1977 FSM not helping.

[Inthenameofweez]

My parts car has a bad pump also. This one is shorted internally. (Sparks when touching each terminal).

So I think I'm chasing more than one issue. I have a burned and replaced fusible link, a bad relay, and a weird response while turning the key to "ACC" and "ON". I'm wondering if any of those specialty Z shops in California have entire EFI harnesses laying around. I hope it doesn't come to that.... At least I have a parts car. Are the harnesses from 75 and (early) 77 the same?

So given that I have the 12V signal going to the fuel pump while the key is "START", what can I confirm is good in this circuit? Simply the ignition switch, wiring, and relay? I may still have a bad ECU or one of the other inputs, correct? I don't even know if my dropping resistors or fuel injectors are okay.

Ugh. I kinda just want to strip it all down and start rebuilding slowly after cleaning and verifying proper operation of each part/wire/component. .

[SteveJ]

For the wiring harness, you could try ZCarSource. They aren't cheap, but they probably have one.

[Inthenameofweez]

Alright, so I've got a new fuel pump into the vehicle. Power relay is good. Sends fuel to the fuel rail like it's supposed to.

It still won't start. It turns over like normal. It gets fuel. But either the fuel rail is clogged or the injectors are not opening.

It is also possible that my plugs are simply so old and worn that all 6 have stopped firing. Or maybe the wires are mixed up. However, very unlikely, I will be replacing plugs and ensuring proper order of wires.

In the mean time, I need to get some node lights to see why my injectors aren't opening...

[240260280z]

Is the fuel rail hooked up correctly? They are usually 1 way. I found out through a very good friend

Get NGK plugs.

[Inthenameofweez]

Yeah, I've checked pictures all over the internet, and my lines/rails are all hooked up right. I was listening with a screwdriver last night and heard no clicks.

I'm wondering if the clicks are too quiet to be heard over the starter motor. Hoping to get plugs and node lights today. Any place that I can verify the proper order and placement of the spark plug wires other than the FSM?

[SteveJ]

Search on this site. Just type firing order into the search box and see how many times it appears.

[Inthenameofweez]

Anybody have some ideas on what would cause the fuel pump to run normally and no fuel injector pulse?

I am looking at the wiring schematic in the Bible and I see a few possibilities. I'm about to run out and start checking with a volt meter to see where my gap in power is, but what is more likely?

Furthermore, where the heck is this damn fusible link? Is this in the engine bay? All engine bay links are OK and I still have no power to injectors.

And this dumb ignition lead wire under the dash? WTF does it do? Haha.

[Zed Head]

The EFI Bible should really be called EFI Cliffsnotes. The book it's based is the FSM. Notice that the "Bible" always refers you to the Service Manual when there's a problem. Download the FSM and read the Engine Fuel section, along with Body Electrical. It has much more detail specific to your year.

There is a separate set of green fusible links (either one or two) for the EFI harness, inline with a wire that comes directly off of the positive post of the battery. It should be clipped to the side of the big metal relay cover right in front of the battery.

The ECU fires all of the injectors on every third spark produced by the coil. It "counts" the pulses through a wire from the negative post of the coil. The tachometer circuit plays a part also, if the tachometer is removed the injectors won't fire. You can test the ECU and circuits by connecting a wire to the negative post, turning the key On, and tapping the wire to ground. You should hear the injectors open and close on every third tap. You'll also get a spark at the distributor on every tap.

If you can't find the "ignition lead wire" you can test for power to the control unit on Pin 10 at the ECU connector.

[Inthenameofweez]

Is what I'm holding referred to the Ignition Lead Wire?

I have the FSM for my 77, but I don't see this green fusible link that is supposed to be clipped to the side of my relay cover. I will go check again.

So if my tachometer is dead for some reason, I won't have injector pulse? As far as I can tell, while cranking, I have no tach reading...

[Inthenameofweez]

Update: I can get a large amount of "sputter" while cranking. I am NO LONGER using starting fluid.

There is some sort of a backfire in the intake manifold that is shooting a blue colored smoke out of the AFM. Not sure if I've got bad gas causing something or not. I'm going to get a 5 gallon gas can full of fresh 91 Octane and hope that I can clean out the junk in there. There are a few connectors inside of the engine bay that are creeping me out...

I'll update in a few with more pictures and video of the "attempted" start.

[Zed Head]

I've never had to use the ignition lead wire for anything so can't really say. But you can check for power at other places, like at the coil, to see if things are working right. I saw in your first post that Pin 10 is getting power. That should mean that one of the the green fusible links is intact, at least. I think that the other supplies the dropping resistors and injectors. Have you checked for power at the injector plugs with the key On?

The ECU won't fire the injectors if the circuit to the tachometer, with its inline resistor, is not in place. I've had the resistor fall out and my engine wouldn't run until I put it back in. It looks like a small (about 1/2" wide by 1 1/2 " long) black piece of plastic with a male and female plug on the same end. It should be taped up in the harness by the relays and fuse box. Or you might just have a bad connection at the tachometer. I have also confirmed that the engine won't start if the tachometer is removed. I'm not clear on why, maybe it's a pull-down line for the ECU circuit (I barely know what that means).

Are you using the stock ignition module? It uses the same blue wire from the coil (-). The wire branches out after leaving the coil.

Edit - just saw your last post. You could be getting sputter from the cold start valve. Injectors could still be dead. Pretty easy to make the injectors fire, with a jumper from the coil (-). It will tell you a lot.

Edited December 20, 2011 by Zed Head

[Inthenameofweez]

I don't understand any of what you are saying. I'm not hunting an issue with the fire. I'm hunting an issue with the fuel. Ignition modules and lead wires make no sense as to why I can get it to run with starting fluid.

And again, I have no green wires in my engine bay. I guess I needs to take a few shots of what I'm working with.

http://www.youtube.com/watch?v=upVSDkadigg