86 coupe, aluminum heads, no mods

I took the car for a drive this weekend. about 50 or so miles. the car ran as I expected it to. I have had the car for about 2 weeks and have had not trouble starting it the dozen or so times. when driving it the few times I have, I noticed that I was charging at 13.3 +. The owner that had it before me said the alternator is less than 2 years old.

I went to start it this afternoon and it just cranked. no fire at all. i hit the starter 3 times for about 15 seconds or so. and the battery was dead.

is the battery shot?

also, I may have done something else kinda stupid. the car being as old as it is.. I left the hatch open to try to let some fresh air in(in the garage for 24 or so hours). I made sure the interior lights went out but is there something else that draws current when the hatch is open?

Ron

 

I would say that is your problem. Charge the battery and see what happens.

 

If you cranked for a total of 45 seconds, I'd say your battery is OK. Never a good idea to crank that long though.

So...
do you have spark?
do you have fuel pressure?

Check the obvious. Go from there.

 

I went home for lunch from work and tried to start. I was surprised because its, as long as I have had it, started right up. I did not have time to check spark and don,t have a fuel pressure meter. I am also leaving on a business trip for a couple of days in the morning so I wont have time to do much between now and when I get back.

sucks because its gona bug me the whole time im gone.

 

I would think the battery should crank for much longer..

 

You really can't let these cars sit too long without a battery tender. Get one asap and charge your battery at lease weekly, if you can't leave it hooked up on a continual basis.

 

45 seconds? seriously? thats a lot of cranking time. OR did you mean to say you cranked it for a total of 15 seconds before the battery died? 15 is short. Thats a little too short. Charging at 13 is a little low too...after start up it should hit 14+ and sit at 13 with most accessories on while you idle. Try cleaning all the battery connections. These cars are VERY sensitive to the quality of grounds and other connections. Plastic cars are 100% dependent on the wires and connections. Good grounds are hard to find.

If you crank on the starter for 45 seconds non stop it'll FRY something. Thats a LOT of battery drain from a small battery. Never grind on the starter for more than 3-5 seconds and then wait before doing it again. If it does not fire off after 2-3 seconds its not going to. IF it regularly takes long cranking times, something is seriously wrong and needs immediate attention.
Old, tired starters will suck a battery down faster than a new fresh starter motor. Takes more amperage to turn an old one.
Avoid long cranking.
Cables get HOT, starters get very hot. Batteries that discharge too fast get hot as well. bad things happen.

Did your PO mention anything about VATS?
your no-fire issues sounds like the fuel was cut off. Starter enable relay bypass possibly?
There is no way of knowing without some basic testing...just guessing and that is something you do not want to do with C4s. It gets expensive.Quick.

Some basic things to buy if you want to live with a C4...

a FSM (first and most valuable of all) get used from fleabay.
a fuel pressure test gauge
a cheap DVM
spark tester
noid lite

 

i didn't crank for 45 seconds straight.. it was maybe 45 total.

PO did not say anything about vats. I thought if there was a vats problem the engine would not crank at all? am I wrong about that?

this is my first vette, I am not up to speed on all the basic testing. I use to have all the tools you mentioned, I just don't right now. on the way home I will pick up a charger and spark tester.

 

I have the same year vette as you, with the alum.heads..their known as 86L versus the 86E (early.Iron heads) After cranking my volts show 14.4 for a short time then reduce down to between 13.5 and 14. I dont believe you have any worries there. A weak battery cranks, but not for many tries. Targa top being open/off should not effect any electrical system. There are no switches there. Always a good idea to have where you at on your thingy over there on the left. Lets folks know if they are in your area...cruze in, help repair, advice, beer drinking, whatever,lol.

 

I was thinking the battery is weak as well. my brain was racing a little while ago. I may not have cranked it as long as I thought. while I have never owned a vette, or a chevy 350 for that matter. isnt it possible to turn the engine over and not have enough amps to start? a weak battery may have enough voltage but not enough amps.. or does this not apply to c4's for some reason that I don't know about yet?.. im still at work so im just speculating at this point. will do some testing when I get home.

my experience with battery's in general is.. if they are a few years old and they go dead.. they are dead. you can charge them and get them back up to 13 or so volts but and it may be good for a few starts but usually once they are a few years old + drained = dead. you just cant get the amps you need. im guessing.. because I don't know but i'm thinking that with all the relays and electronics onboard a C4 that you need a lot of amps at start up.

