Power to injectors

[DC871F]

Did the coil test, didnt hear any injectors firing, grounded them at the ECU plug, nothing either.

Oil and gas in cylinders fired engine off, but still no fuel flow from the injectors.

Edited April 17, 2017 by DC871F

[Zed Head]

When you grounded them at the ECU connector you took the ECU out of the picture.  So you can't determine if the ECU is good or not.  But you could say that even a good ECU won't open the injectors.

How did you do the grounding?  And which pins did you use on the connector?  And was the key On?  Did you measure battery voltage at the pin before you grounded it?  No offense, but you might be missing something.  Not enough detail to tell if you did it right.

You can also power each injector individually.  Some people use a 9 volt battery because they're afraid that a full twelve will damage the injector.  But a short tap or two with full power won't hurt them.  It's the extended current that causes the damaging heat.  A tap or two with a full twelve volts might be enough to pop them open.  It might get you running but they might not be balanced if they've all been stuck.  Kind of odd that you don't get at least one click.

[Captain Obvious]

On ‎4‎/‎14‎/‎2017 at 2:57 PM, DC871F said:

There's no power at the injector plugs, good ole Fluke and a home made tester with a light bulb confirms. If the ECU is not the beginning power for the 6 injector plugs, where would the beginning be?

I'm not a ZX guy, but according to the wiring diagram that Zed Head put in post #2, then you should have +12 volts on one side of every injector plug. At all times. Running or not. Key in ignition or not. At all times. If the battery is hooked up, you should have +12 on one side of each injector.

Try this...

Ground the negative lead of your Fluke on the engine block. Put the Fluke on a 20V DC voltage scale, and probe the connections inside the injector plugs with the positive lead. You should find battery voltage on one of the two connections inside each injector plug. If you don't, then you should test the fusible link that Zed Head mentioned in post #2.

 

[Zed Head]

That's a good point.  Funny that we have those 6 potential short circuits sitting there all the time, with the crappy typically burnt crispy connectors the only thing stopping it from happening.

I don't get too far in to the fine details of of a problem until I know that the measurement techniques are right.  I suspect that DC8 is early on the learning curve, but making rapid progress.

You're the one that pointed out to me that if the other injectors are connected, you'll see voltage on both pins of the disconnected one you're testing, because there are parallel circuits.  So if all are disconnected you see only one pin voltage but if others are connected you'll see voltage on both.  I think that still applies even without dropping resistors.  The wiring diagram implies only one grounding transistor though, but all six terminate there.  Kind of interesting.

[DC871F]

Not new to wiring, I'm an A&P mechanic used to troubleshooting avionics, autopilots, fixing jet engines, etc. I can read a diaphragm. But I am not too big to take advice or learn something new from guys that have been doing this sort of thing alot longer than me.

I have power on both sides of the injector plug, I just got a new set of noid lights which did not pulse.

I show power from the ECU plug pin for the injectors, EFI relay is good, Fuse links are good, good battery, good ground, good gas, good pump, good spark. 

I'm guessing that the injectors can be seized from years of sitting, or maybe the ethanol got to them. Or is it the ECU? 

The car sat for several years, and for ZX's its pretty clean for having so, fuel delivery may have been the reason for it. Tank was completely shot, full of rust, but that may have been due to sitting and not the cause of the problem. I installed a clean tank and replaced a couple fuel lines which showed no signs of sending rust downstream. Fuel rail is getting and sending clean fuel.

 

 

[Zed Head]

When you grounded the injector pin at the ECU connector you did the job that the ECU would do.  So the status of the ECU is unclear.

I've had stuck injectors, in my hand, with battery voltage applied, and tapped them with a screwdriver and heard them free up and click.  So they do get stuck, but come loose.  From the same old engine I had injectors that were stuck and would not come unstuck.  So they do get permanently stuck too.   If the fuel system was open to the atmosphere diffusion will carry any moisture and oxygen through the lines to the injectors.  I've read accounts from a forum back when they were called bulletin boards or usenet or whatever,about sticking an injector just be getting a drop of water on the pintle.  Water is bad.

