grady95

Hey Mazda Brothers,
I found a 1984 SE in a barn a few weeks ago and bought it to turn into an autocross and DE car. I am completely new to Mazda automobiles, so it would really be great if there were some experienced owners on this board who would be willing to offer some helpful suggestions to get the car running.
My first act was to pull the fuel tank out and try to boil it out. This was no good due to varnish and corrosion. A replacement is coming from a boneyard in California. The fuel pump tested dead as well, so it was removed and a new one was purchased today. I'm having trouble getting it to work though. I clamped in some fuel hose to the pump feed lines and stuck the ends into a 5 gallon gas tank in order to have a supply. I have the electrical wires replaced, and when the key is turned, there are 12 volts showing at the fuel pump connections. I have tried a fuel pump gauge clamped right to the fuel line leading to the tank which should show some negative pressure when the key is turned. I am getting no reading. Just going manual, there is no feeling of suction in the line to my finger either.
Haynes manual mentions that there is a relay which needs to be disconnected and jumped in order for there to be a pressure. Their diagram leaves me wondering just exactly where this relay is. I could jump it if I knew what to jump, but I'm unable to pinpoint with certainty where to work.
I gotta' get some fuel moving here soon. Suggestions welcome!!!

jarath

Under the hood on the right hand side near the air cleaner, there is a plug hanging there... believe it is white or black... not the green one as this is for the TPS sensor. You are to jumper the 2 leads together and this will turn the fuel pump on. The fuel pump is being controlled by the trailing ignition & ECU and unless you are starting the car it won't activate.

Rx-7Doctor

iTrader: (13)

You have to ground the pump in order for it to come on. You can't just run 12 volts to it.

In your original thread in the classified section Trochoid gave you the link to the FSM. That will show you how to jumper the fuel pump from the engine bay. When you get the vehicle back to gether you want it wired the way it came from the factory. You do not want the fuel pump to come on without having the motor crank.

jarath

I just verified the connector is white with a black rubber boot around it. Also... I wouldn't try starting the car without first pulling the plugs, running some marvel mystery oil, ATF, etc through it with manual cranks etc. The doc can better explain than I can but if you try to start it after a real long term storage chances are you're going to rip up the seals. I think Trochoid has a discussion on how to properly do this in the past also so might try searching.

grady95

Does it make sense for a minute or so to use the pump in the jumpered mode to basically just fill all the fuel lines, filter, etc with a supply of gas and then pull the jumper off and try to start it up? I will not leave the jumper in place at your suggestion. It seems this might just be a temporary way to prime the system. Right now, all the fuel lines are empty. Is this a reasonable idea?

grady95

Thanks,
One of the first things I did was just that. I pulled all four plugs, cleaned them, squirted a bit of mystery oil into each plug hole and then, with the plugs out, turned it just a bit by tap tapping the starter. It then sat for three days to allow this time to work into the system. I then tried starting it with starter fluid, but no luck. I am going to pull the plugs again today to see if they got fouled up by the presence of the mystery oil.
Thanks for your help!

Jeezus

iTrader: (4)

did you MMO each side of the rotors?

grady95

Yes. I believe so. I shot MMO into each of the four plug holes. Good thing or bad thing???

Anex 570

You should have got it running first, but keep an eye on the plugs now. MMO will stick around until its burned off, and is pretty fine.

jarath

I don't think, imho, MMO will cause you any real big issues, better to have plug issues rather than seal issues I run MMO a lot in smaller 2 stroke engines when they are going to be stored for awhile. You can start the car with the fuel pump plug jumpered, you will just hear the fuel pump running all the time and it is fairly noisey. I did this to resolve a problem where I had the trailing ignition coil and the leading reversed. What happens is, if the coil wires are reversed the signal from the trailing coil never tells the ECU to engage the injectors so it never will fire up. If you spray a lot of starting fluid into the vaccuum lines or down the intake it will turn over a few times but won't stay running.

grady95

Thanks,
I agree, plus are easier to deal with than rebuilding! My current set up with my cobbled together fuel supply is not working, so it will just have to be that the car will not get going until the replacement tank arrives. There is just too much big bore tubing needed here for the pump to work against. I have over 4 feet of big bore hose from the hard fuel line under the car to the gas can outside, This little pump appears not to have the horsepower to prime and maintain that pressure. It does however, move fuel very well on a benchtop test, so I am sure once the tank goes in, the odds are, she will get a good fuel pressure and start. I'll post again after the tank goes in later this week.
Happy New Year, and thanks again for the help.

jarath

Just a thought, you didn't try putting in a regular fuel pump from like an auto store right? You may or may not already know this but a carb fuel pump won't work for a fuel injection system as the pressure is WAY too low. Just something I thought you might want to look at.

grady95

The pump I put in is an Airtex. It was purchased from Parts Plus. They looked up the car and sold me this part. FYI, the new pump is smaller than the original. I had to kinda' crimp in the mounting bracket and add rubber to stabilize it. I don't know if "size matteers" but it is different.
May have made a mistake here, but we'll wait until the tank arrives. If no go, I will need access to the correct pump. Suggestions?

Rx-7Doctor

iTrader: (13)

^ That pump works just fine, I have run them before in Se's.

grady95

I have to think so. A bench test of this new pump went well. It was moving a good volume of fuel with a short line into a gas can as a feed. Looking forward to getting the proper tank in the car again. I believe that this will solve my "problem." I'll keep you informed.
This is a great board. Thanks to all for your help.