fuel pump energize time/demand

[BigM460]

Does anyone know if it is possible to lower or change the demand or energize time when the pumps prime, in the tune?

I'm having issues with blowing clamped hoses off in the tank at the time the pumps prime. Fuel pump demand goes past 50 to 75 and fuel pressure maxes gauge out at 90psi. Pretty sure it's much higher, as it takes over a minute of run time to come back down to a normal level.:(

Have had to change everything over to push-lock AN fittings, but still can only use clamps on the pumps. Hoping for a solution to this pressure issue at start up?

[whitey]

Why is it getting so high?

[justbob]

What pumps are you running, what style clamps, and what size fuel line?


Builder Of Badassery

[justbob]

Double post.

[BigM460]

2 340's, -8 fuel line outside tank forward.

[BigM460]

Pic of current

[justbob]

Is that 3/8" hose at the pumps and is that where it's blowing off?


Builder Of Badassery

[BigM460]

Is that 3/8" hose at the pumps and is that where it's blowing off?


Builder Of Badassery

No, has blown off at every other connection, have changed it all over to the push-locks. Question is, is it possible to change the way the pumps prime? Runs perfectly after start. Just have the issue when I turn the key to start.

[justbob]

I'd imagine a simple adjustment to the tune. The reason I was asking about the hose was the pumps hardly have what I'd call a lip and they are 5/16". Zack told me a little trick he does where he widdles down a 1/2" long piece of the supplied hose to just a sliver and pushes the 3/8" line over it. Worked awesome!

I haven't logged start up pressure yet, but I could maybe tomorrow if someone doesn't get you your answer.


Builder Of Badassery

[BigM460]

I'd imagine a simple adjustment to the tune. The reason I was asking about the hose was the pumps hardly have what I'd call a lip and they are 5/16". Zack told me a little trick he does where he widdles down a 1/2" long piece of the supplied hose to just a sliver and pushes the 3/8" line over it. Worked awesome!

I haven't logged start up pressure yet, but I could maybe tomorrow if someone doesn't get you your answer.


Builder Of Badassery

I'm hoping! I've emailed Jeff, but haven't heard from him yet.
Thought about installing a regulator just to use as a bypass/checkvalve. That is if it can't be fixed with tune adjustment.

[justbob]

He's off Monday's. Not sure what I was thinking earlier as I'm return style now so my pressure is right at 40. Sorry!


Builder Of Badassery

[martyo]

I'm hoping! I've emailed Jeff, but haven't heard from him yet.
Thought about installing a regulator just to use as a bypass/checkvalve. That is if it can't be fixed with tune adjustment.

Dyno day yesterday, Easter for him today.

He will get back in touch with you this evening.

[BigM460]

Dyno day yesterday, Easter for him today.

He will get back in touch with you this evening.

How was the dyno day? Wanted to head down, but these issues took the car down Saturday morning. Good turn out?

[martyo]

How was the dyno day? Wanted to head down, but these issues took the car down Saturday morning. Good turn out?

Insanely packed!

This was our best dyno day ever.

[BigM460]

Insanely packed!

This was our best dyno day ever.

Sorry I missed it. Hopefully will make the next one! Always a good time!

[Zack]

Are you still returnless? That's too much pump for no pressure relief device.

And that does not appear to be submersible fuel line.
You need to run the 2nd pump off of a hobbs switch so its only running under boost.

[CWright]

^^^ That's what we did on mine! ^^^. My second pump comes on at 5lbs of boost.

[BigM460]

Going to wait to hear from Jeff. He is the one that talked me into setting it up like it is. Everything is perfect for driving, just when pumps prime is there an issue.

[Zack]

Going to wait to hear from Jeff. He is the one that talked me into setting it up like it is. Everything is perfect for driving, just when pumps prime is there an issue.

You have the improper fuel lines in the tank for starters sir.

[MOTOWN]

Chris your already half way there! just run a return line , and a regulator , and get some submersible fuel line to go in the tank ,then you will be be return style , and be done with the pressure issues.

[BigM460]

You have the improper fuel lines in the tank for starters sir.

It's sold to use inside a fuel cell, and is good to 350psi. Not following?

[BigM460]

Chris your already half way there! just run a return line , and a regulator , and get some submersible fuel line to go in the tank ,then you will be be return style , and be done with the pressure issues.

Jeff talked me into staying returnless?

[MOTOWN]

Jeff talked me into staying returnless?

I think given your current issue its time to revisit that decision

[Zack]

It's sold to use inside a fuel cell, and is good to 350psi. Not following?

Please post the link!

[BigM460]

Please post the link!

Fragola 900700 kit

You seem very angry all the time?

