Stalling out while in motion
#1
01-06-2019, 08:29 AM
Stalling out while in motion
The quick and dirty backstory. 1981 F-100 Custom, 6 cylinder inline. Bought off of Craigslist from someone that "rebuilt" the engine. Worked well for first six months, changed out starter and starter relay, transmission gasket (1/2 old fluid, 1/2 new fluid), and ignition control module. Will start up with some starter fluid (carb cleaner) sprayed into it, will run with gas pedal pressed in neutral, but will only drive 100 yards before stalling out and will not start back up again (even with the spray) for a few hours or next day. Any help on this would be greatly appreciated. Thank you in advance.
#2
01-06-2019, 09:44 AM
Welcome to the site..
Id verify which is missing on the stall, fuel, or spark.
Since it’s not firing on a spray assist, would seem spark. The module could have been tested prior to a replacement, but if spark is missing, pick up, coil, ignition input drop out all on the plate.
On a no start event, check for a hot active spark, if none, any voltage applied at the coil?
When it’s run in neutral, does it run good/idle? Or a forced run?
Id verify which is missing on the stall, fuel, or spark.
Since it’s not firing on a spray assist, would seem spark. The module could have been tested prior to a replacement, but if spark is missing, pick up, coil, ignition input drop out all on the plate.
On a no start event, check for a hot active spark, if none, any voltage applied at the coil?
When it’s run in neutral, does it run good/idle? Or a forced run?
#3
01-06-2019, 10:11 AM
Welcome to the site..
Id verify which is missing on the stall, fuel, or spark.
Since it’s not firing on a spray assist, would seem spark. The module could have been tested prior to a replacement, but if spark is missing, pick up, coil, ignition input drop out all on the plate.
On a no start event, check for a hot active spark, if none, any voltage applied at the coil?
When it’s run in neutral, does it run good/idle? Or a forced run?
Id verify which is missing on the stall, fuel, or spark.
Since it’s not firing on a spray assist, would seem spark. The module could have been tested prior to a replacement, but if spark is missing, pick up, coil, ignition input drop out all on the plate.
On a no start event, check for a hot active spark, if none, any voltage applied at the coil?
When it’s run in neutral, does it run good/idle? Or a forced run?
When it does start, it runs in idle, with gas pedal slightly pressed for 10 mins then dies out. If no pressure on gas pedal, it slowly dies out immediately.
#4
01-06-2019, 10:50 AM
Easy check,,
Put a spark tester inline and visible to the driver , have the air cleaner off.
When it stalls out,, check to see if there’s a ‘good hot’ spark present while cranking (?)
Next during the no start, looking down into the carb, pump the throttle a few times and see if the accelerator pump is spraying fuel. If a fuel spray/stream is present, the fuel bowl level is adequate and generally not a fuel delivery issue. At least for a no start..
You can also check for pump output for pressure and volume with the fuel line removed, but with the accelerator pump spraying fuel, It should re start if a good spark is or remains present.
If it will idle,, looking into the carb intake and observe , does the carb spill over, flood the engine and cause the stall?
Put a spark tester inline and visible to the driver , have the air cleaner off.
When it stalls out,, check to see if there’s a ‘good hot’ spark present while cranking (?)
Next during the no start, looking down into the carb, pump the throttle a few times and see if the accelerator pump is spraying fuel. If a fuel spray/stream is present, the fuel bowl level is adequate and generally not a fuel delivery issue. At least for a no start..
You can also check for pump output for pressure and volume with the fuel line removed, but with the accelerator pump spraying fuel, It should re start if a good spark is or remains present.
If it will idle,, looking into the carb intake and observe , does the carb spill over, flood the engine and cause the stall?
Last edited by Hayapower; 01-06-2019 at 10:53 AM.
#5
01-06-2019, 10:56 AM
Those carbs like to come loose over time between the throttle body (base) and main body. If you grab the top portion and twist/wiggle, if the carb screws are loose there will be some movement between the two carb portions...
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