If you live near a wrecking yard you might find an old car with EV1 style injectors and buy a couple just for experimentation.  If the gas in the fuel line still smells like gas they'd probably be fine.  You can even take a 9 volt battery in to the yard to test them before buying.  Then you'll have known good injectors to test the system with.

[Captain Obvious]

Sorry, my bad. I must be just getting lost in the description of the problem. When you said:

"I have fuel, spark, but no power to fuel injectors", and
"There's no power at the injector plugs, good ole Fluke confirms."

I interpreted those as "there is no power to the injectors."

But now with your latest "I have power on both sides of the injector plug", that's a step in the right direction and sounds like you're making good progress. Good luck with getting to the root of the problem.

Edited April 18, 2017 by Captain Obvious

[DC871F]

Not lost, just re-routed.

So the Haynes book says make a plug to use in the injector plug, spin the engine above 80RPM which I did. It did not show power (no pulse), then I discovered the FSM here on the site, which I them proceeded to do the various functional test which long story short, I do show continuous power in the injector circuit, but after getting noid lights, I confirmed that there is no pulsing at the injectors, which was in fact what the first original test confirmed when I made up the rig that Haynes said to do. 

I think the root of the problem is the ECU or all 6 injectors are stuck. More to come.

[Zed Head]

I think that you might not be understanding how the injectors work.  They open when current flows through them.  The ECU creates a grounding point, allowing current to flow.  When you grounded the circuit yourself, at the ECU connector, you took the ECU out of the picture as the cause of the problem.  The ECU is at the end of the circuit.

Your train of thought might be stuck on its track.  I mentioned the above before but you haven't acknowledged it and you've repeated the same error in understanding.  No offense intended, but it's clear.  You also aren't giving the information on which pins you used to ground the circuit at the connector, just to show you used the right pins.

With the power of your battery, your Fluke to confirm power, and some lengths of wire (or an old EV1 plug, the connector), you can test the injectors directly at their spot in the manifold.  You might try that.  You'll need to do it anyway, even if you remove them or  buy new injectors.

 

[Zed Head]

Here's a decent video showing how to use a 9 volt battery to open an injector.  The relevant stuff starts at about 1 minute.  Beware sparks.  These videos are scary.

 

[Zed Head]

Here's another one showing all kinds of machinations in order to squirt solvent through an injector the same way that hundreds of gallons of the very powerful solvent gasoline have already passed.  Not suggesting that you clean them this way just that you can open them with a battery.  At 4 minutes.

Incredible how much wrongness a person can ft in to six minutes.  Edit - you can watch injector-testing videos for hours.  Very entertaining.  The best ones probably burned up though.

 

Edited April 18, 2017 by Zed Head

[DC871F]

1 hour ago, Zed Head said:

I think that you might not be understanding how the injectors work.  They open when current flows through them.  The ECU creates a grounding point, allowing current to flow.  When you grounded the circuit yourself, at the ECU connector, you took the ECU out of the picture as the cause of the problem.  The ECU is at the end of the circuit.

Your train of thought might be stuck on its track.  I mentioned the above before but you haven't acknowledged it and you've repeated the same error in understanding.  No offense intended, but it's clear.  You also aren't giving the information on which pins you used to ground the circuit at the connector, just to show you used the right pins.

With the power of your battery, your Fluke to confirm power, and some lengths of wire (or an old EV1 plug, the connector), you can test the injectors directly at their spot in the manifold.  You might try that.  You'll need to do it anyway, even if you remove them or  buy new injectors.

 

I used the pins in the FSM for each injector. So if I went to ground from the ECU connector, the injector should have fired. I understand that it needs a pathway, which I'm pretty sure me grounding at the connector did. Maybe my wording above said something different.

Now, I will go ahead and admit to a major error in my troubleshooting. When I was checking with the noid lights, I forgot to bolt the ecu back up to the bulkhead, so no ground, (cough cough), that came to me about 2am last night in bed, funny how the mind works. I had the ECU out just make sure there was no obvious damage.

SO, I just went out and checked with the noid with the ECU grounded, and yes, pulsing, a long road to this discovery, but I'll take it. Still no fire off.

Injectors next.

 

Edited April 18, 2017 by DC871F