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-   -   2nd gen carb conversion no spark (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/2nd-gen-carb-conversion-no-spark-926802/)

rx7freak13v 10-15-10 07:48 PM

2nd gen carb conversion no spark
 
alright guys,help me out.i just did a delloroto side draft carb conversion to my 88 na 6 port.im using an fb dizzy set up.i must have missed something in the coil wiring part.im using two msd blaster coils because i got them with the carb set up.the trailing ignitor on the dizzy is going to the trailing msd blaster coil and the leading ignitor is going to the leading msd blaster coil.then the coil wire from the leading coil goes to the leading spot on the dizzy and the trailing coil wire goes to the trailing spot on the dizzy.everything there is checked and double checked.i made sure the engine was at tdc before i pulled the cas and installed the dizzy properly.i have no spark coming from the blaster coils.i bought the whole set up from this guy shane last night after hearing his car run.he had no problems.what did i miss? the dizzy supplys the ignitors on the side the signal to spark,correct? someone told me something about tapping into the factory plugs off the trailing coils for the blaster coils too,is this right?if so what color wires do i tap into?help please.thanks in advance.

-roy

Siraniko 10-15-10 08:40 PM

basic rundown
 
each coil + terminal must have a 12V.
1. Use fog lights relay:

30=battery
87/87A=coil + termnal
85=ignition (stock wiring with + when the key is "ON")
87= ground


Coil to Dizzy(Igniter facing the radiator = leading. Igniter facing the alternator = trailing)

Pix of an igniter with wires (left one). the thick black with yellow stripe is your positive wire from the coil's + terminal. Yellow/green stripe is from coil's - terminal. So wire each coil and igniter this way.

http://img.photobucket.com/albums/v3...r/DSC07290.jpg


When you drop the dizzy, be sure it is on TDC (use the flywheel trick as it the best one to use, search)

rx7freak13v 10-15-10 09:14 PM

i don't have a fog light relay....s4 no factory fogs? could i run a wire from my positive side of battery to both coils? are u sure the ignitor facing the radiator is leading?the fsm said opposit,but that wiring diagram is tough to read.

Siraniko 10-15-10 09:25 PM

yes, igniter facing the rad is your leading. yes, run a wire from battery to coil +. be sure to disconnect it to shut off the engine.

now, if the engine cranks but no start:
timing is off
igniters are bad

rx7freak13v 10-15-10 09:46 PM

i have to disconnect the battery wire to shut the engine off? theres gotta be a better way.could i tap into an ignition wire to where it only has 12v when key is on but shut the engine off when i turn the key off?

Siraniko 10-15-10 09:49 PM

jumper wire to battery for now, not permanently.

rx7freak13v 10-15-10 10:11 PM

okay i'll try it. if it starts,what wire should i tap into afterwards?

Siraniko 10-16-10 12:04 PM

while the car is running with the jumper/temp wire, use a test light to locate a constant 12V. For me, its easier to just use a fog light or any automotive relay to ensure that you have a constant 12-V, controlled by stock ignition wire. but its all up to you.

rx7freak13v 10-16-10 08:54 PM

after i switched the ignitor wires around as said above,i hooked up the jump wire and it fired right up.then on start attempt number 2 the old fuel pump that i got with the carb quit working.so i picked up a holley blue and a fuel pressure guage and i'll be installing it tommorow.i'll be tapping into the 2 black wires for the trailing coil to use as my new 12v.thanx for all the help.

rx7freak13v 10-17-10 01:50 PM

by the way,any recomendations on how much fuel pressure i should be running?

Siraniko 10-17-10 06:09 PM


Originally Posted by rx7freak13v (Post 10271938)
after i switched the ignitor wires around as said above,i hooked up the jump wire and it fired right up.then on start attempt number 2 the old fuel pump that i got with the carb quit working.so i picked up a holley blue and a fuel pressure guage and i'll be installing it tommorow.i'll be tapping into the 2 black wires for the trailing coil to use as my new 12v.thanx for all the help.

I never recommend anything without using a relay for protection. Besides, it is best to have an stand alone fuel pump wiring system. also, you can have used the stock FI fuel pump, just need a jumper wire to make it run and a fuel regulator with a return as it is too much pressure. so what type of carb is it?

rx7freak13v 10-17-10 07:30 PM

im running dellorto side drafts (like webers).i actualy decided to use the factory fuel pump with a pressure regulator.i got her running.she ran for about 20 mins and then started popping a little from the exhaust.is this normal?i shut her off and restarted her and since the first time she will run for about a minute and then exhaust tone gets a little raspy and she shuts off.not sure why.but she fires right up every time.i have blocked off everything not needed and removed the 5th/6th port actuators and running a long tube pacesetter header through a resonator and 2.5inch exhaust back through a gp sports muffler.she sounds amazing but keeps wanting to shut off.im trying to diagnose the problem but it's a working progress.any advise would help.

rx7freak13v 10-17-10 10:20 PM

i think the term raspy isnt quit the word to use for the exhaust note.it sounds like someone is pushing their finger against a plast fan blade sound.tomorow im going to install a fuel pressure gauge to make sure 100% that it's not fuel cut.


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