454 mpi hard cold start
04-27-2018, 08:50 PM
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454 mpi hard cold start
I have a 26 ft mirage with a 98 gen 6 454 mag mpi. Ive had the boat out about 5 times this year and it ran great. But the last time I had it out, it had a hard time starting (cold start) I had to give it some throttle to get it going and had to keep it at about 800 rpm to keep it going. after about 45 seconds I could back it down and it ran great. Yesterday I started it on the muffs and it did the same thing. Im not getting any codes.
Also, when I shut it down and started it up about 15 minutes later, it starts up like normal.
Any ideas?
Thanks
Dave
Also, when I shut it down and started it up about 15 minutes later, it starts up like normal.
Any ideas?
Thanks
Dave
04-28-2018, 08:39 AM
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+1 iac
04-29-2018, 04:24 PM
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I put a new cap, rotor, spark plugs and spark plug wires on it. everything looked good but it was time for all of that to be replaced anyway. I am going out right now to change the fuel water filter. I don't think that could be the problem but its due for a new one. I have been reading a lot about the IAC valve (I am new to fuel injection). I think I would like to start with the IAC. is there any way for me to test the IAC I have before I buy a new one?
04-29-2018, 04:35 PM
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If you plug in you could simply read the cycle of the motor, so assuming that you can't pull the IAC out and reconnect the harness, turn the key on and off and the plugger should move a little. It's not really telling you much but is it working or not. You should be able to hear the motor as well.
04-29-2018, 04:42 PM
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If you plug in you could simply read the cycle of the motor, so assuming that you can't pull the IAC out and reconnect the harness, turn the key on and off and the plugger should move a little. It's not really telling you much but is it working or not. You should be able to hear the motor as well.
04-29-2018, 05:27 PM
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Only way I know to read the IAC is with a scanner. The IAC on your motor is the same used on many motors like the Ford and Chevy. Don't know which you have without a serial number
