mercruiser 454 mag mpi will not start

J

Jwaldron

Recruit
Joined
May 30, 2012
Messages
3
Ok any help will be great! Here is the problem. I have a 1996 mercruiser 454 mpi mag that will only start if you spray fuel in the plenum. I have a new tps sensor, new fuel filter, cap and rotor, compression is 150 in every cylinder. Also new mechanical lift pump. I have not scanned for codes because I have no scan tool and there is not one locally. Once you spray gas in the plenum it fires right up and runs but runs rich and dies out if the idle drops 1200rpm. Not sure whats going on??? Any help will be great!
Thanks
 
Don S

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: mercruiser 454 mag mpi will not start

You are going to need to do some fuel pressure checks of the hi pressure fuel pump, and you are going to need a scan tool like this to see what is going on.
Along with the OEM service manual you can download HERE.

Sorry, but it takes tools to troubleshoot these systems.
 
J

Jwaldron

Recruit
Joined
May 30, 2012
Messages
3
Re: mercruiser 454 mag mpi will not start

Don S said:
You are going to need to do some fuel pressure checks of the hi pressure fuel pump, and you are going to need a scan tool like this to see what is going on.
Along with the OEM service manual you can download HERE.

Sorry, but it takes tools to troubleshoot these systems.
Click to expand...

Thanks again for the manual its been a big help! The problem I have now is, it starts up and will not idle most of the time, and if it idles it idles really rough! I unplug the map sensor and it idles great just wont throttle up to good. I replace the Map and same thing happens... I brought it to a local marine and they cant figure it out! And they had a scan tool! Although they dont see many boats up here like this! Any help would be great! Thanks a ton
Jeremy
 
You must log in or register to reply here.
Top