502 EFI hard start
05-09-2004, 08:29 PM
#1
Jerry B
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502 EFI hard start
1993 Fountain w/twin 502 EFI's.
Both engines start fine when cold but one engine starts hard after normal operating temp is reached. Engine cranking speed is fine. I have to apply some throttle to get it to start and that still takes some time. It acts like there is no fuel. I can hear the electric pump in the VSP tank cycle when the key is turned on so I know it's running. After the enging starts it runs perfect until I shut it off again. It does'nt make any difference if it sits for two minuets or 15. It still is hard to start. Seems to me that if the fuel pump was having a problem it would not run right after started. Kind of acts like vapor lock. Both engines are funning about 145 degres. I guess I need to check the fuel pressure but not sur where to do so.
Thanks for anyones help
Both engines start fine when cold but one engine starts hard after normal operating temp is reached. Engine cranking speed is fine. I have to apply some throttle to get it to start and that still takes some time. It acts like there is no fuel. I can hear the electric pump in the VSP tank cycle when the key is turned on so I know it's running. After the enging starts it runs perfect until I shut it off again. It does'nt make any difference if it sits for two minuets or 15. It still is hard to start. Seems to me that if the fuel pump was having a problem it would not run right after started. Kind of acts like vapor lock. Both engines are funning about 145 degres. I guess I need to check the fuel pressure but not sur where to do so.
Thanks for anyones help
05-09-2004, 08:58 PM
#2
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My 502 mpi did the same thing, start fine cold, and after that had to apply throttle. It would not idle good when it warmed up. Ended up being bad IAC valve. It checked good on the test my mechanic run on it as did everything else, but when he took it apart I think he said the plunger on the end was broke off. Not sure if this is your problem or not, but good luck.
05-09-2004, 11:02 PM
#3
Charter Member
Mine does same thing, just one motor gives me fits. I have to give almost full throttle to get it to fire up.
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05-12-2004, 10:10 PM
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Jerry B
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I would like to have it start right. Kind of embarrasing at the dock to have a nice boat with people looking and it just cranks forever before starting. Also puts extra wear on the starter which I dont even want to think about taking off. I used to think the one on my jet boat was bad but I could at least see it. I'm going to get two fuel gages to mount on the engines so I can see a side by side comparison before I start getting into sensors. It could be an IAC but it idles fine. I have a tester at work that will plug into the IAC that will allow me to operate it in and out while engine is running. If idle speed changes I at least know the IAC is capable of working. I will eventually get it fixed and will post what fixed mine. Maybe it will help others.
Thanks for the input.
Thanks for the input.
