3FE Head Gasket (1 Viewer)

[Rush]

@BILT4ME

TPS ohmed out within specs.
But it didn't pass the continuity test called for by the FSM upon completion of adjustment (which I didn't do):

It ohmed ok, so I call it good.

 

[Rush]

I fixed the O2 wiring, from referencing the other one on the truck.

Still doesn't start.

 

[jonheld]

You mentioned that you're not seeing the CHARGE lamp (red light above the voltmeter) come on with the key in the ON position.
Please verify that you're seeing +12 at the 7.5 amp IGN fuse by the driver's left knee with the key in the ON position and that this fuse is good.

 

[Rush]

You mentioned that you're not seeing the CHARGE lamp (red light above the voltmeter) come on with the key in the ON position.
Please verify that you're seeing +12 at the 7.5 amp IGN fuse by the driver's left knee with the key in the ON position and that this fuse is good.

12.4v, fuse is good (beep and ohms both when out of the socket), and the CEL went dark when I pulled it to check.

 

[jonheld]

Please verify that you're getting +12 to the 6 injectors with the key in the ON position. You should see +12 on each of the BLACK/GREEN STRIPE (pin 2) connections.
The ECU grounds (logic low) the other sets of wires (WHITE/LIGHT BLUE STRIPE for bank 1 and YELLOW for bank 2) to fire the injectors.

 

[jonheld]

I don't recall, did you verify fuel pressure at the rail when cranking the starter?

 

[Rush]

12.4v, fuse is good (beep and ohms both when out of the socket), and the CEL went dark when I pulled it to check.

On the IGN/charge circuit topic:
I looked closer at the charge lamp relay, and when touched it buzzes/clicks like it's full of hornets.

Connecting it to battery power yielded no clicking, so I opened it up.
Lo and behold, I found two broken solder joints:

I'll redo those, and test again.

 

[Rush]

I don't recall, did you verify fuel pressure at the rail when cranking the starter?

Yes sir, 48 psi. Down to 42ish when running on starting fluid.

 

[jonheld]

Well, you running out of options here.
You're getting fuel to the rail. IF the injectors are firing, and we still don't know that, then you're getting fuel.
You're getting spark and I assume you're getting air.
If the injectors are firing, then that leaves valve timing and compression.

 

[jonheld]

If you're dumping fuel into the intake and she runs, then the injectors are not firing.

 

[Rush]

Well, you running out of options here.
You're getting fuel to the rail. IF the injectors are firing, and we still don't know that, then you're getting fuel.
You're getting spark and I assume you're getting air.
If the injectors are firing, then that leaves valve timing and compression.

Agreed. Testing injectors in a few.

 

[Rush]

If you're dumping fuel into the intake and she runs, then the injectors are not firing.

Vacuum-tightness hasn't been confirmed yet, either, so I'll work on that too.

Or is that less likely to cause THIS degree of failure?

 

[jonheld]

Vacuum-tightness hasn't been confirmed yet, either, so I'll work on that too.

Or is that less likely to cause THIS degree of failure?

A vacuum leak will cause low/poor/rough idle. If the leak is severe enough, like with a torn intake plenum downstream of the AFM, she'll stall from lack of fuel.
The FP only runs when you crank the starter and after the engine sucks enough air to open the flap in the AFM.

 

[Rush]

A vacuum leak will cause low/poor/rough idle. If the leak is severe enough, like with a torn intake plenum downstream of the AFM, she'll stall from lack of fuel.
The FP only runs when you crank the starter and after the engine sucks enough air to open the flap in the AFM.

Just to confirm, you're saying the AFM opening during cranking -enabling the pump to run- is indicative of good enough vacuum to start/run?
I can buy that, yeah.

 

[Rush]

On the IGN/charge circuit topic:
I looked closer at the charge lamp relay, and when touched it buzzes/clicks like it's full of hornets.

Connecting it to battery power yielded no clicking, so I opened it up.
Lo and behold, I found two broken solder joints:
View attachment 2377912

I'll redo those, and test again.

After fixing this, I now have charge and A/T lights:

Still doesn't start

Testing injectors next.

 

[jonheld]

Just to confirm, you're saying the AFM opening during cranking -enabling the pump to run- is indicative of good enough vacuum to start/run?
I can buy that, yeah.

The FP relay (Circuit Opening Relay) has 2 coils. The first coil is energized from the starter circuit when you crank the starter. The second coil energizes when the flap of the AFM opens.
A symptom of the AFM flap not opening from an air leak or mechanical issue preventing the flap from opening would be that the engine would start briefly and then stall out a second or 2 after you release the key from the START position.
IOW, it would fire while cranking and stall out when key is released from lack of fuel.

This does not appear to be what you're experiencing.

 

[jonheld]

You can also bypass all FP logic by shorting pins FP to B+ on the diagnostic connector, but I thought we already did this.

 

[Rush]

You can also bypass all FP logic by shorting pins FP to B+ on the diagnostic connector, but I thought we already did this.

We did, no joy.

 

[Rush]

The FP relay (Circuit Opening Relay) has 2 coils. The first coil is energized from the starter circuit when you crank the starter. The second coil energizes when the flap of the AFM opens.
A symptom of the AFM flap not opening from an air leak or mechanical issue preventing the flap from opening would be that the engine would start briefly and then stall out a second or 2 after you release the key from the START position.
IOW, it would fire while cranking and stall out when key is released from lack of fuel.

This does not appear to be what you're experiencing.

Correct. It's just failing to accelerate from cranking to idle RPM.
And when off the ground with starting fluid, it's failing to then idle.

 

[jonheld]

Correct. It's just failing to accelerate from cranking to idle RPM.
And when off the ground with starting fluid, it's failing to then idle.

Sure sounds like you're not getting fuel.