Apexi PFC Intermediate Weak or No Spark
 

http://www.rx7club.com/power-fc-foru...spark-1034773/


Quote:
Originally Posted by rx72relax View Post
I am trying to finish up a car that is killing me. I have gone through and tested everything on this car. Start By telling what im working on and PRAY someone out there can point me in the right direction
CAR, 93 rx7
ENG 13b RE
TURBO, Howard coleman Twin Garrett setup
Harness, Rywire single turbo simple setup
ECU, Apexi Power FC with commander, Datta logger
Safe mods, FPR gauge, Wideban, & boost

So I Have No spark with power FC when cranking, Crank angle sensors NE + G are in the right spot, Harness cont good from sensor to ECU, Sensors tested Good, (OHM test) Have power to the coils, OHMs on high tension leads good, Coils test good (even swaped with known good set) Igniter Good (also swaped with known good) Tested Ignition switch, Did wire / pinout on harness to ECU all good, Took ECU cover off nothing burned, Swapped with different PFC same problem, Now if I put in a stock ECU, I have to run direct power to fuel pump but fires right up..
SOMEONE HELP ME KILL THE DEMON iM not on forum often but will be for a minute Please help or email answer direct or PM


Quote:
Originally Posted by misterstyx69 View Post
I think I know..I "heard of this".
So I will give you my take on it.
Your Power to the Ecu is being taken off a spot that will give you 12 volts with KEY ON.
BUT when you turn the Key to START,it takes that power and shuts it down to allow the starter to get juice.
Just like when you go to start your car you can't hear the stereo for a second.
Try an Alternative 12 volt switched wire,that gets power at START too.
If you would like to "test this theory",then just put 12 volts to the power side of the ECU( Instead of switched) and attempt a start up.
Strictly a guess here,but it does sound like that is what is happening..right?


Quote:
Originally Posted by rx72relax View Post
Checking that again now, I checked at harness but I am going to direct route. Thanks.


Quote:
Originally Posted by misterstyx69 View Post
I am curious so post up either way.


Quote:
Originally Posted by D4rw1n View Post
that did not work (it's my car)
Sometimes it will fire with the PFC and then 2 min later we try to start it and have no spark or very weak spark. We have tried swapping to another PFC, no change.
Any other options we could try? rx72relax and I could really use the help.


Quote:
Originally Posted by Gilgamesh View Post
when my PFC showed no crank angle i had the wires backwards, as i had broken connector i tried 4 different configurations before the PFC showed the timing at all.
with the PFC in. jump the starter by taking the ole screwdriver trick. i have aligator clips on a wire that i touch from the positve lead of the starter to the skinny black solenoid switch.
this should be straigt power tothe starter, it shouldn't cut any power to anything.


Quote:
Originally Posted by D4rw1n View Post
The starter works, it just has intermediate spark.


Quote:
Originally Posted by misterstyx69 View Post
post another thread in the PFC section..It would be faster honestly to do that.
New Section is like a Basic section..You need Pro help,which won't come to you fast enough up here,unless someone stumbles upon it!
Good luck to ya..I tried!
As suggested by misterstyx69 I've moved this thread here. Hope you guys can help.



Anyone have any suggestions of things to try?

has the car ever run before you had this problem?

how do you know it has "weak spark"? Are you checking it with a timing light? some timing lights will not pick up the spark signal very well, even though spark works perfectly well

- I'm confused why you would have to jump the fuel pump with the stock ECU and not a PFC.
- What do the plugs looks like and what plugs are you using? The stock-type surface gap plugs will fuel foul very easily and when they do will not spark.
- As suggested above, are you sure you have no spark? Pull a leading wire off the plug, insert a spare plug in the wire and ground the threads to the fender or intake. Have someone crank the engine while you watch for spark.
- Do you see an RPM signal when cranking the engine in the Commander or Datalogit?
- Do you have 12V+ with the key on at the black/white wire at the ignitor? Do you have continuity between the three signal wires at the ignitor and the proper pins at the ECU? Continuity between the three outputs from the ignitor and the proper coils?

Waiting on my mechanic to respond with more precise information.

I know we are using NGK stock plugs (new)
We are pulling the leading plug wire and putting a plug in the wire and watching it for spark.
We do see RPM on the commander and tach.
Not sure about the 12V+ to ignitor, car is at my mechanics shop.

Look at your CAS wiring.