Celica Forums General Discussion Engine and Performance Hard to start after 3-4 minutes

Hello my daughter and i have a 2004 Celica GT. Our issue is after the car has been running and i turn it off say for 3 to 4 minutes it is hard to start. Though after sitting over night it starts right up with out issue. Plus i let it sit fo r30 minutes it starts up just fine. My mechanic and I have checked the obvious Battery, alternator, starter, fuel pump and pressure, ran it on his diagnostics computer and all checked out fine. No crank sensor issues either. thoughts? thanks!

Consider leaky injectors or bad o-rings on those injectors. If gas is able to leak down and flood the plugs or even cause a slight rich mixture, this can cause a hard start or long crank time.

When you say hard to start, do you mean it won't start at all? Or it cranks for a while? If so, how long?

-Connor

Had not thought of that Connor...but totally makes sense. It will start just a long crank after motor is hot. Cold start no issues at all.

Does engine run rough, shaking on idle?

May be low compression on one or more cylinders, may be carbon deposits on valves' seats or piston rings, which lower compression when engine is hot.

Do a compression test.

Also buy Motor Medic's GUNK engine cleaner (WALMART $6), put half quart in engine and idle 10 minutes. Change the oil. Do it a couple oil changes. That should dissolve oil sludge known for 1ZZ engine and clean out valves' seats and piston rings, increasing compression.

I'm gonna bet leaky injectors given your most recent reply. It starts right up when cold because the gas that leaks down has had time to evaporate/"disappear." It cranks for a while when hot because the extra gas is just sitting there. Kind of like when you flood a lawn mower or something.

You all were correct ...leaky injectors. Replaced with new injectors (refurb with new O-rings) starts right up with a hot engine! The old injectors O-rings were completely gone! Thank you so much for your comments!