[RacerX]

He is! Napoleon complex, he's height challenged. :P

Jeff probably just needs to adjust part of the fuel pump voltage table. This table is a starting point for voltage/fuel pressure and the pcm will correct the table over time, but, if the hoses are blowing off, it's likely putting in even higher voltages since it sees no pressure. Have you reset the PCM lately?

[BigM460]

He is! Napoleon complex, he's height challenged. :P

Jeff probably just needs to adjust part of the fuel pump voltage table. This table is a starting point for voltage/fuel pressure and the pcm will correct the table over time, but, if the hoses are blowing off, it's likely putting in even higher voltages since it sees no pressure. Have you reset the PCM lately?

Thank you! Finally someone addressing my question. Just reflashed yesterday. So this is something that it should adjust to on its own?

[RacerX]

Yes. If it doesn't get the correct feedback, it can't populate the table with the correct numbers. If you turn the key, the pumps energize and a line blows off, the computer sees no rail pressure and tries to up the voltage. The key is to lower the table in the tune as a starting point. I actually just loaded the GT40 fp file in sct prp to start with for my twin pumps then datalogged FPUMP_ACT_VOLTS, fuel_rail_pr_psi and FPUMP_FLOW_RATE to use in Livelink Gen2 with a histogram. Those numbers were put into the FPVT in the tune and it starts up better now when the PCM is cleared.

[BigM460]

Yes. If it doesn't get the correct feedback, it can't populate the table with the correct numbers. If you turn the key, the pumps energize and a line blows off, the computer sees no rail pressure and tries to up the voltage. The key is to lower the table in the tune as a starting point. I actually just loaded the GT40 fp file in sct prp to start with for my twin pumps then datalogged FPUMP_ACT_VOLTS, fuel_rail_pr_psi and FPUMP_FLOW_RATE to use in Livelink Gen2 with a histogram. Those numbers were put into the FPVT in the tune and it starts up better now when the PCM is cleared.

I'll admit not sure what exactly your talking about, but........I do think this is my trouble!!!
Had worked fine until the line blew off the first time. Drove it over 20 miles home with just one pump with the leak providing between 25-35psi and fuel pump demand at 100%.
Just remembered that I also cycled the key on and off to get fuel out of the tank. Over 4 gallons.

[justbob]

Thank you! Finally someone addressing my question.


Really?


Builder Of Badassery

[RacerX]

I'll admit not sure what exactly your talking about, but........I do think this is my trouble!!!
Had worked fine until the line blew off the first time. Drove it over 20 miles home with just one pump with the leak providing between 25-35psi and fuel pump demand at 100%.
Just remembered that I also cycled the key on and off to get fuel out of the tank. Over 4 gallons.
!!! :eek: Did you reset the computer after that? I'm sure the PCM learned a lot of bad info!


Really?
What? You ever work on a car? :D

[martyo]

Really?


Builder Of Badassery

No, not really.

I guess it is just better to throw some blame our way since "we" insisted that "he" build his car a particular way. :P

[BigM460]

Really?


Builder Of Badassery

Sorry! Forgot about you! Went off course yesterday.

[BigM460]

No, not really.

I guess it is just better to throw some blame our way since "we" insisted that "he" build his car a particular way. :P

And it works VERY well!
Looking like this is all due to my ignorance to how the pcm works.
Thanks Marty!

[BigM460]

And it works VERY well!
Looking like this is all due to my ignorance to how the pcm works.
Thanks Marty!

Oh and just to clear things up, this is a picture of the first blow off. All my fault used a worm clamp when I didn't have enough of the others. Jeff and crew at Mo's know what works from experience!
Thanks once again Marty!
Jeff went through what has happened to couse this issue and how to correct it.

[martyo]

And it works VERY well!
Looking like this is all due to my ignorance to how the pcm works.
Thanks Marty!

Good deal!

[martyo]

Oh and just to clear things up, this is a picture of the first blow off. All my fault used a worm clamp when I didn't have enough of the others. Jeff and crew at Mo's know what works from experience!
Thanks once again Marty!
Jeff went through what has happened to couse this issue and how to correct it.

One of those clamps does not look like the others... :D

[Zack]

Fragola 900700 kit

You seem very angry all the time?

Not angry at all. If what you posted is actually legit for being submersed, that's a killer find!

I just did some research online, but could not find any definitive answers on whether it could be submersed or not.

[BigM460]

Not angry at all. If what you posted is actually legit for being submersed, that's a killer find!

I just did some research online, but could not find any definitive answers on whether it could be submersed or not.

I did the same. Best I could find was that with some additives that smell may come through the hose. Seems to be working/ holding up great.