NineDeuce

Hi guys. New to the mazda/RX7/rotary world but am eager to learn!

I just picked up an '84 GSL-SE for pretty cheap, non running, was told it needed a fuel pump.


I'm fairly sure it's getting spark, as a spray of carb cleaner in the intake gets it to sputter/fire.

It's definitely not getting fuel because the plugs are bone dry.

When disconnecting the fuel feed line, 5 seconds of cranking puts out at least a few ounces of fuel. So it's working, perhaps not to full capacity, still need to check that.

So I moved onto the injectors.....except I couldn't find them anywhere lol. Are they buried somewhere under the intake?

I hooked up some fuel line and blew into the fuel rail, but it was completely plugged. Is this normal?

Any suggestions?

RotorMotorDriver

iTrader: (1)

The GSL-SE should be putting out 49.8 - 71.1 PSI when cranking, and flowing 1.8 quarts per minute. Id say you possibly need a fuel pump if you are only getting that small of an amount. At 1.8 quarts per minute, that should be almost 1 ounce per second.

Also, blowing into the fuel rail would most likely be "plugged" since the injectors only open for fractions of a second when they are actively "firing". Also, the return line would seem plugged because of the fuel pressure regulator on the fuel rail.

You should also never test EFI fuel pressure by running the pump with the hoses disconnected for risk of fuel spray. You need a proper EFI pressure test gauge to do it correctly and safely, not to mention getting the proper pressure readings.

~T.J.

EDIT: How long was it sitting without running? The injectors could be stuck, among other electrical issues which would prevent them from firing.

NineDeuce

Thanks for the response TJ

That does seem weak now that I think about it. I've got a walbro 255 on another car and that thing puts out serious pressure, but I wasn't sure what to expect with this one.

I'm thinking a fuel system flush is in order. The gas was really smelly and yellow.

I'm not sure how long the car was sitting...

RotorMotorDriver

iTrader: (1)

Does the gas gauge work? How much gas is in it?

There should be a drain plug on the bottom of the tank to drain it. I would start there, get some fresh fuel in it (enough that its not "empty" of course), a new fuel filter, and see what you get from there. If you are still seeing a fuel starvation issue, then I would be checking the power at the pump to make sure you are getting it and verify the relay is working. Then, move onto the pump if the power is good.

Once the pump is putting out proper pressure/flow if you STILL have a starting issue with no fuel, I would look into the injectors and verify they are firing. Im not 100% sure if a noid light set can easily be used - I will be honest and say its been a LONG time since I worked on an -SE. The other way would be a mechanics stethescope (or a screwdriver on the injector and your ear on the handle to hear if the injectors are firing - again, assuming you can snake down to them. If the injectors are in fact trying to fire but you still have dry plugs, then you need to pull them and have them cleaned and flow checked/matched.

If theyre NOT firing, you need to find someone else who has more experience with what other components affect the injector firing sequence

~T.J.

NineDeuce

It's got a little over 1/8 of a tank...

I'll try what you recommended and let you know how it goes! Thanks again.

NineDeuce

Small update...

I drained the remaining gas out of the tank, and didn't see a whole lot of rust which is good! However, the old gas was a red/yellow color and smelled like death. I don't think it's premix, just really old gas I guess...

Also, the fuel pump and filter *look* like they are pretty new (new hose clamps on lines, minimal dirt, new hardware, etc). I plan to double check wiring, and maybe run a flow test with the pump out of the car, wired directly to a batt (eliminate variables), and see if it does the same thing.

I put a couple gallons of fresh gas in it and tried priming the line (I pumped out all the old fuel), but it just kind of spits and sputters. I'm gonna put some more in just to make sure it's not sucking air from the tank.

First I want to double check all the filters. How do I get at the one that's IN the tank?

I appreciate the help RotorMotorDriver, I can't wait to hear this thing run! It's rusty as all hell, but the drivetrain/interior are in great shape. So we'll see how it goes

RX-7 Chris

iTrader: (19)

I would replace the filter before you go any further. The filter in the tank is actually just a screen. To instect it, you have to pull the tank. Mazda no longer sells a replacement screen.

