351 with 2000 explorer efi will run for 1 second

[rjrobin2002]

Good point. Pinch the return and make sure the pump can actually make the pressure.

I do question if 17Lb injectors can feed a 351 with a good flowing intake. I understand the 17s flow more like the older 19s with the higher pressure.

Efi guy was adamant the 17 injectors and explorer returnless 60psi would be plenty for a stock 351 with gt40 explorer heads/upper intake and lightning lower.

I have plans of getting high flow heads, vortec super charger and bigger injectors down the road.

 

[Timmy390]

I'm 100% sure the stock 351W injectors were 19lb orange tops. They were on my 1996 donor van and I'm running them today with the engine warmed up and a nice cam......

Tim

 

[ba123]

Yeah, I wouldn’t do that. Engine should run without maf connected is my understanding but will just run more rough.

The pump might be ok but the regulator is clearly not working. It’s a 58 lb regulator and you’re only at 45. Moving it might get you to 58 but still not ideal.

 

[rjrobin2002]

I'm 100% sure the stock 351W injectors were 19lb orange tops. They were on my 1996 donor van and I'm running them today with the engine warmed up and a nice cam......

Tim

Efiguy said 17pound injectors with 60psi put out more fuel than 19 pound and 40psi.

He is the wizard and I followed his guidance.

 

[Timmy390]

Efiguy said 17pound injectors with 60psi put out more fuel than 19 pound and 40psi.

He is the wizard and I followed his guidance.

Oh go of what he says for sure......

Tim

 

[rjrobin2002]

Yeah, I wouldn’t do that. Engine should run without maf connected is my understanding but will just run more rough.

The pump might be ok but the regulator is clearly not working. It’s a 58 lb regulator and you’re only at 45. Moving it might get you to 58 but still not ideal.

I thought spec was 55-65 and 58 was in the range.

I am gonna move it close and see what it does at 58psi.

But am looking for what regulator I want to run now that will get me 65psi.

 

[ba123]

There’s a Tanks Inc one on Summit.con that adjustable from 35-70 that seems the most reasonably priced. There are plenty others for more but I agree, move it and see as 58 might be fine.

https://www.summitracing.com/parts/tnk-afpr1

 

[ba123]

Also, I’ve thought about running this way and you’re making me thing about it again cause I’m about to do my fuel lines, but my understanding is that you get a much more consistent pressure if you run your regulator AFTER the fuel rails. Pressure is built up and controlled between the pump and the regulator and all excess is dumped past the regulator and to the return line.

You moving yours closer will most likely improve it but still would most likely be even better after although looks like the one you have is designed for before.

 

[rjrobin2002]

Also, I’ve thought about running this way and you’re making me thing about it again cause I’m about to do my fuel lines, but my understanding is that you get a much more consistent pressure if you run your regulator AFTER the fuel rails. Pressure is built up and controlled between the pump and the regulator and all excess is dumped past the regulator and to the return line.

You moving yours closer will most likely improve it but still would most likely be even better after although looks like the one you have is designed for before.

I prefer the regulator after like the early explorers and fox body mustangs.

I was excited about the returnless system, but then I realized I had to run a return line from my regulator and the rwturn style regulator needs to be close to the engine.

So now I have a long return just like the old system, LOL

 

[rjrobin2002]

I am interested in how much 45 verse 65 psi fuel pressure makes. I would uld think it would idle with 45 psi

 

[bigmuddy]

From memory my old 5.0 would like idle around 40-45, this with either a standard on frame pump or the BC in-tank pump. This used the factory mustang lines, basic regulator on the rail.

 

[ba123]

I prefer the regulator after like the early explorers and fox body mustangs.

I was excited about the returnless system, but then I realized I had to run a return line from my regulator and the rwturn style regulator needs to be close to the engine.

So now I have a long return just like the old system, LOL

Still would be cleaner and easier to keep it before, which is why I was thinking about it. I can’t find a good spot for my regulator and might get a different regulator too and was thinking of putting it on the frame rail but pass side would be too close to the exhaust and drivers side I’d have to run to the rails and then return line back...but still might do that to keep it clean.

I am interested in how much 45 verse 65 psi fuel pressure makes. I would uld think it would idle with 45 psi

I would think 45 would be enough for basic running as well, but it's probably not a constant 45 being that far away. My guess, total guess, but might be difficult to regulate that way. Could be a bad guess, but I'd bet money that putting it close would be a noticeable difference at minimum.

 

[rjrobin2002]

Good point. Pinch the return and make sure the pump can actually make the pressure.

I do question if 17Lb injectors can feed a 351 with a good flowing intake. I understand the 17s flow more like the older 19s with the higher pressure.

New MAF made no difference, only runs with MAF unplugged, I gave it some gas for the first time today with MAF unplugged and it revved well and sounded smooth.

So I am gonna get the fuel rail pressure up to 65 with an adjustable regulator and check back.

So why does the unplugged MAF make it idle? It makes it less sensitive to low fuel pressure?

 

[ba123]

New MAF made no difference, only runs with MAF unplugged, I gave it some gas for the first time today with MAF unplugged and it revved well and sounded smooth.

So I am gonna get the fuel rail pressure up to 65 with an adjustable regulator and check back.

So why does the unplugged MAF make it idle? It makes it less sensitive to low fuel pressure?

That’s interesting… maybe because it has no idea how much fuel to allow and it just allows all it can or more than normal. Interesting.

 

[DirtDonk]

How does the original Ford setup deal with “returnless“ pressure control? Does the computer control it, or is there a regulator in the tank/pump module?
If it’s in the tank, is it that hard to set up?
What tank are you running?

 

[rjrobin2002]

How does the original Ford setup deal with “returnless“ pressure control? Does the computer control it, or is there a regulator in the tank/pump module?
If it’s in the tank, is it that hard to set up?
What tank are you running?

It's original regulator is in the tank and the pump keeps 65psi from the tank forward.

I have an external pump with a 59psi regulator after the pump, but am only getting 45psi at the rail.

I am gonna redo my fuel lines and have an adjustable regulator on the firewall and will be able to get my pressure up to 65psi and see if it will idle and run with the MAF plugged in.

I still think the fuel pressure may not be the issue, seems like it should idle with 45psi.

 

[Broncobowsher]

Have you tried pinching the return line yet? Would be a waste of money and time if there is nothing wrong with your existing filter/regulator and it is really a pump that just can't make the pressure.

 

[rjrobin2002]

Have you tried pinching the return line yet? Would be a waste of money and time if there is nothing wrong with your existing filter/regulator and it is really a pump that just can't make the pressure.

Will do when I get home

 

[rjrobin2002]

Have you tried pinching the return line yet? Would be a waste of money and time if there is nothing wrong with your existing filter/regulator and it is really a pump that just can't make the pressure.

Pinched return and fuel pressure climbed to 68psi.

Still only starts with MAF unplugged.

 

[rjrobin2002]

So it still won't stay running with 68psi fuel pressure unless MAF is unplugged.