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740 No Pulse to Injectors, Has Spark

I spent months resolving injector problems and with a new set the problems went away. Thought it was magic. That is not diagnostic testing but simple results.
 
Does a test light illuminate brightly when you connect it between injector positive and a known good ground?

Resistance test injectors.
 
Does a test light illuminate brightly when you connect it between injector positive and a known good ground?

Resistance test injectors.

Last I checked yes, it was bright. I can check again just to make sure.

I’ll check resistance once more. Last time I checked all were around 2.6 ohms, within spec for a low resistance injector.
 
With all injector connectors removed, I got 12.06V at all four positive terminals. 0V at negative, although when I first tested them it showed up to 0.2 (may have been 0.02), but after going over all of them again it showed 0.
Battery voltage was 12.25V. Is this an acceptable drop?
 
Huh? People here focus too much on voltage down to the decimal point. Meh.

Proper method is a test lamp. 12v can pass thru one strand of wire, but not operate a circuit. Or a noid light, for example. And btw are you doing this while cranking? Noid light Lit up dimly key on isn't right, (with they key on, not cranking)
 
Eh, I guess it’s fine then. Probably just the injectors. All showed 2.9 ohms, by the way.

I tested the pulse while cranking, obviously. The noid light was not lit with the key on, only pulsed while cranking.
 
Unfortunately not. I'm probably going to have to bite the bullet and buy a set.

I have a set of high impedance injectors but I think they’re NA injectors which might throw lh2.2 off due to being the wrong size (you’d have to temporarily bypass the resistor pack anyway). Something like 850t injectors and a bypassed resistor pack would probably work perfect.

I’m willing to bet you could get a set of those or factory turbo injectors for next to nothing. If I had the correct set laying around still you could have them for the cost of shipping. Under $5.
 
I have a set of high impedance injectors but I think they?re NA injectors which might throw lh2.2 off due to being the wrong size (you?d have to temporarily bypass the resistor pack anyway). Something like 850t injectors and a bypassed resistor pack would probably work perfect.

I?m willing to bet you could get a set of those or factory turbo injectors for next to nothing. If I had the correct set laying around still you could have them for the cost of shipping. Under $5.

I'll have to check the junkyard to see if they have any P80 turbos over there. I know my cousin has 2 or 3 S70 T5 blue injectors somewhere, but I'd have to find 1 or 2 more.
 
$20 says injectors won't get it started. If you have a noid light that won't blink, what will swapping injectors do for you?
 
$20 says injectors won't get it started.

I'm not the most confident either, but what IS the problem? Honestly I couldn't see it being anything else. Injectors are getting voltage, ECU is getting good ground. Everything else in between has been tested to be good.

Some ECU testing notes with questions...

Pins 5, 11, and 25 are grounds on LH2.2. They show 0 ohms to ground with the key off, and 18 ohms on 5 and 11 and 13 ohms on 25 with the key in position 2. What's that about? Is that normal or am I looking too far into things as usual?
Voltage shows trace amounts... only 0.01-0.02V.
Pin 19 (referred to as "code" on the document) shows 0.5V in KP2. Apparently that's also a ground, actually connected with a factory jumper to pin 11. That could have been a lapse in my testing or just me once again trying to find a problem.
Crazy enough, my old ECU shows 12V here. No idea why.

Then there's the issue of LH pin 21 only showing 1.72V in KP2, but showing a full 12 volts with the key off. Nobody has clarified that... should I have 12 volts in KP2?
It does show above the suggested 0-1V while cranking (1.6V).
 
picture.php


$80 Hantek PC based scope is a step above blinking lights. Yellow is an fuel injector waveform. Blue is a crank sensor waveform. The flat section in the fuel injector waveform is the injector on-time.
 
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