Help on Fuel Injection -
Thread Starter
Drifting
Joined: Sep 2001
Posts: 1,875
Likes: 27
From: Long Beach NY
Help on Fuel Injection -
I just installed a set of Ford #19-21 injectors. I have the stock Fuel Pressure Regulator. A couple of questions.
1. How do I check if it's still good? Will vacuum check to determine if it's holding vacuum tell me?
2. Since Ford injectors are used with 37-39lbs pressure will the stock 43lb pressure of the GM regulator give me the equivalent of #22s with the Ford injectors?
Car is a stock '86 aluminum head model.
thanks
Barrier
1. How do I check if it's still good? Will vacuum check to determine if it's holding vacuum tell me?
2. Since Ford injectors are used with 37-39lbs pressure will the stock 43lb pressure of the GM regulator give me the equivalent of #22s with the Ford injectors?
Car is a stock '86 aluminum head model.
thanks
Barrier
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Re: Help on Fuel Injection - (Barrier)
If you installed FMS 21lb injectors that are rated at 36 PSI from Ford. Using them in a GM system will give you about 22.5lbs/hr
The best way to check your pressure regulator is by using a pressure gauge. With the vacuum connected the pressure should be in the 38 to 41 PSI range, with the vacuum disconnected it should be 43 to 45 PSI.
Just doing a vacuum check on the diaphram does not prove that the seat is sealing properly within the regulator.
The best way to check your pressure regulator is by using a pressure gauge. With the vacuum connected the pressure should be in the 38 to 41 PSI range, with the vacuum disconnected it should be 43 to 45 PSI.
Just doing a vacuum check on the diaphram does not prove that the seat is sealing properly within the regulator.
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Re: Help on Fuel Injection - (tjwong)
I realize my '85 operates at lower pressures, but with vacuum line connected at idle, it should drop the fuel pressure by 8-10 psi.
This is pretty common from what I've seen and heard.
That would put you around 35 psi at idle, and 45 psi at idle with vacuum line off (and plugged at the plenum)
This is pretty common from what I've seen and heard.
That would put you around 35 psi at idle, and 45 psi at idle with vacuum line off (and plugged at the plenum)
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Help on Fuel Injection - (Barrier)
I agree those injectors should flow about the same as your stock injectors.
Indeed you need a fuel pressure gauge to check your fuel system:
1-vacuum control is functioning ok for the FP regulator
2-fuel pressure regulator is not leaking
3-fuel pump check valve is not leaking back
4-injectors are not leaking
With only the FP gauge you can perform check #1 and see if the system is holding pressure. If it's not holding pressure on engine shutoff, using some clamps on the rubber lines near the fuel tank, you can the perform checks #2-#4.
Indeed you need a fuel pressure gauge to check your fuel system:
1-vacuum control is functioning ok for the FP regulator
2-fuel pressure regulator is not leaking
3-fuel pump check valve is not leaking back
4-injectors are not leaking
With only the FP gauge you can perform check #1 and see if the system is holding pressure. If it's not holding pressure on engine shutoff, using some clamps on the rubber lines near the fuel tank, you can the perform checks #2-#4.
Thread Starter
Drifting
Joined: Sep 2001
Posts: 1,875
Likes: 27
From: Long Beach NY
Re: Help on Fuel Injection - (65Z01)
I already checked using your method, and the regulator appears to be good. Since the fuel rail is off, is there a way to check it now ?
Auto Zone sells a standard fuel pressure regulator for about $22 bucks. Is it worth just buying it and putting the new one in ??
Auto Zone sells a standard fuel pressure regulator for about $22 bucks. Is it worth just buying it and putting the new one in ??
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Re: Help on Fuel Injection - (Barrier)
For $22 and the fact that you have the rail off the car. Do it is my best advice. You never know when it could really fail. The injectors you have should work just fine.
Heel & Toe
Joined: Jun 2003
Posts: 23
Likes: 0
From: Columbus MS
Re: Help on Fuel Injection - (tjwong)
If there is no tear in the FPR diaphram and the spring isn't broken, then it should be fine. A new diaphram and spring assy is all you get when you buy a FPR from autozone. Take it a apart and look for signs of damage. No damage, no need to replace it, unless you want to.
[Modified by Twanster2000, 12:30 AM 9/15/2003]
[Modified by Twanster2000, 12:31 AM 9/15/2003]
[Modified by Twanster2000, 12:30 AM 9/15/2003]
[Modified by Twanster2000, 12:31 AM 9/15/2003]