 

Stoped by the house to see if the battery has a born on date. It says 10/12 so if thats true, its less than 2 years old. Its a OReilly s high end house brand. I also live in tucson, which is hard on batteries. So im gona charge it and see what happens.

Also i noticed that the throttle was stuck open. Does that effect the start sequence?

 

not ture..if it turns over with any thing near the speed it needs to crank, it will crank, weak battery or not. A weak battery simply will not hold " a full glass of water"..only half full or less..the endurance isnt there like it used to be ..kinda like an old fart like myself..I can give it hell but not for long like i used to. I think the other guys are running on the right track toward your problem.

The C4 saw other slight changes like the aluminum heads that were on the last 8,000 ‘Vettes produced in 1986. These heads offered a slight performance boost


Corvette Production Numbers by Model
Coupe
27,794
Convertible
7,315
( mine is a gold coupe)

1986 Corvette Production Numbers by Color
White
4,176
Silver Metallic
1,209
Medium Gray Metallic
1,603
Medium Blue Metallic
128
Black
5,464
Yellow
1,464
Medium Brown Metallic
488
Gold Metallic
777
Silver Beige Metallic
1,383
Bright Red
9,466
Silver/Gray
1,049
Gray/Black
1,138
White/Silver
693
Silver Beige/Medium Brown
1,014
Back to top

1986 Corvette Engines

Engine

HP/TQ

0-60

Quarter Mile
5.7L V-8 L98
230 HP @ 4000 RPM
3300 lb-ft @ 3200 RPM
5.7 sec
14.4 sec @ 95mph

taken from http://www.corvetteguys.com/1986-che...-corvette.html

 

It was the hatch that was open. Not the top

 

yep, I have a "weak" battery...left the hatch open for a few hours...battery was dead. Mine has about 8 to 10 "cranks" before it starts to wind down to "walk".
A recharge works..but I know its a dice roll when away from home. Not really driving it now..have bigger issues with the wiper motor and have things tore apart.

 

Holy crap it takes forever to get anything done around here. I finally got back from the store and now have the car hooked up to a charger.. We will see in the morning how it pans out

 

No shouldn't have any thing to do.....



YES!! It matters!
If the throttle is wide open during the start, the fuel system shuts off!
This is how you clear a flooded engine.

Thinking now this might be part your problem?

 

interesting...

I've go the O'Reallys top of the line 7 yr battery thats 1 yr old and mine is also showing signs of weakness.

If yougot 45 seconds cranking..thats not bad. Like I said before, its never good to crank more than a few secs at a time...in short burst. The hotter the starter gets the more amperage it demands..so the problem snowballs.

I'm taking my "top shelf" battery back for them to load test and give me my money back. This is the 3rd from O'Reallys in 4 yrs and I KNOW my alt to be charging at 14...so I'm getting kinda bored with the jumping the friggin car at the grocery store.....

WOT is bad...a stuck throttle is bad too.

I ask about VATS because people do a starter bypass that lets it crank but IF the VATS is active the fuel is still shut off...makes diagnosis harder. In this case its your throttle being WOT that caused the fuel to be shut off totally. It won;t send fuel until the throttle is back in the normal position..idle.

 

"consumer reports" just did a article around car batteries..all sizes...something I didnt know was that certian areas should have a "hot area" battery and some" cold area". It states hot weather areas are actually harder on batteries than cold weather areas..surprising to me. They also listed best buys on different size batteries..Die hard gold recieved alot of first places but not best buys because they are so expensive...some batteries half the price preformed almost as well,,including a few from Wal-mart...interesting reading, you should goggle it...sorry about not having more info but left the mag in my tractor trailer..I am on home time.

 

I have always had good luck with your walmart batteries. I actually try to avoid walmart if i can.

 

You get what you pay for- get a DieHard.