Problems with my 305 TBI to 350 speed denisty TPI swap in my 91 bird.

how can i tell if i have a bad ECM?
i hooked up a SnapOn scanner to the ALDL and it's telling me i have no commincation with the ECM.
i put in all of the info that the scanner needs.it then promps me to turn the key into the run postion.once i do that the scanner screen goes blank for a second then pops back up and says there is no commincation with the ECM.
i checked the grounds going to the ECM and i have good grounds on those pins.i checked to see if i have power going to the ECM.i have over 12 volts going to both of the pins at the ECM.
i tried to pull codes by jumpering A&B at the ALDL.i couldn't do it that way either untill i jumpered A(ground)to a ground.then i could pull codes.i got a code 33 which is a MAP code.i then hooked the scanner back up and it does the same thing but the scanner screen doesn't go blank like before.
the car starts and runs(some times)really rough.

 

did u check all grounds on the motor that happened to me. The vats wasnt grounded and wasnt let the computer spit codes

 

did u check all grounds on the motor that happened to me. The vats wasnt grounded and wasnt let the computer spit codes

 

If you're using a scanner with the vin info from a 90-92 TPI then the scanner is looking for serial data on pin M of the ALDL. More than likely you have serial data on pin E of the ALDL from factory and didn't switch it at the ALDL when you did the swap. Might be the problem.

 

i tried switching the pins at the ALDL and still can not access the ECM with the scanner.
the car fires right up flash's up to 1k rpm's then quikly drops to 500 rpm's.it ruuning very rough but it idles(kindof).i have fuel pressure gauge hooked up to the fuel rail and the gauge say 15psi regaurdless of how many turns i put on the AFPR.when i open up the butterflies it acts like it getting way too much air.the idle drops and tries to stall out.

please help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

TTT

 

Well the TPI won't run with 15 psi of fuel press so start there. As far as the ALDL, go directly to the ECM for it and see if it works there. Just remembered you are using a Snap On scanner so you might as well start gearing up for using a laptop with Moates software to scan with. Much better for your particular set-up. But I believe you have some type of wiring problem or the scanner is bad. A at the ALDL has to have ground and you had to put ground to it. M is the one that needs to have the orange serial data wire going to it from the ECM. THat wire needs to come out at A8 or A9 on the ecm as they are tied together internally. Since you are using the snap on unit it may also need the diagnostig input wire to be correct and that is at E12 and goes to B on the ALDL. Do you have those?

 

well i'm thinking the ECM bad isn't now.
well long story short the car was running last,running alot better than it has been.and the ECM threw a code.so i'm guessing that my prblem with not being able to access the ECM with a scanner is some how in the wiring.

 

You didn't swap out the fuel pump, did you?
The TBI system runs at like 12psi and the TPI runs at like 45.
Sounds like you are trying to run on the TBI pump.

 

i have a Walpro 255 hi flow pump.this is the second one i've had in her.the first one craped out on me.it was only pushing 15psi to the fuel rail.i checked voltage going to the pump and i had more than 12 volts going to it.then i pulled it out and check the resistance across the pump and it read .05 ohms,a new"good"pump should read 1.7ohms.luckily i cheated when it came to putting the fuel pump in.it takes me about 5 minuites to pull it out and about 20 minuites to put it back in.

i'm thinking i mite have a vacume problem.i think i mite have a pin hole in the AFPR.i'm going to change the diaphrame monday or tuesday.

i'm open to ideas people?

 

ttt

 

i changed the diaphram yesterday and still running the same,like she's starving for fuel.
i pulled the the second "new" Walpro out to check the ohms of the pump.it read .05 ohms should read 1.7 ohms.so i have another bad pump.i e-mailed Ron at http://www.autoperformanceengineering.com today and he told me he would get another pump in the mail for me.i'm glad he's a stand up guy.

i'm really starting to loose faith in these pumps

 

i'm still having problems accessing the ecm through the ALDL with a scanner.

i need some help!