1986 f150 302 efi getting spark and correct fuel pressure still won't start
05-03-2015, 07:38 PM
#11
It was running great and it all started with a slight miss, as a little time went on the harder the miss. It finally quit running and it wouldn't start. The fuel pressure at the rail is 40lbs. It has spark, not sure what to look for on how strong it should be
05-03-2015, 08:20 PM
#12
Truck will run at 30 to 45 psi fuel pressure, so that's good enough. I look for a healthy blue spark. A wimpy looking yellow one is not optimum.
Best way to check spark without all the fancy gizmos is to plug a spare spark plug into the end of one of the wires then use a booster cable from the metal body of the plug to battery ground.
Now crank the motor and see whether you've got a good hot spark.
fuel/air, spark and timing are required for ignition. If you have those, it should fire.
I'll read the thread from the beginning and see if I can think of anything to add.
Best way to check spark without all the fancy gizmos is to plug a spare spark plug into the end of one of the wires then use a booster cable from the metal body of the plug to battery ground.
Now crank the motor and see whether you've got a good hot spark.
fuel/air, spark and timing are required for ignition. If you have those, it should fire.
I'll read the thread from the beginning and see if I can think of anything to add.
05-03-2015, 08:27 PM
#13
OK, look for a good spark. A weak spark could indicate a weak coil or bad wire/cap.rotor.
If you have a spark, starting fluid will be the best way to bypass the injectors/fuel system.
Give it a 3 second burst straight into the throttle body. Then crank it. If it fires, it's a problem with the injectors not opening.
If it doesn't, and you have spark, it would most likely be a timing issue.
That's all I've got at this point.
If you have a spark, starting fluid will be the best way to bypass the injectors/fuel system.
Give it a 3 second burst straight into the throttle body. Then crank it. If it fires, it's a problem with the injectors not opening.
If it doesn't, and you have spark, it would most likely be a timing issue.
That's all I've got at this point.
05-03-2015, 09:02 PM
#14
OK, look for a good spark. A weak spark could indicate a weak coil or bad wire/cap.rotor.
If you have a spark, starting fluid will be the best way to bypass the injectors/fuel system.
Give it a 3 second burst straight into the throttle body. Then crank it. If it fires, it's a problem with the injectors not opening.
If it doesn't, and you have spark, it would most likely be a timing issue.
That's all I've got at this point.
If you have a spark, starting fluid will be the best way to bypass the injectors/fuel system.
Give it a 3 second burst straight into the throttle body. Then crank it. If it fires, it's a problem with the injectors not opening.
If it doesn't, and you have spark, it would most likely be a timing issue.
That's all I've got at this point.
05-05-2015, 07:34 AM
#17
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I had the same problem- I checked every thing and warrentyed out all of the parts that I could- desided to put the engine on top dead center, then I had my son watch the rotor while I turned the crank backwards, when he told me the rotor started to move, I stopped turning. Went up to see where the timing was. I was off by 15 degrees. To much slack. I then started to tear down to the timing chain-found out that the cam sprocket teeth were chewed up.