Hey All,

Let me lead by saying that I'm not very handy when it comes to my car. I've done brakes/rotors, replaced the air valves, plugs/coils/wires and headlights and that's about it over the decade I've owned this car.

I've got an issue where it refuses to start after fueling up every time and occasionally while just hot. Last year, I took it in and had the alternator replaced and that seemed to fix it for a while, but then it started again. After filling up with gas, it takes about 40 minutes before it will start again. When this happens the engine cranks very fast but won't turn over. After say 20 minute so the engine starts to have a more weighty sound to it which gets fuller as more time passes and by 35-40 minutes it starts. When it does finally turn over and the car revs, it seems like it's taking a lot of effort to do it.

Once it's running however, there are no symptoms that I've been able to detect outisde of the fact that my gas mileage seems to be quite poor (maybe 10-12 mpg), but over the last year 90% of my trips are a once a week ride down to the grocery store.

I'm guessing the recommendation is going to be an engine compression test, but with COVID running wild I really dont want to take it into the shop unless I have to as this is my only vehicle. I have this vaccum hose that has a pretty severe crack in it I noticed just before COVID started, I wrapped it in duct tape as a temporary measure, but we're now over a year and I still haven't been able to get it fixed. Could this be at all related?

Mileage: 110k
Engine replaced by dealer at 67k
battery replaced at 108k
Alternator replaced at 108k

 

Definitely sounds like compression

But it could be lots of other things as well...

Given that compression is a big problem....checking it first is a good idea. It could be fuel pump or other fuel issues or even a strange electrical problem... but starting at the compression test will save you a lot of grief looking for less likely weird things that you will have to figure out if the compression is good

 

It will definitely not run well with a crack in a vacuum hose, but that by itself doesn't entirely explain the hot start problem. Usually that's compression.

Also the 10-12 mpg is not doing your catalytic converter any favours (which may be what has lead to compression loss).

It might be time to bring it to someone (Mazda?) and face the music. You don't want to wait until it doesn't start at all.

 

Pre throttle body...won't be a vac leak...but it is post MAF so will cause Fuel Trims ..but not a significant problem that
size

 

Thanks for the feedback all. Texas just rescinded their waiver on inspections/registration due to COVID so it looks like my hand it going to be kind of forced soon anyway.