Starting problems.

[Blackie1337]

I could use some ideas here, my friends ae86 just wouldn't start the other day, ran fine the day before.
It just cranks forever without a hint of firing.. (except a tiny little attempt the very first crank after it's been standing for a long time).
Checked that it gets fuel, and spark. Yes to both.. Its not an AFM car so thats out. There are also no error codes.

It smells of burned electronics under the hood, but I'm not able to locate it. All the fuses are intact though.
The smell came after jumpstarting it using the engine lift hook as ground, and that didn't work. (I thought that was supposed to be a good ground point?)
So the smell "could" be unrelated to the problem, because it happened after the car wouldn't start.

I'm not an expert by a long shot, and could use some options..

[Blackie1337]

I thought so too, but I cant seem to find any, can someone tell me where the different wires are located?
I ohmed the engine block, and the intake manifold to the ground on the battery, and they check out as a solid connection.. Though the hook did NOT work..
Where should I check for continuity?

[Red]

All it takes is one bad wire, one chafe, in between the AFM and the ECU, or to the fuse block under the hood. You've got to pin out all the wires in the AFM/EFI circuits or at least runs hands and eyes over them to make sure it isn't that simple, and that hard to spot. If the ECU isn't getting a "running ok boss!" signal from the system, it will shut down the ignition and fuel.

[Blackie1337]

Shouldn't I get an error code from the ECU if that were the case? (the "running ok boss" part)
But yeah, I suspect there to be a grounding issue, but I don't know how to locate it, and it has to be a major wire thats burned properly to make that kind of smell..
I do not think its a burned wire in the harness.

I will put it on stands and have a crawl under it tomorrow, I was just hoping someone had any ideas of what could be the reason for the symptoms above, EXCEPT for the burned smell, because that happened after the car wouldn't start.

[Blackie1337]

Oh I forgot to mention one last symptom that was there since the problems started.. The ignition switch won't turn off sometimes. As in, you turn the key back from the start position, but it keeps cranking. You have to turn it back and forth a couple of times to make it stop.

[Red]

'Shouldn't I get an error code from the ECU if that were the case? (the "running ok boss" part)'
Maybe on the later models but the '85 only had ten diagnostic codes and "I can't find my head!" isn't one of them.<G>

" The ignition switch won't turn off sometimes. As in, you turn the key back from the start position, but it keeps cranking. You have to turn it back and forth a couple of times to make it stop."
That changes everything. Sounds like it is simply the starter getting stuck (they do as they get older, jammed by dirt and congealed grease) or the ignition switch failing. If you follow the harness up the steering column, you can unplug it and use a multimeter to test the ignition switch. Or, use the dash light or radio to confirm that the ignition switch is turning on and off normally, without trying to start it. Or use a test light or voltmeter on the starter's ignition terminal (not the heavy main power cable) to see if the ignition switch really is or isn't cutting off power when you turn it.

the car still may not start, there may be more than one problem, but if the starter isn't shutting off, the only two parts that can make that happen are the starter and the ignition switch.

[Blackie1337]

Haha, ok so the ECU isn't that smrt..
And yeah, I realize the ignition thing probably isnt very hard to fix, most likely corrosion and dirt, but it seems weird that it never did it before the car wouldn't start.. But anyway, that problem can't be related to the no start issue.. ?
And again, how can the car get spark and fuel but not start?? Or at least attempt to start.. The only thing left is compression, but I don't have a tester. And it seems pretty unlikely that the car suddenly lost all compression on all cylinders over night..
(Eventhough the engine looks like the inside of an oildrum)

My procedure for testing spark: Attach plug in wire, hook up jumpercable to block (right next to the sparkplug hole), and to the plug.. Crank, and sparks fly like a good boy..
Testing fuel: tried just cranking and pulling the plug, its wet and stinks of fuel.. + undoing the fuel filter connection and the fuel rail and start the pump, everything checks out..
Testing ground I've just done with a multimeter, but I realize that doesn't really but any strain on the grounds, so not an ideal test.. But again, it sparks like it should..
Its as in the timing suddenly became way off for no apparent reason.. I asked him if he stalled it or anything that could have made the belt jump a few teeth, but no, he just parked it like everyday and the next it was dead..

[Blackie1337]

Ok I got it running, just to eliminate it completely I changed all the sparkplugs... and after some grinding it finally fired into life.. Ran rough as poo for the first 30 sec but then got better.. Now it starts properly after I ran it for a while..

Now onto the stinky problem.. the battery light is on, so I guess the alternator or a component around it is fubar..

[Red]

Because so much stuff interacts through the ECU, it can get hard to figure out which kid stole the cookies from the cookie jar.

