Secondary fuel pump dead?

[Subfixer]

Car runs fine, except when at full throttle going through the gears. Then acts like fuel shutoff. For short bursts of full throttle, everything is ok. I'm thinking the secondary pump isn't keeping up, or only the primary is working.

Sent from my Pixel 4a (5G) using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)

[Young1]

Most likely yes. To confirm perform the fuel pumps amperage test on the red pigtail at the wiper motor. Your meter will read 7-9 amps if both are running. 3-4 amps if one is running. Details in the Stickies.

[A26B]

Do you still have the Secondary Port Throttle (SPT) system still in place?
If so, test the vacuum pump and each of the vacuum actuators. A failure of any 1 of those 3 items can cause the same symptom.

[Subfixer]

Secondary Port Throttle (SPT) system is still in place. Entire system was checked by Marc when my 415 was built less than a year ago. Vacuum pump doesn't cycle at all. Pretty sure its a pump. Will be replacing both today.

[Subfixer]

My first check was the current draw. Current reads 9.3 Amps, so it seems both pumps are running.
Next check will be fuel pressure.

[Subfixer]

Fuel pressure check.... not good.
Only 42psi at cold idle.

[Subfixer]

I really am disappointed in aftermarket Chinese parts.
After replacing both pumps with Delphi FE0039 units, I now have a combined fuel pressure of 20psi.....

[A26B]

Secondary Port Throttle (SPT) system is still in place. Entire system was checked by Marc when my 415 was built less than a year ago. Vacuum pump doesn't cycle at all. Pretty sure its a pump. Will be replacing both today.
If the vacuum pump doesn't cycle at all, how do you know if it is still working?

[Subfixer]

Vacuum pump does cycle, just not excessively. About once every 45 seconds after initial pump up.

Put old (original) fuel pumps back in for now.
After removing and replacing the assembly 3 times, I'm now an "expert".

[Subfixer]

Any recommendations for "good" fuel pumps?

[2poor4aZR1]

Just browsing the web,

https://www.lingenfelter.com/product/L710030390.html

Asking out of genuine curiosity, any reason you can't swap the OEM fuel pumps for a set of Walbro 255s? I mean, it would mean modifying the factory mounting brackets.

[HAWAIIZR-1]

Any recommendations for "good" fuel pumps?

Are you sure you don?t have a crack in that plastic Y? They are old and brittle; Carter200 makes a replacement if so.

The other option is the stainless steel single pump unit that Dan on here makes.

At first I bought the Y connector, but I decided to just go stainless single pump and never looked back.

[Subfixer]

I have Carter's Y replacement. The new single pump option looks good, but it seems to be rated up to 550 hp. That would be right on the edge for my 415 which is approaching 600hp.

Sent from my Pixel 4a (5G) using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)

[Matt B]

Any recommendations for "good" fuel pumps?I bought a set of GM OEM pumps following an advice here in the forum. They're made for big 455ci (?) Suburbans. Never installed them (mine are looking and working very well) but they look proper.
Also they were NOT made in China, something I really appreciate.

I can look for the exact type but it's also somewhere here in the forum.

[HAWAIIZR-1]

I have Carter's Y replacement. The new single pump option looks good, but it seems to be rated up to 550 hp. That would be right on the edge for my 415 which is approaching 600hp.



Sent from my Pixel 4a (5G) using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)



Got it; I did not notice your signature and I understand. I would love to have your problem. Lol. I thought Lingenfelter sold good pumps?

[Subfixer]

New pump kit from Lingenfelter arrived today. 2 pumps, made in USA, adaptor pigtails, new bolts, o-rings, gasket, socks. Only thing missing are the 2 tie wraps that hold the pumps in the holders.

Lingenfelter part #: L710040390 (high flow)
For Standard flow: L710030390

Sent from my Pixel 4a (5G) using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)

[Raykahn]

Hey Subfixer, glad to see you got pumps that will work for you.

I wanted to say that in a previous conversation Haibeck told me that the 67 GPH pumps that come with the single pump conversion kit are capable of supplying up to a 650hp engine.

I think you went the correct route here, but its worth noting at least should you ever need it in the future.


Sent from my iPhone using Tapatalk

[chesnut]

Subfixer,

Replaced my '92 original fuel pumps with 2 - Walbro 5CA400 pumps and they work great.

Gary
....

[scorp508]

New pump kit from Lingenfelter arrived today. 2 pumps, made in USA, adaptor pigtails, new bolts, o-rings, gasket, socks. Only thing missing are the 2 tie wraps that hold the pumps in the holders.

Lingenfelter part #: L710040390 (high flow)
For Standard flow: L710030390


Subfixer, did you go with the high flow or standard? My primary pump stranded me yesterday and this looks like a nice "may as well do both" solution. I considered going to a single pump, but I kind of liked being able to run on only the secondary to limp home if the primary dies again.

The car is currently around 540 crank HP, so I'm thinking perhaps the high flow option provides a little assurance I don't need to go to something even bigger later if I do any more modifications.

[Subfixer]

I got the high flow pumps as I'm pushing around 560 crank hp.

Sent from my Pixel 4a (5G) using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)

[scorp508]

I got the high flow pumps as I'm pushing around 560 crank hp.

Subfixer, did you need to do any modifications to get these pumps to fit into the sending unit? I received the kit from Lingenfetler and all ways going smoothly until trying to slide the new pumps into the frame.

My stock pumps measure ~36.75mm in width.
20602

The Walbro GSS340 pumps I received from Lingenfelter in the high flow kit measure ~39.18mm in width and will NOT push into the holder.
20603

https://walbrofuelpumps.com/255lph-walbro-gss340-intank-fuel-pump.html.html

I don't see how these are going to go in without cutting a slit in the side of the frame for each pump, then praying to the zip-tie gods it holds together.

[Subfixer]

Yes. I split the holder down one side. Secured with tie wraps.

Sent from my Pixel 4a (5G) using ZR-1 Net Registry mobile app (http://r.tapatalk.com/byo?rid=90383)