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Re: Exactly WHY is my car hard to start when warm?
[Re: 1_WILD_RT]
#328204
08/30/09 10:04 PM
08/30/09 10:04 PM
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Joined: Nov 2007
Posts: 1,522
Orleans, Ontario
moparcanuk
pro stock
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pro stock
Joined: Nov 2007
Posts: 1,522
Orleans, Ontario
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Quote:
Mine lights off instantly... I think the new fuel boils off due to engine heat.. In a modern fuel injected car where the fuel is injected & the fuel is always pressurized it's a non-issue but a carburator where the fuel sits on a hot engine....I've blocked the crossover & added a heat shield...
http://images.google.com/imgres?imgurl=h...sa%3DN%26um%3D1
This solved my buddy's starting problems so I tried one on my 440 air grabber. Had to remove it as there is not enough clearance. 
I'm going to try blocking off the heat risers and add a thin aluminum spacer with 2 gaskets. 
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Re: Exactly WHY is my car hard to start when warm?
[Re: 63stabamatic]
#328207
04/30/13 09:01 AM
04/30/13 09:01 AM
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Joined: Jan 2003
Posts: 25,200
Upper Midwest
MoparforLife
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 25,200
Upper Midwest
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Quote:
My hot starting problems were solved by going to non-ethanol fuel which is becoming more available here in the Rochester NY area. It started at marinas as the ethanol was killing marine fuel systems and engines. I now use it in everything. Here is website:
http://pure-gas.org/
Reason is that alcohol blends tent to have a much lower boiling point and will not take as much heat soak and will spill over the needle and seat causing a flooded condition. Starting warm/hot engines using blended fuels as you would a flooded engine by holding the pedal to the floor opening the throttle blades to allow more air to help clear the condition should help. Along with using a non blended fuel if possible.
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Re: Exactly WHY is my car hard to start when warm?
[Re: MoparforLife]
#328208
04/30/13 07:12 PM
04/30/13 07:12 PM
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Joined: Jan 2003
Posts: 5,303
Land 'O Lakes
RoadRunnerLuva
master
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master
Joined: Jan 2003
Posts: 5,303
Land 'O Lakes
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After reading the entire thread here...I admit to having the same problem. My setup is just a stock 360 engine with a Weiand dual plane manifold. A 3 year old Edelbrock #1406 600 cfm carb (junk IMO) and ceramic 1-5/8 headers. The car starts fine when cold....has NO spacer or shield on it.... when just warm, it very hard to re-start. This is even in 50-60 degree weather as others posted. I ordered (just about 2 hours before reading this thread) a 1/2" wood spacer and an aluminum heat shield kit from Jegs. I hope this helps out...and if not, I'll try the return line trick I read on here too. 
Plymouth Makes It!
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Re: Exactly WHY is my car hard to start when warm?
[Re: RoadRunnerLuva]
#328209
04/30/13 08:11 PM
04/30/13 08:11 PM
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Joined: Jun 2006
Posts: 5,159
CT
GTX MATT
master
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master
Joined: Jun 2006
Posts: 5,159
CT
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I read through this thread yesterday but didn't respond because the issue at hand was an old post, but here's my opinion.
While fuel percolation is an issue sometimes (and I have noticed with E-brocks in particular that I can hear the fuel boiling when I turn a hot car off, so listen for this) I think the majority of issues are cars with incorrectly set up chokes and incorrect timing.
How often do guys adjust their electric chokes?
In your case, with no spacer, I would start there. You don't need a half inch spacer or anything if you don't want one, but you can buy a thick carb flange gasket (like the factory ones) or stack a few of the thinner ones. However, if by warm you mean the car is 140 degrees you really shouldn't be having percolation issues, but a 195 degree engine with no spacer is going to have issues when turned off.
If it will re-fire within 2 minutes of being shut off but not after 10, then percolation is probably not your issue.
Now I need to pin those needles, got to feel that heat
Hear my motor screamin while I'm tearin up the street
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Re: Exactly WHY is my car hard to start when warm?
[Re: jbc426]
#328210
05/02/13 11:05 PM
05/02/13 11:05 PM
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Joined: Jul 2003
Posts: 5,180
upstate western ny
sogtx
master
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master
Joined: Jul 2003
Posts: 5,180
upstate western ny
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I like this idea ... Or you have a bad needle seat. Or misadjusted float levels.. Quote:
I had this problem and was also baffled until I spoke with Doug Dutra, the famous slant six guru. He explained what was happening:
When you shut off a warm engine, the heat from your engine's intake manifold is boiling the fuel in your float bowl and causing it to drip into the intake etc causing an excessively rich condition. This happens because the fuel percolation drops the float and allows more fuel from the still presurized fuel line, between the fuel pump and the needle and seat to flow more fuel into the carb to bring the float level back to normal. This continues until the pressure in the fuel line between the fuel pump and the needle and seat goes to zero. In the mean while, a significant amount of fuel has now percolated out of the carb AND the pressurized fuel line between the fuel pump and the carb (until the presure is released by the process). Quite a bit of gas ends up in the intake every time you shut off a hot motor.
