1987 v6 woes

[OftenWrongNeverUncertain]

Also, when I first try to crank it without fuel in the intake, it fires up then stops before it self sustains.

 

[franklin2]

You should have a common colored wire to the injectors. I believe it's red? See if you have power on this wire when cranking. All the injectors are fed a constant 12v, and then the ECM grounds the other side of the injector to make it fire.

Grounding would be another thing to check. If you get a good 12v on the common injector feed, take your meter and put it across one of the injectors. You should get 12v when the ECM grounds, or "fires" the injector. If not, the ECM is not firing the injectors, could be a bad ground somewhere or connector problem on the engine somewhere.

 

[OftenWrongNeverUncertain]

How does it ground each injector individually? I only see 3 wires coming off the injector harness, a red that is hot, a green and a red with black stripe. If the computer controls each injector tor individually via ground, and I have 6 injectors, shouldn't there be 6 individual grounds coming off the injectors to the computer?

 

[OftenWrongNeverUncertain]

The red is giving batter voltage. I put the voltmeter to AC setting and inserted the ground probe into the negative wire, and put the positive on the battery. It read in the milivolts. I switched to DC and again, milivolts.

 

[OftenWrongNeverUncertain]

I found this answer to my question on this forum:

Each injector has a red wire, 12volt key on, just daisy chained from one injector to the next

Non-sequential fuel injection will just have 2 grounding wires from computer, seen here: https://www.therangerstation.com/te...es/Diagrams_ElectronciEngControls2_9_3of3.JPG

Its called Batch Fire injection, in the case of a V6 engine 3 injectors open at the same time, then next rpm the other 3 open

So 2 injectors open on passenger side(1, 2) and 1 injector on drivers side of engine(4)
Then next rpm its 1(3) and 2(5, 6)
Keeps the lower intake full of air/fuel mix and each cylinder just sucks in what it needs

In sequential injection each injectors would have its own ground wire from the computer
Most Rangers didn't get sequential injection until 1995 and up

 

[OftenWrongNeverUncertain]

So I'm going to start looking for how the computer determines the engine position to know when to fire the injectors. Hopefully it's simple and broken.

 

[OftenWrongNeverUncertain]

For posterity...

So it seems there is a sensor on the distributor that tells the computer where the engine is in the firing order. PIP or some such. Still learning.

 

[rusty ol ranger]

For posterity...

So it seems there is a sensor on the distributor that tells the computer where the engine is in the firing order. PIP or some such. Still learning.

I believe thats handled by the TFI but im not 100% sure.

But i would say you have a wireing issue or a bad ECM

 

[OftenWrongNeverUncertain]

I need to find out why pumping the throttle like a carburetor keeps it running and letting off kills it.

 

[alwaysFlOoReD]

I need to find out why pumping the throttle like a carburetor keeps it running and letting off kills it.

You're running rich. Pumping the throttle let's in more air, the opposite of carb.

 

[tw205]

Ford EEC-IV/TFI-IV Electronic Engine Control Troubleshooting

www.therangerstation.com

Here is some interesting reading if you wanna know how the whirligig thingy talks to the whatchamacallit to provide lightning.
Helped me track down codes and diagnose ignition issues.

 

[rusty ol ranger]

Have you replaced the MAP?

 

[franklin2]

For posterity...

So it seems there is a sensor on the distributor that tells the computer where the engine is in the firing order. PIP or some such. Still learning.

Seems like you are picking this up on your own, I am impressed. The computer knows the position of the engine by the pickup inside the distributor. The wheel inside has one "spoke" that is more narrow or wider than the other "spokes" , I forget which.

Have you pulled the codes yet? The computer can sometimes hint at what is wrong with a certain code it may give you.

 

[OftenWrongNeverUncertain]

I've tried to pull codes. Even though I have a spot on the dash that says "Check Engine" it doesn't illuminate. My multimeter is digital so I need to buy a test light.

 

[OftenWrongNeverUncertain]

Have you replaced the MAP?

I have not. Reckon that's next.