HAILERS

Series four 86-88 fsm. On line free.

bryant

well heres the deal. one day the car just started clicking when you hit the key like sio was going bad or something so put new starter. stopped for 5 trys then same thing. then about a year or so later it started draining the battery so i took an aftermarket alarm off cause i thought it may be the prob. was not so then took alt. off got tested was no good so got one and a new battery. still after night go to crank and the battry is dead. then got k&n air filter racingbeat road race header,racing beat alt&main underdrive pulleys went to install main pulley and the key fell out so had to remove radiator,fan and fan shrowed oilpan, front cover&cas. reinstalled everything and thats when it started acting funny. connect the battery and all the int. lights come on and wont go off. and this is without the key in the ign. when you put the key in and turn to on a buzzer comes on and wont go off.so got another ecu cpu put in my car and still same thing. and thats were we are now.pulled every relay i could find and tested but all were fine.but it would crank before just wouldnt stay charged.now wont crank

bryant

also when it was clicking i replaced the ign. switch to so it should not be the probiem.

bryant

ok 1f is 0, 3i is .4, 3j is .4, 2a is 12 volts 2c is 12 volts 2r is 12 volts 3a is 12 volts 3c is .3, 3g is 12 volts so i got the main relay tested again and it is good so tested to see if there was power at the relay and got about 0.1 volts so what next? trace that wire?

HAILERS

ouch. You just gotta be reading the plugs wrong. See the picture I attached showing the plugs? That view is looking into the side of the harness plugs from the WIRE side, not the side that connects to the ECU. I'm sure that's what has happened. Try again.
https://www.rx7club.com/forum/attach...postid=1291996

HAILERS

I can look at your readings and invert the plug, and it bothers me that if 2R is really 2B, that ain't good. Because 2B should have a output voltage of , what 3-4 volts, not 12 volts.

So that's why I hope you get a chance to check the figures again.

Those plugs are read from top row, far right, *A* and just below it *B* and then top row second one over *C* and just below that one *D*, and on and on and on and on and on. That's looking at the wire side of the plug.

If 2B has 12v instead of 3-4 volts........I'd suspect the ECU is gone bye. bye and another should not be put in its place until you find out why the boost/pressure sensor has 12v on it at its output.

Then again, maybe I'm in one of my panic moods.

HAILERS

Have you done any maintainence on the boost/pressure sensor lately????? You might try disconnceting the Boost/pressure sensor plug and seeing if you have any spark. All other plugs connected up when you do that.


I have a theory about what happens if someone accidently gets the wires crossed at the boost/pressure sensor or puts a series five FCD on a series four and vice versa. I think it destroys whatever component drives the reference voltage out of the ECU at pin 2A, and at the same time destroys the device that drives the signal to the Lead and Trail coil assy's.

I have a popped ECU I bought sometime ago, and it will not start a car. All the inputs are good, but the reference voltage out of it, is KAPUT. The fellow I bought it from had a incident with his boost/pressre sensor and a FCD.

bryant

WILL TRY AGAIN

bryant

1f 0, 3i 12, 3j 12, 2a 11.5, 2c 11.5, 2r .3 , 3a .3, 3c 12,3g .3 hey do you know why the grounds are showing .3 and .4 volts? this should be right

RETed

With your DMM, touch the two probes.&nbsp Does it show .3 or .4 volts?&nbsp Then your grounds are fine...


-Ted

bryant

it shows 0

HAILERS

Sorry, I forgot to attach all the ECU print outs.

I think the ECU is whacked. See how you should have 4.5 to 5.5 volts at pin 2A???? You say you have 11.5 volts. Was that with the plug on the ECU and the key to ON (Not start, please)?? If it was, then I think the ECU is a gonner.

1F was supposed to have 12volts. I'm not too worried about that one.

Read the grounds with the key to off. And put the meter on ohms when you do that. Not a concern.

2C has 11.5 volts on it?????? Supposed to be a ground. Huh! I am pretty sure you did these checks with the connectors off the ECU. The connectors have to be on the ECU. The 11.5 volts on the pin 2C is just reading the voltage back thru a bunch of coils/solenoids.

So just do the readings again, except leave the connectors on the ECU. You can unbolt the ECU to make it easier to access the back of the plugs.

Your getting there.

bryant

ok

bryant

been raining for 2 nights so when i can ill check prob. tonight.

bryant

3I 12
3g 12
3e 12
3c 12
3a 0
3j 12
3h 12
3f 12
3d 0
3b 0
2q 12
2o 12
2m 12
2k 0
2l 2.5
2g .1
2e .1
2c .2
2a .4
2r 0
2p 12
2n 12
2l 4.2
2j 2.5
2h 0
2f 0
2d 0
2b 0
1w .8
1u 0
1s 0
1q .7
1o.5
1m .9
1k.9
1i 0
1g 0
1e 12
1c 12
1a 0
1x 0
1v 0
1t .7
1r 10.2
1p .7
1n .7
1l 0
1j 5.4
1h 12
1f 0
1d .2
1b 0

bryant

1u has 0 should have4.4 with key to on.2p has 12 should have under2.0?3d has 0?3g has 12volts should be ground??? all checked with key on and ecu pluged up. oh ya i had the ecu and cpu unpluged when the lights are on on the idot panel with no key in the ignition. when turn key to on after 2 seconds starts buzzing and dont stop till you turn off. so i think there is more than ecu and cac wrong.

bryant

hey whats a digital code checker

hugues

the digital code checker is probably a big black box mazda techs use to help in diagnosing. I'd like to see one of those.

W/r to your ecu pin readouts,
just check if the inputs to the ECU are correct

If the inputs are correct but the outputs are incorrect, then the ECU is bad.

If the inputs are incorrect, then go deeper into the troubleshooting of the systems involved before doing anything else.

Not much help here but it's still a bump.

Hugues -

bryant

was the leading coil.
thanks
bryant

bryant

it was leading coil plus cas.
thanks
bryant