turboteg2nv

Hey guys,
I installed a custom turbo kit and can't get the car started now. For some reason the injectors aren't firing; but it has spark and fuel pressure. I installed DSM 450cc injectors with resistor box and Walbro 255 fuel pump.

Anyway, I'd like to know if the injectors are getting enough power (12v) to open? I tested my injector clips with the ignition on and got 3.9 volts on the left (+) wire, and about 12.8 volts on the right side. Can someone else test their injector clips to see if mine are ok?

I'd really appreciate any help to get my car movin!!!

turboteg2nv

Also, this was tested with the clip OFF the injector. And I need to host a picture of a resistor box wiring diagram that I made up, I did it differently than most on here do and want to check with you guys to see if you think it's alright. I've tried registering with we-todd-did but haven't got a confirmation email yet. thx

leadfoot78

I don't have a resistor box so I can't help, but I can bump it up!

turboteg2nv

Thanks. up again.

I checked the volts on the injector clips on my bro's 95 Talon awd and he had about 12volts on each side.

Joseph Davis

Testing with clip off versus clip on... lol. Doesn't indicate anything, bro.

FYI, you can calc voltage drop with the circuit intact based on injector + resistor pack resistance. Netsearch ohms law pls.

turboteg2nv

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by J. Davis &raquo;</TD></TR><TR><TD CLASS="quote">FYI, you can calc voltage drop with the circuit intact based on injector + resistor pack resistance. Netsearch ohms law pls.</TD></TR></TABLE>

Not sure what I should be looking for here. I'm just wondering if something isn't grounding the injectors properly or what exactly is wrong.

Joseph Davis

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turboteg2nv &raquo;</TD></TR><TR><TD CLASS="quote">Not sure what I should be looking for here. </TD></TR></TABLE>

Continuance, resistance, voltage.

Continuity is obvious - is everything electrically connected?

Resistance is obvious - should only have resistance across the injector and across the resistor hackjob.

Voltage is where you are getting confused. If there is no ground available, then the only voltage you read at the injector, or with the injector unplugged is battery voltage. If there is a ground and you put the DVOM inline, you just read battery voltage. If there is a ground and you put the DVOM across a component, you read the voltage dropped across that component.

Here's where it gets tricksy: If there is a ground, and you put the DVOM across ground and X point in the wiring, you see however much voltage there is at that point in the circuit. From the injector power at the fusebox to ground you get battery voltage (12v unless alternator is charging at higher voltage). Between resistor hackjob (lets say 7 ohms resistance) and injector (lets say 3 ohms) you have 3.6 volts. From the "backside" of the injector to ground you have 0 volts. If you don't understand where I am getting these numbers - as I said, netsearch ohms law. It's first day curriculum in the first electronics class, and not hard to master. As soon as you figure out what is supposed to be happening in the system, and compare that to what is going on, solutions become obvious.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turboteg2nv &raquo;</TD></TR><TR><TD CLASS="quote">I'm just wondering if something isn't grounding the injectors properly or what exactly is wrong.</TD></TR></TABLE>

"something" in this application is the ECU. battery 12v --&gt; ignition switch --&gt; resistor hackjob --&gt; injectors --&gt; ECU --&gt; battery ground.

ILLICON3000