injectors not firing reeds hot at rest when ignition is on, on both sides of injector plug,when all injectors are plugged in or just one other one is that normal?I was under the impression that only one wire was hot then it got a negative Pulse through the other wire....going to try changing stator to see if its bad....to see if I get signal to ECM

 

You will read 12+ thru the other injectors if you unplug one and test both sides of the plug. Its the way the batch-fire circuit works. You are on the right track, look for why the ECM isn't firing them.

 

What year is the car?

Do you get flashes if you connect a timing light?

If VATS kicks in then the injectors will not pulse. 1986 and newer.

All 8 injectors are connected together in parallel. You will see 12 volts on both pins of the injector connectors unless you unplug ALL of them. Then you will see 12 volts on the fused side and zero volts on the other pin (light blue or light green wire).

 

The injector drivers are open collector and fire by pulling the line to ground causing current to flow firing the injector(s). So you will see +12Vdc on each injector pin when it's not being fired.

 

They're actually open drain since the injector driver(s) are MOSFETs. ;-)

For the non-electronic people, MOSFET is an acronym and means Metal Oxide Semiconductor Field Effect Transistor. I'll bet you're happy to know that...

 

Ordered stator and I'm in the middle of replacing it and I'll probably put a new Ignition module also....have a set of Noid Lights ,as soon as I put distributor back in I'll check to see if I'm getting a negative Pulse. ...if I do,it should fire it up.....again thanks for the info will get back to you guys if that doesn't work

 

You need to have DRPs (Distributor Reference Pulses) from the ignition module to the ECM. The ECM uses them to synchronize the firing of the injectors to the rotation of the engine. DRPs come from the ignition module. A timing light will tell you if the distributor is working.

You still didn't state a year, but if your car has VATS (1986 and later) it can also disable the injectors. Usually if the engine cranks then VATS is OK. The exception is if somebody has bypassed the VATS starter enable relay.

 

The other wire does not actually get a negative pulse. It actually get grounded by the ECM for a few milli seconds to fire the injector. This momentarily completes the circuit. This can be seen with a noid light connected across the injector wires.

 

The o.p. needs a FSM to learn how this system actually works. It looks like he is "thinking" old school and trying to diagnose a 'new technology' EFI.....ain;t gonna work even after throwing $500 in parts at the problem....which I have NOT seen anywhere ?

exactly what is wrong ? besides ....it don't run ?

#1 tip
the hot wires on a C4 mean less than a Nigerian PhD in Business

The GROUNDS in every circuit do ALL the work, all the communication between sensor/servo and ECM. There are lots of circuits that only show 5v. That's Normal.
The FSM explains all these mysteries, as there are far too many to detail here.

ALL injectors on each side fire together. 4 act like 1 Noid lite will show the inj cycling. A test lite will show that the circuit is live. that's usually enough to move on.....

Has the VATS been messed with? Monkeying around with VATS and not doing it right, will cause problems just like this.
it won't run. More like, it CAN'T run. VATS is complicated.

There IS spark? if so.....
There IS fuel pressure? Takes 30 psi to even burp. 40 to make it run.

do you have a gauge? how MUCH pressure? You CAN SEE the inj pulses on the FUEL test gauge when the engine is cranking over...the gauge will flicker during cranking as pressure drops, showing the inj ARE cycling and using the stored fuel pressure.

No gauge? oh well.

Whats the original problem, again?