76 D-jetronics problems, Only one injector working Options

[Malpais82e]

I have a 76 914 that's been in my barn for 10 years. Trying to get it running again. I’ve searched this forum and other forums and the internet extensively, and can’t find an answer, or don’t recognize it!
My questions are:
1: Can bad or maladjusted trigger points shut down 3 injectors and allow one to work?
2: If the throttle switch, when throttle is stroked, cycles one injector about 20 times, shouldn’t it make all injectors click? Just one does.
3: Does the throttle switch bypass the Control Unit or at least the computing in the Control Unit?

What I’ve done so far:
Sprayed gasoline into the throttle body. Ignition system and timing work – thing runs and sounds good.
The relay board and sockets needed cleaning, and I got the relays working so the Fuel Pump and control module have power as I’ve read they should. Fuel pump runs a few second when key is turned on. Pressure is about 30 psi.
I’ve also read that moving the throttle (and switch) should, cause the injectors to “click”). Only #4 cylinder injector does anything.
I then re-did the grounds and rang out the wires to all injectors - grounds to ground and power wires to appropriate connections on the Control Unit - all had continuity.
I took the injectors out and sure enough, only #4 sprays gasoline. If I move the #4 wires to another injector, it works, so only #4 connector is getting a signal and at least one other injector will work if it had a signal.
The rest won't even click. I tried a different control unit – same symptoms and only #4 injector doing anything!
I'm thinking of trigger points, but if they are bad/misadjusted, a pair of cylinders would fail instead of three, wouldn't they? And bad trigger points wouldn't keep the throttle switch from cycling all four injectors, would it?
Thanks for any ideas or guidance. I’m about frustrated and out of ideas. Maybe a little a little dynamite………………………….

Gordon

[Dave_Darling]

It could be multiple problems adding to each other, which makes for even bigger headaches.

The trigger points run pairs of injectors, on the diagonals. I believe that's #1 paired with #4, and #2 paired with #3.

I believe the grounds are paired with the lefts together and the rights together.

Debris in the fuel tends to affect the right-side injectors first, because they're closest to the supply.

The "accelerator enrichment", I think, only activates whatever injector pairs are currently selected by the trigger points.

The injectors are always grounded. The ECU supplies them with voltage to get them to open. Does every injector connector have a good solid ground on one wire? Does it intermittently have voltage on the other wire? A "noid light" plugged into those two wires can tell you if there's electrical signal or not.

http://members.rennlist.com/pbanders contains pretty much everything that anyone knows about D-jetronic EFI these days. Read through it and take in as much as you can.

--DD

[Malpais82e]

Dave, Phil and all others, thanks for the replies.

Dave, while a newbe on this forum, I used several forums 10 or so years ago, and always valued your advice. I'm sure there are others in this forum that have great info too. Today, I put in an alternative '74 harness and now two injectors fire (increased by one!). Makes me think the harnesses are the issue.

I think I read somewhere that the throttle switch "clicks" the injectors up to 20 times per throttle travel and therefore provides "accelerator" pump function?

I've heard of a "noid light". What are they and can I make one? What is the voltage to the injectors?

The two injectors that now fire are both on the pass side, so doesn't seem like the trigger points.

I'm wondering if the stabs in the CPU and the harnesses are dirty. I'm going to take a pencil eraser and clean them. If I have a noid light, I may strip a little of the old harness near the CPU and see if a signal is coming out.

There appear to be firm grounds on one wire on all injectors. I'll check the grounds again on the drivers side, since they are not injecting.

Thanks again, Gordon



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It could be multiple problems adding to each other, which makes for even bigger headaches.

The trigger points run pairs of injectors, on the diagonals. I believe that's #1 paired with #4, and #2 paired with #3.

I believe the grounds are paired with the lefts together and the rights together.

Debris in the fuel tends to affect the right-side injectors first, because they're closest to the supply.

The "accelerator enrichment", I think, only activates whatever injector pairs are currently selected by the trigger points.

The injectors are always grounded. The ECU supplies them with voltage to get them to open. Does every injector connector have a good solid ground on one wire? Does it intermittently have voltage on the other wire? A "noid light" plugged into those two wires can tell you if there's electrical signal or not.

http://members.rennlist.com/pbanders contains pretty much everything that anyone knows about D-jetronic EFI these days. Read through it and take in as much as you can.

--DD