Very difficult to start when cold, fine when hot.

[dan ritchie]

I haven't seen the problem, but this is what I'm told:

In the mornings the car does not want to start when cold. It will catch a spark or two, but then dies. This will happen for 15-30 tries, and is "just like my 79 chevy, like it has a carb" All of a sudden it starts normally,and starts normally when it's warm.

The thing is that once it fires up, it runs fine. If it wasn't for this cold startup issue there wouldn't be any problems. No hesitations or misfires, and pulls strong. The fuel filter was replaced, and there was a performance increase, but still the same issue at startup.

Ever heard of this happening? Any ideas what it could be? The car is a 95 with a 6 bolt swap. It ran fine for a few weeks and this seesm out of nowhere.

 

[DSMPowerTSi]

My car has been doing the same exact thing since it started to get cold around here. It took me about 15 minutes to start yesterday. I took out my plugs and got all the carbon buildup off the tips and it fired up perfect this morning. I didnt notice any performance decrease when it was hard to start but I dont want to throw out my starter over a 10 dollar set of plugs. Give a set of new plugs a try

 

[sTeCz|GsT]

ive been having the same issue, my car doesnt liek to start even its its warm out and my motors cold . any ideas?

 

[dan ritchie]

That was one of the things I suggested but because it ran fine we overlooked it. Good to know it can start bad and run good if the plugs are dirty, I'll pass it along and let you know what happens. Thanks!

My car has been doing the same exact thing since it started to get cold around here. It took me about 15 minutes to start yesterday. I took out my plugs and got all the carbon buildup off the tips and it fired up perfect this morning. I didnt notice any performance decrease when it was hard to start but I dont want to throw out my starter over a 10 dollar set of plugs. Give a set of new plugs a try

 

[gsx951]

Check the coolant temp sensor that's mounted in the thermostat housing. The big one with the two wire plug is the sensor that reports engine temp to the ECU. If the connection is damaged (broken wire etc.) the car will be very hard to start.

 

[dan ritchie]

Check the coolant temp sensor that's mounted in the thermostat housing. The big one with the two wire plug is the sensor that reports engine temp to the ECU. If the connection is damaged (broken wire etc.) the car will be very hard to start.

It only happens when the car is cold. If the car starts, and you shut it right off, it will start right back up again. Also, if it's been running and sits for a bit it will still start up as long as it hasn't been overnight.

 

[Old Mitsu Tech]

Back in days of old, all cars had a little metal flap that went over the carburetor. When the engine was cold, the flap closed off air to the intake. This made the mixture very rich, which was necessary for cold engine start and run. As the engine warmed up, the little metal flap slowly opened up to allow more air into the engine. This was so the engine wouldn't run too rich as it warmed up.

Flash forward. No more little metal flap. We now have EFI. The Powertrain Control Module is sitting there and when you put the key in the ignition and crank the engine over, it goes. "whoa, someone is starting the engine!" I wonder how much fuel to give it? I need to see how cold it is today. It then checks the coolant temp sensor to see what the ambient temperature of the engine is each and every time you start it. If it's cold, the pcm modulates the injectors longer to allow a longer fuel spray into the intake. The warmer it is, the less it modulates the injectors. The very first sensor the computer looks at on cold start is the coolant temp sensor. Never forget that! The other sensors don't start coming online until the pcm goes into closed loop. The coolant temp sensor has everything to do with that too. If you don't believe me, just unplug your ect and drive it a couple of days. You will then see what I mean.

Good Luck

 

[dan ritchie]

Back in days of old, all cars had a little metal flap that went over the carburetor. When the engine was cold, the flap closed off air to the intake. This made the mixture very rich, which was necessary for cold engine start and run. As the engine warmed up, the little metal flap slowly opened up to allow more air into the engine. This was so the engine wouldn't run too rich as it warmed up.

Flash forward. No more little metal flap. We now have EFI. The Powertrain Control Module is sitting there and when you put the key in the ignition and crank the engine over, it goes. "whoa, someone is starting the engine!" I wonder how much fuel to give it? I need to see how cold it is today. It then checks the coolant temp sensor to see what the ambient temperature of the engine is each and every time you start it. If it's cold, the pcm modulates the injectors longer to allow a longer fuel spray into the intake. The warmer it is, the less it modulates the injectors. The very first sensor the computer looks at on cold start is the coolant temp sensor. Never forget that! The other sensors don't start coming online until the pcm goes into closed loop. The coolant temp sensor has everything to do with that too. If you don't believe me, just unplug your ect and drive it a couple of days. You will then see what I mean.

Good Luck

Check the coolant temp sensor that's mounted in the thermostat housing. The big one with the two wire plug is the sensor that reports engine temp to the ECU. If the connection is damaged (broken wire etc.) the car will be very hard to start.

I got to hear the car tonight...it would sputter, 3-5 fires, then die. Sounded like a lawnmower that's been sitting for a while. Then I noticed that the fans were coming on when he was trying to start it...turns out the temp sensor was unplugged. We'll find out tomorrow if it worked. Thanks guys!

 

[surel0ser]

I had the same problem the day before Thanksgiving and Thanksgiving day the car started up and ran fine. Leave in Friday night, and Saturday night, go to start it Sunday and nothing. I get power, head lights, over head lights, dash, radio blah blah blah, but when I try to turn it over nothing. When I turn it over it sounds like its pulling instead of cranking. Tried for a while in case it was the temp like mitsu tech said. Im wondering being I'm having this problem if its my starter and not the plugs.

 

[Old Mitsu Tech]

If yours is a manual trans, it could be the clutch swith out of adjustment or just bad. Check for voltage on the little pin on the starter with the key in the cranking position. If you have battery voltage there, it's likely the starter/solenoid. If not, check the relay. Get a schematic and follow back. You will eventually find it.

Good Luck

 

[MrBoxx]

If yours is a manual trans, it could be the clutch swith out of adjustment or just bad

Where were you when I needed you? My car had the same problem (not starting) and I bought and installed a new starter for it, which didn't solve the problem. Tow to Satan, where he tells me it needs a "new starter" which they installed for $450. Upon receipt of my car back, it won't start with the clutch in, but starts fine with the clutch out. The starter I bought, which was returned to me, tested perfectly well. If I'd known it was the clutch switch (which i'm pretty sure it was, and I'm pretty sure that Mitsu knew it too) I'd have just disconnected it.

So, to sureloser, check that switch out before checking the starter. It might save you a little cash.