Help me diagnose a 323 GTX, Kind sirs

I'm not sure why my brain won't connect with this one.

It will fire up, start immediately, then cut off like it's got no fuel. Every time, same results.

It's acting like the MAF sensor is disconnected, but it is not. Coil is well grounded.

It sat for a long time, and was shelved in mid-project status, so it is possible something was disconnected that didn't get reconnected, but I've gone over it pretty thoroughly. Trans was out, exhaust, clutch, shifter cables, center console, front struts and suspension and air intake systems were all out of the car. Anything in the vicinity of those systems could have been disrupted, but I have checked pretty carefully, and I'm not seeing anything disconnected. Fuel system was not messed with, and it's got fresh fuel in the tank.

I've got spark, fuel (at least initially), and it's throwing a code, but I don't have a tester.

Thoughts?

Are there cheater methods to read the codes?

I don't have a manual on this one, and my brain is tired.

I'm not too familiar with the 323 GTX, but it sounds like the injectors aren't pulsing. I'd start out by spraying a little starting fluid in it to verify that it is in fact a fuel issue. Then I'd put a noid light on the injectors to see if they are pulsing. I'm guessing that there's a crank sensor that's unplugged or something, causing the computer to think the engine's not turning, and in turn not sending power to the injectors.

doesnt that 323 share a lot with the Proteges and Probes of similar vintage? What do they have over on their forums? I found a ghetto way to read codes from my cars forum that involved just turning a screw on the outside of the ECU and reading check engine light flashes and matching it up with a chart. Im sure theres something similar with you ECU, just gotta find out what.

EDIT:

Dunno if you are a brave soul, or even if this works with the 323, but this is a little morsel I gleaned from the Mazda Forums:

Mazda Forumi said: Ok the paper clip trick is when you bridge out a pin in the 17 pin dlc plug under the hood Once the "paper clip"/jumper is connected, the check engine light should flash in a certain sequence, like Morse code. You may need an authorized Mazda dealer to read it for you... but a web search (Google, Yahoo, Bing) might be helpful too

EDIT The SEQUEL More EDITING!

BOOYAH!
http://codes.rennacs.com/plugins/MazdaEFI/MAZDA-EFI-10-1-Mazda.php

I know the GTX uses the same air flow meter as a 1.6 Miata (or a very close relative), and if this call had come in for a Miata I'd ask: did you try to disconnect the wiring from the AFM by undoing the two screws on each side of the wires? It won't come off that way, but it will allow you to break one of the wires inside. It's usually the wire that sends the "keep alive" signal to the fuel pump so it keeps running once the car has started.

If it were a Miata, I'd tell you to put a jumper between FP and ground in the diagnostic box underhood. This bypasses the keep alive signal and runs the fuel pump constantly. If the problem is solved, we have a diagnosis. Figure out how to hotwire that pump and give it a try.

I used to have a GTX manual, so not any more. All I can do is pretend it's another Mazda of the same vintage.

Pumpkin Escobar wrote: doesnt that 323 share a lot with the Proteges and Probes of similar vintage? What do they have over on their forums? I found a ghetto way to read codes from my cars forum that involved just turning a screw on the outside of the ECU and reading check engine light flashes and matching it up with a chart. Im sure theres something similar with you ECU, just gotta find out what. EDIT: Dunno if you are a brave soul, or even if this works with the 323, but this is a little morsel I gleaned from the Mazda Forums:

Mazda Forumi said: Ok the paper clip trick is when you bridge out a pin in the 17 pin dlc plug under the hood Once the "paper clip"/jumper is connected, the check engine light should flash in a certain sequence, like Morse code. You may need an authorized Mazda dealer to read it for you... but a web search (Google, Yahoo, Bing) might be helpful too

EDIT *The SEQUEL* More EDITING! BOOYAH! http://codes.rennacs.com/plugins/MazdaEFI/MAZDA-EFI-10-1-Mazda.php

this is the same process to check for codes on my all trac. paper clip does the charm!

