rx7freak13v

my brother picked up a 90 s5 gxl.when we checked out the car we knew the tach didnt work.just figured it wasa blown fuse or bad guage.after a couple months now of searching out this problem.we realised that as your turning the engine over,the tach bounces but as soon as the engine starts it stops.we looked in a little further and checked the trailing coils.as the engine rotates the coils fire,but once the engine starts the coils the coils quit firing.we pulled and cleaned up all the grounds,then tried swapping in the trailing coils from my gxl (i know these work) and still the problem exists.then we took apart and cleaned up the ignition switch but the problem is still there,although the volt meter reads that it's carging better now lol.i've spent so much time searching but havent found much.i did find a post that said something along the terms of running a jumper from the leading coil to the trailing coil to make the tach work....and it does now but the trailing coils still have no spark once the engine is running.anyone have any ideas?im thinking maybe cas (im pretty sure that sends the signal to the coils to fire,correct me if im worng) or the ecu?please someone help.any ideas would be appreciated.thanks in advance.............

satch

iTrader: (1)

Have you tried to start the car w/the leading coil unplugged to verify if the trailing coil was working? What grounds have you worked on that are related to the trailing coil?. The coil needs to be bolted to the fender in a proper manner for a good ground to be made otherwise it won't fire. Is the plug which supplies the wires from the ECU plugged into the trailing coil making a good connection? Try cleaning this connection. Have you checked the voltage output of the ECU pins related to the trailing coil? This data can be found in the FSM. Have you checked the ohm reading of the CAS? Again, this info is supplied by the FSM.

danegerous

iTrader: (10)

I had this same issue forever, changed chassis harness, 3 separate coils and all. Turns out the engine harness was bad somewhere.

RockLobster

iTrader: (7)

Is the check engine light on?

If so, and maybe if not (light burned out), the car is in limp mode and you need to figure out why...

You will need a working Check Engine Light (MIL). Or a test jumper light...

Read through the FSM, this will help you a lot.

rx7freak13v

actualy,my check engine light is on.i pulled the spark plug wire and shoved a spark plug into the end and sat it on the fender.the plug had spark while the engine was turning over but once it started the plug stopped firing.the coil is plugged in and connections are clean.havent checked the ohm readings,havent realy had time to search out the information.i work double shifts almost everyday and havent had alot of time to search.however,i do have a mulimeter so when i find the ohm numbers then i can check it.if anyone has any other ideas,please let me kno.thanx

satch

iTrader: (1)

There is a green plug near the leading coil with one wire to it. Put a jumper wire inside this plug and ground the other end to the negative battery terminal and then turn the ignition key to on and await to see if your "check engine light" will provide you with a code to compare from the list of possible abnormalities.

are-ex

im having trouble with my trailing coil as well, only one is sparking, its not the high tension leads because i have new ones, and i have a question is the trailing coil spark meant to replicate the leading coil spark becasue my coil that works sparks once when the car is turning on, not continusouly like the leading ?

rx7freak13v

wow that seems rather simple.i'll give this a try as soon as i find the code list to match it to.i'll be going to work soon but i'll keep u posted.i may not get to try this till tomorow.thanks

satch

iTrader: (1)

http://www.banzai-racing.com/FD&S5_error_codes.htm

rx7freak13v

srry its been so long guys.alright so after i swapped in yet another coil pack,the tach began to wok fine and i checked rthe plug again same as before and everything is working properly.the check engine light even went off and the exhaust note changed.but after driving thr car for a lil while the tach stopped and the check engine light came back on.checked the plugs and no spark.this went on for a lil while,swapped in another set of coils and so on.now i have learned that if the coils stop and the check engine light comes on,if i shut the key off and turn it back on realy (flash the key) to where the engine never shuts off completly that the light will go off and everything is fine.but sometimes it'll only stay off for a few seconds where other times it'll stay off for a while.but i've noticed that this problem happens daytime for the most part.my brother drives about 15 minutes to get to work and he has to flash the key at least twice.yet tonight darktime,he gave a friend a ride to see his old boss (40 miles each way so 80 miles) and never had any problems.i can't figure this out.the only code that is thown is the coil pack (when its not firing) and emission sensors because we ditched the rats nest.however,if the coils are firing then the check engine light is not on.any help would b great.right now im leaning towards ignition switch or ecu.but i can't afford to keep spending money on guesses.please help.

rx7freak13v

anyone know what the relays does that sits behind the trailing coils and in front of the main relay?i tapped it with a wrench because it sounded like it was clicking but continuously,after i tapped it it only clicks when turning the key and then satys on.the check engine light stays off for a while but then after all day it came back on.could this relay be the problem or was that just coincedence?

satch

iTrader: (1)

It's likely that you're describing the starter cut relay. It's found on cars with the factory alarm and is part of the starting circuit so its purpose is for starting the car . If this relay has a single plug connected to it then it's the starter cut relay while the main relay would have two plugs going to it.