Engine idle rough or stalls on cold start, Please help!! Options

[mechedjun]

Hey guys, I got a 1994 Celica GT 2.2L with an idle issue. I know this issue has probably been beat to heck but I can't seem to get a straight forward answer. I'm looking for someone who's gone through the same issue and hopefully can advise with their fix. So here's the situation.

During the cold-ish (say 30 Degrees and up) days, the engine will start up but immediately drop to an low idle and ALMOST stall. It'll continue to idle rough for about 5-10 seconds then it'll run normally. On really cold days (say under 30 degrees), the engine will stall. On these days I would have to hold the throttle to approximately 2000rpm for about 10 seconds and the engine will run normally. It ONLY does it on cold days and ONLY on the first start of the day. Once the engine has run a bit, it doesn't matter if I leave it (in the same cold temperature) for hours, it'll start up normally (as long as the start is within the same day).

Here are the things I've already done.

1. Changed coolant temperature sensor
2. Cleaned throttle body
3. Checked for vacuum leaks (none were found)
4. Checked MAP sensor (reads at correct voltage per pressure)
5. Changed valve cover gasket including re-sealing half-moon
6. Changed spark plugs
7. Changed spark plug wires
8. Checked EGR Valve (Opened correctly at 10psi vacuum)

So basically I'm pretty much stumped. Here are the things that I haven't tried but pretty sure isn't the issue.

1. Fuel injectors
2. Cylinder compression leak

Reason: The car recently passed emissions with flying colors. No excessive burning or signs of blow-by were detected during the emission, suggesting fuel isn't passing past the piston rings. I get average 25-26mpg, bang on where I should be, suggesting combustion ratio (Air/Fuel Ratio) isn't offset. No signs of power loss, even taking off from the cold start (after the engine idles normally).

There are two other symptoms with the car that may or may not be related.

1. Once a day, when the car comes to a stop (at the red light for example), the engine will "jerk" once with idle dipping very slightly for fraction of a section. Looks like minor knock to me. Weird thing is that this "knock" happens after significant time passes from the cold start but the time difference is random. Sometimes it'll do it 15 minutes after it set off in the morning or after hours of driving. Further more, it ONLY does it ONCE a day. Not sure if its related.

2. The coolant temperature gauge in the car reads a little..."funny". Not sure if its supposed to do this so let me know if what I'm going through is normal. On higher temperature days (50 degrees or more) the gauge will read normally (needle is pointing slightly lower than the middle). However, on colder day (depending on how cold it is) the gauge will read low as almost C, even after I've driven 6 hours non-stop. Granted I was traveling to New Hampshire and the outside temperature was 25 degrees with me traveling through it at 70-75 mph, gauge reading close to C just doesn't seem normal. Weird.

Anyway, I've been yakking too long. Thanks for reading and let me know if anyone has any thoughts.

-Dave

This post has been edited by mechedjun: Mar 6, 2012 - 6:56 PM

[revelsumgt]

Yes, have you checked your lambda sensor? These engines are vaccum controlled, a sensor such as that will give out the wrong signals to the ECU.

From my experience after rebuilding my engine due to oil consumption, It was running rough on cold starts, I checked to vaccum leaks.. none..

After scratching my head for a while, I decided to clean the lambda sensor with carb spray. Fixed! Because my car was sitting for months, I guess all the burnt oil settled on it. I would give this a shot, my engine is a 7AFE.

Hope this helps

[mechedjun]

Hmm I'll try that and see what happens. Thanks

-Dave

[pipes]

idle air control valve

also a tstat wont hurt either lol

This post has been edited by pipes: Mar 5, 2012 - 9:58 PM

[enderswift]

x2 on the thermostat. My car was giving me the same temperature fluctuations as what you described before I swapped it.

[-m0nz-]

bad alternator? most likely..

i also had the same problem before but mine was running rich and it idle's up and down! and lots lots of black smoke!
i swapped my engine to a newer one and its just one vaccum line thats put on the wrong side.. it was pretty stupid! yea..

[mechedjun]

I was afraid it might be the thermostat. Just ordered a new one and I'll switch out whenever it gets in and report back. Thanks guys.

-Dave

This post has been edited by mechedjun: Mar 6, 2012 - 7:15 PM

[TannerEsser]

Hey guys, I got a 1994 Celica GT 2.2L with an idle issue. I know this issue has probably been beat to heck but I can't seem to get a straight forward answer. I'm looking for someone who's gone through the same issue and hopefully can advise with their fix. So here's the situation.

