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Username Post: Just swapped in a electric fule pump to replace a mechanical fuel pump        (Topic#357297)
jbander 
Poster
Posts: 6

Reg: 07-19-19
07-19-19 08:57 PM - Post#2771118    

The engine is a 355 carbed engine in a 87 Camaro which did have a mechanical pump on it. I put in a Carter p4594 electric fuel pump (https://www.jegs.com/i/Carter/180/P4...B&gclsrc=aw.ds) and connected the pump to the tank and the existing fuel line and at the engine I by passed the mechanical fuel pump. and connected directly to the carb. I still have the mechanical on the engine disconnected from the tank and I closed off its return line back to the tank. The electric fuel pump is connect to a fuse in the fuse box with a jumper. This car still has the computer in it from when it had a fuel injected 305 in it. The pump stays on all the time , and it runs like hell.
So could this be a computer thing or should their be a pressure switch turning the pump on and off. It says 12lb pressure at the carb , the mechanical was 4 at the most.
I always leave out information that is needed so If You need more information just ask if you would , Thank you.



 


someotherguy 
Senior Moderator
Posts: 28979
someotherguy
Age: 49
Loc: Texas
Reg: 08-01-03
07-20-19 06:21 AM - Post#2771129    
    In response to jbander

Way too much pressure for a carb. Look up your carb model but the recommended fuel pressure is likely closer to 6psi. A bypass-style regulator may be the answer.

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
jbander 
Poster
Posts: 6

Reg: 07-19-19
07-20-19 07:32 AM - Post#2771133    
    In response to someotherguy

I changed fuel pump because I've added Nitrous and the nitrous calls from 8 to 10 psi. I'm by passing the ecm so what turns the pump on and off When the ecm is bypassed.



 
acardon 
Ultra Senior Member
Posts: 11261
acardon
Loc: DFW TEXAS
Reg: 03-25-05
07-20-19 09:33 AM - Post#2771144    
    In response to jbander

  • Quote:
I'm by passing the ecm so what turns the pump on and off When the ecm is bypassed.



You can't regulate the fuel pressure by turning the pump on and off. The pump will run anytime the key is on. Normally, the only time the fuel pump is turned off on an EFI car, is when the key is on and the engine isn't running after 5 seconds or so. That's for safety reasons. A regulator is needed to lower the pressure or it will over come the floats and flood the engine.

Don
66 Corvair (driving)
57 2dr HT (driving)
56 2dr HT (waiting to be restored)


 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17348
grumpyvette
Age: 71
Loc: FLORIDA USA
Reg: 03-16-01
07-20-19 01:50 PM - Post#2771158    
    In response to acardon

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...




IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


Edited by grumpyvette on 07-20-19 01:54 PM. Reason for edit: No reason given.

 
jbander 
Poster
Posts: 6

Reg: 07-19-19
07-20-19 07:37 PM - Post#2771183    
    In response to grumpyvette

Good grief three regulators.



 
65_Impala 
Very Senior Member
Posts: 4227

Reg: 12-29-02
07-21-19 08:37 AM - Post#2771222    
    In response to jbander

You still have the EFI pump in the tank? That might be all the pump you need. Was it TBI or TPI?



 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17348
grumpyvette
Age: 71
Loc: FLORIDA USA
Reg: 03-16-01
07-21-19 08:56 AM - Post#2771225    
    In response to 65_Impala

re-routing the lines can be done so only two regulators can accomplish something similar

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


Edited by grumpyvette on 07-22-19 09:58 AM. Reason for edit: No reason given.

 
jbander 
Poster
Posts: 6

Reg: 07-19-19
07-22-19 09:39 AM - Post#2771291    
    In response to 65_Impala

  • 65_Impala Said:
You still have the EFI pump in the tank? That might be all the pump you need. Was it TBI or TPI?

The EFI pump is gone or disconnected. and I'm Running a Carter p4594 now.Originally it had a 305 in it. Its a 87 camaro.




 
65_Impala 
Very Senior Member
Posts: 4227

Reg: 12-29-02
07-23-19 06:38 AM - Post#2771362    
    In response to jbander

Gone or disconnected... Gone means not in the tank anymore. Not sure what disconnected means, but it doesn't mean it's been removed.

The old efi computer would have nothing to do with some tap off the fuse block. 12PSI is too much for a carb. You should have some kind or protection for an accident like an inertia switch or pump operated from a oil pressure switch. The pump should also be powered from a properly installed relay circuit.

Overall, I suggest you learn how to build a proper fuel system before trying to use that nitrous.



 
jbander 
Poster
Posts: 6

Reg: 07-19-19
07-23-19 08:54 PM - Post#2771410    
    In response to 65_Impala

Thanks folk my regulator comes tomorrow.



 
jbander 
Poster
Posts: 6

Reg: 07-19-19
07-25-19 08:15 AM - Post#2771525    
    In response to 65_Impala

Learning about nitrous is exactly what I'm doing here. The regulator came and it is installed runs great.



Edited by jbander on 07-25-19 08:16 AM. Reason for edit: No reason given.

 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17348
grumpyvette
Age: 71
Loc: FLORIDA USA
Reg: 03-16-01
07-26-19 10:52 AM - Post#2771663    
    In response to jbander

glad to hear we could help

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


 


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