hpmotors

Hello All,

I have a 1985 GSL 12A with a fuel problem. No power to the fuel pump, but the pump does run if I put 12V to it.

Schematic I have shows a "Fuel Pump Cut Relay" which powers the pump - but it does NOT show me where this stupid thing is. I've looked under the hood & dash but can't find a relay with the right color wires (2-BW, 1-LW & 1-BY).

Anyone know off hand where this thing is or maybe someone has access to a better manual that gives locations of electrical gizmos? Sure would be great to get a shout out!

What I am in the midst of is trying to rejuvenate this old car that only has 61,000 miles on it but which has been parked for over 12 years! and yes, we do have compression

cheers

Henry

Dread Nought Racing
Pelzer, SC

mazdaverx713b

iTrader: (91)

Henry, you may also want to test your trailing ignition, and more specifically your trailing ignitor. if it has failed, you will get no power to the relay for the pump to activate. do you have a factory service manual?

hpmotors

Good Question!

I do have spark on the trailing plug - engine cranks & runs if you squirt gas down the carb - it just doesn't keep running. Just to make sure, I just tested it with my trusty spark plug tester thingie (don't even know what its called but it is an inline light that goes off every time the coil fires) and it was sparking away.

No on the factory service manual. I do believe they show the location of components - at least my OEM- MX5 Miata books show component locations so I presume the RX7 ones would also.

Thanks for the thought!

Henry

gsl-se addict

iTrader: (3)

This should help:

https://www.rx7club.com/showthread.p...***+fuel+relay

The FSM can be found here:
http://foxed.ca/foxed/index.php?page=rx7manual

See if you can bypass the relay. As Dave mentioned, usually it is due to lack of spark on trailing (ECU uses that signal to tell if the car is running and activates the fuel pump relay if it is running). Could be a disconnected tach wire at the coil (does the tach work?). Or could be a bad or disconnected relay.

Good luck.

Kent

hpmotors

Kent,
Fandamtastic! Great Link. Found the sucker! Under the dash just on the right side of the steering column. Now it would be a lot nicer if they had put the thing under the hood - but at least I can get my hands on it!

According to the schematic the ecu must ground out the circuit, otherwise it simply be powered on whenever the key was on. Haven't gotten it out yet, but your post was the exact information I was looking for.

I didn't mention that while I can get the pump to run, it is bad as it has zero pressure when tested. A new unit is coming from Mazda and is supposed to be delivered tomorrow - at least now I can get power to the thing! Next step is to see whether or not that silly carb needs to be rebuilt or not and to install a new clutch master cylinder. A lot of stuff can go bad in 12 years ! Thanks Again!

Henry

gsl-se addict

iTrader: (3)

Henry,

No problem. When you powered the pump, did it sound like it was trying to pump or did it make a hum like it was locked up? I helped a guy do an S5 swap into his GSL-SE (sitting for 7+ years) and that gas was nasty. Was sticky, stinky, and was the color of Pepsi. Needed to clean/seal tank, clean pickup tube, replace soft lines, replace pump, clean injectors, etc. Bad gas sure makes a mess of things.

I was asking about the pump because the pump may be good..the pickup or somewhere else in lines may just be completely clogged (pump trying to pump, but can't).

I would try to blow some compressed air through them to make sure they are clear. It would also be a good idea to replace the soft lines if you haven't yet. Especially the ones to/from the tank. Those seem to never get replaced. The ones near the fuel pump or in the engine bay will sometime get replaced with a new fuel pump or a new/rebuilt engine, but the ones at that tank are often ignored.

Good luck.

Kent

hpmotors

Kent,

Pretty sure the pump is bad. I already changed out the gas tank - other one was extremely rusty - with new filter and good used fuel pickup and level indicator. Cleaned out the supply and return lines with air and put in 5 gallons of fresh gas.

I have the pump hanging down under the car so I can clearly hear the thing when it comes on - makes a nice running sound. When powered up and fuel line outlet disconnected it pumps a pretty good flow into a can but as I said, when I put a gauge on it and close off the return line the pressure is zip. There is the barest perceptible twinge of the needle when the return is closed, and I mean barely. The increments on the gauge are 1 pound and it doesn't budge over a half psi and then goes back to zero.

Obviously the hope is that when all is said and done the motor will prove itself. Other than paint on the horizontal surfaces, this is an extremely clean 85 GSL - been in Georgia all its life (until now) and has NO rust Some of the interior plastic bits are sun dead - that ol southern sun is hard on car interiors but even there most of it is nice. Heck, even that silly joy stick for the stereo balance works!

On the fuel pump, found out that a stock Mazda OEM part was cheaper than aftermarket replacement but a bit more than a generic unit. But that generic thing would require plumbing and wiring changes.

I really hope I don't have to rebuild that carb though - I really do not like working on the stock 4 bbl with all of those solenoids etc.

I'll let you guys know when we get her running! After this, I've got to put the tranny back in my T2! Then I've got to get my Blakely Bantam back together! Too much fun.

Henry