'86 MJ 2.5L ECM....good?

[eaglescout526]

Once it starts and dies, don't attempt to restart it, I want to observe the ISA, I suspect it to be faulty and causing some issues.

[SoCalManche]

27 minutes ago, eaglescout526 said:

Once it starts and dies, don't attempt to restart it, I want to observe the ISA, I suspect it to be faulty and causing some issues.

Here you go! I've got two videos:

 

This one is no throttle action; https://drive.google.com/open?id=14IB4XZfqUeMbPIFs4aRrsI7Rhd37Oc1o

 

This one is with some throttle play; https://drive.google.com/open?id=14JrFWTSTD2GFR-o9MKPTkDXVNxCwTHkj

[eaglescout526]

Hmm, still weird to see no fuel pressure, but the engine sounds fine an healthy, I wonder where the plum of smoke comes from. But yeah that ISA isn't doing anything. Its not extending for the next start up or nothin. It can be taken apart, cleaned and lubed up just so that way you don't have to buy a new one. A on the ISA connector is ground, and D is the extend for the motor. If that can be tested to make sure the motor works, I would suspect the ISA gears are jammed.

[SoCalManche]

1 minute ago, eaglescout526 said:

Hmm, still weird to see no fuel pressure, but the engine sounds fine an healthy, I wonder where the plum of smoke comes from. But yeah that ISA isn't doing anything. Its not extending for the next start up or nothin. It can be taken apart, cleaned and lubed up just so that way you don't have to buy a new one. A on the ISA connector is ground, and D is the extend for the motor. If that can be tested to make sure the motor works, I would suspect the ISA gears are jammed.

What is the voltage supposed to be?

[Ωhm]

Does the plunger on the tip of the ISA move in and out? Can you move it?

[SoCalManche]

2 minutes ago, Ωhm said:

Does the plunger on the tip of the ISA move in and out? Can you move it?

If I pull back the throttle linkage, the plunger pops up, and it feels like it is spring-loaded. I can pushed it down and it will pop up after I release.

[Ωhm]

Connect DVOM between B+ and D2_13. KEY OFF. Does voltmeter change state (0vdc or 12vdc) as you work the plunger in or out?

[SoCalManche]

4 minutes ago, Ωhm said:

Connect DVOM between B+ and D2_13. KEY OFF. Does voltmeter change state (0vdc or 12vdc) as you work the plunger in or out?

I'm going to be very specific here with how I administered the test.

 

B+ & D2_13 = 11.87V with key off.

- If I pull back throttle linkage and plunger pops out, there is no change in voltage.

- If I press the plunger in with my hand, voltage increases to 11.88V.

- If I let the throttle linkage push the plunger back in naturally, it stays at 11.87V.

[Ωhm]

So its 11.8vdc all the time.

[SoCalManche]

1 minute ago, Ωhm said:

So its 11.8vdc all the time.

I mean, if we're rounding, 11.9V at all times, but yes.

[Ωhm]

Understood, close enough.

Let's look a WOT switch. Same test except use D2_6. Work lever on WOT. 

[SoCalManche]

3 minutes ago, Ωhm said:

Understood, close enough.

Let's look a WOT switch. Same test except use D2_6. Work lever on WOT. 

Same voltage. Initial readout is 11.87V. When switch is clicked in, it is 11.88V.

[Ωhm]

I thinking both switches are bad. Try to START vehicle with WOT switch disconnected.

[SoCalManche]

4 minutes ago, Ωhm said:

I thinking both switches are bad. Try to START vehicle with WOT switch disconnected.

Threw some fuel in the TBI; WOT disconnected; it fired the same way it does with WOT switch connected.

[Ωhm]

Maybe I need to look into my testing methods. But I still think both switches are bad. Try START with ISA and WOT disconnected.

[SoCalManche]

3 minutes ago, Ωhm said:

Maybe I need to look into my testing methods. But I still think both switches are bad. Try START with ISA and WOT disconnected.

Both disconnected; it fired again with fuel added to TBI, then died after fuel was burned off.

[Ωhm]

Question for INJ NOID LIGHT user. Does NOID LIGHT dim or flicker during engine CRANK? 2.5L

[SoCalManche]

19 minutes ago, Ωhm said:

Question for INJ NOID LIGHT user. Does NOID LIGHT dim or flicker during engine CRANK? 2.5L

I'm assuming this isn't for me, right? Lol..

[Ωhm]

No, its a question for the world.

[eaglescout526]

Theres a switch and a motor in the ISA, when the throttle plate hits the plunger, it clicks the CST switch inside telling the ECU that the engine is in idle position. The motor inside turns gears to either extend or retract the plunger to give the desired idle speed for open and closed loops of operation. Like I was saying, the ISA can be take apart to be cleaned and lubed. 

 

But the manual will say to just replace it if it is bad.

[SoCalManche]

16 minutes ago, eaglescout526 said:

Theres a switch and a motor in the ISA, when the throttle plate hits the plunger, it clicks the CST switch inside telling the ECU that the engine is in idle position. The motor inside turns gears to either extend or retract the plunger to give the desired idle speed for open and closed loops of operation. Like I was saying, the ISA can be take apart to be cleaned and lubed. 

 

But the manual will say to just replace it if it is bad.

Yeah, I took it apart, but now I'm trying to put it back together and the gears don't seem to be aligning. Seems to be a clearance issue.

[SoCalManche]

I'm an idiot. Small gear flips over. It fits.

[eaglescout526]

Lol gets the best of us. Doesn't look terrible but grease is pretty dried.

[SoCalManche]

2 minutes ago, eaglescout526 said:

Lol gets the best of us. Doesn't look terrible but grease is pretty dried.

So just shove some grease on that silver around the hole?

[eaglescout526]

Yeah when I did mine I just put some lithium grease in there around the gears and called it good.