Explorer 98, bad engine start and reaction to gas pedal ?

[999fff]

Hello, I am addressing you, the owner of the second generation Explorer 95-01. My Explorer (4.0 V6 SOHC 1998) misstarts (dies - will stay on until the third or fourth try) and has a bad throttle response when driving and even when pulling off in such a style that it tends to choke to a stop when pulling off at an intersection, but eventually catches on and drives off.
___
I have already replaced:
1) spark plugs + cables + distributor (coil)
2) air weight sensor (start improved) + air filter
___
Could someone please advise me on which direction to focus next?
I'm thinking of a throttle valve? pump in the tank? fuel filter ?
... or something else ?

Please let me know if you have encountered something similar.

PS: diagnostics showed nothing

 

[donalds]

Do a fuel pressure test

Read this thread Is my fuel pump bad 1999 ford explorer shoc 4.0. Lots of pictures on the replacement

Repair starts on post 36

 

[Mbrooks420]

I’d test the fuel pressure as stated above. I’d also clean the MAF and throttle bodies with the appropriate cleaners.

No check engine light?

 

[999fff]

I’d test the fuel pressure as stated above. I’d also clean the MAF and throttle bodies with the appropriate cleaners.

No check engine light?

How do they test the fuel pressure? I'm not a mechanic, never have been. Can you give a simple type of what and how to do and what tools I will need?

 

[Mbrooks420]

How do they test the fuel pressure? I'm not a mechanic, never have been. Can you give a simple type of what and how to do and what tools I will need

Fuel pressure is tested with a gauge very similar to a tire pressure gauge. It is tested on the fuel rail on top of the motor.

 

[Mbrooks420]

Different engine but same procedure. Most auto stores will rent you the tools.

 

[999fff]

I have a SOHC 4.0 V6. I think the blue plug should be for testing the fuel... ? You who have a SOHC 4.0 V6 please confirm if this is the case.

 

[donalds]

Yes you are correct that's your fuel test port

 

[999fff]

The pressure gauge showed nothing at all even when I just turned the key. When I started it for the second time, the engine ran, but the needle did not move at all.
What am I doing wrong ?

 

[donalds]

Try removing the valve core from the test port
Standard value core tool

 

[999fff]

Try removing the valve core from the test port
Standard value core tool

Valve core, you mean the means? to make a hole?

 

[wollimann]

The test port is a shrader valve with a pin, this pin must be pushed in by the end of the gauge hose fitting.

What about your LPG system, everything is well adjusted, no problems?

 

[999fff]

The test port is a shrader valve with a pin, this pin must be pushed in by the end of the gauge hose fitting.
View attachment 454114

I see, the same principle as the valve in a tire. This middle part to be pushed is right on the vehicle and on the test hose with the gauge there is a straight center with a rubber band. I don't know if this center pin can be removed somehow on the car

 

[wollimann]

I don't know if this center pin can be removed somehow on the car

Do not remove the valve insert! You have to buy the matching test equipment to get the real fuel pressure.

 

[999fff]

Do not remove the valve insert! You have to buy the matching test equipment to get the real fuel pressure.

I bought a set specifically for testing fuel pressure. In fact, I don't even know what I should look for a specific end of the manometer hose. I bought a set, so one of the ends fits exactly on the valve.

 

[wollimann]

I bought a set, so one of the ends fits exactly on the valve.

But something must be wrong, if there is no fuel pressure the engine would not start.
You can try to push the valve pin in with a screw driver, caution fuel comes out wear savety glases!
If the fuel pump is ok there must be 30-45 psi. The pressure should stay if you shut of the engine (with attached gauge).
If the pressure falls down emedietely there is a leak inside the fuel tank.

In most cases the short rubber hose cracked and a part of the pressure went away inside the tank.
But fuel pumps do not last forever. Did you hear the fuel pump with ignition on?

 

[999fff]

But something must be wrong, if there is no fuel pressure the engine would not start.
You can try to push the valve pin in with a screw driver, caution fuel comes out wear savety glases!
If the fuel pump is ok there must be 30-45 psi. The pressure should stay if you shut of the engine (with attached gauge).
If the pressure falls down emedietely there is a leak inside the fuel tank.

In most cases the short rubber hose cracked and a part of the pressure went away inside the tank.
But fuel pumps do not last forever. Did you hear the fuel pump with ignition on?
View attachment 454116

I don't think I heard the pump sound, or at least not particularly loud. However, it is strange that even though the pressure gauge did not show anything, the engine started and even when the gas was added, the rack did not move. So I will try to push the needle with a screwdriver when turning the key to the first position. But I still know that when I disconnected the tester tube, the rubber seal was red on both hose connections.

 

[wollimann]

Maybe you need a adaptor for the test tube, this adaptor should push the pin in,
so the pressure will reach the gauge.

I got this tester with the adpator fitting.

Fuel Pressure Tester Kit | OTC Tools

otctools.com

 

[999fff]

Maybe you need a adaptor for the test tube, this adaptor should push the pin in,
so the pressure will reach the gauge.
View attachment 454117

I got this tester with the adpator fitting.

Fuel Pressure Tester Kit | OTC Tools

otctools.com

Couldn't it also be a problem that my pressure gauge doesn't have a vent line? that air would get to the pressure gauge and the fuel would not push it out? I only have a Manometer with one tube, no other side lead.
I'll look at the adapter to see if it's in the package, but I don't think there's anything like that...
In any case, I don't know what such an adapter should be called, according to what to choose. In appearance, they almost all look the same. When I'm at the car, I'll try pushing the needle again to see if there is any pressure after pushing.

Next question - what if the fuel does not appear after pushing it even with the key in the ignition?

 

[donalds]

The problem is is the pressure tester is not depressing the valve core You can remove the valve core and test You can then replace it back Jesus Jesus