hi 1989 trans am gta convertible 5.7 tpi will only run when spraying fuel down the throttle body. fuel pump primes power to all fuses and relays. vats light coming on with ignition and going out when cranking. have got power to both injector connector pins but not pulseing. has had new distributor coil ignition module and pick up coil. do you think its the ecm/ecu what else could it be. sounds great when running so i realy want to get it going. by the way happy christmas to all. would make my christmas if i could get this thing going any help would be much appreciated thanks

 

If the fuel pressure is at least 30# and the distributor reference pulses are getting to the ECM, there isn't much left but the INJ1/INJ2 fuses, wiring, or the ECM (including VATS).

 

inj1/inj2 fuses are ok i havant testest fuel pressure yet as i thought no injector pulse is the first thing to look at. what wire do i test from the distributor to the ecm

 

I would disconnect all 8 injectors and put a noid lamp on one of them and see if it flashes while you crank, then start plugging them in one by one and see if the light goes out each time. I am not sure how the TPI ECMs work, but I know I've seen a shorted injector take out all of them on other GM cars.

 

thanks for the replys will give it a go. does anyone know what grounds the injectors.

 

The ecm will ground the injectors once it receives drp. The ecm ground is tied into the tps mat ect ground behind the rh cylinder head.

 

Since this is a 89 you can also check with a vom hz setting the passkey signal pin B6 of the ecm 30hz 50-60%.

 

if i get to the ecm what wires do i check to make sure power is getting to the ecm

 

one quick way to see if the ecm is powered on is turn the key on and jumper a to b of the aldl if the mil starts blinking code 12 the ecm has power. On the 1227165 ecm b1, c16 are battery power and a6 is switched 12v. You should also ohm your injectors a shorted injector can cause the injector driver to not work.

 

right thanks for the info what i cant understand is when i had it running with fuel down the throttle body it was ok for about 30 sec it was running by itself with no fuel down the throttle body then just petered out. and the bloke i bought it off tried messing with it and theres wires and plugs off everywhere but think i have got them all back in place now. not sure if its the resister on the key as light is coming on and off as it should. however i will ohm the injectors next i think. also anyone no where the ecm is under the dash or seat thanks

 

not sure where you are located but it maybe easier to find a 1227808 ecm if needed.

 

ok whats the differance in the normal ecm and 1227808 will a ecm out of any trans am 5.7 tpi be ok in mine or do i get my one rebuilt. also do you no if the performance chips are any good for these cars as some people say there good and some say there a waste of money

 

If you are in Australia the 1227808 from a holden is the same as your 1227165 ecm. Unless you have engine modifications a new cam and cylinder heads and have the car tuned live for these changes is the only benefit you can get from a eprom change. Aftermarket chips will change fan on and off temps and wot timing a real waste of money. The ecm is under the dash in a plastic holder on the passenger side.

 

great thanks for your help tuned performance i will have a look at it soon and see what its doing any problems ill give you a shout thanks again and all the best

 

 

thankyou mate thats just what i needed. now i should be able to find out her problem next week and get it running soon. thankyou again been the world of help