Hard Start

[jlwelding]

When eng is cold my friends 12v will fire right up but when hot eng will crank a try to start but no go, crack the throttle and it will fire right up.What's up with that?

[ISX]

That issue plagues all 12V's, many say it is normal but I don't think they would have sold if the salesman at the dealership told you to pump the gas. It is very interesting that it doesn't do it when cold, that would be the most likely time to need to crack the throttle IMO since the engine is cranking slower. If you go on cumminsforum, theres a million other people with the same issue, they just ignore it. I've been trying to find the culprit but I think it is something very elusive when trying to find the cause. I have some theories but lack equipment to try it out, not too fancy of equipment but fancy enough to cost a little bit of money. One thing I don't get is I can run my truck all day, turn it off, start it back up, still won't start until 10 cranks, though starts on half a crank with the throttle. Does exactly the same thing cold or hot out, cold or hot engine temp, I have no clue what the deal is. The fuel shutoff solenoid kicks it way out of the way but, hmm. All this talk has sparked some ideas. I'm going out to the truck to try some more things God I love having that AFC off, just the aluminum plate over the hole and I'm in, if only it were that easy with other things

[jlwelding]

This 96 mod just started this misterious crack the throttle after he was pleged with alge in the fuel. Says everything was cleaned up, droped tank and it was spotless. I thought air leak after he said droped tank. :shrug:Truck has about 80k, all stock but the fuel plate. And that was just minior work there.

[ISX]

Wellll I went out and did some messing around. If you get right down to it, all that happens when you step on it a little is the rack moves forward, giving it more fuel, making it start right up. There seems to be something tedious going on that causes the truck to start worse and worse over the years to the point where it needs some throttle to get it to start right up. I started it a ton of times, first watching the rack. When I let it crank forever, the rack did seem to move forward (more fuel) as the engine was cranking over. As the engine began to crank faster, the thing started. With the engine off I would think the governor weights would be at full fuel since the throttle is set at idle speed and the engine isn't running, but that doesn't seem to be the case at all. Seems to be relaxed in a midpoint state, waiting for engine speed to build. Guess I don't get why that is. I found a forbidden screw that adjusts the rack which I of course adjusted thinking the rack must not be far enough ahead. Well that didn't do anything but raise the idle ~30RPM. I think I will mess with that screw some more and check out some other things. I wonder if worn out governor springs have anything to do with it. I need to check out a truck that works correctly and see exactly what it does.

[mr.mindless]

For what it's worth I have a fresh g-spring kit in my 280k P pump and hot or cold engine doesn't effect startup that I've noticed-but I almost always give it a sneeze of accelerator pedal when starting. Usually when I lean into the cab and start it while standing on the ground it's at or NRA operating temp and it starts just a skosh slower, but I'd say 3 cranks. Nowhere near 10. Mine starts like crap in cold weather due to timing, going to back that off a couple degrees when I do my cam. Unrelated overall but timing has a HUGE effect on p7100 starting since it's [relatively] fixed.