The VAFs on these things are getting old, and they do fail.

Once again proving himself to be the Sultan of Heroism and Abject Zoom in All Affairs Mazda, (AKA: SHAZAAM) Keith gets the win on this one.

While I did not try to remove the AFM by removing the 2 screws, it had been messed with. Jumper to the fuel pump got it running.

Now, I've just got to find the break in the wire/ sensor/ connector.

Thanks guys!

Anybody got an AFM they want to part with??

Sounds like the perfect excuse to 'Squirt the thing and get rid of the VAM.

That was actually my original intent, but right now I'm not trying to make a project. I'm trying to make it saleable- time to move on.

If I remember correctly, you can get to those wires if you remove the black D-shaped cover on top of the AFM. Or a new AFM. I'm not sure if the Miata ones are a direct replacement, but I think they are. Hmm, there might be one buried in my garage, I'll try to look this weekend.

Keith wrote: If I remember correctly, you can get to those wires if you remove the black D-shaped cover on top of the AFM. Or a new AFM. I'm not sure if the Miata ones are a direct replacement, but I think they are. Hmm, there might be one buried in my garage, I'll try to look this weekend.

Yeah, I went and poked around my garage/yard for a Miata one with no luck. Paul, if a first or second gen RX7 one does you any good I probably have those.

SV, is this the white one you bought at the 07 Challenge?

Yes.

Well, it's not the AFM. Pulled the "D" cover, and no damage. Just to make sure, I put the AFM from my Miata in it, and it acted the same way. FWIW, the Miata AFM fits, though the airbox and filter are smaller and the output is a smaller diameter.

Guess I'm gonna start tracing wires. I gotta figure why the FP isn't getting the signal from the AFM.

Anybody have a wiring diagram for one of these?

Anybody know how to reset the computer codes?

Here's a diagram for a '88. I'm not sure what year yours is but if can't be that different.

http://www.spitfireefi.com/files/88mazdagtxschematics.pdf

Page 18 of 67 appears to be the GTX schematic (4wd w/ turbo)

SVreX wrote: That was actually my original intent, but right now I'm not trying to make a project. I'm trying to make it saleable- time to move on.

For how much? Did you find the broken connection?

Paul, the wires on my $2010 GTX were super brittle...we had the damnedest time figuring out why the water temp gauge wouldn't work. Visual inspection was deceptive, though; a slight tug on the wire off the engine block and it crumbled immediately. So don't just look, roll them between your fingers.

Also, my $2010 GTX did the same thing when we swapped the engine, but in our case, an intercooler hose was blocked. You've probably checked that, but just in case...

No, it's definitely the fuel pump signal.

When I put a hot jumper to the FP, it runs just fine.

Pumpkin Escobar wrote: For how much? Did you find the broken connection?

That depends on how much I put into it. Are you making an offer?

iirc, those afms in the mx6's could get a dead spot and send a no-flow signal that would cut the fuel pump at idle, since they spend a good bit of time in that part of the sweep, if you have someone hold the flapper open a bit farther, and it stays running, thats the problem.

also seconded on the worn out wires comment, they can get old and crumbly and break the conductor without breaking the insulation. especially with the kind of heat seen in turbo engine compartments

not yet...but tax returns are just around the corner.

Strizzo wrote: iirc, those afms in the mx6's could get a dead spot and send a no-flow signal that would cut the fuel pump at idle, since they spend a good bit of time in that part of the sweep, if you have someone hold the flapper open a bit farther, and it stays running, thats the problem. also seconded on the worn out wires comment, they can get old and crumbly and break the conductor without breaking the insulation. especially with the kind of heat seen in turbo engine compartments

It's not just idle. Won't stay running if I pump the pedal either.

Pumpkin Escobar wrote: not yet...but tax returns are just around the corner.

You know where to spend it.

I've got an electronic copy of the GTX manual if you want me to toss it your way. Can also ship you the AFM off one of my GTXes if you want to try it.

Don't think it's the AFM.

The manual would help, however.