Pulling out of the gas station last friday with a full tank of ethanol free gas, my FD suddenly lost power and began smoking profusely. I quickly turned into the nearest plaza using the inertia I still had to get me halfway up a hill in front of a fireworks store. A nice man and his two sons ran towards me and kindly offered to push me up the rest of the hill into a parking spot so I could get out of the right of way. I got down on the ground and looked under the car to see fuel spewing on the pavement from the passenger side engine bay. Lots of things running through my mind all at once-- mainly, is this the end of my FD that has served me so well for the past twenty years? I have heard of FPD failures but I just replaced mine 6 years ago and only drive the car once a month. The smoke began to build. I grabbed the small fire extinguisher I keep velcroed to the passenger side footwell and called 911. I then called Cam at Pettit who picked up right away and told me to unscrew the gas cap to depressurize the system. The fuel leaking from the engine bay stopped. I'm pretty sure this saved my car.

The firefighters showed up and asked me why I hadn't done an LS1 conversion! They also laughed at me and asked to drive my car when I get it working. After spreading some clay on the puddle of fuel and pushing my car to a safer spot they were gone after a few minutes.

Grateful to firefighters and this forum which recently helped me replace my radiator fans with RX-8 ones, wire them properly, and find a bad solenoid.

I don't think I'm going to attempt to repair this myself but any suggestions on how to modernize a stock fuel system would be appreciated. Stock FPD, injector o-rings, and new vacuum lines where needed? Is it possible that I blew a rotor from running too lean?

 

=

 

Firemen seem easily distracted by RX7. Best throw a tarp over it before they arrive.

We had a small emergency at our house a few years ago.

While one fireman attended to that; the rest congregated around my car!

Perhaps they were expecting it to burst into flames?

 

Thanks Redbul! I'll keep that in mind for next time...

 

Yes. Best to pull over and stop the engine.

If you smell excess gas.

 

The good thing is finding fuel leaks typically isn't hard, and if it's a large leak like that it should be even easier.

Jumper the F/P and GND connectors in the diagnostic terminal under the hood and turn the key to On. That will run the fuel pump continuously. You'll see and smell the leak pretty quickly.

The OEM parts rarely leak if left alone and if so it's a VERY minor leak that's easy to smell and gives warning. Quite possible someone messed around with something in the past and that is what failed. You may have to pull the upper intake manifold if it's something in or around the lines that's leaking.

Use OEM parts and OEM fuel lines and OEM clamps. Period. Parts store stuff will fail on you again.

Dale

 

I should put that pic on my fridge where I'll see it daily. Maybe I'll be finally convinced to sell mine and get something sensible like a Miata.

 

Agree on OEM.
Not saying it’s the case with the OP, but seems like I remember an older thread mentioning temptation on the part of some to use non-metric high-pressure fuel line because it was hard to find the right size in chain parts stores…and/or it was easier to install on the hard lines than metric since the SAE stuff was slightly bigger.

 

Normally I'd agree on "don't try to be cheap because it backfires", but I think we should be clear on something. 5/16" is 7.9375 mm, the correct size for both stock FC and FD fuel lines. SAE J30R7 is Non-EFI fuel hose (for Carburetor or vacuum use only). J30R9 is Fuel Injection Hose (correct for this application). J30R10 is Submersible Fuel Injection Hose (for In-tank use). All are available at any parts store.

As for clamps, I'm going to agree with Dale Clark. This is an area where saving $0.03 is a bad idea. However, a T-bolt clamp will serve its purpose considerably better than the OE Spring Clamps which lose tension with age.

On Series 4 FCs, the Fuel Pulsation Damper is often removed and a Banjo Bolt plus fitting put in its place. On Series 5 and later, it is integrated into the primary fuel rail. Perhaps cutting the FPD off (use precautions) and welding on a 06AN fitting would be a suitable option here? Then you can use a 06AN hose end on the existing 8mm fuel line for a leak-free permanent solution. If using a regular 06an hose end, It'll be a bit tight pushing it in (that's what she said), but going slow and using a little lube will do the trick (that's ALSO what she said)

Aaron Cake performed a similar operation on his 1976 Cosmo by tig welding two 06AN bungs onto a Series 4/GSL-SE primary rail. I would imagine it would be about the same once the FPD is axed from it on newer ones.

