Hard Start after Warm-Up
Thread Starter
Navigator
Joined: Feb 2003
Posts: 9
Likes: 0
From: Oak Park Ca
Hard Start after Warm-Up
I own a 1980 Corvette, runs great ( now that the vacuum leak is fixed) but after the car has been driven when I shut it off it won't restart. It's not the battery or volts as it cranks fast it just won't catch and fire up. Feels like not gas is getting to engine. If I sit and wait after several attempts to restart, the car will suddenly come to life and starts right up. Any thoughts? Carburator or ignition or what?
Once it starts it runs like a dream.
Thanks to the gentlemen that helped me with the vacuum leak which was causing a shaky idle. That's fixed - Thank you.
Once it starts it runs like a dream.
Thanks to the gentlemen that helped me with the vacuum leak which was causing a shaky idle. That's fixed - Thank you.
Instructor
Joined: Apr 2003
Posts: 248
Likes: 1
From: Kansas City MO
Re: Hard Start after Warm-Up (Corvette Lady)
I have the exact same issue with my '78 TA. I put a new battery and starter on and the only reason that it helped is it brought my cranking RPMs up enough that I can "power through" with about 1/4 throttle until it kicks off.
It seems like what I've heard called "vapor lock" but I'm not sure excatly what the problem is or how to cure it but I'm pretty sure it's carb related. Any gurus out there want to enlighten us? :confused:
It seems like what I've heard called "vapor lock" but I'm not sure excatly what the problem is or how to cure it but I'm pretty sure it's carb related. Any gurus out there want to enlighten us? :confused:
Thread Starter
Navigator
Joined: Feb 2003
Posts: 9
Likes: 0
From: Oak Park Ca
Re: Hard Start after Warm-Up (Corzvette69)
Got your email, thanks. When a starter is overheated I thought you just heard a clicking sound from the engine, am I wrong? because my engine is winding up just won't catch, no clicking sound. But you may be on to something which is why after I wait a few minutes it finally starts - starter would be cooling down. Thanks!
Instructor
Joined: Mar 2003
Posts: 235
Likes: 0
Re: Hard Start after Warm-Up (devveldogg)
Doesn't sound like a starter issue to me. Might be a weak fuel pump. Where it can get the fuel in better when cold cause the choke is kicked on. Where after it is warm the choke is off and less Vacuum is created making it harder to take in fuel. Especially if the pump is weak. Also could be the ignition modual. These have been know to cause problems when the car gets hot. I would do some simple checks next time you have a problem. Pull a plug out and check for spark, hold it against something to ground it. Don't hold it with your hand, use a screw driver or something that has a plasitc handle. Then get somebody to crank the engine over while you watch the plug to see if it is getting spark. If it is then your problem is elsewhere. To check to see if your getting fuel, take the air cleaner off and look down the carb while somebody cranks it over. Be Carefull, do not look straight down the carb, kinda look from the side. If it were to backfire through the carb you might be painting on new eyebrows. Thats where I would start. Good luck.
Safety Car
Joined: Jun 2001
Posts: 4,004
Likes: 2
From: Severna Park Md
Re: Hard Start after Warm-Up (Corvette Lady)
Since it cranks fast but wont start I would rule out a starter problem. Vapor lock is caused by fuel in the lines boiling from high underhood temps. An engine expierencing vapor lock will usually start at first but then die out shorly after. From what you describe, it sounds like an intermitant problem of no spark to the plugs. You probably have an HEI distributor which uses an ignition module mounted inside the distributor to controll spark. I would suspect the module is causing the problem. They can fail intermitantly like that. Next time it happens, open the hood and tap on the base of distributor with a tire iron. It may fire right up then, which could support the faulty module idea. The HEI on my truck would do this and I could get it to start right away most of the time by tapping the dist base. Somehow it would shock the module into function again. I recently replaced that dist and have had no problems with it since.