This is how you fix it:
#1 Use two gaskets and a sheet of aluminum to isolate the carb from the intake manifold. This will likely require longer carb studs. Be sure to check for hood clearance. (this helped a lot, but did not eliminate the problem completely)
#2 Install a fuel return line from a 3-nipple fuel filter, which is available from any autoparts store between the fuel pump and the carb, and the fuel tank. The third nipple on the 3-nipple fuel filters has a metered orifice to limit the amount of fuel it flows. I had to install a return line and a 2 fitting fuel sending unit on my 68 slant six car to complete this installation. The car had an original 5/16 fuel line, so I added a 3/8ths line as the main fuel line and used the 5/16ths line as the return. I bought a dual fitting fuel sending unit for less than $50 off ebay, ran the lines, installed the 3-nipple filter. I never had a hot start problem again.
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Re: Exactly WHY is my car hard to start when warm?
[Re: sogtx]
#328211
05/02/13 11:19 PM
05/02/13 11:19 PM
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Joined: Dec 2007
Posts: 1,357
central Florida
VL21
pro stock
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pro stock
Joined: Dec 2007
Posts: 1,357
central Florida
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Quote:
#2 Install a fuel return line from a 3-nipple fuel filter, which is available from any autoparts store between the fuel pump and the carb, and the fuel tank. The third nipple on the 3-nipple fuel filters has a metered orifice to limit the amount of fuel it flows. I had to install a return line and a 2 fitting fuel sending unit on my 68 slant six car to complete this installation. The car had an original 5/16 fuel line, so I added a 3/8ths line as the main fuel line and used the 5/16ths line as the return. I bought a dual fitting fuel sending unit for less than $50 off ebay, ran the lines, installed the 3-nipple filter. I never had a hot start problem again.
Back in the early '90s I had a '66 Valiant, I had installed the super6 2bb intake setup on.
I did something similar, only not running a return line, I just T'd the hose from the 3rd nipple into the fuel line BEFORE the fuel pump.
My reasoning was that there was no pressure there, so anything bled off at the filter was just bled off.
So, was it just my imagination that made me think it solved my heat soak problem? 
It takes gasoline to interest me.
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Re: Exactly WHY is my car hard to start when warm?
[Re: cataclysm80]
#328213
05/03/13 07:34 PM
05/03/13 07:34 PM
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Joined: Apr 2005
Posts: 4,913
new berlin wisconsin
Mr T2U
master
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master
Joined: Apr 2005
Posts: 4,913
new berlin wisconsin
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Quote:
Quote:
This might make you feel better.
Mine has gotten to the point that it won't even start when warm. Nearly had it towed last week when I shut it down to fill up with gas. By the time the tow truck arrived it started and I was able to drive home. Fires up great cold, runs great, but if I turn it off and try to restart hot I can just crank away till the battery is nearly dead.
My original 1938 ford flathead does that same thing. I've been told it's caused by a bad coil that fails when it gets hot.
Check your spark next time it happens.
Tav
i had the same problem with my hemi. i have a electric fuel pump with a MSD ignition system. it used to start instantly hot or cold. then i started to have hot start problems that got worse over time. i replaced the coil without any improvement. i changed the distributor and the problems went away. a friend did some voltage test to the pick up coil and found that the pick up coil changed resistance when i warmed up.
Last edited by Mr T2U; 05/03/13 07:35 PM.
perception is 90% of reality
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Re: Exactly WHY is my car hard to start when warm?
[Re: 63stabamatic]
#328216
05/04/13 06:36 PM
05/04/13 06:36 PM
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Joined: Jan 2003
Posts: 14,470
renton, Washington
ph23vo
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,470
renton, Washington
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Quote:
My hot starting problems were solved by going to non-ethanol fuel which is becoming more available here in the Rochester NY area. It started at marinas as the ethanol was killing marine fuel systems and engines. I now use it in everything. Here is website:
http://pure-gas.org/
yep mine went away just by doing the non eth fuel.. we have a few stations around here that sell it..headed there in a few minutes actually!
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