Go Back   Rotary Car Club > Tech Discussion > RX-7 2nd Gen Specific (1986-92)

RX-7 2nd Gen Specific (1986-92) RX-7 1986-92 Discussion including performance modifications and technical support sections.

Reply
 
Thread Tools Display Modes
Old 11-22-2010, 02:36 AM   #1
sv51macross
Rotary Fan in Training
 
Join Date: Oct 2010
Location: Ann Arbor, Mi
iTrader: (0)
Posts: 47
Rep Power: 0
sv51macross is on a distinguished road
Default Fuel rail (preassembly) testing

Tomorrow (okay, this morning) I'm going to be reassembling Lucy's fuel system with four replacement injectors and all-new grommets/O-rings, and a replacement PD. Here is a photo as best as I could take of the primary rail.

http://sadpanda.us/images/285598-ER3BLVO.jpg

It seems that the fuel is leaking from the top of the leading injector and the wetness on the rest of the rail/PD is just 20 years of dust wicking and sticking the fuel. Obviously, I'm going to replace the injector and rubber seals, but is it wise to not replace the rail/PD? The engine only has about 80k on it, and the replacement rail/PD has 64k on it. If it is prudent not to replace the PD and keep it on hand as a spare, how should I store it so as to prevent further degradation of the internal rubber diaphragm?

Lastly, to make sure the PD is not leaking, I want to pressurize the fuel system. I was going to button the rails back together and use duct-tape to hold the injectors in their rail bosses. After that, plug the pump back in and hot the ignition. Is this a bad idea?






__________________
1990 Mazda RX-7 NA; Lucy, after the main antagonist from Elfin Lied.
Eventual plans? Something cyberpunk and spicy.
sv51macross is offline   Reply With Quote
Old 11-22-2010, 04:32 AM   #2
Grappler
Rotary Fan in Training
 
Join Date: Nov 2008
iTrader: (0)
Posts: 31
Rep Power: 0
Grappler is on a distinguished road
Default

I'm not really sure what you mean by button the rails back together or use duct tape...

Have you looked into using a banjo bolt at all? The rail itself should be fine its mainly the PD you should worry about.
Grappler is offline   Reply With Quote
Old 11-22-2010, 06:29 AM   #3
Pete_89T2
Lifetime Rotorhead
 
Pete_89T2's Avatar
 
Join Date: Apr 2010
Location: Elkton, MD
iTrader: (1)
Posts: 874
Rep Power: 15
Pete_89T2 is on a distinguished road
Default

If your '7 still has the stock wiring harness, I would recommend installing both rails on the motor, jumper the yellow fuel pressure test connector (located by the passenger side strut tower). When you switch the key to run, you'll hear the fuel pump running and will know in a hurry if/where it's leaking from.
Pete_89T2 is offline   Reply With Quote
Old 11-22-2010, 09:48 AM   #4
My5ABaby
Sigh.....
 
My5ABaby's Avatar
 
Join Date: Feb 2008
Location: Murfreesboro, TN
iTrader: (6)
Posts: 2,377
Rep Power: 19
My5ABaby will become famous soon enough
Default

I support putting in a banjo bolt where the PD is and eliminating that problem area all together.
__________________
1986 Sport: 132k miles, 5A (Sapphire Blue Metallic), Tokico Blues, Racing Beat Springs, Custom LED tailights (only S4 LED tails in the world), SSR Mark II, Racing Beat exhaust, S5 black interior, Rotary Resurrection rebuild at 120k miles

Community Service Manual

RotorWiki

"Imagination costs nothing; we could build square locomotives or fly to Mars" - Felix Wankel

Yesterday is history, tomorrow is a mystery, but today is a gift. That is why it is called the "present."
My5ABaby is offline   Reply With Quote
Old 11-22-2010, 10:43 AM   #5
C. Ludwig
Rotary Masochist
 
Join Date: May 2008
Location: Floyds Knobs, IN
iTrader: (5)
Posts: 494
Rep Power: 17
C. Ludwig is on a distinguished road
Default

That's an S5 primary rail. The PD is integral to the rail. This PD is not subject to the same failure (leaking) as the removable S4 PD and cannot be replaced with a banjo bolt. Clean it up and put it back together just as it is.

Install new o-ring on your injectors, just as you've said you're going to. Lube the o-rings before you try to insert the injectors in the rail It's very easy to nick the o-ring and ruin it when you try to insert the injectors into the rail without lube. I like to use assembly lube, motor oil works fine though. Just don't install them dry.

If this is a turbo car you can hook both rails and all the fuel lines up to the engine/manifold before installing the upper intake and pressure test the system that way. I would do that before trying to pressure test the system off the engine. If you do try to pressure test the system off the engine, use safety wire to hold the injectors tight in the rails. You need something very strong to hold the injectors. Tape will not work. You can use properly installed safety wire though to hold the injectors to the rails and jump the test terminal to run the pump just as you described. Doing this on the engine is a safer option though.
__________________
_______________________________________________



One stop Haltech, AEM, Syvecs shopping. Installation and tuning.
http://www.lms-efi.com
Free support. Drop us an email.
chris@lms-efi.com
502-515-7482
Facebook @LMS-EFI
C. Ludwig is offline   Reply With Quote
Old 11-22-2010, 12:09 PM   #6
sv51macross
Rotary Fan in Training
 
Join Date: Oct 2010
Location: Ann Arbor, Mi
iTrader: (0)
Posts: 47
Rep Power: 0
sv51macross is on a distinguished road
Default

@ Ludwig,
I thought they were subject to the same failures, it was just harder and more expensive to replace. As my sig says though, Lucy breathes without the aid of a hairdryer, so probably different than what you're suggesting.
__________________
1990 Mazda RX-7 NA; Lucy, after the main antagonist from Elfin Lied.
Eventual plans? Something cyberpunk and spicy.
sv51macross is offline   Reply With Quote
Old 11-22-2010, 08:45 PM   #7
NoDOHC
The quest for more torque
 
NoDOHC's Avatar
 
Join Date: Sep 2008
Location: Sheboygan, Wisconsin
iTrader: (1)
Posts: 855
Rep Power: 17
NoDOHC will become famous soon enough
Default

Yeah, you can test the primary rail, but you have to have the secondary rail too, as it has the FPR on it. You can hold the injectors in with duct tape if you like, I prefer rubber bands. As an alternative, if you have extra fuel line, leave the fuel rail in the upper intake manifold and simply attach long line to test it.

I really like that fact that I can test my fuel system before installing the upper intake on my 4-port.
__________________
1986 GXL ('87 4-port NA - Haltech E8, LS2 Coils. Defined Autoworks Headers, Dual 2.5" Exhaust (Dual Superflow, dBX mufflers)
1991 Coupe (KYB AGX Shocks, Eibach lowering springs, RB exhaust, Stock and Automatic)
NoDOHC is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 06:54 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Hosted by www.GotPlacement.com
Ad Management by RedTyger