EFI vapor lock....SOLVED!!!!

[Rox Crusher]

Thanks Gunni and Eck. I wrapped the threads with the yellow tape and seems to be holding for now. No leaks.

Took it for a test drive around the neighborhood and it wasn't good. Lots of sputtering on acceleration. Idles fine.
32 psi on the fuel pressure gauge.
Yes, the hoses are hooked up correctly.
No kinks in the hoses.
Both pumps are getting power.

What else should I check?

Seems like it hasn’t been hot enough to be vaporlock.

How long does it hold the 32 psi after you shut it off?

Fuel filter location and condition ?

[cw72]

Throw a new fuel filter at it, I had the same issue when I redid my fuel system. Actually did a quick little “delete” just to see if anything changed as I drove around the block. (Probably not smart so do at your own risk I suppose) Sure enough it ran perfect so I ordered a serviceable one right then so I can pull and clean it out wherever I am.


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[Gregg]

My set up is very similar to the pic Eck posted up.
Tank---NEW cheapo filter---LP pump----accumulator----HP pump---NEW filter---injectors---Return to accumulator---tank

32 psi and was at 22 psi an hour or so later

What's a quick little delete?

Eck-What post HP filter do you use?

[cw72]

Bypass the filter for testing purposes is what I meant. If the filters are both new that shouldn’t be the issue then. What cheap filter are you using?


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[Gregg]

https://www.amazon.com/FRAM-G3-In-Line- ... CEJ61BQS6V

[cw72]

Good enough GPM and clear so you can see contamination probably rules that out.

You said you were EFI, do you have an fuel pressure regulator on the rail?


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[Eck]

My set up is very similar to the pic Eck posted up.
Tank---NEW cheapo filter---LP pump----accumulator----HP pump---NEW filter---injectors---Return to accumulator---tank

32 psi and was at 22 psi an hour or so later

What's a quick little delete?

Eck-What post HP filter do you use?

I am using this one:
Edelbrock Pro-Flo EFI Replacement Fuel Filter
Part Number: 350-3596
https://www.jegs.com/i/Edelbrock/350/3596/10002/-1

[Gregg]

I'm still having problems with sputtering and occasional backfire when accelerating or putting load on the engine (going up a hill). I tried going without the hp filter but that didn't change anything.

Primed and after the engine is off the psi is 40
Idle psi is 34
Before I go after the injectors is there a way to test the pressure regulator?

Thanks!

[Eck]

https://axleaddict.com/auto-repair/How- ... -Regulator

A new FPR is about $50 at O’Reilly’s.


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[Gregg]

FPR passed the tests. Thanks for the link.

[Kinder]

Jog my memory, this is a stock tank with the factory pickup/sending unit right? You might consider pulling the pickup out and confirming the “sock” isn’t falling apart and plugging the pickup.

[Gregg]

Quick Update:
I pulled the upper intake and got to the injectors. I soaked, cleaned, tested, and blew them all out. I ordered a rebuild kit and put it all back together. No change. Idles fine but sputters on acceleration or load.
I had a spare hp pump so I threw that in and it ran the same as with the other pump. I guess I could through a new FPR at it but I'm guessing it won't change anything.

Primed psi is 34ish
Idle psi is 34ish
With Engine off it holds at 40 psi for awhile.

Not a stock tank but an older 22 gal (thanks for chimng in Kirk)

Anything else guys can think of?

Thanks.

[Gregg]

I replaced the FPR with a a new one and it didn't change anything. I'll post up on CB.com and get a few more opinions. Feel free to chime in if you have any thoughts.
Thanks guys!

[Rox Crusher]

Perplexing

[mickphatmac]

did you check your timing?

[Gunnibronco]

I'm just stabbing at this, but could it be a dirty mass air sensor or bad TPS?

[Viperwolf1]

I don't remember, is this mustang or explorer EFI? If it's explorer you can't change the timing.

[mickphatmac]

I don't remember, is this mustang or explorer EFI? If it's explorer you can't change the timing.

AHHHaaaa!!! did not know that!?

[Gregg]

did you check your timing?

No. I thought the explorer computer adjusted that....

[Viperwolf1]

did you check your timing?

No. I thought the explorer computer adjusted that....

So this is explorer efi? Coil packs and no distributor?

[Gregg]

It "was" a mustang efi but we swapped it over to the explorer harness and coil pack a few years ago.

Oh, I changed my air filter and cleaned the MAF a couple months ago

As for the TPS---if it were faulty, would it sputter if I rev -ed it in park/neutral. Only asking because when I rev it in neutral it sounds / responds great.

[Viperwolf1]

Well the good thing about the explorer EFI is you can hookup a good scanner and look at all of the sensors while they are working. You can also see if it has any codes stored. I might know a guy with a scanner.

[Gregg]

Is it close to " Larry the Cable Guy"?

I videoed the FP gauge driving around the hood: idles at 36 psi and during acceleration it'd go up to 40-41 psi. I figured the FPR knows what its doing but could there be too much gas and bogging the engine down?

[Viperwolf1]

Is it close to " Larry the Cable Guy"?

I videoed the FP gauge driving around the hood: idles at 36 psi and during acceleration it'd go up to 40-41 psi. I figured the FPR knows what its doing but could there be too much gas and bogging the engine down?

More like Kevin the scanner guy.

I think your fuel is fine at this point. Need to start looking at other things. Burnt plug wires maybe?

[Gregg]

Is it close to " Larry the Cable Guy"?

I videoed the FP gauge driving around the hood: idles at 36 psi and during acceleration it'd go up to 40-41 psi. I figured the FPR knows what its doing but could there be too much gas and bogging the engine down?

More like Kevin the scanner guy.

I think your fuel is fine at this point. Need to start looking at other things. Burnt plug wires maybe?

Looks like I owe Phil a case of Corona

Cylinder #5 wire looked suspicious. I checked the resistance and it was clear that nothing was getting through. The wire looked okay but inside the boot was really corroded. I cut the wire above the boot (tested it again with an acceptable reading) and replaced it with my spare boot/crimp. It actually ran slightly worse so I cleaned the spark plug terminal (also corroded) and that was it. Back on the road for now.

I thin k it was corroded because my PS reservoir is making a mess of anything that touches it. The coating on the wire was looking rough so I'm guessing the PS fluid made its way down to the boot...Time to get more spare boot/crimps.....

I love fixing one thing while another thing unknowingly fails and f**ks up the whole trouble shooting process. Nice catch Phil. Thank you!

[TOOLMAN]

Nice! Now can we move onto other things?