Difficult starting Camry

Messages
574
Location
los angeles
Friend's 2002 Camry is having difficulty starting in the afternoons during the hot summer sun in southern california. The starter turns over ok, but the engine has difficulty starting. She usually remidies it by stepping on the gas slightly while starting the car, which pretty much starts it. It starts normally in the morning. The car is not ever parked in garage. I suspect needing the slightly step on the gas pedal suggests its a fuel issue - maybe some techron in the fuel may help clogged injectors? although why is it fine first thing in the morning? leaking injectors also doesnt make sense - why is it ok in the morning? if it were plug/distributer or battery related, then why would stepping on the gas help? Wish i could give you more info, but this is all I got over the phone. Just looking for some feedback before I get a chance to check out the car later.
 
Messages
4,998
Location
Milwaukee, WI
I'd clean the Idle air control valve first. It's fairly easy on the V6, real easy on the I4. Google camry IAC and you'll find pics. Use throttle body cleaner while the engine is running. Otherwise, a standard tuneup with plugs, pcv, oil and filters might not be a bad idea. Maybe get the battery tested.
 
Messages
12
Location
Arizona
I would also recommend cleaning the IAC valve first. Especially if the check engine light is not illuminated and there are no codes set. I had a problem on my 2000 sienna with 100K miles. I had to remove the valve to really clean it well, it was coated with black sticky substance. I would first try throttle body cleaner as bepperb has suggested, to clean it without having to remove it.
 
Messages
25,041
Location
ON, Canada eh?
 Originally Posted By: Kev401
Mass air flow sensor could be out of whack...
+1 \:\! Or it could be the temperature sensor that feeds the ECU. Try disconnecting one at a time and starting the car so the ECU uses factory values instead of sensor information. Even if the TPS was bad, it would still start, it would just run a bit rough, but if the Temp sensor or Mass-Air Flow is bad this would cause the problems you described. This is all assuming the car has seen regular maintenace and the wires/plugs have been changed if necessary. Always check the simple stuff first \:\!
 
Messages
10,597
Location
Nokesville, VA
A bad TPS could be putting the thing into clear-flood mode (injectors OFF) at startup if it somehow sent a signal like it was at WOT. It won't start up that way.
 
Messages
25,041
Location
ON, Canada eh?
 Originally Posted By: brianl703
A bad TPS could be putting the thing into clear-flood mode (injectors OFF) at startup if it somehow sent a signal like it was at WOT. It won't start up that way.
True... But the likelyhood of it being at the right resistance of WOT, during the rest mode would be 1 in a million. I would think that the Mass-Air flow/Temperature sensor would be more prone to cause a problem than this. You are right though...
 
Messages
10,597
Location
Nokesville, VA
All it needs to be at the right resistance of WOT is a short between the wiper and the +5V feed. The loss of the ground connection to the potentiometer will also do the same thing...make the potentiometer output 5V. Either way, the computer thinks it's at WOT. It's easy enough to check with a multimeter, in any case.
 

ajchien

Thread starter
Messages
574
Location
los angeles
Do you guys think it is the TPS or IAC even though there seems to be no troubles after the car is started? even at idle after starting?
 
Messages
433
Location
Melbourne, Australia
Possibly an engine coolant temperature sensor that is reading cold all the time. Starts fine in the morning because the injectors are putting in the right amount of fuel for a cold start. On a warm start, the injectors are putting in too much fuel, making the mixture rich. Stepping on the accelerator slightly allows more air to pass through the throttle plate, and leaning the mixture out somewhat, and allows the engine to start.
 
Messages
19,479
Location
Chicago Area
Since opening the throttle helps, it is the IAC or TPS. Faulty IAC will not flow, and needs more opening that the throttle provides. A bad TPS could not be reading right when closed. But probably a dirty/faulty idle air motor. Any other sensor is not affected by throttle opening.
 
Top