During the cold-ish (say 30 Degrees and up) days, the engine will start up but immediately drop to an low idle and ALMOST stall. It'll continue to idle rough for about 5-10 seconds then it'll run normally. On really cold days (say under 30 degrees), the engine will stall. On these days I would have to hold the throttle to approximately 2000rpm for about 10 seconds and the engine will run normally. It ONLY does it on cold days and ONLY on the first start of the day. Once the engine has run a bit, it doesn't matter if I leave it (in the same cold temperature) for hours, it'll start up normally (as long as the start is within the same day).

Here are the things I've already done.

1. Changed coolant temperature sensor
2. Cleaned throttle body
3. Checked for vacuum leaks (none were found)
4. Checked MAP sensor (reads at correct voltage per pressure)
5. Changed valve cover gasket including re-sealing half-moon
6. Changed spark plugs
7. Changed spark plug wires
8. Checked EGR Valve (Opened correctly at 10psi vacuum)

So basically I'm pretty much stumped. Here are the things that I haven't tried but pretty sure isn't the issue.

1. Fuel injectors
2. Cylinder compression leak

Reason: The car recently passed emissions with flying colors. No excessive burning or signs of blow-by were detected during the emission, suggesting fuel isn't passing past the piston rings. I get average 25-26mpg, bang on where I should be, suggesting combustion ratio (Air/Fuel Ratio) isn't offset. No signs of power loss, even taking off from the cold start (after the engine idles normally).

There are two other symptoms with the car that may or may not be related.

1. Once a day, when the car comes to a stop (at the red light for example), the engine will "jerk" once with idle dipping very slightly for fraction of a section. Looks like minor knock to me. Weird thing is that this "knock" happens after significant time passes from the cold start but the time difference is random. Sometimes it'll do it 15 minutes after it set off in the morning or after hours of driving. Further more, it ONLY does it ONCE a day. Not sure if its related.

2. The coolant temperature gauge in the car reads a little..."funny". Not sure if its supposed to do this so let me know if what I'm going through is normal. On higher temperature days (50 degrees or more) the gauge will read normally (needle is pointing slightly lower than the middle). However, on colder day (depending on how cold it is) the gauge will read low as almost C, even after I've driven 6 hours non-stop. Granted I was traveling to New Hampshire and the outside temperature was 25 degrees with me traveling through it at 70-75 mph, gauge reading close to C just doesn't seem normal. Weird.

Anyway, I've been yakking too long. Thanks for reading and let me know if anyone has any thoughts.

-Dave

it sounds alomst normal to me but maybe your thermostat is stuck open?

[TannerEsser]

double post sorry

This post has been edited by TannerEsser: Mar 8, 2012 - 11:18 AM

[mechedjun]

New thermostat and the problem is still here wow. It actually got a little worse since it tries to stall even in warmer temperature now (just not as bad as in cold temperature). My next move, test and/or replace

Oxygen sensor
ECM
Intake air temp sensor

If none of those things work, I just might pull this engine out and go office space on its @$$

-Dave

[rave2n]

TPS Sensor?

[Artega]

I had the same problem. Cold start would stall unless I hold the throttle up. I would blip the throttle and it would rev then come back down below where idle should be and then stall.
So this problem for me actually happens while I’m driving and shifting gear.

I changed out the Throttle position sensor and it didn’t help.
Finally took it into a shop and they couldn’t come up with anything. But they did adjust my TPS while connecting it to OBD reader. The problem went away.
So for me the problem might not be a faulty TPS, but it fixed the problem after it was properly adjusted.

I hope that helps.

[crankine3]

New thermostat and the problem is still here wow. It actually got a little worse since it tries to stall even in warmer temperature now (just not as bad as in cold temperature). My next move, test and/or replace

Oxygen sensor
ECM
Intake air temp sensor

If none of those things work, I just might pull this engine out and go office space on its @$$

-Dave

I second the O2 sensor.

I had similar issues on a different car, though more of the jerking and odd idling at a red light (no knocking). Replaced thermostat, flushed out the water, and checked EGR along with vacuum tubes , same issue, but once I replaced the O2 sensor it resolved it. The sensor was caked over with nastiness, barely could get the sensor out.

[Syaoran]

IAC Valve.

[mechedjun]

I think I've figured it out. Found a crack on the inner seal to the oil filter cooler bolt and the cooler housing itself. I think the engine is losing pressure through the crack. Hopefully copper sealant will do the trick but if not looks like I'll need to replace the whole assembly...Dang...

-Dave

This post has been edited by mechedjun: Mar 15, 2012 - 7:38 AM