5.9 magnum JTEC+ cold/warm start issues

[jbliss15]

well, the truck starts fine on a cold start, or a warm start like if you turn it off and then start it within a few mins.

but say it sits for 20mins, then it long starts. i can't tell if its too lean or too rich.

when there is a long start condition is it usually too lean? it seems like engines usually start when they are really rich.

i tried adjusting the start throttle position to open further doesn't seem to make a difference.

just maybe a point in the right direction will help me, i can't use the scanner it doesn't work with this PCM for some reason

[[email protected]]

there is a parameter call prime shot i belive you need to mess with that to richen it up for starting its like the old school pump before you start with a carb, best thing you can do is get a wideband gauge so you can see whats going on with the fuel i recommend that with anyone wanting to get into tuning.

[jbliss15]

I have a wide band and I've been tuning with it.

[hexdummy]

Have you checked to see how fast your fuel pressure drops off when you turn off the engine ? Sounds more like you have a faulty fuel pump check valve, that?s a very common issue and the symptoms are as you described.

[jbliss15]

Have you checked to see how fast your fuel pressure drops off when you turn off the engine ? Sounds more like you have a faulty fuel pump check valve, that?s a very common issue and the symptoms are as you described.

everything was 100% perfect before i put the bigger injectors in and changed the tune

[jimmyZJ]

I had same issue with a 4.7lHo, cold stat no issue, after it sits more than 15 to 20mm then extanded cranking time, injectors were leaking into the cylinder creating a too rich mixture.
I'm not saying your injectors are leaking but your mixture might be too rich to the point that it doesn't ignite in this condition, make sure your air temp and coolant temp are around same when cold

[jbliss15]

It was the injectors. I put the stock 24s back in and it was fine. I could hear them hissing through the tb lol