Full throttle issues. Advice please.

[Metta]

Hey guys,

So I recently bought an explorer 1998 4.0 SOHC UK version with some small issues. I’m a mechanic and got most of them done such as idle valve, inlet gaskets upper and lower and few other things.

From day one I’ve had an issue with full throttle bogging out even at idle. ‘Overfueling I think’ so even at idle when half throttle car revs fine as normal right up the Rev range and back down, now when you open the throttle up fully I get spluttering. I have a video attached, the plugs have been changed 2 months back under a full service including fuel filter. The EGR is blanked off from previous owner but I don’t believe this would cause the issue.

Any help and advice would be perfect.

 

[C420sailor]

How do the fuel trims look? Does it do this under load?

MAF clean? When have the intake manifold gaskets last been replaced? Fuel pressure?

 

[Metta]

How do the fuel trims look? Does it do this under load?

MAF clean? When have the intake manifold gaskets last been replaced? Fuel pressure?

As per previous post it only does it under load and when stationary only in full throttle, I have done the inlet gaskets 2 weeks ago.

MAF I’ve cleaned with Electrical cleaner and tried another, I’ve not tested fuel pressure as I don’t have a tool for that, I may be able to load live data on the diagnostics tho.

 

[Mbrooks420]

You won’t get a fuel pressure reading from the OBD.

Pretty sure it’s not a DOHC.

 

[Metta]

You won’t get a fuel pressure reading from the OBD.

Pretty sure it’s not a DOHC.

That is not DOHC it’s a typo and for some reason I can’t edit the thread to SOHC.

Sorry I’m just after some help as I’m a bit stuck and I’m chucking parts at it and as you can appreciate it takes a week or so to get parts delivered to the UK

 

[Mbrooks420]

That is not DOHC it’s a typo and for some reason I can’t edit the thread to SOHC.

Sorry I’m just after some help as I’m a bit stuck and I’m chucking parts at it and as you can appreciate it takes a week or so to get parts delivered to the UK

No worries. The worst feeling is doing a bunch of work to still have the problem. I’d see if any of your local auto stores loan fuel pressure gauges.

 

[C420sailor]

I’d def check fuel pressure. It’s rare that these machines run excessively rich—typically the opposite.

 

[Metta]

No worries. The worst feeling is doing a bunch of work to still have the problem. I’d see if any of your local auto stores loan fuel pressure gauges.

I’ll be able to grab one today, and check it over that way. Did you see the video?

Thanks

 

[Metta]

I’ve managed to get a pressure tester, will be doing this tomorrow and I’ll send the fuel trim readings over too.

Wee update - When hot it idles up and down about 200RPM, after a drive it the wouldn’t start. May be linked?

I can’t see any vac leaks doesn’t mean there isn’t any tho.

 

[Metta]

No worries. The worst feeling is doing a bunch of work to still have the problem. I’d see if any of your local auto stores loan fuel pressure gauges.

The inlet gaskets I done 2 weeks back, new air filter fuel filter idle valve and cats.

The EGR needs a new pipe so I’ve bypassed that for now. That shouldn’t be the issue I’m getting in the thread first post

Thanks guys any help will guide me

 

[Mbrooks420]

What was the fuel pressure?

 

[Metta]

What was the fuel pressure?

I’m waiting a tester getting dropped off, should be anytime today. I’m all for saving these motors I’ve took a good liking to it enjoy it more than me second motor.

Did you see the video? Assuming the drop to 0 isn’t a good sign when the symptoms start it’s drinking fuel too.

 

[Metta]

What was the fuel pressure?

What would be best for me if you could ask me what you need from me and I’ll get all the data together for you in the best post mate? I appreciate your guidance.

 

[410Fortune]

are you hitting a rev limiter???
I mean it sounds like you are talking about punching full throttle while idling, when the engine revs up it starts to sputter. Isn't this a rev limiter? keeping you from over revving the engine?

 

[Metta]

are you hitting a rev limiter???
I mean it sounds like you are talking about punching full throttle while idling, when the engine revs up it starts to sputter. Isn't this a rev limiter? keeping you from over revving the engine?

Good question mate, no, it does this from idle it reaches say 2,000 RPM then stuttered and just bogs out it’s no where reaching the limiter

 

[Mbrooks420]

Sounds like you’re running out of fuel to me. A fuel pressure test (gauge placed on the fuel rail of the motor) start it up. Check the pressure. Check the pressure when it’s acting up? It’s very possible it’s just low, and you need a pump.

 

[Metta]

Sounds like you’re running out of fuel to me. A fuel pressure test (gauge placed on the fuel rail of the motor) start it up. Check the pressure. Check the pressure when it’s acting up? It’s very possible it’s just low, and you need a pump.

Okay, I shall do a test tomorrow, the lean bank and and two codes in the photo that rings alarm belts to me as I’ve done the inlet gaskets but it’s came back up again.

Could this be related to loss of fuel?

 

[Mbrooks420]

Yes. Not getting enough fuel is the same as getting unmetered air. At your trucks age it’s due for a pump.

 

[Metta]

Yes. Not getting enough fuel is the same as getting unmetered air. At your trucks age it’s due for a pump.

Can you advice via rock auto what pump kit to get? I’m from UK so rock auto is the only site I’ve used so far I may as well do the job regardless of what the fuel pressure comes back with which I’ll do tomorrow I have the kit now.

I will most likely do the job correctly by dropping the tank rather than cutting an access hole

 

[donalds]

Sometimes you just have to bite the bullet and buy the test gauge and not a cheap one
The fuel pressure gauge kit
You will use it again
Just saying...