90 Talon Injector Firing problem*Wisemen Steve*

[CPHunter]

So i have a problem with my Injector. i did a NOID test and i didn't get a light. i got 12v from the injector. I have this Matco Injector Pulser that i put on the car, and since i can only do one cyl at a time. i loaded them up and i could hear the injectors shooting. the car tried to start but with not all injectors being able to shoot. it just dies shortly. My dad thinks my Injectors aren't getting a ground. Ive replace MPI relay,fuse, Confirm that the fuel pump works.CAS. My ECU i believe works. Open it up and saw that the Caps where good. and when i turn the Key my boost gauge moves. Any ideas

 

[luv2rallye]

The injector turns on when the ECU grounds 1 side. The other side goes through a ballast resistor to +12V. So if a ballast resistor was say burnt it may have way to high a resistance to fire the injector but would still read +12V with a voltmeter. As this is a real possibility I suggest unplugging those resistors and measuring their resistance (usually around 6 ohms but they all should be the same). Not sure where on a 1g they are but on a 2g they are on the firewall behind the intake manifold so you might look there (probably a 6 pin connector).

 

[steve]

The injector resistor pack on a 1G is also on the firewall. http://members.shaw.ca/dsm.1000q/Engineprimer/1G/respack.htm

Do any of the injectors fire using the ECU?
Do you have a datalogger? Do you see the RPMs during cranking? What about on the tach?

Steve

 

[CPHunter]

The injector resistor pack on a 1G is also on the firewall. http://members.shaw.ca/dsm.1000q/Engineprimer/1G/respack.htm

Do any of the injectors fire using the ECU?
Do you have a datalogger? Do you see the RPMs during cranking? What about on the tach?

Steve

how do i get the Injector to fire just using the ECU? My logger isn't working, The Tach Moves while cranking. i don't know if that helps much

 

[CPHunter]

The injector turns on when the ECU grounds 1 side. The other side goes through a ballast resistor to +12V. So if a ballast resistor was say burnt it may have way to high a resistance to fire the injector but would still read +12V with a voltmeter. As this is a real possibility I suggest unplugging those resistors and measuring their resistance (usually around 6 ohms but they all should be the same). Not sure where on a 1g they are but on a 2g they are on the firewall behind the intake manifold so you might look there (probably a 6 pin connector).

i just did the resistor and it came back with 6ohms.. so my guess is ECU?

 

[steve]

how do i get the Injector to fire just using the ECU?
My logger isn't working, The Tach Moves while cranking. I don't know if that helps much

I went back and reread your first post and I think it answered my question.
Cranking the car you don't hear any injector firing and that was confirmed by using the noid light on each. The Injectors do fire if you use the Matco Injector Pulser.

I wanted to see if the ECU was seeing the CAS and TDC signals, the tach moving says that the ECU is firing the coils but if the ECU isn't showing RPM on he logger then it isn't going to fire the injectors.

Steve

 

[CPHunter]

well i found that pin 110 isn't getting any power, pin 103 is always hott (normal) and pin 102 is grounded, but pin 107 is hott. i know pin 107 should be a ground, and pin 110 should on when with the key.

 

[steve]

well i found that pin 110 isn't getting any power, pin 103 is always hott (normal) and pin 102 is grounded, but pin 107 is hott. i know pin 107 should be a ground, and pin 110 should on when with the key.

Recheck your results and make sure you don't confuse where the pins are. It's not physically possible for 102 to be grounded while 107 has 12v on it since the pins are tied together on the circuit board. To do so would create a bit of smoke before the MPI fuse popped.

Review http://www.dsmtuners.com/forums/showthread.php?t=246467 and note that the pin in the upper left is the lowest #. If you flip the plug over and look at if from the side that plugs in then that same lowest # pin is on the upper right.

Steve