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-   -   502 mpi hard restart (https://www.offshoreonly.com/forums/general-q/376803-502-mpi-hard-restart.html)

lush 08-22-2022 11:14 AM

I didn't try the noid lights but the weekend before i unpluged the fuel pump wire and when i cranked it at full throttle fuel pressure held but a low idle it would drop fast. I replaced the ign module but not the pickup. yesterday the dash tach would move when cranking but didnt on the computer ( but even with it running the rpm on the MEFI scan is all over the board)

DrFeelgood 08-22-2022 11:18 AM

I could be totally off base here, but I always think of a leaky injector or two, when a warm restart is difficult and aided by clear-flood mode. I know you had them gone through, but that doesn't mean they are all still good.

lush 08-22-2022 11:44 AM

Besides watching for rail pressure to drop is there any other test besides pulling them out and finding a shop to test them?

DrFeelgood 08-22-2022 11:47 AM


Originally Posted by lush (Post 4842339)
Besides watching for rail pressure to drop is there any other test besides pulling them out and finding a shop to test them?

Looking at plugs might give clues about a rich condition in one or more cylinders. Wouldn't be a slam dunk for a leaky injector but it might narrow down which injectors are suspicious?

DrFeelgood 08-22-2022 11:50 AM

Also, this might be a stretch, but if you pull the plenum and use a borescope in each intake port, you might be able to see an injector tip leaky when the rail is pressurized.

lush 08-22-2022 12:10 PM

Thats a good ideal. I tried that a week or two ago but i only have a cheap scope without a side shooting camera. Maybe its time to upgrade :)

lush 08-23-2022 01:04 PM

I was just thinking about possible leaking injectors and when i shut it off Sunday it was only seconds before i tried to restart it with no luck. Could they leak that fast?

DrFeelgood 08-23-2022 01:11 PM


Originally Posted by lush (Post 4842493)
I was just thinking about possible leaking injectors and when i shut it off Sunday it was only seconds before i tried to restart it with no luck. Could they leak that fast?

My knee-jerk reaction is probably not, but I guess it depends on the severity, and how many of them.

zz28zz 08-23-2022 03:34 PM

A trick I did on my car was to pull the fuel rails up 6" or so (leave fuel lines connected), pull the injs and install them in the fuel rail, power up fuel pump and see if any leak. Not sure this will work on your eng or not. My injs had little clips to secure them in the fuel rails.

DrFeelgood 08-23-2022 03:53 PM

The MEFI-1 injectors definitely don't have retention clips so you could wind up shooting the injectors out of the rail once it's pressurized, with a mess of fuel spray. I'm not sure about the later MEFI 3style but I think the same is true for those.


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