New Mexico Pig Build (1 Viewer)

[Ol Yeller]

You have a healthy wire gauge to the pump? Good ground? Tank is clean, no restriction to pickup?

Just throwing ideas....

 

[Megadoomer]

How are you returning the fuel back into the tank? Could it be it is restricted?

 

[abqcruiser]

14 gauge wire to the pump and a good ground to the frame at the back. The 3fe wire schematic shows no dedicated relay inline to the pump. Should I have one there?

Doomer, Pablo and you are hammering me to check that again, so message received. I'll go back through it for a double check.

 

[PabloCruise]

What cap do you recommend?

I went with a replacement cap for my application - '74 Pig.

 

[wngrog]

I went with a replacement cap for my application - '74 Pig.

So an OEM FJ55 gas cap is

A) vented
B) will fit an FJ60?

 

[PabloCruise]

Hey TJ,

This 2fe is desmogged, so maybe I'm simplifying things too much. Currently my line from the charcoal canister is running to a port that's tapped into the front of the intake manifold. I was assuming that the moment the engine fires up that a vacuum is created and the vapors would be drawn into the intake without any help from the ecu.

Since Pig Party 2017, when I was having vapor lock issues, I've since fixed the problem. So I think the evap system is working. Besides, wouldn't running the engine with the gas cap off eliminate a venting issue? The fuel pump still struggles without the gas cap on.

A couple of different thoughts going on in here...

Direct vacuum off the intake that is un-switched will provide constant vacuum on the can. This is interesting because in theory you could create a vacuum in the fuel tank if the vent line on the bottom of the charcoal can were plugged. You might want to confirm your charcoal can is working properly. Fuel vapor should be able to enter the can from the tank and get trapped at the top. The purge line should be able to evacuate the can. There should be a vent line that is open to atmosphere on the bottom of the can to keep the can at atmospheric pressure. The vapors will stay at the top, so will not likely escape, unless the can never gets purged. You don't want engine vacuum sucking that can in on itself during purge cycles, or creating a vacuum in your fuel tank, which you report. Make sure the can vent is functioning. Makes sense?

 

[PabloCruise]

A couple of different thoughts going on in here...

Direct vacuum off the intake that is un-switched will provide constant vacuum on the can. This is interesting because in theory you could create a vacuum in the fuel tank if the vent line on the bottom of the charcoal can were plugged. You might want to confirm your charcoal can is working properly. Fuel vapor should be able to enter the can from the tank and get trapped at the top. The purge line should be able to evacuate the can. There should be a vent line that is open to atmosphere on the bottom of the can to keep the can at atmospheric pressure. The vapors will stay at the top, so will not likely escape, unless the can never gets purged. You don't want engine vacuum sucking that can in on itself during purge cycles, or creating a vacuum in your fuel tank, which you report. Make sure the can vent is functioning. Makes sense?

Here is a basic picture from the internets:

 

[PabloCruise]

Hey TJ,

Since Pig Party 2017, when I was having vapor lock issues, I've since fixed the problem. So I think the evap system is working. Besides, wouldn't running the engine with the gas cap off eliminate a venting issue? The fuel pump still struggles without the gas cap on.

Part 2: Vapor lock occurs when the fuel is changing from liquid phase to vapor phase in your fuel lines. The fuel pump is designed to move liquid, not vapor, so problems occur. The switch to vapor can occur when temperatures climb, and/or when pressure drops (remember the science class when your teacher boiled water at room temp by pulling a vacuum?)

I wouldn't make the connection that "I think my evap is working b/c I no longer have vapor lock". You should be moving fuel from the tank to the rail at ~45 p.s.i. - it will be very difficult to vapor lock at that pressure.

What I would do to confirm evap system is move low pressure air through all the vent lines from tank up to the can. Make sense?

 

[PabloCruise]

Hey TJ,

The fuel pump still struggles without the gas cap on.

Every time I try to move on from this post I see one more thing...

Is the fuel supply to the pump unrestricted? For sure?

Could your pump be getting blocked by debris?

Are you pre-filtering your pump? (low pressure)

Are you filtering (high pressure this time) fuel before the rail?

Have you checked delivery volume at the rail?

Have you checked pressure in the rail?

No need to go through what I went through. This was sitting in the inlet to my pump:

 

[PabloCruise]

Have you checked you fuel pressure in the rail? Confirmed the return line is flowing well?

How are you returning the fuel back into the tank? Could it be it is restricted?

Doomer, Pablo and you are hammering me to check that again, so message received. I'll go back through it for a double check.

Have you checked pressure in the rail?

I think this will tell you a lot!

 

[PabloCruise]

So an OEM FJ55 gas cap is

A) vented
B) will fit an FJ60?

A) I will take your word
B) I don't know, never tried! I don't have a 60...

 

[wngrog]

My AFI has a 7-9# fuel pump. Does the 3F use a high pressure pump?

 

[Megadoomer]

My AFI has a 7-9# fuel pump. Does the 3F use a high pressure pump?

I see that the 3FE need 46 psi.

 

[PabloCruise]

My AFI has a 7-9# fuel pump. Does the 3F use a high pressure pump?

3F - as in Carb?
Or 3FE = FI?

FI requires ~37 PSI in the rail IIRC.

 

[abqcruiser]

Pablo,

I probably slept through that part of science class, so I'm playing catch up now.
I had the gas tank inspected and cleaned during my resto, doesn't mean there's no debris in there now though. I have a low pressure filter before the fuel pump and an oem 3fe fuel filter in the engine compartment before the rail.

I'll read up on the evap systems and try to test everything.

Thanks

 

[PabloCruise]

Pablo,

I probably slept through that part of science class, so I'm playing catch up now.
I had the gas tank inspected and cleaned during my resto, doesn't mean there's no debris in there now though. I have a low pressure filter before the fuel pump and an oem 3fe fuel pump in the engine compartment before the rail.

I'll read up on the evap systems and try to test everything.

Thanks

Interestingly enough, that picture of all the debris that was occluding my pump came from a tank that had been sent out to the radiator shop...

 

[Witzer78]

Being a newly minted pig owner, this thread is nothing short of awesome. For your rear bumper by Bump It Offroad. You mentioned having to make a few minor mods to get it installed. If you don't mind, what exactly did you do to get that on? I love the look of that bumper. I'm going to have to re-read all 15 pages of this like 10 times. Truly inspiring.

 

[abqcruiser]

Being a newly minted pig owner, this thread is nothing short of awesome. For your rear bumper by Bump It Offroad. You mentioned having to make a few minor mods to get it installed. If you don't mind, what exactly did you do to get that on? I love the look of that bumper. I'm going to have to re-read all 15 pages of this like 10 times. Truly inspiring.

Thanks for the kind words! I honestly can't remember what the minor mods I did on the bumper. I remember having to do a little shimming to get it to sit right, but that was more to do with my frame ends being a little tweaked. The fit and mounting holes were pretty spot on. I can't remember the owner's name at Bump It Offroad, but he was awesome to work with. He used the same template for the bumper that he made for @PabloCruise.

 

[PabloCruise]

Mike Smith is the owner of Bump It Offroad (BIO).

Great guy!

 

[Witzer78]

Thank you abqcruiser! I appreciate your taking the time to follow up, and thank you PabloCruise for the added information! The pig is my better halfs daily driver, and if I can talk her into it, I see a new bumper in the future! I hope you both have an awesome weekend!