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Le Mans Master
Joined: Nov 2000
Posts: 8,220
Likes: 208
Re: Hard Start after Warm-Up (Corvette Lady)
If you don't even get the clicking sound, it's the solenoid, that is enjioying too much heat! I had the same problem. You can try to solve it with some Termo Tec stuff. I just swapped for Hamburger mini starter, it was the final cure! :cheers:
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
Re: Hard Start after Warm-Up (Corvette Lady)
Had this same problem. Cold the car started right up but pull in for gas, shut it off and you prayed it would start. After a few attempts it fired right up but it was embarrassing cranking it and wondering if I was going to need it pushed away from the pumps.
It turned out to be an leaking foat bowl. The fuel would leak out the bottom of the carb when the motor was shut of flooding the motor. After a few attempts at starting the motor would clear itself of raw fuel and fire right up.
How I discovered this is when I got home I removed the sight plugs in the fuel bowls, in my case 4 of them with twin carbs and watched the floats. Sure enough one level dropped.
I left it over night and the one dropping was clearly going down continually. I replaced the metering plate and all my starting problems went away.
If it' s a holley the metering plate can develope and internal leak. It most likely in not the gasket. I tried replacing the gasket after remachiing the gasket surface to make the plate flat but it never worked.
Good luck with your problem but is sure sounds like a leak to me.
It turned out to be an leaking foat bowl. The fuel would leak out the bottom of the carb when the motor was shut of flooding the motor. After a few attempts at starting the motor would clear itself of raw fuel and fire right up.
How I discovered this is when I got home I removed the sight plugs in the fuel bowls, in my case 4 of them with twin carbs and watched the floats. Sure enough one level dropped.
I left it over night and the one dropping was clearly going down continually. I replaced the metering plate and all my starting problems went away.
If it' s a holley the metering plate can develope and internal leak. It most likely in not the gasket. I tried replacing the gasket after remachiing the gasket surface to make the plate flat but it never worked.
Good luck with your problem but is sure sounds like a leak to me.
Le Mans Master
Joined: Jan 2003
Posts: 6,575
Likes: 1
From: Tuttle OK
Cruise-In VIII Veteran
Re: Hard Start after Warm-Up (norvalwilhelm)
Had this same problem. Cold the car started right up but pull in for gas, shut it off and you prayed it would start. After a few attempts it fired right up but it was embarrassing cranking it and wondering if I was going to need it pushed away from the pumps.
It turned out to be an leaking foat bowl. The fuel would leak out the bottom of the carb when the motor was shut of flooding the motor. After a few attempts at starting the motor would clear itself of raw fuel and fire right up.
How I discovered this is when I got home I removed the sight plugs in the fuel bowls, in my case 4 of them with twin carbs and watched the floats. Sure enough one level dropped.
I left it over night and the one dropping was clearly going down continually. I replaced the metering plate and all my starting problems went away.
If it' s a holley the metering plate can develope and internal leak. It most likely in not the gasket. I tried replacing the gasket after remachiing the gasket surface to make the plate flat but it never worked.
Good luck with your problem but is sure sounds like a leak to me.
It turned out to be an leaking foat bowl. The fuel would leak out the bottom of the carb when the motor was shut of flooding the motor. After a few attempts at starting the motor would clear itself of raw fuel and fire right up.
How I discovered this is when I got home I removed the sight plugs in the fuel bowls, in my case 4 of them with twin carbs and watched the floats. Sure enough one level dropped.
I left it over night and the one dropping was clearly going down continually. I replaced the metering plate and all my starting problems went away.
If it' s a holley the metering plate can develope and internal leak. It most likely in not the gasket. I tried replacing the gasket after remachiing the gasket surface to make the plate flat but it never worked.
Good luck with your problem but is sure sounds like a leak to me.
Le Mans Master
Joined: Jun 2002
Posts: 8,339
Likes: 24
From: I can walk to MA
Re: Hard Start after Warm-Up (Avette4me)
I support two of the above theories:
Norvals idea of the carb leaking into the intake ... and ...
John's idea of an intermittent ignition module.
I have seen these symptoms in both these cases before.
Good luck. The ignition module is the easiest to fix or try - IMO.
:seeya
Norvals idea of the carb leaking into the intake ... and ...
John's idea of an intermittent ignition module.
I have seen these symptoms in both these cases before.
Good luck. The ignition module is the easiest to fix or try - IMO.
