[1971_c10]

Hey Vic, man I'm with Ramjet51 and sorry I missed checking out your truck at the C10 Nats and meeting you. I was there with my truck C10CJ but I wound up spending most of the day Friday dodging the rain (me, the truck got soaked) then down at the autocross and then most of Saturday at the autocross as well. If you watched any of the autocross I was the turquoise (looked green in the TX sun to most) '71 with no bed floor.

On your engine issues, so sorry to hear the trouble you've had. The hard starting is very interesting. I'm running an aftermarket ECU so I can't offer much there but sounds like there might be too much advance at cranking speeds. The LS loves tons of advance at idle and up, but that needs to be dropped down to around 15 deg at start. Ask your tuner what he's done to the advance curve in the start region. If you haven't checked the fuel pressure in a while it'd be good to double check that as the regulator will "wear in" a little and *might* be low. If pressure has dropped too low it causes the ECU to spray the wrong amount of fuel, but that doesn't explain the hard starting. Does your ECU do a pump prime? i.e. if you key on but don't start, does the pump run for a few seconds? On a return setup the pressure will bleed down completely when off, so if there is no pump prime, you need to crank long enough to get enough pressure for the injectors to fire. Also, battery voltage can cause issues during starting. If your voltage drops too much at the coils, injectors, or ECU that can very well cause issues even with a good battery. Hopefully you've got those guys wired to the battery with some heavy gauge wire and the ECU power (not the switched power) is to the battery directly and not on a distribution block. I have a brand new red top Optima and it's working ok so unless you got a dud the battery is probably fine like you said. It replaced a 10+ year old yellow top that was having issues and causing me all sorts of problems.

I can offer up a few things on a couple other symptoms. On the oil consumption, you may need a baffle in your valve cover (as simple as a piece of metal over the off take with a standoff to allow airflow) to reduce the oil loss to the catch can. On the idle issues, since you mentioned PCV in one of your posts, I'll offer that the PCV flow can be fighting the IAC control. What happens is the PCV becomes an air source that the ECU doesn't know about, so the IAC winds up fighting that extra air flow. If you've put a different cam in the engine (sorry, I joined your build late) this can exaggerate the problem as if the PCV isn't a fixed orifice or tunable it might be jumping back and forth between idle flow and cruise flow which will really cause issues and cause the engine to stumble and stall. Fuel pressure, fuel quality and throttle blade idle position do also play a role (along with the base fuel map). A simple test would be to unplug the PCV to the intake (plug the intake) and start the truck. If it runs better could point to too much air coming through the PCV at idle.

For the record, I filled my tow pig up a couple times at Love's (diesel) and it ran like crap on those tanks. So I started avoiding Love's. If their diesel sucks the regular petrol probably isn't any different.

Sorry for the long post. Just trying to offer up some info based on learnings I've had over the years.