Leaking fuel rail
06-07-16, 04:26 PM
#1
Senior Member
Thread Starter
Leaking fuel rail
Hey guys, I've got an 85 gsl-se with the stock 13b. Recently I started smelling gas while it was running and saw fuel dripping out what looked to be the pulsation dampener. I read up on how this was a standard malfunction and bought the dampener eliminator bolt from Atkins rotary. When I replaced it and started the car again, it leaked exactly the same way. I don't think it's the injectors or the fuel lines. Could it be the fuel rail itself? Does anyone know a good aftermarket fuel rail for a gsl-se? Or had any similar experiences in the past?
06-07-16, 09:31 PM
#2
84SE-EGI helpy-helperton
Pulsation dampners are there for a reason, per Mazda. The 2nd Gen cars have a bigger issue with failure here than ours do, but people keep removing them for some reason...
Are you sure it's not the front injector leaking from the upper O-ring and spraying forward. The only way to be sure is to remove the UIM and have a look after shunting the green connector at the AFM to pressurize the fuel system.
The fuel rails on these cars are dead-nuts simple and not a lot to go wrong. I would also look closely at your fuel lines to ensure that they're High Pressure Fuel Injection hose and not low pressure carb fuel hose. The high pressures will case low pressure hose to crack throughout and cause leaks all over the place.
Are you sure it's not the front injector leaking from the upper O-ring and spraying forward. The only way to be sure is to remove the UIM and have a look after shunting the green connector at the AFM to pressurize the fuel system.
The fuel rails on these cars are dead-nuts simple and not a lot to go wrong. I would also look closely at your fuel lines to ensure that they're High Pressure Fuel Injection hose and not low pressure carb fuel hose. The high pressures will case low pressure hose to crack throughout and cause leaks all over the place.
06-08-16, 08:51 AM
#3
Senior Member
Its most likely your crush washers, the one on the pulsation damper is large diameter with 3 tabs to hold it centered.
Pulsation can certainly cause problems, it was the root cause when we set my car on fire last year. I had installed a new fuel system that had the regulator mounted back at the pump with a return direct to the fuel cell.
That meant that I only had a single -6 line running to the engine which was nice and simple.
The problem was that I had unintentionally set up the worst possible set of conditions for pulsation problems, a 3 inch long fuel rail with 2 injectors about an inch apart, it didn't help that the old SE ECU I am sure was firing the injectors at the same time. What happened is that at a certain RPM, in my case 5000, the injector firing frequency set up a resonance in the fuel rail and shut off the fuel flow. The car fell on its face and started misfiring like crazy. Once you got over 5500 it was fine and would rev out as far as we wanted to rev it. At the time I didn't understand the problem and in the heat of battle I turned the only **** I had and increased the fuel pressure, which made it better but still bad. Eventually the drivers learned to drive around it trying to never let it fall under 5000 and revving out to 9000, right before it caught fire we ran some of the fastest laps of the day. The damage was done though, the backfiring and even higher exhaust temps from running way rich with the increased fuel pressure completely blew apart our muffler and when it went it took the muffler heat shield with it. That was on Saturday, we went into town and bought a new 3 inch muffler for Sunday but it also blew out. Running with the blown out muffler and no heat shield the fuel in the fuel cell boiled and ran out the vent tube where it eventually caught fire.
On my new setup with a S5 intake and 4 injectors I machined little distribution blocks with pulsation dampers on both fuel rails. I used dampers from a Hyundai that are 3/8 NPT.
Pulsation can certainly cause problems, it was the root cause when we set my car on fire last year. I had installed a new fuel system that had the regulator mounted back at the pump with a return direct to the fuel cell.
That meant that I only had a single -6 line running to the engine which was nice and simple.