:seeya
Melting Slicks
Joined: Dec 2000
Posts: 3,407
Likes: 2
From: Carmichael CA
Re: Hard Start after Warm-Up (Corvette Lady)
Definitely a carb problem. Chances are the engine is running too rich, possibly due to the choke not opening all the way or not soon enough. A quick test would be to drive it until it gets warmed up, then shut it down, take the air cleaner off and inspect the choke plate to make sure it's in the wide open position. If not, then adjust it so that it's open all the way...it should then start fine.
During spring and fall the air temperature is moderate so the choke may not be adjusted well enough to open all the way during spring, or close enough during the fall. When I was a fleet mechanic I found that some vehicles always need some adjusting to their choke during the change in seasons.
Hope this helps
During spring and fall the air temperature is moderate so the choke may not be adjusted well enough to open all the way during spring, or close enough during the fall. When I was a fleet mechanic I found that some vehicles always need some adjusting to their choke during the change in seasons.
Hope this helps
Pro
Joined: Jan 2002
Posts: 695
Likes: 0
From: Ashley Michigan
Re: Hard Start after Warm-Up (Corvette Lady)
Just to get things straight, does it try to fire? but can't stay running? I didn't see where you stated one or the other. If it fires, but doesn't stay running, I'd go with a starter- selenoid's bad. Had that problem on my car, now starts everytime, no problem.
Pro
Joined: May 2001
Posts: 596
Likes: 0
From: Yardley PA
Re: Hard Start after Warm-Up (Steve Grodin)
If you have heat soak the starter won't turn the engine over. :chevy
It could be vapor lock. vapor lock means that the fuel in the lines gets very hot and builds a fuel vapor. This gets pumped into the carb. And then the car won't drive. However VL usually means that the car starts on the gas in the fuel-bowl and then stops.
So you more likely don't have a strong enough spark. Or you have the carb dumping fuel down the manifold. Does it smell "rich" after a successfull hot-start? If so, you probably get too much gas.
Good luck. This kind of troubleshooting can be a pain :(
Prost:cheers:
Stefan
Burning Brakes
Joined: Dec 2000
Posts: 1,183
Likes: 2
From: Des Moines Iowa
Re: Hard Start after Warm-Up (Rockn-Roll)
Agree with Rockn-Roll and others suggesting a fuel rich problem to me.
My '81 acts just like Norval said, and after running a short while, like going to gas station and shutting it off, sometimes it won't re-start, and I take the air cleaner lid off, and stick a screw driver in choke butterfly to hold it open, and the engine then starts right away! I guess I need to adjust the electric choke or linkage, but I don't see any adjustment screws on my electric choke, just rivets.
My '81 acts just like Norval said, and after running a short while, like going to gas station and shutting it off, sometimes it won't re-start, and I take the air cleaner lid off, and stick a screw driver in choke butterfly to hold it open, and the engine then starts right away! I guess I need to adjust the electric choke or linkage, but I don't see any adjustment screws on my electric choke, just rivets.
Instructor
Joined: Apr 2003
Posts: 248
Likes: 1
From: Kansas City MO
Re: Hard Start after Warm-Up (norvalwilhelm)
It turned out to be an leaking foat bowl. The fuel would leak out the bottom of the carb when the motor was shut of flooding the motor. After a few attempts at starting the motor would clear itself of raw fuel and fire right up.
Thread Starter
Navigator
Joined: Feb 2003
Posts: 9
Likes: 0
From: Oak Park Ca
Re: Hard Start after Warm-Up (Corvette Lady)
THANKS TO ALL OF YOU WHO REPLIED TO MY POST. THE PROBLEM IS SOLVED ..
IT TURNED OUT TP BE THE DISTRUBUTOR. THERE WAS NO SPARK AT ALL. HAD ROTOR, IGNTION COIL AND MODULE REPLACED. CAR STARTS FINE NOW.
THANKS AGAIN FOR EVERYONES SUGGESTIONS.
IT TURNED OUT TP BE THE DISTRUBUTOR. THERE WAS NO SPARK AT ALL. HAD ROTOR, IGNTION COIL AND MODULE REPLACED. CAR STARTS FINE NOW.
THANKS AGAIN FOR EVERYONES SUGGESTIONS.
