Removing the "rats nest" on an FD
 

In the fall just as I was putting my FD away for the winter I noticed a fuel leak left fuel on the floor of my garage. Now that its warm out again (Its sad how I consider +3 celcius to be warm. . .), I decided to take a look at the problem.

I am a beginner mechanic, so my knowledge is limited: I was able to get the TB and UIM off without much hassle, but I'm hesitant to touch the nest of vacuum hoses that lies beneath. Is it really that difficult?

I've tried searching for writeups, but I find that they all concern 1st or second gen RX7's or are people going to single turbo upgrades.

What exactly needs to be taken out so that I can see the primary fuel rail, and hopefully diagnose the fuel leak? Is there a section in the FSM that deals with this, I couldn't find it? Thanks.

Nathan

Tons o stuff to read in the FAQ. This will get you started.

Vacuum hose diagrams:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/vacuum-diagrams-stock-simplified-sequential-non-sequential-single-turbo-749702/#post8113663

Vacuum hose removal tips:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/infamous-vacuum-hose-job-422528/

Vacuum hose replacement how to: (thanks Rated R1)
http://rx7.voodoobox.net/howto/vachose/vacjob.html

Vacuum hose: solenoid ( rats nest ) removal, lots of photos:
http://www.face2faces.co.uk/RX7/howto/ratsnest1.htm

Vacuum hose reliabilty test (scientific experiment): Viton vs. Neoprene vs. Silicone (thanks TracyRX7)
http://www.geocities.com/MotorCity/G...5/hosetest.pdf

Oh, and search " fuel pulsation dampener"

Paul

Be ready to replace Solenoids, vac hoses, FPD, screws, and other assorted baked goods



Later

Personally, I like to cut the baked hoses and remove the solenoids one-by-one. Then remove the fuel hoses and lift the whole rack out.

Only after you have the solenoids clear of the engine bay would I recommend removing the hardnened hoses. You can use a razor blade to shave down the hose until the nipple is showing, at which point a careful twist will snap it free.

Not sure if this link was posted but I also wrote up a rats nest job: www.davidgeesaman.com

Dave

OK thanks for all the useful info! Turns out that the previous owner had simplified the system and replaced the hoses with silicon so I shouldn't have to worry about the hoses cracking. . .

Here's a shot of where I am now:

Attachment 709814

And here's a shot of where I need to be so I can see the fuel rail/FPD (found from an older thread):

Attachment 709815

So basically the best route to take is to just take note of where everything goes and start unplugging things?

Remove the ignition coil bracket, undo the fuel lines, then unbolt the rack from the engine. You might also need to undo the oil filler neck.

If I were you I'd convert to non seq also while you are in there...

lat link did not work. which type of hose was best?

+1 in the middle of that right now.

If the sequential system is still working right, just keep it for now...

I'd replace all of those Mazda check valves with the VITON diaphragm CV's that Dale Clark sells. Four for $15, just do a search for his name and e-mail him. I just spent around $3K replacing all the rubber under the hood and performing all the "reliability mod's" listed in the FAQ's. While you're in that deep you might as well go for broke.

I started out to just replace a broken double throttle solenoid and everyone here came up with great suggestions on how to spend more of my money...so now I can pile on too!

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/thank-you-rx-7-club-forum-821404/

Thanks everyone for all the useful information, the task at hand seems a little less daunting now. I'll definately check out those check valves from Dale Clark; anything for better reliability!

So its really not that hard to remove the whole thing as it comes out in one piece... On the back of the motor the lines are connected to a bracket you can 1.(remove the three 12mm bolts holding down the plate or 2.) If you can get a philips screw driver in the back between the fire wall and brakcet you can remove the screw holding the rats nest to that bracket.
For the front remove the alt. and there are 3 philips screws remove the bottome one and the one attatching a line to it... Then remove the assorted vaccuum lines from where they come from and the whole thing should come up in once piece.. just label where each end went for re-install... After that you should have clear view on the injectors/fuel rails. Hope that helps...

Chris

One more question:

Some of you mentioned that I'd have to disconnect fuel lines. This may sound like a silly question, but how do I test for a fuel leak when the fuel lines aren't connected? Can I reconnect them once the rats nest is out?

I know the car is leaking fuel, but I'm not sure whether its the injectors or the FPD yet.

Ifin' I was you...I'd just call Ray Crowe at Mallory Mazda and order a Fuel Line Recall kit (it has all fuel hoses/rubber items) and FPD and replace everything. If memory serves me, the Recall Kit has all injector O-rings too (ask Ray). I know it sounds monetarily punishing...but you can't get to any of this stuff without tearing everything off the top of the engine...and you aren't going to want to go back in again when you have a leak shortly after putting it all back together. If you don't know how old the FPD is, I'd swap it out for new. Cuts the chances of a fire way down and gives you piece of mind.

It's only money...and you can't take it with you when you go...so leave it in great shape for those of us who are left;)

Take a look at this:

https://www.rx7club.com/showpost.php...&postcount=255

also you can make your rats nest more simple. Check out my post to see what David Garfinkle (Gafinkle Motorsports) made for me.

+1 for this. The recall kit is pretty reasonably priced and you replace a ton of the fuel parts. You get better clamps too. I also preemptively replaced my stock FPD.

Why would anyone spend money on a crappy fuel system that could fail again one day?

My Garfinkle Motorsports fuel system will last forever and never have any issues. It it is worth the cost. My FD has 38K miles and I dont want to be back in there fooling with the fuel system ever again.
Look up my post to see the thread My SSM FD build.

The post-recall fuel lines are very durable, with the exception of the FPD. I see little reason to spend much more money on fancy fuel rails and lines if the car is stock or nearly stock.

I'm pretty sure that the previous owner did the fuel recall since a) there are some shiny newish looking screw clamps holding on the rubber fuel lines, and b) When I imported the car into Canada I got a "recall clearance letter" saying "there are no outstanding recalls on this vehicle".

As for the FPD, I ordered one last fall the day after I noticed the leak;)

Its been cold the last few days, but hopefully I'll get out there tomorrow.

My recall kit came with "double wall" pressure camps for the fuel lines not screw clamps. That doesn't really help prove or disprove your diagnostics but I'll throw that out there.

Can you help me understand what cause a brand new (with recall kit and new FPD) stock fuel system so prone to failure that its a risk after one day?

OK thanks parid, so how would I tell if the recall kit is installed? I still suspect that it is because of the recall clearance letter, but I want to be sure. Does someone have a picture showing the difference between pre- and post- recall lines?

If the large, short black fuel line that connects to the forward part of the fuel rail is a banjo bolt (kindaofa metal doughnut/ring with a bolt going through it) instead of just a large bolt...you have the fuel recall done. But more importantly, when was it done? 1994? 1995? Two years ago? If it was done back during the original recall (15 years ago) some of the O-rings and other small parts contained in the "kit" could be hard as rocks or cracked. My car only had 19K on it, but the recall was performed in 1994...after looking at some of the rubber I replaced with the new "kit"...I was glad I did. If you don't know when the recall was complied with, it would be prudent to do it while you got her opened up. It's the little shit that will bite you in the ass.

My car is nearly stock, still running twins and my upgraded fuel system was probally around the same cost as getting it all new from mazda! This way my PD and FPR have been moved to the driver side away from the exhaust/motor and has all Stainless Steel lines that have fittings instead of rubber hose that can fail and clamps that just help to tear the rubber.
Again this IMO was the best setup for myself and I now never have to worry about a fuel leak where I would always be thinking about that if I stayed stock.
My FD has 38K miles and mostly stock, but now it will be reliable.