When I got my car it had really bad gas in it. I drained the tank and thought all was good. Even though rust wasn't coming out when I drained it the filter was still clogging. I ended up having to have the tank dipped.

NineDeuce

Ya, I'm gonna try the filter first before I pull out the pump (maybe I'll be able to return the new one i got)

If the filter and pump don't work, then I'll probably end up dropping the tank. If the screen is really bad I'll probably just run without it (maybe add another small filter before the pump, but I think the main filter should be up to the job)

Just for your amusement, here's the gas I drained out:


And here's the rusty POS in question


There's literally a hole in the driver's side wheel well due to rust. I saw the GSL-SE badge and excitement overcame good judgement, lol. Oh well, the motor seems to be solid and I love beaters with strong engines!

-Gamah

iTrader: (1)

wait just a little longer before changing the filter... maybe you can get your fuel to match the color of your paint!

NineDeuce

lolz, it's already pretty close!!!

RotorMotorDriver

iTrader: (1)

Sounds like you are on the right track. If the pump and such look new, its logical to assume someone has been in there messing around, so I like the plan to test the pump out of the car. At the very least with test leads straight to it from a power source to see if it sounds/gets any healthier. Again, a pressure gauge would be the best way to troubleshoot this. Chasing fuel pressure issues via guess work is no fun. On the upside, getting the old gas out and fresh in is a good start.

As for the rust, all 1st gens are prone to rust out under the storage bins in the wheel well area. Search around for "wheel well rust" or "storage bin rust" and you will see plenty of pictures, and even repair work. Its a lot of work, but it can be repaired, which IMO, might be worth it to preserve an -SE that much longer.

Also, I see you have a targa band on the car, is that the factory Mazda targa band? It should say Mazda on the side if so I believe. There were aftermarket companies that made them as well. Nothing too amazingly special other than you dont see them all too often.

~T.J.

RX-7 Chris

iTrader: (19)

my car is running a 1/2" in/out carb filter between the tank and pump with no intank filter.

NineDeuce

so ignoring all my fuel tank/line issues, lets try to get this thing to start...

I've tried running the fuel pump directly to the rail pulling fresh fuel from a small gas can. This put ~40psi pressure in the rail which is right on spec with the FSM.

However, it's still not making its way into the combustion chamber. So either the injectors are clogged, or they're not firing.

How can I check that the injectors are firing properly? I tried going through the steps in the FSM, but couldn't find some of the connectors they were mentioning.

I checked the fusible link for the ECU and injectors. when i unplug and replug in the injector wire, I can hear a clicking from the general area of the injectors. Does this necessarily mean that they are receiving the correct signal from the ECU? I don't hear any clicking when I do the ECU wire.

I'm just trying to make sure there's not anything I've overlooked before I pull off the entire "dynamic chamber" and pull the injectors. I'm assuming they're going to need a good clean anyways.

Any thoughts?

NineDeuce

upon further research, it seems I've got the classic "no trailing spark/injector power" issue.

Leading plugs are the only ones firing, although both coils have power. SO this could mean bad coil or wiring, right?

where does the small spade connector go? I tried swapping coils (swapped spade connector and high tension lead, left the +12v), and that didn't work.

I need some sleep...

EDIT: Nvm, I rechecked with my timing light and I am getting spark from the trailing coil. Although it seems intermittent...might try new plug wires all around. Could poor connections on the plug wires cause an injector problem?

The FSM says there is an injector wire that should have continuity with the spade connector on the trailing coil. How can I check this? Is there an injector subharness plug somewhere?

Thanks for being patient

959595rotor

I may have a solution,take a look at the black Igniters you have bolted(Screwed) on your Dist try crossing(exchanging ) the plug in clips from one to the other,to see if the lead plugs fire and the trailing plus do not,if the spark has moved, just remove the bad igniter replace it and reverse the connecters to their original location

74RX4

iTrader: (10)

2 wires should be connected to the negative terminal of the trailing (front) coil. One is Yellow/green the other is a gray shielded wire. Yellow/green goes to trailing ignitor and the Tach. The gray wire transmits the ignition pulse to the ECU so it can determine when to fire the injectors.

NineDeuce

Ok, I see that both wires are present @ the spade connector.

