locklej

I read all the other threads and have tried everything. 85 SE floods at the first short attempt to start. It floods the plugs and gas runs out of the bottom plug holes. I tested both injectors, fuel pump, gas filter, and ignition.

I understand the ECU controls the flow of gas. Where is the ECU located on a 85 gsl-se and what am I missing in my testing? Thanks

mazdaverx713b

iTrader: (91)

the ecu is located under the carpet, under a metal panel on the passenger side. you will need to remove the speaker cover, and the door sill plate. you can then pull the carpet back to reveal the metal panel. i believe four 10mm nuts hold this on. under there you will gain access to the ecu. have you checked the fuel pressure regualtor? is compression good?

gump

I've never messed with the ECU, but I have had a few tough times with flooding. How many times have you done the long unflooding procedure? I thought for sure there was something else wrong with my SE but I just had to do the long unflooding procedure numerous times, with two different set of plugs, and jumper cables on the battery from another running car to keep it charged (most important). Good luck. You'll get it eventually.

web777

This happen to me before and it was the fuel regulator.

locklej

I attemted the flooding procedure two times. The procudure that I used with to remove all the plugs, spin the motor 20 seconds with coil wires removed, add atf to the bottom plug holes, and reinstall the plugs, wires, and start. It idled for 15 seconds each time and shut off.

Thanks for the location of the ecu. I'll check it out and if someone has a better way of unflooding a SE let me know. I also, have 85 with a 12a, so I'm comparing the compression to a 12a and it sound and feels the same. I'm planning to buy a pressure gauge tomorrow.

jimmdog

when I put the new engine in my SE I had to pinch off the fuel inlet line crank the engine with a remote starter button for ever once it began to barely run I slowly released the needlenose vice grips then held it about 3/4 throttle thats my crazy *** method try it if you want Ive also done the same thing on 2 Gens. Good Luck

hotty

I also had that problem after a lot of driving.. etc etc.. Instead.. I ran a new wire to the fuel pump and installed a toggle switch to the left of the steering wheel near the interior dimmer switch. Now, i crank the engine over and it fires, then i flip on the fuel pump. You just have to remember, when you shut the car off, turn the pump off as well.. it also doubles as a anti-car theft device, because without knowing about it, you can start my car for ~3 seconds then your SOL.
hope that helps bud.

locklej

I'm starting to think that maybe the pressure regulator is not working properly. The fuel system seems to be flooding all four plug hole. I mean when I turn over the motor with the plugs removed I get a fog of gas from each hole and it never stops.

I'm reading that the pump should not pump until the igniton is engaged, but on this car it pumps when I turn it to on, it pump full blast. I removed and check the Air Flow Meter (AFM) and it checked out OK based on the Hayes manual, so I'm thinking I should purchase a pressure gauge and test the gas return pressure.

LongDuck

It is correct that SE's will only pump fuel when the ignition is on and the engine is either cranking (to start) or already running. This is to prevent high pressure fuel from pumping in such a way as to contribute to a flooding situation due to 'leak down' of the injectors between when you insert the key and when the engine actually starts - or when turning the engine off, but continuing to listen to the radio or whatever, which in a carb'd car can leave the fuel pump running.

The issue with SE's is that they are pushing fuel at up to 50-60 psi when the fuel pump is running, and you need to have that volume going somewhere (ideally, into the running engine) so as not to overpressurize the fuel system. Mazda designed this by allowing for a means to test injector seals, but only allowing the fuel pump to run when the engine is cranking or running.

The fuel pump shunt is a 2-lead plastic plug located by the AFM and the idle mix adjuster, which, when shunted by routing a wire from one lead to the other, it allows the fuel pump to run with the ignition switched on (but not cranking). This is so that you can test the fuel system for pressure without the engine running, i.e., so that you can hear the fuel being pumped past the injectors and so that you can leak test the installation before you reinstall the upper intake manifold.

If you can hear the fuel pumping when you insert the key and before you are cranking, you might want to check the shunt connector to be sure that someone didn't shunt this over for test and forget to remove the wire. Simple fix, if that's the problem. Otherwise, you may have a short in your electrical system that's running the fuel pump on ignition and not limited to starting/running.

locklej

Ok, I removed the jumper from the shunt connector and resolved the fuel pump running before actual starting. I checked the fuel pressure on the inlet and outlet when attempting to start and both are 65 PSI. The Hayes manual states at idle I should have 36.97psi. I also checked the air flow meter and it is operating properly based the Hayes manual requirements.

Should the pressure regulator reduce the pressure going to the return? If the ECU controls the voltage going to the fuel pump and the pressure, what is telling the ECU to supply all this gas pressure?

jimmdog

The fuel pressure is controled by the reg. to roughly 35 lbs. the excess fuel goes back to the tank on the return line. See if you can regulate the pressure maually with a pair of pliers on the presssure hose and try to keep it running. Be careful if you have loose hose clamps the hose might blow off. If this works more than likely the reg. is bad

locklej

If I clamp off the supply gas line it does attempt to start.
I'll give it a shot. Thanks

locklej

I understand why it would attempt to start now. I installed my pressure gauge in line with the supply and clamped down on the hose and it is impossible to control the pressure between 25 and 40 psi. It shoots to 65 psi within seconds of hitting the ignition.