Hi Scotty,
I recently purchased a beautiful 1995 Celica in Southern California. It started great until the weather dipped below 45 and now it won’t start unless I give it gas for a couple minutes to warm up the engine.
It’s ODB1 and not throwing codes so I have no idea how to troubleshoot and can’t find anything on the net about how to do so.
So far I’ve replaced spark plugs, tubes,air filter and the fuel filter. The car seems to be running just fine and even starts perfectly in hot weather.
Thanks!
Mike
After a lot of troubleshooting, I found a vacuum hose on the underside of the throttle body that was disconnected (right before where the throttle body connects to the idle air intake valve). After reconnecting and cleaning the throttle body, it starts correctly - high idle when cold until it warms up. I’m guessing it was disconnected for a previous owners cold air intake. If anyone can tell me why connecting that hose changed the way my car idles, that would be awesome!
You could try checking that fuel pressure is within spec at the fuel rail and cleaning the fuel injectors. Also make sure that temperature sensors are working properly. (Cold starts require more fuel than warm or hot starts.)
Thanks! I’ll clean the fuel injectors and check the pressure. By temp sensors do you mean coolant sensors? Or Air intake temp sensors or both?
Whatever sensors are used by the fuel injection system to determine ambient temperature.
I'm thinking along the same lines as @chucktobias.
Those old OBD1 setups weren't very sophisticated compared to today's engine computers.
I doubt your computer is comparing the ECT to the IAT on a cold start (open loop).
I'd start by testing the ECT sensor. The one with 2 wires for the computer, not the one with 1 wire for the gauge.
I found an ECT sensor temp/resistance chart for yours. (I put a purple dotted line on it for around 40-45 degrees temperature because you said that's when you're having a problem.)
So, the colder the engine coolant temperature the higher the resistance.
Grab a cheap multimeter and before the 1st start on a cold morning, disconnect the ECT sensor electrical connector, switch the multimeter to read ohms and touch one probe to one terminal on the sensor and the other probe to the other terminal on the sensor.
On a 40-45 degree morning you want to see around 4 kiloohms. Nothing less than 3 kiloohms.
((1 Kiloohm [kΩ] = 1,000 Ohm [Ω]))
ODB
OBD
now it won’t start unless I give it gas for a couple minutes to warm up the engine.
How can you warm it up if it doesn't start up? I'll assume you mean it starts but it doesn't run, or stalls out soon unless you hold the accelerator.
Try spraying starting fluid down the intake. That should tell you if it's a fuel problem.
also check out the question above yours
https://carkiller.com/scottykilmer/qa/car-starts-for-a-few-seconds-then-died