Hot start?
Thread Starter
Racer
Joined: Apr 2008
Posts: 436
Likes: 2
Hot start?
Been playing with the zz454 a few days now. When the engine is cold (I.e. Came out in the morning to drive it) it fires up almost instantly. However, after driving around for a while and then turning thecar off (I.e. Stopping for gas), it's a bitch to get started again. Every time it goes like this...turn over and engine turns real slow, like a low batt sort of. Then I let off, wait 10 sec then try again, this time engine/starter sounds completely normal, but it won't start...it's just not getting ignition, but there's definitely gas in the carb. This could go from 2-6 attempts. Once it finally starts, it runs fine. No starting problems when allowed to sufficiently cool.
I have a 750 speed demon. Any ideas? Thanks!
I have a 750 speed demon. Any ideas? Thanks!
Drifting
Joined: Apr 2008
Posts: 1,540
Likes: 51
From: Lexington Park Maryland
Le Mans Master
Joined: Jan 2006
Posts: 6,504
Likes: 139
From: Butler Pa
Every time it goes like this...turn over and engine turns real slow, like a low batt sort of. Then I let off, wait 10 sec then try again, this time engine/starter sounds completely normal, but it won't start...it's just not getting ignition, but there's definitely gas in the carb. This could go from 2-6 attempts. Once it finally starts, it runs fine. No starting problems when allowed to sufficiently cool.
I have a 750 speed demon. Any ideas? Thanks!
I have a 750 speed demon. Any ideas? Thanks!
Burning Brakes
Joined: Dec 2008
Posts: 971
Likes: 45
From: Middlesex NJ
The condition I if find odd is that its the initial cranking after being stopped for only a few minutes that is slow. Almost like you have fluid leaking into the cylinders (carb leaking down quickly) or too much advance. If you stop cranking for a few and then retry the engine it cranks like normal in your description but wont start like being flooded? Heat soak wont go away that fast in my opinion.
I am not sure if you have an electronic distributor or not. I wonder if your distributor is overly advanced due to excessive play in the shaft or maybe the module is acting up when hot.
I had an HEI with a sloppy shaft give me crazy advance when you would try to start at times. You would have a condition like yours then crank it again and the engine would start just fine. Very weird.
Sounds like flooding with either gas or coolant leaking or an advance issue with the distributor.
You could also check the pinion clearance on your starter. Maybe its just too close when the engine is hot and binding up at times. Lots of variables to consider.
good luck
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Thread Starter
Racer
Joined: Apr 2008
Posts: 436
Likes: 2
I have a gm high torque mini stater. I'm guessing the shield is still a good idea, but I wonder about the carb thing. I have an HEI dizzy set at 4 deg initial timing like gm calls for. That sounded very low to me and some on here said that, but with the help of a very experienced mechanic the engine idles well at that setting. Seems like flooding makes sense...what specific things on the carb should I check?
Edit: something else I thought of. When working on things, there was several times I started the engine, ran for a few minutes, then shut off. I'd then start it up a few min later to check progress and it would start fine. This seems to only happen when the car has been run for an extended period of time. If the carb was leaking fuel, wouldn't the engine flood regardless if it had been running for 2 min or 20 min?
Edit: something else I thought of. When working on things, there was several times I started the engine, ran for a few minutes, then shut off. I'd then start it up a few min later to check progress and it would start fine. This seems to only happen when the car has been run for an extended period of time. If the carb was leaking fuel, wouldn't the engine flood regardless if it had been running for 2 min or 20 min?
Last edited by FlyViper; Feb 4, 2010 at 12:45 PM.
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
Whats heat soak?