The problem was that I had unintentionally set up the worst possible set of conditions for pulsation problems, a 3 inch long fuel rail with 2 injectors about an inch apart, it didn't help that the old SE ECU I am sure was firing the injectors at the same time. What happened is that at a certain RPM, in my case 5000, the injector firing frequency set up a resonance in the fuel rail and shut off the fuel flow. The car fell on its face and started misfiring like crazy. Once you got over 5500 it was fine and would rev out as far as we wanted to rev it. At the time I didn't understand the problem and in the heat of battle I turned the only **** I had and increased the fuel pressure, which made it better but still bad. Eventually the drivers learned to drive around it trying to never let it fall under 5000 and revving out to 9000, right before it caught fire we ran some of the fastest laps of the day. The damage was done though, the backfiring and even higher exhaust temps from running way rich with the increased fuel pressure completely blew apart our muffler and when it went it took the muffler heat shield with it. That was on Saturday, we went into town and bought a new 3 inch muffler for Sunday but it also blew out. Running with the blown out muffler and no heat shield the fuel in the fuel cell boiled and ran out the vent tube where it eventually caught fire.
On my new setup with a S5 intake and 4 injectors I machined little distribution blocks with pulsation dampers on both fuel rails. I used dampers from a Hyundai that are 3/8 NPT.
06-08-16, 02:58 PM
#4
Senior Member
Thread Starter
Thanks for the information you guys. You've given me a lot to think about. I'll definitely go back with the dampener as opposed to the eliminator bolt I'm using now. The other thing I was wondering was, when I removed my old dampener, the plastic cap seemed completely fine. No cracks or holes. Isn't that what usually causes them to fail? Could it have just been the washer the whole time?
06-09-16, 11:07 PM
#5
84SE-EGI helpy-helperton
Possible, the plastic cap is only there as a dust cover and to keep people from messing with the one and only screw which sets the pressure on the internal diaphragm. Dont mess with that screw, and you should be fine. Again, 2nd Gen pulsation dampners are well known for failing, while 1st Gen are not. I'm still running the original on my car after 32yrs and 223k miles...
06-10-16, 03:45 PM
#6
Senior Member
Thread Starter
Possible, the plastic cap is only there as a dust cover and to keep people from messing with the one and only screw which sets the pressure on the internal diaphragm. Dont mess with that screw, and you should be fine. Again, 2nd Gen pulsation dampners are well known for failing, while 1st Gen are not. I'm still running the original on my car after 32yrs and 223k miles...
06-30-16, 10:55 PM
#7
Senior Member
Thread Starter
You were right longduck, all it took was new crush washer for the pulsation dampener and new injector o-rings and problem solved. Thanks a lot for the advice guys!
Trending Topics
07-05-16, 12:23 PM
#9
I am having a similar issue with a leaky fuel rail. I believe fuel is coming out of the pulse regulator itself, but now I am wondering if I just need to replace the copper washer.
Do you know the symptoms of a failed pulse regulator? Would it leak around the screw?
Do you know the symptoms of a failed pulse regulator? Would it leak around the screw?
Possible, the plastic cap is only there as a dust cover and to keep people from messing with the one and only screw which sets the pressure on the internal diaphragm. Dont mess with that screw, and you should be fine. Again, 2nd Gen pulsation dampners are well known for failing, while 1st Gen are not. I'm still running the original on my car after 32yrs and 223k miles...
07-06-16, 01:33 AM
#10
84SE-EGI helpy-helperton
Start a new thread unless it's directly similar to this issue. You won't know unless you get your upper intake manifold off and pressurize the rail using the bypass jumper. Only then will you know where it's leaking from, as you can see everything sitting on top of the engine.
To answer your quick question - they don't tend to leak from the screw, as that part is sealed. They tend to leak where they attach to the rail, and that's why a new copper crush washer will fix it. Good luck,
To answer your quick question - they don't tend to leak from the screw, as that part is sealed. They tend to leak where they attach to the rail, and that's why a new copper crush washer will fix it. Good luck,
Thread
Thread Starter
Forum
Replies
Last Post