Injector driver problem

[luvmygst]

Does anyone happen to know what chip actually drives the 4 injector drivers? I have a 1g computer that just keeps the injectors open all the time. I have checked all the actual transistors , emmiter resistors etc.. I just cant seem to trace where the driver signal comes from. I think the computer is trying to do the right thing because when I log the car(when you can get it to start) It give correct readings for the IDC and time in m/s for injector pulse, so the computer is trying I just cant find what is driving the transistors on to keep the injectors open.. Any ideas would be appreciated. Thanks

 

[BISHILVR]

What is an emmiter? No such component, that is a leg of a transistor. How did you check them? you would have to desolder any component to check it. There is no "chip" that drives the injector, the microprocessor determines the "on" time of the injector by following a "look up table", then it outputs a logic high or low to another circuit which then turns the injector drivers (basically switching power transistors) on and they send a ground out to your injector, completing the circuit. Maybe you have a damaged ecu, or a bad maf sensor that is causing your problem.

 

[luvmygst]

What is an emmiter? No such component, that is a leg of a transistor. How did you check them? you would have to desolder any component to check it. There is no "chip" that drives the injector, the microprocessor determines the "on" time of the injector by following a "look up table", then it outputs a logic high or low to another circuit which then turns the injector drivers (basically switching power transistors) on and they send a ground out to your injector, completing the circuit. Maybe you have a damaged ecu, or a bad maf sensor that is causing your problem.

An emmitter resistor is the resistor that follows the emmitter leg of the transistor, and part of the bias for the transistor, keeping it from blowing up. THe ones in this computer have been subjected to alot of heat, like the person ran low impedence injectors with no resistor pack, drawing too much current. I think I have found the driver chip though. any more ideas are wecome.

 

[BISHILVR]

You would be talking about the collector , and we dont refer to resistors around a transistor as emmiter resistors, collector resistors etc, we have other names for them generally Rb, Rg, etc depending on their function. If someone ran low impedance injectors without a ballast then the damage would most likely be done to the quad driver, aka power transistor that is heat sinked on the edge of the board.

 

[luvmygst]

You would be talking about the collector , and we dont refer to resistors around a transistor as emmiter resistors, collector resistors etc, we have other names for them generally Rb, Rg, etc depending on their function. If someone ran low impedance injectors without a ballast then the damage would most likely be done to the quad driver, aka power transistor that is heat sinked on the edge of the board.

I wont argue wording with you. I have always reffered to them as emmitter resitors in power applications , but oh well. There is no quad driver The 1g computer has 4 seperate transistors that drive the injectors. Damn a schematic would be helpfull. I have traced the drive back to one chip, that is fed off of the processor, I am going to repace it and see what happens. Like I said the logger says that the injectors were working fine. It gives me the IDC and pulse width, so I dont think its the procesor. I just replaced all of the emmiter resistors, as well as the resistor pack that is in the same area just in caseof heat damage. not to be a smart assI appreciate the effort to help but I have 2 degrees in electronics and know what the bce of a trans is. collector is tied to ground, the emmitter goes through 1 200j 1w resitor for each injector, then to the harness. Thanks for trying to help though if you have any other ides shoot em at me. Thanks

 

[steve]

I have 2 degrees in electronics

If you have two degrees in electronics I'm confused by why you can't spell emitter or can't draw the schematic of the injector drivers.

Perhaps you have a different datasheet for the injector drivers than I do, but it sure looks to me like each injector is connected to the collector, not emitter, of it's driver along with an RC snubber for the inductive kick when they are switched off. The bases of each driver are driven via the series resistors from the 74HC02 outputs. That should be more than enough to figure out what's wrong.

Steve

 

[BISHILVR]

Lol, quad driver was a generic term, Gm uses them in their ecu and does the same thing but in a different package. The collector is the output as we have said.

 

[luvmygst]

If you have two degrees in electronics I'm confused by why you can't spell emitter or can't draw the schematic of the injector drivers.

Perhaps you have a different datasheet for the injector drivers than I do, but it sure looks to me like each injector is connected to the collector, not emitter, of it's driver along with an RC snubber for the inductive kick when they are switched off. The bases of each driver are driven via the series resistors from the 74HC02 outputs. That should be more than enough to figure out what's wrong.

Steve

what number is on the injector driver? The data sheet I pulled has the collector tied to ground and the emitter driving the injector. The guy that gave me the computer said his dad had worked on it and could not get it to work. He could have changed the drivers. (I hope not ) Does any one know the p/n for the injector driver , because if you say the collector is connected the the injector its not what is in this computer, I have drawn my version of the schemmatic ,from the board in front of me with the data sheet for the drivers. The collector is gronded, the emitter goes through the R/C to drive the injector. Then every thing else sound about like you said , the hco2 drives them. Dou you happen to know the part number for the driver? I will edit in a few minutes and tell you what is in the computer I have.(its in the building)

 

[steve]

2SD1415

From now on please check your postings for spelling, capitalization, and punctuation. That also includes only quoting the parts your replying to, in order clarify what your saying.

Right now your postings tell me you can't be bothered to proof read them or format them for readability.
If you don't value my time why should I spend any of it on you?

Steve

 

[steve]

I will edit in a few minutes and tell you what is in the computer I have.

Well? It's been 4 days. Did you fix your problem?