cleksutin

In the never ending odyssey that is my 1979 project car, I've come up with a few questions I cant seem to locate the answers too:

First: The car seems to have a lean condition. I've come to this conclusion due to the flames shooting out the muffler, the exhaust glowing red after a few mins. of poor running, no power (at all) and I just don't believe the timing went out after 50 feet of driving (the car was running well before I moved it. Someone mentioned to me that this could be caused by poor spark on the leading plugs. So what is considered poor spark? Can this be caused by the leading coil going bad? Do they even work like that (as in can the slowly fail or only partialy work)? I've done the old "pull the plug and hold it to the block" to see if it's sparking, and it is, but it looks small and down inside the plug, so I'm not sure that's legit.

Is there a way to test the coil directly? and if it's bad will the coil from an 85 work?

Second: Can anyone point me in the direction of a smog delete for the SA?, I have the one for the FB, but the rats nest is different on my 79 vers. my 85.

This community has been more helpful then any of the books I own, so thanks you yet again for putting up with my dozzy questions..... again.

Leks

Rotor_Venom08

iTrader: (3)

flames mean rich not lean, but thats not always a clear indicator that its running rich, if you have an exhaust leak it will shoot flames also. is your air pump hooked up? if its not chances are youve overheated the exhaust and its either melted or ruined. to my knowledge thats its primary function. but my knowledge is based off of FB's so maybe its different for you.

Qingdao

iTrader: (3)

Have you checked the fuel flow from the tank? 30 YO tank might have some garbage in it/30 YO gas lines might not look any better.

Test the reisistance on the coils. Look in the FSM to get the resistance numbers (I don't know them off the top of my head).

Coils will swap all around. In my experince they are all the same. I use a set of Accel coils on my 79 with points. Accel has proven (at least to my experince) to be a good/cheap brand.


How old are your points?

cleksutin

Tank and lines are good, Ive done extensive work to both. And to a previous poster, I misspoke, I meant a RICH condition, not a lean condition. I have no idea on the age of the points, the engine is a rebuild (by a professional) with only about 40k on it, and the carb rebuild only has about 500 miles on it. The coils, however, look original, the plugs and wires are fairly new. It was also smoking really badly when this started, and the smoke reaked of unburnt gas. The air pump and smog control are still in place, but I did replace all the vacuum lines (I think) Keep in mind it was: running fine> Moved it 50 feet> Now this

Qingdao

iTrader: (3)

Points dude... Cheap eazy to replace

When it comes to points ignition look to the points for failure first. If you have weak spark thats where I would start.

Oh and I forgot to mention the redneck coil pack check... Shake the coil. You should hear liquid move around inside of it. Coils will go out when they don't have the oil inside.


My points will light up the engine bay when laid on top of the block; so you might be on to something with the bad ignition.

cleksutin

LOL!! A man after my own heart

I see in your sig your a fellow 79 owner, nothing like a classic japanees sports car eh?

Maybe you can help me with this one: while out in the shop trying to work this all out, I though I killed the starter, so I pulled it and tested it per the FSM, and it's fine. I tried to run some funky wiring (not my strong point I'll admit) the starter spins but when it engages the engine it's acting like the battery is dead (you know, that slow cranking that will never start an engine?) What is between the ignition and the starter that would cause that?

Also, any recommendations as to where to by points from? I'm assuming Autozone isn't gonna carry what I need :/


PS do you you still have all the smog control on yours?

rx7lives

Maybe my memory is going but I thought 1979 Rx-7s had a 6 volt coil. Can anyone confirm or deny?
Your spark should be visible and if it looks like it's inside the plug and not across the tip and ground lug, you could have shorted plugs from oil or whatever. Reminds me of my Kawasaki triple.

Qingdao

iTrader: (3)

Do you have oil pressure?
I know there isn't a factory gauge on your 12A, but you can check the oil pressure by spinning off the oil filter and turning the car over. I'll warn you oil is gonna go everywhere if you do have oil pressure.

I can tell you from personal experience this engine will NOT run for crap without oil pressure. It chews up the bearings in a heartbeat. (Just ask my bearings from last time I built the 13B)

Also, if your engine isn't spining very fast that would account for a weak spark.



I'd get the points from a Mazda dealership. Or factory replacements. The Mitsubishi logo is stamped all over the ignition so I would assume they made the oe points. If not them then Denso. I'm actually on the hunt for a good set myself (just as a spare for the glove box).


@: rx7lives

Last time I was under the hood I recall my ignition is running 12vdc, but I could be wrong. I'm gonna check now cause curiosity's got me.

haha my buddy just got an H1.... I used to have a T500 smoker, and I'd carry a handful of spare plugs just for the fouling. Fortunatly my current Yamaha smoker uses two spark plugs... one to burn and one to ignite just pull the plug wire and switch over whenever weak spark arises.








EDIT:
Oh, and my emmissions stuff is all gone on my 12A. It was gone before I even got the car I've never even seen it in person. I've seen the air pump because it was in the tuberware container of parts that came with the car.

I do know, from my freind's Datsun experiences, that air pumps and emissions equipment will make hella backfiring and noise and all kinds of problems when the car isn't running right. But I wouldn't rip it all off till I figured out what was making the problem in the first place.

cleksutin

Removing the emissions was always in the cards for this car, I just want to get it running right first. Old card resto addum I guess: make it run BEFORE you start changing things.

Ok, so when I get home from work I'll check the following:

Oil pressure

Points

coil

As for my starter issues: is there a relay in that circuit that could have gone bad?

Qingdao

iTrader: (3)

nope just a solinoid wire that runs from the key and a big old 12 volt postive wire runing to it.

t_g_farrell

iTrader: (1)

Definitely sounds like weak spark. Also check the ground to the drivers side shock tower and the
condition of the ground cable itself. This might account for both the weak spark and the weak
starter. The ground cables are known to disintergrate over time internally and that ground
connection can get nasty since its exposed a bit in the engine bay.

