hard to start after driving

[amm888]

my 76 400 k5 (which is for sale in the sale forums) has been sitting around more than not, and she's kinda hard to start now, takes some pumpin on the peddle (but she does it, even after no action for 2 weeks), but the worst part is that after i drive her somewhere she's nearly impossible to start. she'll turn over and over and over....until the battery dies. the other day this happened, so i made a call to get picked up, and after my ride got there i decided to give her one more go - and she started!?

now is this just a bad battery? the batt is less than two years old, but i have let it die a few times and had to recharge it.

what i don't get, is that if it is just the battery, how come she's harder to start after a drive?

thanks for any input

alex

 

[Can Can]

What are the symptoms of the hard start? Can you smell gas?

Have you checked to see if you're getting fuel in the carb when it's not starting? Is there a chance you're vapor locking? A weak mechanical fuel pump will cause poor starts after being parked and the heat from the block soaks into it. I had similar issues and I replaced the mech. pump with an electric pump about 11
years ago, with no problems since......

It could also be an ignition module. They sometimes get weak and too much heat(like sitting in a hot engine bay) can cause them to temporarily wimp out, although when they die they're usually done for good.

Check for fuel and spark next time she won't start after sitting. Then you'll know which one is to blame. Good luck, and keep us posted, brother.

 

[txhotrod]

I had the samwe problem with mine. Turned out to be a bad alternator and a bad ground. Hope this helps.

Blazerkid

 

[amm888]

thanks for the posts guys. i can't smell any gas during the start, and i can't think of any unusual symptoms. sounds like she's cranking normal, just wont catch (start). i'll try and figure out how to check the carb for fuel and/or spark and take it from there...think i'll re-charge the battery one more time as well. is it true that once a typical battery is allowed to die it's never really the same afterwards?

 

[MTMike]

My old 79 used to hard-start while hot, and someone told me to put some sort of thermal carb spacer in there. I had taken it out when i changed carbs and thats when it started, so I put it back in and it cured the problem.

 

[BlazerFarm]

The first thing that came to mind when I read your problem was that the starter might be getting too hot as you drive around. I think there's a heat shield between the engine and the starter to prevent the starter from cooking from the engine heat. I'm not sure if there's supposed to be a heat shield on the 400 or not. I'll check my '76 shop manual when I get home.

I had a friend with a '77 Firebird that used to actually rub ice on his starter if he was stranded and couldn't get the car started. After the starter cooled down it started right up.

Of course, I could be barking up the wrong tree alltogether.

 

[dyeager535]

He says it's cranking normal, so assuming by the noise the poster can tell the starter sounds the same with the engine hot or cold, starter isn't going to be the issue..

 

[BlazerFarm]

Yep, I missed that.

 

[Desert Yeti]

all good advice.

To check for fuel, pull the air cleaner, peer down the throat of the carb (carefully and with the ignition OFF) and work the throtle with your hand. When you "floor" it, you should see a mist of gas in the carb throat from the accelerator pump.

Checking for spark is a little trickier on HEI trucks (can't just pull the coil wire) but checking at one cylinder should be a fair indication of any large scale ignition issues. Be a little careful doing this... the voltage isn't lethal, but it's enough to surprise the hell out of you!

My first guess on reading your post was vapor lock. Good luck!

 

[Tracktor]

I had a truck with a simliar problem, it was a bad fule line which was allowing the prime to bleed off. It had to reprime everytime you went to start it. Another time it was vapour lock from an improperly routed fuel line. However, I wouldn't rule out electrical problems as they always seem to pop up when hot...................

 

[amm888]

wow...thanks for all the suggestions guys. i'm gonna see what i can figure out this weekend. could any one of these particular problems be the result of letting her sit too much the last few months? i never had anything like this happen when i used to driver her more often (so i don't think it has to do with a heat shield or spacer...).

i recharged the battery and now she starts fine off the bat, but again, after a drive i have to crank her for way too long, even after letting her cool for about an hour...but after she sat for 18hrs or so she started up great...?

just thought of one more thing: she sounds like she's cranking normal when i try to restart her after a drive, but she wont catch quickly, and after letting her crank for 5 plus seconds (or so) the cranking slows down like the batt is drying or something...i assume this is normal for cranking for that long?

i think i'll check for the "mist of gas" first (thanks yeti), and take it from there...