

If you are using a 2 transistor circuit with a USB adapter that is your problem. The 2-transistor circuit is more of a hack than a real circuit. It does not comply with the RS232 standards and since you are using a USB adapter I doubt the adapter is going to tolerate it.

That is why I build the circuit above, so it's 100% compatible with RS232 standards, does not steal power from the serial port to run, and just plain works.

Just a note, neither of these circuits "comply with RS232", if GM had put in a nice simple RS-232 2-wire serial communications interface, instead of its half witted 1-wire token ring type serial interface, we wouldn't be having this converstaion. I have an idea as to what in particular is crapping out the USB adapter....(how the USB ground is handled).

Maybe i'll dig out my old 486 laptop w/win 95 and see if that'll run TunerPro, at least it has a true RS232 port. god will it be slow though.

[IsaacHayes]

I mean the converter circuit. The 2 transistor thing is a hack and the circuit I have above outputs true RS232 specs. The chip that is used outputs a compliant signal/etc.

[thor124]

Well, I finaly got this working over the weekend. Never found a laptop with a real rs-232 port, so i lugged my desktop out to the car.

It would seem that I have a vacum leak, and a bad O2 sensor, if i'm interperting the results.

At idle MAP is reading 33kPA. What should this be reading? If i rev the engine while parked(can't do a moving test) to around 2500RPM, it'll even go as low as 10kPA, then bounce around a bit. Highest reading i observed was 42kPA.

For the O2 sensor reading, it varries between 200mV and 800mV, which is good. But how frequently should it change? The websites I read said about 4 or 5 times a second. Mine takes about 2-3 seconds to go from low to high to low again.

I also have a few questions about TunerPro RT - IsaacHayes, the .ads file for monitoring tells me to send a disable comms command before connecting. Whats this do? Do i need to renable when i'm done?

Also, do i need to send the command to swich modes to read engine codes? How's that work?

[robertisaar]

Well, I finaly got this working over the weekend. Never found a laptop with a real rs-232 port, so i lugged my desktop out to the car.

It would seem that I have a vacum leak, and a bad O2 sensor, if i'm interperting the results.

At idle MAP is reading 33kPA. What should this be reading? If i rev the engine while parked(can't do a moving test) to around 2500RPM, it'll even go as low as 10kPA, then bounce around a bit. Highest reading i observed was 42kPA.

For the O2 sensor reading, it varries between 200mV and 800mV, which is good. But how frequently should it change? The websites I read said about 4 or 5 times a second. Mine takes about 2-3 seconds to go from low to high to low again.

I also have a few questions about TunerPro RT - IsaacHayes, the .ads file for monitoring tells me to send a disable comms command before connecting. Whats this do? Do i need to renable when i'm done?

Also, do i need to send the command to swich modes to read engine codes? How's that work?

you don't have a vacuum leak, thats a normal MAP reading for idle.
o2 also sounds fine, what rate are you sampling at? while you're driving, you'll probably see the o2 switch that much, but at idle, it takes longer.
the disable command gets sent automaticly, no you don't need to reenable. as for reading codes: when you've got the car connected, press F4, that'll bring up the aldl screen, look in the bottom left corner of it. see a list of aldl commands? scroll down to check codes or whatever it is, hit it a few times, then click on your flags tab.

[thor124]

you don't have a vacuum leak, thats a normal MAP reading for idle.
o2 also sounds fine, what rate are you sampling at? while you're driving, you'll probably see the o2 switch that much, but at idle, it takes longer.
the disable command gets sent automaticly, no you don't need to reenable. as for reading codes: when you've got the car connected, press F4, that'll bring up the aldl screen, look in the bottom left corner of it. see a list of aldl commands? scroll down to check codes or whatever it is, hit it a few times, then click on your flags tab.

Thanks Robert... I'll try to post a log of the car misfiring/loosing power under load once I get my hands on a laptop w/a serial port.

[robertisaar]

Thanks Robert... I'll try to post a log of the car misfiring/loosing power under load once I get my hands on a laptop w/a serial port.

i did the easy thing, bought a USB ALDL cable from aldlcable.com. cost $60, but it makes life that much easier...