18RG swap question... - Toyota Nation Forum : Toyota Car and Truck Forums

TeRcElIcA · 03-07-2006, 07:45 PM

I have a 1975 Celica... I finished putting in the 18RG... I havent worked on the car for a few days, and well sinse I worked on it today... It wont start... I have the engine in, starter connected, the fuel hoses connected, radiator hoses, all that crap connected. My only problem is when I try to start it, the spark plugs DONT fire. I changed out my distributor coil... and still no fire. I looked at the cap and rotor and those are fine. what am I missing here guys? I know the spark plugs wont fire because we took each one out and started them one at a time, and didn't see or feel anything. These spark plugs are almost brand new, I used them on my old engine for about 300 miles. Thanks again

stepho · 03-07-2006, 11:33 PM

I have an 18R-G in my 77 Celica.

Does the Coil + terminal have power ?
It should be around +9V (12V or higher before the resistor, 9V after).
Make sure you still use the resistor (bypassing it will fry the coil after a month or 2).

Are you using points or electronic ignition?
Points have one wire from the dizzy to the coil.
EI has 2 wires from the dizzy to the ignitor - the ignitor then feeds the coil.
It is possible to have either setup on an 18R-G (I've tried both).
I can supply wiring diagrams for both.

- Stepho

TeRcElIcA · 03-08-2006, 12:07 AM

I think I was using Points. but I changed my ignition coil to one I found at the junk yard off a supra. So right now, I'm trying to go EIS... Can you send me the wiring diagram? Lets say I had points... and tried to change it to EIS... do you have any pictures of what it might look like also? I think I have the set up completely wrong...

....

stepho · 03-08-2006, 12:25 AM

Easiest way is to use whatever you had in the old engine.
The 18R-C, 20R, 22R and 18R-G dizzy inards are all compatible even though the dizzy body may be different.
So take the guts of your old dizzy, put it into the new 18R-G dizzy body and wire it all up exactly as it was before with the old engine.
This is how I had my 18R-G setup for a couple of years.

Once I had figured out how EI worked, it was a simple 1 hour job to shift to EI.
If you are confident and have all the relatevant bits, then EI is much better than points.
If you are not sure, then just duplicatethe old system

I highly recommend the Haynes manual because it has a very good wiring diagrams for both points (early models) and EI (later models).

You can see the wiring diagrams ei.pdf and points.pdf I made at
http://autos.groups.yahoo.com/group/...ng%20diagrams/

- Stepho

TeRcElIcA · 03-08-2006, 12:34 AM

ACTUALLY... I have EIS, but I changed the ignition coil is what I meant. We thought it was points because it looks all weird with all the resistors that came with it... I'm trying to look at the diagrams right now... but keeps saying error...

TeRcElIcA · 03-08-2006, 12:39 AM

my computer wont open pdf... for some odd reason.. BUT going back to the topic.

This is sorta what I did with what I have... Correct me because I need the help anyway

stepho · 03-08-2006, 12:58 AM

EI uses the same coil as a points system using a resistor (ie don't use an older coil designed to be used without a resistor).

I'm guessing that you simply made a mistake in the wiring between the coil and the ignitor.
Watch out that the 18-GEU's (as opposed to the 18R-G, 18R-GR and 18R-GU) had the ignitor inside the dizzy (ie 2 plastic lumps in the dizzy rather than usual one).
These wire up identical to a points system.

You need a resistor between the key switch and coil + otherwise you will fry the coil after one month.
If you have an early style EI (external ignitor) then you need 2 wires betwwen the dizzy and ignitor.
If you have a late style EI (ie ingnitor internal to dizzy) then you need a single wire from the dizzy to the coil for the coil - signal and another to take power into the dizzy (usually taken from the resistor - in my ei.pdf just imagine the ignitor being placed inside the dizzy body.

See if you can get the PDF files to work.
It's a real pain to have to send GIF files because the lines are not as accurate.

TeRcElIcA · 03-08-2006, 01:13 AM

OK, I need to get a resistor... maybe even the one that came stock with the car? I have a resister that isn't being used. The coil I found is a Accel Universal Performance Coil off a 86.5 + supra. I also have the 2 wires coming from the Dizzy, like you said. I believe it is an external ignitor then.

so do it sorta like this

stepho · 03-08-2006, 01:20 AM

The Acceel universal coil shoudl be fine and I;m reasonably sure it will want a resistor.

Take the cap off the dizzy and have alook inside.
If there is one solid lump of curved black plastic about 4cm long then it wants an external ignitor.
If there is two solid lumps of curved black plastic about 4cm long each then one of them is the internal ignitor.
The major difference is that the sire going to an external ignitor have very small voltages on them.
The wires coming from an internal ignitor have 9V-12V.
If you get it wrong you might fry the external ignitor.
So we must check to find out which type you have.

- Stepho

stepho · 03-08-2006, 01:23 AM

Oops, forgot to mention,
The coil + comes via the resistor.
The Ignitor wants the full 12V (asuming you require the external ignitor and are not using an internal ignitor).

- Stepho

TeRcElIcA · 03-08-2006, 01:24 AM

HOld on I'll take a look

TeRcElIcA · 03-08-2006, 01:51 AM

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TeRcElIcA · 03-08-2006, 01:52 AM

It's dark right now. But I think I don't have that curved black plastic so possibly not an internal igniter.

stepho · 03-08-2006, 02:05 AM

Okay, now we know what you have.
Photo 384 very clearly shows points (little electric jaws that open and close when the shaft spins).
So you can either go back to a completely old style points system or go forward to a completely EI system.
What you have at the moment is a mix that will never, ever work.

I suggest points because it is the easiest to understand.
Upgrade to EI later when you have time to study it and time to play with combinations.

battery +12V to keyswitch.
Keyswitch to resistor.
Resistor to Coil + and condensor (little 1cm round can).
Dizzy to Coil - (and tacho if fitted)
Standard universal coil designed to be used with an external resistor.
No ignitor.

Try to get my points.pdf file working because it contains wire colours (subject to change for different years/countries but reasonably close) and the resistor bypass circuit for using the starter motor.

- Stepho

TeRcElIcA · 03-08-2006, 02:15 AM

OHHH I C I C... I know what those little condensors are... where does the condensor go on the coil? can I still use the coil that I have? or do I need to find the the same kind as my old one?