Megasquirt Key fails to turn off car?! 0.o
06-19-15, 06:20 PM
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Key fails to turn off car?! 0.o
My board was missing the jumpers between the IAC outs and the JS0-JS4 pins.
I added those. Good news, my fan and tach now work!
Bad news: Removing the key with the engine running does not turn off the engine! It works normally if I unplug the megasquirt.
What did I screw up?
Tach is running off JS11 as the Zeal board is using JS10. I didn't change anything else...
I added those. Good news, my fan and tach now work!
Bad news: Removing the key with the engine running does not turn off the engine! It works normally if I unplug the megasquirt.
What did I screw up?
Tach is running off JS11 as the Zeal board is using JS10. I didn't change anything else...
07-31-15, 09:22 PM
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did you find your answer? i had an s5 alt in my s4 i had charning problems i swaped out the wires ont he alt plug and found the car would not stop running after that as it was back feeding past the ignition 
08-21-15, 03:15 PM
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Canned. I got CORNED!
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Totally forgot about this thread, hah! Issue has not been resolved.
I had coils, injectors, and megasquirt all fed from one relay. I tried swapping the megasquirt to it's own relay, this seemed to work for a few days, but then it started happening again.
Both of these relays pass through constant battery power, but are activated via switched 12v, per diagram here:
http://www.aaroncake.net/rx-7/megasq..._schematic.gif
Interestingly, I did have an S5 alt at the time this thread was posted, and it was wired wrong! I have since swapped to an S6 alternator, and wired it properly, but still having the same issue.
I had coils, injectors, and megasquirt all fed from one relay. I tried swapping the megasquirt to it's own relay, this seemed to work for a few days, but then it started happening again.
Both of these relays pass through constant battery power, but are activated via switched 12v, per diagram here:
http://www.aaroncake.net/rx-7/megasq..._schematic.gif
Interestingly, I did have an S5 alt at the time this thread was posted, and it was wired wrong! I have since swapped to an S6 alternator, and wired it properly, but still having the same issue.
08-23-15, 10:38 AM
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Engine, Not Motor
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There actually is an error on that schematic. The relay coils should go to switched 12V. Now I've never had an issue with over-running caused by the relay coil backfeeding the 'Squirt (the transistor won't really allow that) but it COULD happen. Easy to prove though. Just unplug the fan relay and see if the car stops running.
As for the S5 alternator issue, was the wiring on the car changed to match? Search the 2nd gen forum for alternator swap diagrams.
As for the S5 alternator issue, was the wiring on the car changed to match? Search the 2nd gen forum for alternator swap diagrams.
08-25-15, 09:36 PM
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Unplug the fan relay? Under the hood?
I believe I did the alternator wiring correctly. I found some time to pull it off the car tonight, will get it tested tomorrow and report back.
I believe I did the alternator wiring correctly. I found some time to pull it off the car tonight, will get it tested tomorrow and report back.
Stock alternator was never wired correctly, appears to have only had one wire running to it from the fuse box. I was getting 12v with the car off, 12.5v with the car idling, and 13.5v at cruise, with some weird spikes of 8v and 18v thrown in for good measure! I decided to start fresh with an S6 alternator swap.
Picked up an S6 alt and machined my S5 pulley to fit it. I added completely new wiring for the plug. L terminal runs back to the W/B wire on the FEM-01 connector inside the car, near the original ECU. The S wire runs to a 15 amp fuse, which gets it's power from the circuit breaker. B+ on the alt is fed from the stock underhood fusebox, which gets its power from the positive cable on the starter. (and from there, the circuit breaker).
After the swap, the car idled at 13.5V and ran at 14.7V at anything over 1500RPM. Not quite what I was expecting, but worlds better than before! I spent about 4 hours driving around and re-tuning the car without any weird voltage issues.
Upon returning home, I turned the key off and the car kept running, which has been happening every once in a while since I added the IAC jumpers to the bottom of the megasquirt board for some reason. (It stopped doing it for a few days after I seperated the megasquirt and coil/injector battery feeds into two seperate relays, but started again after the alternator swap!) Usually, I just reach over and hit the circuit breaker when this happens and it kills the car. Today, the car was still running with the circuit breaker and the key off.
Unsure of what to do, I turned the circuit breaker back on, which killed the car.
Now, I have 11.8V at all times with the engine running. No loose wires or blown fuses.
Picked up an S6 alt and machined my S5 pulley to fit it. I added completely new wiring for the plug. L terminal runs back to the W/B wire on the FEM-01 connector inside the car, near the original ECU. The S wire runs to a 15 amp fuse, which gets it's power from the circuit breaker. B+ on the alt is fed from the stock underhood fusebox, which gets its power from the positive cable on the starter. (and from there, the circuit breaker).
After the swap, the car idled at 13.5V and ran at 14.7V at anything over 1500RPM. Not quite what I was expecting, but worlds better than before! I spent about 4 hours driving around and re-tuning the car without any weird voltage issues.
Upon returning home, I turned the key off and the car kept running, which has been happening every once in a while since I added the IAC jumpers to the bottom of the megasquirt board for some reason. (It stopped doing it for a few days after I seperated the megasquirt and coil/injector battery feeds into two seperate relays, but started again after the alternator swap!) Usually, I just reach over and hit the circuit breaker when this happens and it kills the car. Today, the car was still running with the circuit breaker and the key off.
Unsure of what to do, I turned the circuit breaker back on, which killed the car.
Now, I have 11.8V at all times with the engine running. No loose wires or blown fuses.
Last edited by The Shaolin; 08-25-15 at 09:40 PM.
08-26-15, 05:20 PM
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Well, alternator is dead. Unsure if due to factory defect or my wiring.
The white/black wire runs to a dash light, right? Shouldn't I get a battery light with the ignition on and the engine off?
Should there be a diode on either of the wires on the alternator plug to prevent back-feeding?
The white/black wire runs to a dash light, right? Shouldn't I get a battery light with the ignition on and the engine off?
Should there be a diode on either of the wires on the alternator plug to prevent back-feeding?
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08-29-15, 10:23 AM
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Engine, Not Motor
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This thread contains wiring diagrams for the S4/S5/S6 alternators into an S4/S5 chassis:
https://www.rx7club.com/2nd-gen-arch...g-help-783859/
https://www.rx7club.com/2nd-gen-arch...g-help-783859/
08-31-15, 08:04 AM
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Canned. I got CORNED!
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Yes, I used that diagram to get it wired up. It doesn't mention a diode or answer any of my current questions.
What effect is unplugging the fan relay going to have?
What effect is unplugging the fan relay going to have?
08-31-15, 11:15 PM
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if its back feeding power to the ecu it can keep power on to the ecu and keep it running non stop. till you cut the power to it. like unplugging all relays one at a time till ur car stalls
09-01-15, 09:38 AM
#11
In the meantime, I am fortunate enough to be able to kill the car by pulling either one fuse or one of four different relays. I guess my pickiness about keeping circuits separate does pay off
09-10-15, 07:18 PM
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odd thing.... my squirt had some noise problems. moved my ground to the chassis, car ran like poop. moved it to the block at a different spot then the last. now the car wont start and i noticed the "ignition" stays on all the time. kill the power from the dead man switch and turn it back on and key is now off squirt is powered off as well. did an other test turned key on turned it off power to car is still on and same with squirt. pulled the ground wire off and all power drops off. if noticed this after i tried to re-flash my squirt and it froze on me. not sure if a realy is staying on and back feeding the fuse block. il try and update my flash to the new firmware and see what happens
