1G No Injector Pulse

Nihil · Mar 16, 2011

This is a copy n paste from another forum, I wasn't having much luck and there seems to be a lot more knowledge over here...so...

*paste*
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'91 GSX, I've got spark, I've got fuel, I've got 12v at the injector connector, but, with a test light connected to the injector plug ends, and while cranking the car over, I've got no pulse.

I'm thinking it might be the ECU, the caps are fine though, the ECU was obviously repaired, there was a sticker on the ECU from some electronics company.

I'm not sure how to test from here, I was told I could remove the ECU and jump the power supply pin to each injector pin and test at the injector plug to see if the harness is good, and if so, it's probably the ECU injector drivers?

I tried this, but with the ECU removed, battery connected, key turned to On position, I didn't seem to have power at the pins I should have. I have the 1g pin out, and from looking at it, it would be a mirrored image since I'm working on the plug end of things rather than the ECU end, correct?

Any advice, ideas or insight on this is much appreciated
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Spln_Hrd · Mar 16, 2011

If the injector has power to it, and isn't driving(being grounded). The problem is either wiring, pcm, or cam sensor.

I would check and see if you have spark, if you have spark the cam sensor is working. In the field as a drivability and diagnostics specialist on japanese imports for the last 6 years I would say the odds of a wiring problem are fairly low, but I would make sure the pcm has proper power and ground sources.

92AWDHX40 · Mar 16, 2011

Check the wiring, something isnt right look into that

Nihil · Mar 16, 2011

I've got spark...

From my understanding, the CAS controls spark, I've got spark, so I was told it wouldn't be the CAS?

Though, initially, I had no spark, I checked the PTU, it passed, then along with new plugs and wires, I magically had spark again and no fuel.

So, if the CAS controls both, I could see where this thing's goin south and is doing intermittent things.

If I pull the CAS and rotate it with the key in the ON position, it will send spark and injector pulse, if no injector pulse, or spark, or neither of both, it's a bad CAS?

Nihil · Mar 19, 2011

So, CAS is sending spark, and while rotating it by hand, it sounds like the IAC/ISC is making some noise too, when I unplugged the IAC I could hear something else, but...

With a test light hooked up to the two wires on the injector connectors, I'm not seeing any pulse, but I do have the 12v power at the pos wire on the connector...

Nihil · Mar 28, 2011

So, I figured it out, there's a fail safe, if the ignition isn't working right, it will cut fuel, that's why I wasn't getting any injector pulse, once I cleared the code, I got it to run...

It ran like crap when I got it to start, I moved the harness around and it ran like it should, it turns out, it's the wiring....that's why everything was checking out fine...

Now, I need to figure out how to test the wiring, it seems to be somewhere in that area, near the PTU and coil plugs, I've got the loom all pulled back and the wires look fine, as I figured they would...I would think there'd be a way to test at each plug in to see where the faulty wiring is.

Any suggestions?

andrew4g63 · Jan 13, 2012

You ever fix this?

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1G No Injector Pulse

Nihil

Spln_Hrd

92AWDHX40

Nihil

Nihil

Nihil

andrew4g63

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