new engine won,t start after running ...

grumpyvette

Administrator
Staff member
daprincipal said:
Should've known...

Just had my 468 completely built brand new motor. Quick fuel carb, electric choke.
Hydraulic roller motor, forged everything. Full MSD ignition, box, and coil blaster, and billet dizzy.

Car ran fine up until the cold weather hit, thought it was out of fuel went and put a couple of gallons of gas in it. Carb is pumping fuel by the accelerator pump. Cleaned with some carb cleaner. And still no start and I'm stumped. Fuel filter looks good, no clogs in fuel line, and fuel pump is working properly.

Thought about adjusting the electric choke to possibly richen the mixture, but I'm ruling that out until dead last.

Any ideas I'm very new to the carbed world, and this is my 1st car with a carb..

Any tips or ideas would be appreciated.
high pressure air and some carb cleaner solvent can be very helpful cleaning out sticky or dirty parts
nozzle.gif


carbcleanery.jpg

When trouble shooting a no start condition,it helps to have a multi meter and shop manual,then you should always drop back to the basics and don,t assume a darn thing is functional until you prove it to be so!
obviously check the valve adjustment, and ignition timing with a timing light, if the engine spins , and the starter , and battery connections if it won,t spin.
verify your getting fuel at the carb,and if the fuel filter is not fairly new change it out for new, and the float level is correct,verify that TDC on your timing tab and damper reflect real TDC, on the piston, verify the ignition timing is set correctly and that your actually getting spark at the plugs.
look for loose vacuum lines and loose electrical connections and check your coolant and oil fluid levels, pull trouble codes if you can, check all the fuses in the fuse panel.
Verify theres 12 volts at the battery before you start , and about 13.7-14.2 volts when the alternator spins, check your grounds resistance from frame to battery neg. with an ohms meter. verify the battery terminal connections are tight and not corroded

verify the plug gap is set at about .045 and your ignition wire ohms resistance is hopefully UNDER 1000 ohms per foot
pull a plug and verify your getting compression and the plugs are not soaked in fuel and fouled

viewtopic.php?f=70&t=967

viewtopic.php?f=70&t=875

viewtopic.php?f=70&t=4683

viewtopic.php?f=55&t=109

viewtopic.php?f=55&t=1115

viewtopic.php?f=55&t=1639

viewtopic.php?f=70&t=2798

viewtopic.php?f=44&t=882&p=45944&hilit=propane+leaks#p45944

http://garage.grumpysperformance.com/index.php?threads/no-computer-now-what.13973/#post-71209

infrared thermometers are a very useful tool to track down issues with tuning, or mal functioning sensors
T504-4254_product.jpg

viewtopic.php?f=50&t=138&p=168&hilit=infrared#p168
viewtopic.php?f=55&t=109


A quick VALVE ADJUSTMENT IF DONE CORRECTLY HAS THE POTENTIAL TO CLEAR MANY ISSUES RELATED TO IMPROPERLY ADJUSTED VALVES AND WHILE IT MAY NOT BE YOUR ISSUE ITS A FAIRLY COMMON SCREW-UP RELATED TO TUNING ISSUES
A visual inspection tool that easily fits thru a spark plug thread hole is valuable at times
PV618.jpg

GOOGLE PV-618 and PV-636
READ thru BOTH THESE RELATED THREAD's, ON FINDING TDC and related info

viewtopic.php?f=70&t=1015&p=1864&hilit=tabs#p1864
viewtopic.php?f=52&t=966&p=13811#p13811
chevfireor.gif


TUNING SKILLS MAY BE VERY USEFUL
viewtopic.php?f=55&t=109&p=44341&hilit=+reading+plugs#p44341

viewtopic.php?f=50&t=383&p=470&hilit=vacuum+gauge#p470

a leak down tester is always a good test tool to have access too
viewtopic.php?f=50&t=41&p=49&hilit=+leak+gauge#p49

SUM-900010-TL.jpg



http://www.harborfreight.com/cpi/ctaf/d ... mber=93547



vgauge.gif


BTW remember those cheap crappy fuel filters I told you to never use
glassfilter.jpg

well heres where they come in handy, you plug them into the rubber fuel line between the vacuum gauge and the intake plenum where they act like a pulse dampers making the vacuum needle stay a bit more steady and easier to read



A MULTI METER AND TIMING LIGHT WILL BE USEFUL
image_12926.jpg

http://www.harborfreight.com/5-in-1-dig ... 98674.html

http://www.summitracing.com/parts/MSD-8991/
timinglite6.jpg

boosted applications almost always require a richer fuel/air mix ratio,
n/a applications tend to foul plugs if the idle below about 2000rpm runs near 12.7:1 f/a ratio where max power is generally found
while every engine will require custom adjustments, the basic starting points will hold remarkably consistent
start by doing a compression test , and all cylinders should be within 7% max,and by verifying TDC and your timing tabs and damper reflect true tdc.
set the carb floats and verify your getting near 5 psi of consistent fuel pressure and ideally your using a fuel pump that can supply at least 50% more fuel volume than your engine requires with,the engine at max loads at max rpms
Idle- up too about 2500 rpm try for 14.7:1-15:1 f/a ratio
from about 2500 rpm- too about 4500 rpm try to smoothly and predictably transition the fuel/air ratio mix richer to about 13.5:1
from about 4500 rpm- too about 6500 rpm and higher ,try to smoothly and predictably transition the fuel/air ratio mix richer to about 12.5:1
your using reasonably fresh spark plugs with a .043 gap, ignition wire with a ohms lower than 500 ohms a foot resistance,the exhaust back pressure is less than 1 psi at peak rpms.

this is only a starting point on the engine tune but it generally gets you in the ball park and tends to reduce the chances of the engine reaching detonation conditions.
the ignition advance curve needs to be checked,the electrical grounds are checked,
your engine is running at least 10-15 psi of oil pressure per 1000 rpm with the correct engine clearances and your alternator and battery provide consistenly 13 plus volts at idle thru max rpm


volumetric.gif

FuelFlowDiagram02a1.jpg

Stoich.gif


chart3e.jpg





http://garage.grumpysperformance.com/index.php?threads/carb-tuning-info-and-links.109/

http://garage.grumpysperformance.com/index.php?threads/setting-up-your-fuel-system.211/
 
Last edited by a moderator:
Back
Top