Morbidgorilla

Hello
I recently picked up a 79 sa22 12a electronic ignition.
Starting is a bit rough and the idle is rough as well. when starting sometimes I get a spark from the pos batt terminal and it heats up rather quickly. fuel pressure is erratic between 7-10 psi.
However I disconnected the pos batt cable from the battery to check if the alt was working properly and the Idle smoothed right out also the fuel pressur dropped to a steady 4.5 psi. I am still learning electrical systems and dont really have a clear grasp on how they work. I will be happy to post any pics that might help diag.
other bits
relocated aftermarket fuel pump on drivers side shock tower wired directly to leading ignition coil this was causing the pump to operate when key was turned to the acc position so I installed a kill switch to prevent flooding
trailing ignition coil is wired directly to disributor
I appreciate any help
Cheers!

No_love_for_pistons

iTrader: (4)

Just a suggestion, but are the batt terminals corroded at all? If there is any resistance on the pos cable or batt terminal the result might be heat dissipation. Also might want to check to make sure your grounds are clean.

Morbidgorilla

no corrosion on batt terminals
the grounds are all on bare metal and squeaky clean

DivinDriver

iTrader: (15)

Ifyou have access to a voltmeter (if not buy one, they are inexpensive) check the voltage of the battery when it's out of circuit. You may have a shorted cell inside the battery that's causing it to draw excessive current while charging.

Does the starter RPM sound normal, or is it slow at all in turning the engine?

Also, check your charging voltage while the engine is running; you may have an overvolt condition. 79's had relay-based voltage regulators that are prone to misadjustment or failure. That would account for the high fuel pressure as well. You want to fix an overvolt condition quickly - - it can fry a lot of equipment, some hard to get these days.

You say that it's a 79 with electronic ignition - - but 79's came stock with breaker points, so some kind of conversion work must have been done. It's possible that something was mis-done in the process.

Morbidgorilla

battery is brand new
starter initialy in strong then sounds sluggish as it trys to start
how would I check the charging voltage at the alt or the batt?
no breaker points so I am guessing it was converted at some point
thanks for the help!

Kentetsu

How are the connections at the starter? I think DD ^^^ has the right idea, but I think a bad connection at the starter could also be a potential cause...

DivinDriver

iTrader: (15)

Download the Factory Service Manual & Wiring Diagrams from the link in the FAQ ( http://foxed.ca/foxed/index.php?page=rx7manual ); detailed testing procedures are in there.

Basically, check voltage across the battery with everything connected and the engine running. Should be no more than about 14.5 volts, as I recall (check manual for spec.) To cause the symptoms you're seeing, it would have to be very, very high.

Voltage out of the battery when disconnected and fully charged should be around 12; a shorted cell will drop it by about a volt and a half.

Be careful about running the car too much til you solve this, though. Overvoltage can make a real mess of your electrical system.

20B 3 Rotor

iTrader: (7)

definately sounds like a starter problem, I just had this happen to me on my car. Turned out my starter was trying to draw to much, overheating my postive cable, bought a new starter, everything is fine, and starts beautifully now. You should take your starter in to get tested, then go from there.

Now if only I could figure out my other electrical issue, like why the gas door release turns on my passenger signal, lol.

Morbidgorilla

downloaded the manual
checked the alt its good
batt is good
now the starter slugged out of juice gonna check that next
the connections are good to the starter

Morbidgorilla

ya know I was sick of my subaru cuz I never needed to do any thing to it and now I am completely happy with having to actually work on my car

gsl-se addict

iTrader: (3)

I would go for new battery cables. You may have internal corrosion causing a high resistance. Replacing them will also eliminate the possibility of a poor connection between the terminals and the wires.

Morbidgorilla

tested the starter its volt reg was caca
found a new one for 47$ at Bonds going to do that and the pos/neg batt cables
will update once parts arrive
THANKS!!

Morbidgorilla

installed the new starter the pos batt cable/terminal is no longer heating up
volts at the pos cable while running are 13.1-13.4
idle and fuel psi still high while positive batt cable are hooked up not as bad though

Sgt.Stinkfist

iTrader: (6)

long or extended cranking draws lots of amperage and could be heating up the wires

©ØÐËߣüË

iTrader: (1)

Also what type of cables do you have. Copper or aluminum. Just because the older aluminum cables get weak sometimes. I had a issues with that, so I changed everything to copper. Copper is a much better conductor.

Morbidgorilla

aluminum still
I have to wait for next weeks unenjoy-ment check to do the wires

Kentetsu

Yeah, any corrosion in the cables adds resistance. And resistance = heat.

Seriously, when I replaced my cables it fixed issues I didn't even know I had......