"And again, how can the car get spark and fuel but not start?? Or at least attempt to start.."
When my AFM signal was out, sometimes it would crank and catch and then quit. Sometimes it would backfire, weakly, once. Mainly it would just crank and crank perfectly normally without firing up. So, I'd still suspect a bad wire or at least, want to make sure the old wiring was trustworthy.

"The only thing left is compression, but I don't have a tester."
OK, buy a bottle of cheap wine. With a cork, not a screw top. Now drink the wine, come back to the car with the cork after you've sobered up. How the cork in the spark plug hole and crank the engine. If you can't quite hold the cork in the hole and the pressure pops it out? You've got compression.
Or you find an Autozone or Perp Boys, they do free tool rentals and they can lend you a compression gauge. Even if it runs, you'd want to know how even the compression is across all cylinders. Tells you how healthy the engine is or isn't. Not as much fun as buying the wine though.

"And it seems pretty unlikely that the car suddenly lost all compression on all cylinders over night.."
Attacked by Honda Ninjas, who stole the valves in the night!

"Testing ground I've just done with a multimeter, but I realize that doesn't really but any strain on the grounds,"
Folksmake grounds some too much like something new and special. They're just wires, if they look clean and tight and they do run to ground, don't worry about load testing them. If they're all green and punked out, just replace them with tinned (silver) ground straps, nothing fancy needed.

"he just parked it like everyday and the next it was dead.." One bad wire that chafed through would do that. If that wire only affected starting--not running--it could chafe through while you were driving, with no affect on how the car was running. And just prevent it from restarting. Check out the Toyota VAST ignition system and the EFI/COR fuel cutoff wiring, there's "stuff" here that no other car has in quite the same ways.

[Blackie1337]

Haha. I like you! Your colorful
And that wine cork idea was pretty resourceful! Of course it doesn't tell you the amount of compression but at least it tells you its there.. I'll remember that one.
I've been looking at the electrical diagram of the EFI and yeah, it is pretty complex..

Well, in the end everything I could think of testing checked out ok, so in a last ditch effort I changed all the plugs since that was the most likely fault, and it worked.. Weird, because the old plugs look ok and sparked.. I guess just not enough...

But now I still have the alternator problem to solve.. though, I'm pretty confident that the alternator is stuffed.. Probably because of using the block as ground when jumping the car.. Sure not gonna do that again. And from the smell I bet the diodes in the voltage regulator are fried.. I wanna to say it smelled like condensers popping though.. Need to take the alternator out and have a look at it when I have the time, and its not -10c outside

Oh and I tested the wires from the alternator to the battery + and ground and they are fine..

[Red]

Using the block as a ground point won't hurt, absolutely not. But the safest way to jump start cars these days, is to leave the dead car turned off. Use the other car to charge the dead battery for 10-15 minutes, ignore it while that happens. Then disconnect the other car & try to start from the battery.

Because alternators and electrical systems, especially in the new cars, are just too delicate sometimes and if there is a problem in one car, it can take down the other one. Charging the battery & using it to start? Perfectly safe for both cars.

I had fixed (new diode frame) an old alternator after replacing it and put the fixed one on the shelf as a spare after I had it tested & confirmed 100% good and fixed. Last year I needed the spare and it tested 100% BAD. I'll swear that can't happen and the guys who tested it blew it. These things don't just go bad on the shelf, so watch the guys when they bench test it.

[Blackie1337]

Hm, I wonder how the alternator could have gone bye bye then.. But using the hook on the block did not work, it just bogged down and didnt get any power when trying to crank it.. to me that sounds like a weak ground.. right? The problem is, which path did it take to ground..

Yeah I've been reading that.. but the AE86 isn't exactly a new car, I just hope the computer didn't get fried..

Man that sucks.. And of course you can't prove anything so whatcha gonna do

[Red]

That's why I charge instead of jumping, I don't want to hear about "what cna you prove" if something does go wrong. ANother reason all the instructions now say to hook up the negative cable to a ground instead of the battery post, is to prevent a spark on the battery from setting off a battery explosion. Those are still common enough to blind people every year. From an LATimes article online:
" the National Highway Traffic Safety Administration.... [1996-7] study estimated more than 7,000 people were treated annually in hospital emergency rooms for injuries that involved car battery explosions, chemical burns, contamination resulting from being splashed with battery acid and electrical shocks involving battery cables or posts. The study estimated that 32%, or 2,280 people, were injured in battery explosions."

Alternators don't need much excuse to die. You ate the wrong cereal for breaksfast? Tied your left shoe before your right? OK, time for the alternator to blow. And don't even ask why you can go through three in a year or two, then go ten years without any problem.

The bogging down usually means weak power, which could be a bad battery, bad ground, bad positive supply, low power from anything in the circuit. A voltmeter would help you chase that one down.