6.2l mpi hard start

[k4ubr]

it is hard to start. have to advace throttle to start . on the scan tool im only seeing 52% iac duty at idle.. when i do iac test wile running there is no change in the motor rpm. ( once started it runs fine)

this is a 2005 6.2l bravo3 , frest rebuild, new plugs,wires, cap,rotor, iac, fuel filters, fuel pressure 42psi not running 38psi under full load.. has any one seen probles with leaking inj. on late modle mpi.

PS.
A BAD NEW MANIFOLD STRAIT FROM MERC. DUMPED SALTWATER IN THE MOTOR.
STUCK RINGS. SO THIS IS WHY IT WAS REBUILT

 

[JustJason]

Re: 6.2l mpi hard start

So what does the IAC read at 1500rpms? It should go up and down with throttle.
Any black smoke on start up?
Most importantly... how is your cranking rpms.... does it crank fast like your car... or slow like an power walking grandmother.

 

[Fun Times]

Re: 6.2l mpi hard start

it is hard to start. have to advace throttle to start . on the scan tool im only seeing 52% iac duty at idle.. when i do iac test wile running there is no change in the motor rpm. ( once started it runs fine)

this is a 2005 6.2l bravo3 , frest rebuild, new plugs,wires, cap,rotor, iac, fuel filters, fuel pressure 42psi not running 38psi under full load.. has any one seen probles with leaking inj. on late modle mpi.

PS.
A BAD NEW MANIFOLD STRAIT FROM MERC. DUMPED SALTWATER IN THE MOTOR.
STUCK RINGS. SO THIS IS WHY IT WAS REBUILT

Any engine is acceptable to have leaking injectors when they go bad.
You would find that with either doing a fuel injector balance test, Or you could get lucky and watch how fast your fuel Pressure gauge goes down at the fuel rail after key off. What does the new spark plugs Look Like now?

Is your Battery new and in good working order with a minimum Cold cranking amps of 750 or 950 Marine Cranking amps? You will need to make certain of that, And that the the battery is still in like new condition.

Also if your (IAC) is not moving then you will need to get a service manual out and start testing the wiring going to the (IAC) wire plug harness to make sure the "PCM" is doing it job of telling the (IAC) to do it's job. And remember as you now know the hard way, just because the (IAC) is new does not mean it's working correctly.

Have you cleaned the throttle body/Plate area yet?

Good luck to you with it, Sorry to hear about your new exhaust manifold being bad from new.