How come when the car was new it never had a so called "heat soak" problem?....'everything gets hot under a hood...So hot you cant remove some parts for hours waiting for it to cool down to a temperature where it could be handled...... I would look for evidence of a bad ground right under the battery on the transmission cross member and brush it clean then reattach it...A car will seek ground wherever it can find one, even as remote as steel brake lines..Or a shift cable or possibly the emergency brake cables. Starters are often incorrectly blamed for such experiences that you are having...
the factory Delco mini gear reduction starter used on late model 454`s and 350`s thats been suggested is a good choice 'IF' its the starter...but starters that restart engines are normally good and test that way....
the factory Delco mini gear reduction starter used on late model 454`s and 350`s thats been suggested is a good choice 'IF' its the starter...but starters that restart engines are normally good and test that way....
Thread Starter
Racer
Joined: Apr 2008
Posts: 436
Likes: 2
I actually think it's a flooding issue. The slow turning is kind of weird, but after adjusting the carb (for a different reason), the problem is not nearly as bad. Lars' paper mentioned the speed demon boiling fuel after shutdown, thus leading to gas released into the manifold...i.e. flooding. I haven't had a chance to get the heat shield he recommends. I'm thinking that will probably solve it, but for now, it's good enough. Thanks for the help.
Burning Brakes
Joined: Dec 2006
Posts: 780
Likes: 0
From: Also available in sober.
I had a terrible problem with my new Holley carb heat soaking and boiling fuel into the manifold after the car was shut off. To prove it to myself I drove the car around on a warm day and then parked it. I took the air cleaner off and waited a minute or two and PRESTO, I could look into the carb venturi and see the fuel boiling out of the booster venturi and down into the manifold. I have since installed an aluminum heat shield and the problem seems to have subsided.
Melting Slicks
Joined: Apr 2002
Posts: 2,337
Likes: 14
From: Norfolk VA
How come when the car was new it never had a so called "heat soak" problem?....'everything gets hot under a hood...So hot you cant remove some parts for hours waiting for it to cool down to a temperature where it could be handled...... I would look for evidence of a bad ground right under the battery on the transmission cross member and brush it clean then reattach it...A car will seek ground wherever it can find one, even as remote as steel brake lines..Or a shift cable or possibly the emergency brake cables. Starters are often incorrectly blamed for such experiences that you are having...
the factory Delco mini gear reduction starter used on late model 454`s and 350`s thats been suggested is a good choice 'IF' its the starter...but starters that restart engines are normally good and test that way....
the factory Delco mini gear reduction starter used on late model 454`s and 350`s thats been suggested is a good choice 'IF' its the starter...but starters that restart engines are normally good and test that way....
Well when the car was new it, the vehicle came with a starter heat shield for starters. Also, factory vehicles came with cast iron rams horn exhaust manifolds. Some if not most members run headers which increase engine compartment heat. Also most leave off a third insulated wire that is a ground to the starter. The aftermarket solenoids do not tolerate the heat too well and the thin wire that is wrapped around the solenoid cannot tolerate the resistance to it (engine heat) and it usually takes 5-10 minutes for the engine compartment to cool enough to allow the starter to crank at it's proper speed.
Last edited by Oldguard 7; Mar 3, 2010 at 05:50 PM.
Pro
Joined: Nov 2009
Posts: 684
Likes: 0
From: Alberta
I had a 1974 BB Vette with OEM exhaust manifolds that was missing the starter heat shield.
So I went and bought the one for a BB truck engine (cheaper than the Vette part by half back in 1985) and had it installed, solving the hot start problem I had.
Ran the stock QJ carb as well.........never had trouble with it.
So I went and bought the one for a BB truck engine (cheaper than the Vette part by half back in 1985) and had it installed, solving the hot start problem I had.
Ran the stock QJ carb as well.........never had trouble with it.
Last edited by 10caipirinhas; Mar 3, 2010 at 06:11 PM.
Advanced
Joined: Jun 2006
Posts: 94
Likes: 0
From: Chehalis Wa
changed both ground cables, one from the battery, and one under the engine. There was corrosion inside of the battery cable. It seemed to be OEM as it still had undercoating on it. 32 Year old Battery cable... go figure, Now I have higher charging voltage too.
Solved my problem with hot start.
Solved my problem with hot start.