But the tach isn't moving when I crank it over. I'm about to check continuity to the ECU.

NineDeuce

it's got continuity from the spade on trailing coil to ecu pin U. Checked the voltages of injector #20, main relay, and ignition coil (T), they all were 12v.

so those all seem to check out, but my tach still isn't working, and the injectors aren't spraying

but when i plug in the injector fusible link i can hear them both clicking. does this mean that the ecu isn't sending the proper control signal to the injectors? how is this related to the tach?

i tried switching the ignitors but it didn't change anything

74RX4

iTrader: (10)

Have you found this manual?
http://www.jimrothe.com/mazda/84_tra...ual/index.html
Section 4B describes how the injectors are fired.

Can't think of anything one thing that would make the tach not work and injectors not fire except a bad trailing ignitor. Since you switched ignitors with no change I would suspect two separate problems.

Just in case. Make sure the fuel lines are connected correctly. The main fuel line should be connected to the metal pipe that connects to a rubber line that connects to the Pulsation Damper on the front of the fuel rail. The slightly smaller return line connects to the metal pipe that connects to a rubber line that connects to the Pressure regulator on the rear of the fuel rail. From the factory the metal pipe closest to the firewall is the return, but over the years the pipes get bent into different positions.

959595rotor

If there is still no spark from the trailing coil,,and you tested both coils and both coils are hot when your Ignition is on,and the trailing one does not fire, check the wiring from the dist back to the coils and check and clean all clip and pin connectors,including deep down inside the coils, or you may have a broken wire in that harness (coils to dist ),if after checking the harness the coil wire is still not working you may have a broken wire in the trailing Igniter pick up wiring which is under the rotor in the Dist if the coil wire(high tension) to the cap is working but does not fire the plug you might have a bad Cap,(cracked,or carbon arcing deposits,and or a (dirty )Rotor,if you can clean those as well. also try installing new plugs too it certainly can't hurt..If all else fails pull start the car and let it run for a few minutes (15 to 20) and try some High tension coil pulls on the cap and coils to see if the are working at idle then recheck every thing again, the bug is in there..........somewhere and I'm thinking electrical good luck..**

NineDeuce

Thanks for all the great suggestions guys. It's a big help

Fuel lines are routed correctly, and I DO have spark (although I noticed that trailing/leading flash at different rates). From looking at the dist cap it seems that this is normal though, right?

I pulled off the dynamic chamber to take a look at the injectors. They were dirty as hell. I hooked them up to 12V to check operation, and one of them made a much weaker clicking sound than the other.

So I'm hoping that everything is wired and working correctly, but the injectors were so gummed up with the old fuel that they were sticking. I should have the new injectors in a few days, I'll keep you posted.

Btw, anyone have any experience with the GB Remanufactured injectors from RockAuto? They're like $28 each after the core charge!! All the local auto parts stores want ~$150 each. Just want to make sure they're not crap

74RX4

iTrader: (10)

Rock Auto is usually pretty good. Most people just have the injectors cleaned. http://www.witchhunter.com/ is a popular, reputable choice. Around $50 a pair with shipping. Takes about a week. I would get new o-rings and grommets for the top and bottom of each injector. Mazdatrix has them.

INJ UPPER GROMMET 84-92 ALL 13-2520-8574 $2.64
INJ LOWER GROMMET 84-88 ALL 13-2570-N326 $2.00
INJ O-RING 84-92, RX8 ALL 13-2530-8574 $2.64

NineDeuce

So it turns out that RockAuto doesn't actually have them in stock (although GB reman will still do a "rebuild" service similar to witchhunter)

I think I will go with witchhunter based off of all the satisfied customers in the 7 world. Do I need to buy the o-rings? It seems like witchhunter replaces them as part of the service. I'll double check.

74RX4

iTrader: (10)

I think you"re right. New o-rings may come with the cleaning. I've had problems with both upper and lower grommets on different cars. If yours are not cracked or crushed you might be able to reuse them, but new ones are cheap.

Hec's 79 gs

I had the same problem with se model good fuel pressure at the pump and no start, checked the fpr and bingo! You may want to change it since the intake is already off.