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-   -   odd problem, please assist (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/odd-problem-please-assist-415165/)

SidewaysFC 04-14-05 03:46 PM

odd problem, please assist
 
Ok, this has happened 3 or 4 times to me so far.

Car will stop starting, with all fuses looking good and the coil packs tested ok (.6 ohms trailing/.3-.4 ohms leading).

So, I go and check for spark by taking out L1 spark plug wire from the spark plug in the engine, and use the cheapest spare spark plug I could find in the plug wire while someone cranks the engine. All of a sudden it sparks, shocks the shit out me and starts up.

Problems I think might relate from readings other "No Spark" threads: sometimes after having trouble starting, then finally starting on its own, the tach will cut out until the next time I start the car up; hesitation, usually after car is hot or when volts get below 13.2 volts.

Since then, I have gotten a new battery and have run the car on a wideband and gotten 12.2-12.4 afrs on stock ecu at 10.5 psi and at night. Makes me think fuel is getting where it needs to go. Although I have never tested afrs while the car is having the hesitation problem. Also, car is flooding more often since the engine has been broken father in, about 10k miles. Walbro and (4) 620cc injectors with no piggybacks might be the cause. Timing is advanced to 15 degrees. Fuel cutoff switch went bad so I bypassed it, removed it and connected the wires directly to each other instead of adding another cutoff switch.

ANY ideas? I kow I threw out a lot of info.
-J

J-Rat 04-14-05 03:52 PM

Possible flaky CAS? It just happened to a friend of mine. HE couldnt get the car started for nothing. He removes the CAS, cleans everything up, re-stabs CAS, and now it works fine..

SidewaysFC 04-14-05 04:00 PM

what needs to be cleaned though, I popped the black cover off and everything looked new and squeeky clean.

J-Rat 04-14-05 04:02 PM

The connector where it feeds into the harness.

WAYNE88N/A 04-14-05 04:05 PM

The CAS circuit has two plugs- one at the CAS, and the other below the brake master cylinder. Check them both. One puts up with a lot of vibration, and the other gets fluid spilled on it every now and then.

To troubleshoot even further, read the CAS input pulses at the ECU (2 pairs, 4 different pins) while starting to make sure they're good.

With all of that fuel, though, you sure it's not just a flooding problem?

SidewaysFC 04-14-05 05:55 PM

wasn't flooding until recently, drove it w/o a flooding problem for quite some time.

how do i check the pulses? DMM? what setting?

will look into those connections though.

WAYNE88N/A 04-14-05 07:04 PM

Look up the pins in your FSM. The voltages will be tiny, less than 1v, so have a good calibrated meter. It is, after all, just a tiny version of a permanent magnet generator, which means that while it's spinning slowly (during start), the voltage will be small. But you should still be able to see it on a meter. A digital unit with a duty cycle function will show it, or a simple analog meter will show RMS-type voltage, which means a peak-to-peak voltage of about 1.5v from the sine waves recieved will show about .8 to 1v on the scale...

Make any sense???

SidewaysFC 04-14-05 10:11 PM

sure, i just installed the flux capacitor wrong ;)

"It is, after all, just a tiny version of a permanent magnet generator, which means that while it's spinning slowly (during start), the voltage will be small."
-(It) is what?

And I should be having readings of about .8v when stabbing the appropriate pins?

WAYNE88N/A 04-14-05 10:43 PM

"It" is the CAS. What else would was I talking about, lol?

Sure, .8 sounds good. Don't freak if you only get .4 or whatever, what you're looking for is anything above zero when cranking. If each of the 4 CAS inputs to the ECU has voltage during cranking, your CAS is most likely good...


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