 

Ok. Anything but anecdotal suspicion on OEM spring clamps losing tension? I’ve never had any such issues.

 

In such times, have the dealer do an inspection.


When this happens, go to your dealer!

 

A spring hose clamp, and I've had 100's of them, has never, in my experience, lost tension. In fact, it's just the opposite - screw type clamps always lose tension due to rubber creep, where the spring types mostly compensate for that.

 

^Agreed, same experience. The only time an OEM spring clamp might lose some of its tension is if the wrong tools & wrong procedures were used to remove them, and the spring clamp gets a bit twisted or stressed too much during removal.

 

Excellent points and I do agree. But we're all replying to this thread because of something that "shouldn't happen" did happen. Plus, who knows how many times spring clamps have been removed and put back on too. Also, in the Cosmo Workshop Manual, it says pretty clearly on diagrams near each clamp "交換" which is Japanese for "Exchange" or "Replacement". If in doubt "Better safe than sorry" is something all of us can agree on, especially for fuel lines.

 

Replacing spring clamps with new ones is a good idea. Replacing 25-year-old rubber hoses is an even better idea, those are more likely to be the failure point than steel spring clamps. I wouldn't trust aftermarket screw-type clamps on fuel lines.

Glad to hear your car is safe, please update the thread when you find the problem.

 

If a spring clamp is in good condition, not mangled from install or removal, it can be re-used many times over. It's pretty obvious if it isn't going to do the trick.

IMHO there's no reason to remove the pulsation dampener. If that's the leak cause, buy a new one and you're good. A new one will most likely outlive the car. There's a good reason Mazda put it there and hacking a bypass is another spot that a leak could happen.

For hoses, I've tried using SAE hoses on the FC back in the day, they would either be too loose or too tight for my liking. Either get metric fuel injection rated hose or Mazda OEM hose if that's the failure point. Mazda did upgrade all the fuel lines with the fuel line recall and the new hose is fantastic for heat resistance and longevity. You used to be able to buy that recall kit but I think it's NLA which is a shame, that was a cheap way to get most of the parts of the fuel system. It came with all the lines, clamps, crush washers, O-rings, you name it.

Worm drive non-lined clamps have no business on an FD and especially not on fuel lines. They cut into hose and will loosen over time. It's a disaster waiting to happen. There are worm-drive clamps that are lined and say "fuel injection clamps" - those are better but still kind of suck. OEM spring clamps are set it and forget it.

Of course we're just speculating, it could be any number of things that is leaking. Hopefully OP will post up with what was found. A large leak should be a cinch to find but it could be some deep work in the rat's nest to fix.

Dale

 

Thank you all for your input and I've learned a lot from this discussion. I decided not to do the work myself. I live to far from Cam now so I called Mike Lowe in Sarasota and I'm going to bring it over there on 1/10. Will def post follow up. I'm also very curious now that I know it could be other things besides pulsation damper.

 

I edited my original post because I thought it was a joke when I read the comment by the firefighters, then reread it and realized it wasn't. I'm glad you're safe and definitely consider it a blessing you've only had to post here 20 times in 18 years!

Hopefully they figure it out and get it all squared away. Curious what they decide with the FPD.

 

The FPD puzzles me, primarily because it seems to have a tiny rubber stopper on top, which in many cases, I have in my parts bins, has deteriorated away. Why have this failure point?

Or is the little rubber stopper not critical?

 

So did OP figure out exactly what leaked?

 

the aftermarket stuff typically is the wrong OD to use the spring clamps, so its kind of a no go there. Mazda also uses amazingly good quality hose, and the aftermarket can't match it, by miles.

 

He said he's taking it in Jan 10th.

 

We've switched to Gates Barricade fuel line in the shop. It is resistant to all the garbage ethanol they keep mixing in to many fuels. The issue with the oem spring clamps is when they are used with aftermarket hose which may be a slightly different outside diameter and they do not clamp securely.

 

I've never cut one open but I believe that is what holds the diaphragm in place.

 

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