Random but frequent hard/no starts - 93 Elantra

93 Elantra, 5-sp, 1.6 L

Cold starts without complaint every morning.

But in the normal routine of doing short park-then-go trips with
several start/shutoff/restarts, say, while doing shopping/errands
around town, the car won't start sometimes...unless it sits...and
sits...and sits...for awhile. Without this nap it'll just crank and
crank and...well, crank some more. Usually there's a gas smell too. It
may be coincidence...or not...that it seems to happen on warm/hot days?


Then, after sitting awhile, when it does eventually start, it trembles
for a few seconds, and all is well again.

I can't make the car do this on demand, however. The problem is
predictably frequent but not predictably reproduceable.

Appreciate any diagnostic suggestions!

Thanks,

rib

 

My son's '94 Scoupe with the 1.5 had this exact problem. It was due to
a defective coolant temperature sensor.

When this sensor dies, the computer thinks the engine is cold and feeds
it too much gas when cranking. The car will start fine when you first
crank it in the morning but will leave you sitting around town in
parking lots for 20-30 minutes until the engine cools sufficiently to
start with the rich mixture.

The sensor was located on the thermostat housing on the 1.5 engine.

 

You may also be interested in whether you have fuel and spark when
cranking.

 

Thanks, hyundaitech and Screwtape!

But hyundaitech's reply reminds me that I neglected to mention that while
the engine cranks and cranks, exhaust is choking out the tailpipe. When it
finally does start, POOF! a big stinky smoke cloud, then once running
fine. I'm also pretty sure this engine is burning some oil, having to add
a liter after 2-3,000 kms. Uh-oh.

Thanks,

Bob

 

Hey Screwtape! The problem turns out to be exactly the same as your
son's '94 Scoupe, ie. a defective coolant temperature sensor.

Problem instantly solved!

Thanks!

***
rib