Starting Issues

[oles0012]

I have a '97 ES 300 that's been a tough nut to crack regarding some starting issues. When the car is cold (or has been sitting long enough for the engine to equal outside temperature), it starts like a gem. However, when I have been driving it long enough for the engine to heat up to normal temperatures, and stop the engine briefly, it acts as though there's no fuel injection. It will start, then die quickly. I then have to pump on the gas while starting it again to 'prep' it, idle it to about 2000 rpms for about 5 seconds then usually it's fine. But without giving it a little gas upon starting, it will not catch. It wants to fire up without any help, but doesn't quite get there. Although I have not been witness to it, my wife says it's ocassionally stalled on her when idling at a stop light, but neither of us have had any problems with it cutting out when driving. I've very recently changed the plugs, wires, and fuel filter, but there's been no difference in result. I've read a couple suggestions for similar problems, being the IAC Valve. Would cleaning it resolve this issue? I'm open and appreciative of any feedback. Thanks!

[steviej]

I have a '97 ES 300 that's been a tough nut to crack regarding some starting issues. When the car is cold (or has been sitting long enough for the engine to equal outside temperature), it starts like a gem. However, when I have been driving it long enough for the engine to heat up to normal temperatures, and stop the engine briefly, it acts as though there's no fuel injection. It will start, then die quickly. I then have to pump on the gas while starting it again to 'prep' it, idle it to about 2000 rpms for about 5 seconds then usually it's fine. But without giving it a little gas upon starting, it will not catch. It wants to fire up without any help, but doesn't quite get there. Although I have not been witness to it, my wife says it's ocassionally stalled on her when idling at a stop light, but neither of us have had any problems with it cutting out when driving. I've very recently changed the plugs, wires, and fuel filter, but there's been no difference in result. I've read a couple suggestions for similar problems, being the IAC Valve. Would cleaning it resolve this issue? I'm open and appreciative of any feedback. Thanks!

possible, however, I would also suspect the coolant temperature sensor.

best way to find out is to have a technician hook a scan tool to monitor all sensor signals upon a cold startup and then when the problem occurs.

steviej

[oles0012]

awesome, I will try that. Thanks, Stevie!

[homemechanic]

Coolant temperature sensor would NOT stall your car while it's hot. The coolant temperatuer sensor is to just trigger your fans to run at certain temperature. The other temperature sensor gives your gauge a reading as to the temperature of your coolant.

I don't think your sensors are giving you problems.

I would suspect either your fuel pump is starting to have intermittent problems or the starter is about to go.

I would suspect the fuel pump first because you have to step on the gas paddle.

One quick thing you can do is stop by some part stores and they will have a meter to check your starter at no charge. I know Kragen in the west coasts do that at no charge.

[steviej]

Coolant temperature sensor would NOT stall your car while it's hot. The coolant temperatuer sensor is to just trigger your fans to run at certain temperature. The other temperature sensor gives your gauge a reading as to the temperature of your coolant.

not true.

in our modern highly electronic, highly emission sensitive vehicles, the ECU does use the reading from the coolant temperature sensor to help adjust the fuel air ratio. The temp of the engine is vital in determination of the proper amount of fuel and air needed to run efficiently.

steviej

[JPI]

I have a '97 ES 300 that's been a tough nut to crack regarding some starting issues. When the car is cold (or has been sitting long enough for the engine to equal outside temperature), it starts like a gem. However, when I have been driving it long enough for the engine to heat up to normal temperatures, and stop the engine briefly, it acts as though there's no fuel injection. It will start, then die quickly. I then have to pump on the gas while starting it again to 'prep' it, idle it to about 2000 rpms for about 5 seconds then usually it's fine. But without giving it a little gas upon starting, it will not catch. It wants to fire up without any help, but doesn't quite get there. Although I have not been witness to it, my wife says it's ocassionally stalled on her when idling at a stop light, but neither of us have had any problems with it cutting out when driving. I've very recently changed the plugs, wires, and fuel filter, but there's been no difference in result. I've read a couple suggestions for similar problems, being the IAC Valve. Would cleaning it resolve this issue? I'm open and appreciative of any feedback. Thanks!

I would try to clean the IAC. If the problem doesn't go away. Check your fuel pressure and ignition.

JP Importz

[oles0012]

Ended up being the IAC after all. Totally makes sense why it was giving me problems only when the engine was hot and when the moisture in the air was high. Hot engine made the carbon build-up gooey, causing the IAC door to stick to the chamber walls. Moist air also contributed to the stickiness, causing the same effect. Thanks for the help, everyone!