When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
So I've had my 72 f100 for about 6 months now. Everytime I cold start it. It starts right up if I pump the gas once. After it warms up and I go to the store and leave it in the parking lot for no more than 10 minutes I come out and try to start it. I don't give it any gas and when I turn the key it sounds like it's about to start but then doesn't and I have to give it almost full gas to have start up. Does anyone have this problem or know a solution? I feel like having it sit for 10 minutes it shouldn't have to be given gas to start up. My grandpa had the motor rebuilt back in 2006 and the engine only has about 8000 miles on it and I replaced the spark plugs/wires in August. Thanks for all the help
Just to add to yours...mine won't start in the am without holding my foot on the gas for a few minutes and I also have the same issue when I get somewhere and let it sit for just a couple minutes. In the warmer weather though it will fire up with no issues in the am or after motor cools but like Jake, when motor is warm...takes a while to get started
You both have carburetion issues. Mine kicks right off with one pump in the morning, then just turn the key the rest of the day, no matter the interval of sitting.
My last 390 gave me fits in the warm weather. The gas would perk out and flood it on a short hot soak, like running in a store for 10-15 minutes. I tried different spacers and nothing cured it until I put a 350 Holley on and I never had another problem. I had one other 68 360 that would vapor lock in the summer heat. and stall after a hot soak.
I have no explanation why only certain trucks do it but some do, maybe a blown power valve??
hey guys i have a 71 f-250 sport custom that i have replaced the coil the points and condenser also re added the ballast resistor and im having issues getting to fire back up it has an edelbrock 650 cfm carb and a 950 performer intake on a 390 bored .30 over and its giving me alot of issues with starting any help would be appreciated
My last 390 gave me fits in the warm weather. The gas would perk out and flood it on a short hot soak, like running in a store for 10-15 minutes. I tried different spacers and nothing cured it until I put a 350 Holley on and I never had another problem. I had one other 68 360 that would vapor lock in the summer heat. and stall after a hot soak.
I have no explanation why only certain trucks do it but some do, maybe a blown power valve??
I had this issue with an Autolite.. the accel pump bellow had a small pinhole which caused the fuel bowl to drain and flood the engine. If after a short stop, it was really hard to start because the fuel hadn't had the time to evaporate. If it sat for longer, then it would fire right up.
The same issue could happen, for example, if the needle wasn't properly seating.
Most of the problems can be the result of the "excuse" that we have to put up with as gasoline. I have seen aluminum shields that were put under the carberators that extended out as wide as possible that acted as a heat sink.
Blocking off the heat riser passage between the head and manifold may also help if it does not get too cold where you live.
Also be sure that the bypass circuit is putting 12 volts to the coil when cranking, and of course electronic ignition with a good coil like a MSD Blaster 2 may help.
The final answer of course is fuel injection as a throttle body conversion, not cheap but the overall driveability makes it worthwhile.
As above, you have carburetor issues. Ignition does not know whether or not the engine is hot or cold.
Pull the carb and rebuild. Then set the choke properly and your problems will go away.
Most of the problems can be the result of the "excuse" that we have to put up with as gasoline. I have seen aluminum shields that were put under the carberators that extended out as wide as possible that acted as a heat sink.
Blocking off the heat riser passage between the head and manifold may also help if it does not get too cold where you live.
Also be sure that the bypass circuit is putting 12 volts to the coil when cranking, and of course electronic ignition with a good coil like a MSD Blaster 2 may help.
The final answer of course is fuel injection as a throttle body conversion, not cheap but the overall driveability makes it worthwhile.
..
2x on the starting by pass circuit. But guess most guys have no idea where or how to check this.
Ford had issues yrs ago with the ign. switch that the round rear plug contacts. These were never recalled but should have..
These causes hard starting issues & restarting.
A fast test is by hot wiring it when your having hard starting issues.
Place a jumper wire from Batt+ to the coil+ and try starting it.
Not saying this is your issues but sounds like heat soak or choke is not opening all the way.
orich