Please help with fuel pressure test results

[410explorer]

UPDATE

results of a fuel pressure test while running it has 32 psi with spikes to 40psi when revved up but when I turn the key to the on position I only get 20psi which instantly starts to fall to 10 psi would that be a leaky duel injector or a weak pump? My scanner data is showing a lean condition in bank 2 I wanted to add a video but it says the file is to large

 

[J_C]

You could post a video on youtube or vimeo, etc and link to it here.

If it stays at 32PSI to 40PSI while running, it seems that the leak you may have, is not enough to be causing the lean condition and your pump is not too bad. You could try a jug of techron fuel system cleaner in the gas and let it run a while, though I would also wonder about an intake manifold gasket leak.

No trouble codes set, especially misfires? I noticed in your other topic that you recently bought it. Does it still have some potentially very old fuel in it?

 

[410explorer]

You could post a video on youtube or vimeo, etc and link to it here.

If it stays at 32PSI to 40PSI while running, it seems that the leak you may have, is not enough to be causing the lean condition and your pump is not too bad. You could try a jug of techron fuel system cleaner in the gas and let it run a while, though I would also wonder about an intake manifold gasket leak.

No trouble codes set, especially misfires? I noticed in your other topic that you recently bought it. Does it still have some potentially very old fuel in it?

No the fuel has been cycled through I have replaced the intake plenum gaskets and can long detect any vacume leak with starting fluid or smoke it's not missing the plugs and wires are new and I tested that every cylinder is firing it runs better now but now power under load and let me be specific tge fuel pressure holds 32 at idle if I pick the rpm up to 3k the pressure quickly spikes to 40 then drops to 30 psi while holding 3k and if I cycle tge key on just 1 time without starting the pressure only raises to about 28 psi maybe 30 and immediately drops to 20 then to 10 but if I cycle the key more then 1 time the pressure builds to 30 and holds my fuel trim numbers are sometimes lean at start but bank 2 evens out to acceptable range bank 1 is stayig atheist +20 it idles and revs in neutral great and has no power ùnder load

 

[410explorer]

You could post a video on youtube or vimeo, etc and link to it here.

If it stays at 32PSI to 40PSI while running, it seems that the leak you may have, is not enough to be causing the lean condition and your pump is not too bad. You could try a jug of techron fuel system cleaner in the gas and let it run a while, though I would also wonder about an intake manifold gasket leak.

No trouble codes set, especially misfires? I noticed in your other topic that you recently bought it. Does it still have some potentially very old fuel in it?

J.c I have never uploaded to YouTube di you have a Facebook I could shoot you the video on? I'd appreciate your feed back a it seems when it's cold both banks appear lean but fully warm only bank 1 I had look back through scanner data

 

[410Fortune]

32 is a little low I would like to see 36-38
But 32 is in spec

Is there fuel in the vacuum line to the regulator?
When you unhook the regulator does the pressure jump up to 40? It should

My guess is when hot your pump is getting weak. Consider a new pumpo, strainer and filter soon

The pressure dripping off as soon as the key is off is not a big deal on these trucks, there is a little orange sock on the end of the return line in the tank, they get weak over the years and do not hold pressure
As long as you have proper fuel pressure while running, that is what matters

Lean is usually intake gaskets if it affects both Bank. Since you just did gaskets and are still lean on one side and vacuum leak test shows no leaks… I would continue to test fuel rail pressure, especially when engine is hot and has been running for some time
clear code see how long it takes to come back

 

[410explorer]

32 is a little low I would like to see 36-38
But 32 is in spec

Is there fuel in the vacuum line to the regulator?
When you unhook the regulator does the pressure jump up to 40? It should

My guess is when hot your pump is getting weak. Consider a new pumpo, strainer and filter soon

The pressure dripping off as soon as the key is off is not a big deal on these trucks, there is a little orange sock on the end of the return line in the tank, they get weak over the years and do not hold pressure
As long as you have proper fuel pressure while running, that is what matters

Lean is usually intake gaskets if it affects both Bank. Since you just did gaskets and are still lean on one side and vacuum leak test shows no leaks… I would continue to test fuel rail pressure, especially when engine is hot and has been running for some time
clear code see how long it takes to come back

Yes when I unhook the regukator the fuel pressure jumps up to 40 iv also noticed though when I Rev the motor the pressure quickly spikes but does not hold falls back to about 30psi holding the motor at 3k iv noticed when cold the fuel trim numbers are about perfect they get leaner as it gets warm and when I Rev the motor it leans out and I'm still severely lacking power I believe it's the fuel pump being weak also because if I turn the key to on 1 time the pressure only jumps to 20 psi and immediately starts to rapidly fall I have to cycle the key 3 times and the line pressure builds to 49 and holds I was trying to rule out the inje tors I can't afford both right now would the weak pump be causing my lack of power

 

[410Fortune]

Yes weak pump cannot deliver enough fuel = no power

Injectors are under $100 for refurbished just fyi

Drops to 30 psi is a little low when you bump the throttle

Consider a new pump strainer and filter
I use Bosch pumps only
If Bosch is not available since Covid supply chain issues you can run a ac delco, Carter, Delphi, or carquest house brand are all decent pumps

 

[Project91Jp]

I bought a Carter assembly recently. Be sure to test it before installing. Mine had a loose crimp on the negative side.

@410Fortune are the injectors priced by the set or individually?

 

[410Fortune]

Set

Checkout eBay

OEM Bosch Set of 6 Fuel Injectors For 1991-1992 Ford Explorer 4.0L V6 | eBay

Warranty is issued with every set of re-manufactured fuel injector. This warranty is non-transferable. The first step is to notify us of your specific issue. Genuine Set of 6 Bosch Fuel Injectors. Re-Manufactured original Bosch fuel injectors.

www.ebay.com

I did a quick search and came up with these

Check the seller ratings
There are lots of people who get these at the junk yards and remanufacture them, sell on eBay. You want a good set so check seller ratings and reviews

 

[Project91Jp]

Thanks. Rockauto had some as high as $70 a piece.

 

[410Fortune]

Yea and anything less than a Bosch 4 hole is not worth $2… run factory Bosch 4 hole injectors only!
They clean them, rebuild them, flow test them and match up sets with other injectors that had same flow results… hopefully. This is why we have to check the seller ratings and reviews everyone and their mother thinks they can yank junk yard injectors and resell them