Was hoping to get some advice or a few ideas to continue troubleshooting. I have an '06 H3 with the 5 cylinder engine here in Calgary, AB. During the colder winter months it starts perfectly, no issues, runs smooth and fires up as soon as I crank every single time. Zero issues in the colder winter months.

As soon as temps rise in the Spring/Summer I have an issue where it will fire up and then the RPMs drop to zero immediately. I can't be sure but it seems it happens more often when I'm in a hot parking lot. I've tried leaving the ignition on for a bit before cranking, does not seem to help. After 2 or 3 tries it will fire up like normal. Never happens while driving, only when starting after parked do the RPMs drop to zero and I have to crank again.

I recently saw an error code for the crankshaft sensors so I replaced both. Also replaced the fuel pump thinking it might not be supplying enough pressure and possibly the fuel in the line evaporating. No change, same issue. Any common issues with intermittent hot starting with these? Any parts to look at next? Thanks!

 

I'd have a look for green crusties. Dismantle the fuse box and clean. Check grounds at 105 and 106 [iirc] they are located behind air cleaner box on fire wall and right next to abs/ebcm on fire wall. There is guy who has an youtube video on running fuse box through dishwasher lol take a look at that.

 

Just some rrandom thoughts. But it is a starting place.

 

Are you still trying to use the crappy azzed OEM Battery Terminal Connectors?

 

Will take a look at the fusebox tonight, will reseat everything and clean all contact surfaces with electronic cleaner, worth a look. Battery terminals were changed out last year.

This issue only pops up when the environment is hot though, 27C/80F while sitting in a parking lot. I know that metal connections can expand or solder joints can crack with temp fluctuations but what I'm seeing only happens during initial startup and doesn't return. It's never crapped out while running or moving.

It seems to me that during initial startup either my fuel supply gets cut out temporarily for a few seconds or there is a sensor telling the engine to shut down, but again, only when it's hot outside. It's never stranded me, will start up like normal on the 2nd or 3rd try. Very intermittent though, will be fine for 3 weeks straight even when it is hot out.

 

Hmmmm.
maybe the idiot vats pass lock system is freaking out. Have you tried replacing the unit. I did mine last year because of wierd starting issues. Conversely a relearning could maybe help.

 

I had not considered the pass lock system, will definitely start reading up on how to replace it. Good idea, thanks. When the pass lock works as intended, will it let the engine crank and fire up and then shut you down? Or does it make the truck completely dead when you initially turn the key?

 

The Pass Lock cuts the gas {iirc}.