Hard starting when hot

[armadillon]

+1. A common problem. Mine had that issue as well. Good old flooding and long cranks to get excess fuel out.

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[cp2295]

What'd you do to fix your hard starting armadillon?

 

[shane96ranger]

The fuel pressure regulator is what he is talking about. It can still deliver proper pressure and be bad. It is a very common, and often overlooked issue when you experience hard starting in hot conditions. Drive it to get it up to temp and then pull the vacuum line and watch it for a few minutes. If it starts seeping fuel out of the nipple, there's your issue.

Posting from the Galaxy.

 

[cp2295]

I thought the thing on the rail was the damper? Should I still check the vacuum line for gas anyways, I always thought the pressure regulator was in the pump, I have a 99 3.0 fuel system but a 98 4.0 engine.

 

[RonD]

I thought the thing on the rail was the damper? Should I still check the vacuum line for gas anyways, I always thought the pressure regulator was in the pump, I have a 99 3.0 fuel system but a 98 4.0 engine.

You are correct, Ford switched to "returnless" system in the late '90's, so no FPR on the rail.
Pulse Damper on the fuel rail does have a vacuum line for safety reasons, in case of a leak fuel won't drip on warm engine or exhaust.
Costs nothing to check that line for fuel smell or fuel, so why not?

 

[shane96ranger]

I'd check it, yes. Didn't realize you didnt have the FPR, my bad.

 

[cp2295]

Just wanted to ask Ron how do I check injector voltage and coil voltage which wire(s) do I probe?

And what's the ckp volts suppose to be at? Which wire the blue or the grey?

 

[cp2295]

The starting fluid trick didn't work btw, it actually made it worse, could've been that it's old starting fluid but either way it made the truck die when It turned on at first and I had to crank it awhile

 

[RonD]

The V6 coil pack will have 4 wires, 1 is 12volts from Key/ignition switch, the other 3 are computer controlled grounds to power and fire each coil in the pack.
So remove connector, turn key on and check for 12v at that connector, it will be one of the end wires.

Injectors are powered from the EEC relay when key is turned on, Ford injectors only have 14ohms between the contacts, so you can test either wire for 12v if connector is still hooked to injector, or if you take off the injector's connector 1 wire will have 12v.

 

[cp2295]

Okay should I do an ohms test too on the injectors or just check their voltage?

 

[RonD]

You can, but usually it is only needed if you are chasing a misfire.
12-17ohms is a range

 

[cp2295]

Okay and is it possible I sprayed too much starting fluid to make it chug when it started? Or is it definitely spark related?

 

[cp2295]

So I checked it when it was cold and it showed 12.2 volts at both the injector and the coil (I only checked 1 injector). Then I tried checking it right after it was hot and I blew the PCM diode fuse so I don't want to try that Again, but I was talking with a dude who said it could be a leaky injector causing too much fuel to get into the cylinder then it floods it and causes it to chug when it finally turns on, because that's what it does I have to rev it to turn on otherwise it'll just die. Then me adding starting fluid only complicated the issue.. Really just gotta get a fuel pressure tester, maybe I wasn't hooking it up right, is there a certain procedure?

 

[cp2295]

Also when I sprayed the starting fluid in I saw white smoke come out the intake, is this normal or is this excess gas? And this was before I sprayed it like when I took the PCV line off, so it wasn't the starting fluid smoking

 

[RonD]

Turn key on
Press gas pedal to the floor and hold it there
Crank engine

It should NOT start
The above is the "clear flooded engine" routine in all EFI computers
Key on with no Crank signal(CKP sensor showing no spin at crank)
TPS(throttle position sensor) at 4+volts, foot to the floor, wide open throttle(WOT)
This turns off fuel injectors but leaves spark on.

If engine fires intermittently then you have a leaking injector.
If you retest and unhook 1 spark plug at a time, when firing stops you found the cylinder with leaking injector.

CLEAR FLOOD MODE
If for some reason the engine should become flooded, provisions have been built into the computer to help clear this out. If during cranking of the engine you depress the throttle more than 80%, the ECM will enter what is called “clear flood mode”. In this mode the ECM commands a delivered Air/Fuel ratio to very lean (usually 20:1). The ECM will stay in clear flood mode as long as the throttle is 80% or higher and the RPMs are less than about 600. As soon as throttle position falls below the 80% threshold or RPMs go above 600, the ECM disables clear flood mode and calculates fuel delivery based on coolant temperature and other factors it normally uses.