Mongoose

iTrader: (2)

I did a search first and found some info but no answers. I just finished up a swap from TBI to TPI. Car runs good and I can get codes from the SES light. The problem is I can't get info from my scanner off the ALDL. I can key the scanner to show the data list and I get an error message "No info,check connections". I'm aware of TBI using pin E for data and TPI data on pin M and I know that the majority of cars were wired for both. Mine has both but just to rule it out I swapped the pins anyway and still get no response from the ecm. I've checked all the wiring from the ecm to the aldl and everything checks out. I even ran a jumper straight from the ecm to the aldl and still nothing. The ecm is a fresh reman unit so I don't really have a reason to suspect it and other than running two jumpers to bypass the VSS buffer no mods were done to the wiring harness. I thought the scanner was bad after all this but tried it on my brother's '94 and it worked perfectly. The cartridge covers 1984-1995 OBD-1 GM cars. My car is a 1990 and this same scanner has worked fine on this car prior to the swap. Where do I go from here?

Kevin91Z

iTrader: (1)

What scanner are you using? Also, did you change the VIN in the scanner to a TPI car? If the scanner has the VIN of a TBI car it cant talk to the TPI computer. TPI has a F (305) or an 8 (350) as the 8th digit.

Mongoose

iTrader: (2)

Yes, I had it keyed in as a TPI car. It's an Actron but I'm not sure of the model number. This version doesn't go with a specific VIN, you key in a letter which matches a corresponding year (L=1990, M=1991, etc.) and it lists TBI, 5.0 PFI and 5.7 PFI for the fuel injection systems. It's an older scanner though and has worked on both mine with TBI and with my younger brother's '91 TPI Formula when he had it.

Mongoose

iTrader: (2)

The scanner in question is an Actron 9110 and I was mistaken about it working with bro's '91, he bought it after he had purchased his '94 so we have no way of knowing if it will work with TPI.

Fast355

iTrader: (2)

Here is what the ALDL should look like. A TBI car has 160 Baud and the later TPI's have 8192 Baud. When I switched my earlier TBI setup over to the later model PCM with 8192 baud rate, I had to move the ALDL's Serial Data connection. Immediately my scan tool started reading.

Mongoose

iTrader: (2)

I tried that and it didn't help. I even ran a jumper from the ecm to the aldl bypassing the harness and still nothing.

Fast355

iTrader: (2)

One other idea, is this the Actron model that has to be plugged into the 12 volt power plug? If it is, make sure that your cigarette lighter outlet is working. I know my Actron will not connect on its backup battery only, it MUST be plugged into the vehicles electrical system on GM OBD1.

Mongoose

iTrader: (2)

Checked all that and still nothing. I don't think this Actron has a backup power.

Fast355

iTrader: (2)

BAD ECM or a Memcal that is not properly seated can cause this too.

Mongoose

iTrader: (2)

Made sure of the PROM so the only thing left is the ECM. Can this problem exist and everything else be fine?