DivinDriver

iTrader: (15)

79's used a series ballast resistor setup, and different coils from the later years. I don't have the '79 FSM, and the wiring diagram does not list voltages, but generally a series resistance will lower the voltage drop across other components in the circuit. the 80 and later cars with 12V electronic ignition call out a different coil part number.

AutoZone still carries points sets for the '79.

It would make sense to run points at a lower voltage - - it would make them last longer, with less arcing.

The 79 factory wiring diagram around the points is... kinda suspect. The way it's drawn up doesn't make immediate electrical sense. I know the 80 diagram is flat-out wrong in this same area - - I had to correct mine.

+1 on checking your grounding provisions; bad grounding can mess with both ignition quality and starter performance. It's like putting a kink in a garden hose.

Qingdao

iTrader: (3)

Good point with the ground, but if thats fine then here is the FSM ignition walkthrough :P


Points springs should "begin to seperate at 1.1#s" of pull.

Condensors should have a capasity of .24 uF (I don't know how to type mu)

The points gap should be .45mm (which is big as hell from what I normally deal with)


Coil pack testing:

Test the primary resistance with an ohmeter. 1.21-1.48 is ok

External resistor should be 1.26-1.54 ohms



But a bad ground conection on the engine or the battery would definetly do you in.

cleksutin

bad grounds? man it's my VW days all over again...*sigh* Ok, I'll start with the grounds first.

Also, there are THREE wires that come off my starter, not two. One goes to the battery, one goes to the ignition (these are the wires attached to the posts and nuts) and a third that, as far as I can tell controls the electro-magnet that drives the spur gear forward.

Also the starter issues started AFTER the poor running, The starter was working just fine while I was working the possible poor spark issue. The reason I was asking if there was some analouge electronic back magic between the ignition switch and the starter is this: If I jun a jumper between the 12v post on the starter to the ignition switch post on the starter, instead of the starter cranking over, the hot start assist gizmo starts running...

... yeah I know...

Leks

PS: all you guys are awesome!

rx7lives

I believe that the wire from the starter bypasses the ballast resister during cranking so it gets a bigger spark. You might want to ensure that that part is working, too.

Qingdao

iTrader: (3)

I've got to stop reading this forum...

Last week or so I read some thread about a cloged gas tank... and last week I had to take my tank off and flush the bjeasus out of it because of a clog after reading the thread.

And just earlier tonight I sputtered to a stop with hella backfiring and the AFR peged on rich. Poped the hood and went STRAIT to the points. Slid a dollar bill in their and cleaned the 30+ YO points off and drove home. BUT I'm still gonna need new ones.

cleksutin

ok, how about this:






Ok.

1: is the 12v lead, goes straight to the battery

2: Goes to the ignition (the key)

3: I have no idea where this goes (neither does the FSM as far as I can tell) but if I disconnect this, the the magnet wont engage.

Now, with everything hooked up in the right spot, if I turn the key the magnet engages but the starter wont spin. If I jump 1 and 2 while the starter is still in the car, the starter wont work but the hot start assist motor starts spinning.

If I take the starter OUT of the car and and ground it AND apply 12v to 1 and 2 the starter spins just fine.

As you can see from my bad-*** art work, I have no idea whats going on, but I'm begining to think it has to do with crazy Japanese spirit gods or something.

Qingdao

iTrader: (3)

3 suplies 12vdc (high amperage) pos power to the starter motor. 1 is where the power comes from (the battery post high amperarge)
2 turns the switch to conect 1 and 3 by suppling the solinoid with 12vdc pos (low amperage).

Qingdao

iTrader: (3)

Well, I don't have a points issue and this isn't the OP's problem. I just thought it relevent to the thread.

I got new points and one new coil (thats all they had at the store)*, and the car fired up and warmed up good. I went to take her down the road and then blap blap burrr blap blap... deadend ignition. Limped home and when I was under the hood my buddy pointed out the RED HOT balests.

I spent a while searching the internet for new/used balests. Apparently they are a thing of the past 100%. FYI the MSD brand replacement part number is MSD8214. The man at the auto store said he had one, but I want a good pair to last me another 30+ years.


* they had other coil packs but none of them matched in color and I was being picky.

cleksutin

Ok here's what Ive found: 1 has good power (duh) 2 has 11.9 vdc with the key turned to start, and 3 never has power, regardless of what I do. 3 runs back to a little box that also has the wire fore the hot start assist motor (solenoid?) I'm guessing that 3 need power when the key is turned?

God I really wish I had taken that electronics course in college.

Is it possible to skip all this non-sense and install a push-button start system? I tried this before, but apparently I suck at this and had smoking wires (don't worry only ones I had added) in about a minute.

It really sucks that I cant get past this to work on the ignition problem...

leks

cleksutin

Hmmm no more takers?

cleksutin

Ok, how about this? I ran a new wire to the starter and got it cranking over. did a spark check and I even got the engine to catch a few times, then the starter got hot and killed the battery in about 30 seconds. Is that a bad starter?

Qingdao

iTrader: (3)

Seriously sounds like a bad ground now....

cleksutin

Yeah, I'm inclined to agree with you now, I'm seeing some melted insulation on the positive bat cable by the post. I see there's one on the drivers side strut tower and a ground wire that goes to the block by the starter, any I'm missing?

Leks

85rotarypower

To clear things up a bit I found that the stock 79 coils were 9 volt external resistor units. The 12 volt coils used on later cars have internal resistors. For a test the external ballast resistor set can be bypassed to test with a 12 volt coil if needed if you don't want to buy a new 9 volt coil before testing for bad ignition.