Hey guys,

for a couple months my truck has had trouble starting when she's cold. It usually starts and for about 10 seconds idles very low, roughly 200rpm, then it kicks up to 1200-1500 like it's supposed to and returns to a normal idle after the truck warms up. Seems like this issue started a couple days after I replaced the pcv valve. About 1 out 5 cold starts it won't even idle low, it will just stall, but on the immediate next start it fires up like normal and jumps up to the 1200-1500 range like it's supposed to. I'm stumped, any ideas?

 

Could be bad new PCV valve, or wrong one

PCV valve should be closed at startup then barely open at idle and then open up more and more as RPMs go up

Drawings here: https://www.htmanual.net/images/posi...smdec1005n.gif

IF...............PCV valve is not closing when engine is off then that is a BIG vacuum leak for engine to overcome on startup, once it has good vacuum it sucks PCV Valve closed so starts to work normally

Small vacuum leaks cause higher idles and lean mix, BIG vacuum leaks cause stalling engines

Remove PCV hose and plug opening or hose, then try cold start and see if its better


In some model years and in some areas PCV Valves were heated, because they would freeze open or closed after sitting overnight or 6 to 8 hours, depending on outside temps

 

I'm in Hawaii, so temps shouldn't be an issue.


I'll try, do you think it could be the seal between the pcv valve and grommet?

 

 

No, not the grommet, I would take the PCV valve off the hose and plug the hose so no vacuum leak, then do test start

Since problem started right after new PCV valve was installed that's where I would start
Could be something else, but thats where I would start

 

I'll try, thanks for your help.