Tunerpro RT $4F connection problems

[duecepipes22]

Thanks again for your help guys! Mark, I'll give that a try tomorrow and let you know how it goes. My truck is a heavy 3/4 ton so I used the HD adx, maybe I should have used the LD? I'll try some stuff tomorrow and report back.

Whats the purpose of ALDL mode if you can't data log with it?

[EagleMark]

Whats the purpose of ALDL mode if you can't data log with it?

It's for diagnostics but I don't know what to use it for? I can diagnose anything without, so maybe I need to learn a new trick?

[1project2many]

ALDL Mode... had to dig out the old books on that one since it's been so many years since I had to play with it.

"ALDL (10K or Special) Mode (not used on all engines)
In this mode, all information incorporated into a specific engine and ecm is obtainable. However, in this mode the system operating characteristics are modified as follows.
... Closed loop timers are bypassed
... EST (spark) is advanced
... IAC will will control engine idle to 1000 RPM +/- 50 rpm
... On some engines canister purge will be enabled
... P/N restrict functions will be disabled"

As I remember it, we used ALDL mode in carbureted applications. You would do neat tricks back in the day like speed warmup along or search for vacuum leaks or force closed loop right away to start adjusting the computerized carburetor's rich and lean stop. Or you would crank the engine rpm up to 2500 so the exhaust manifolds would get red hot and burn the carbon off the O2 sensor and the plug tips. Remember that in those days we still diagnosed much of the car with a voltmeter and common sense. ALDL data on a CCC car was extremely slow and in road test mode it was sometimes limited or not available.

Also, for a while you could force ALDL mode and get through sniffer emissions tests. Eventually the states caught on and would flag you if idle was too high. So you'd run it in ALDL mode at 2500 to get the cat and exhaust super hot then pull the connector and run the sniffer test right away.

You can also put a 3.9K resistor across A and B to force the ecm to run in backup fuel if you're so inclined.

Why the OP needs the 10k resistor is a mystery. I'd suspect the logger software/hardware combo, not the ecm, is at fault.

[EagleMark]

Well the only trick I think this would be helpful for would be dead of winter warm ups... or if you need data from a $6E Camaro... I can't beleive all that 10K resistors in cables have only caused me trouble and I have yet to need one!

[duecepipes22]

Well I reinstalled tunerpro and was able to connect with the $42 files without using the resistor however when I looked at my TPS% it read 28% at .55v so I think either there is a glitch in the file or the two are not completely compatible? I was still unable to connect with the $4f but I'm going to keep messing around with it. Any other suggestions?

[EagleMark]

Don't worry about the TPS % reading as it is just a conversion from voltage. Unless you installed the hack which would be accurate.

Post the $4F adx file you have, no reason for it not to work, it is a simple 160 Baud conection same as $42.

[duecepipes22]

This is the file that I downloaded from here. I hope the attachment works.