Car Advice - Cold Weather - Toyota Corolla

asechrest

asechrest

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asechrest
Car: 2003 Toyota Corolla, 215k miles, manual transmission

My auto experience: rudimentary DIY stuff -- oil change, tire rotations, serpentine belt replacement, front struts replaced, brake jobs. I have a nice floor jack and tools. I know very little else about cars.

Issue: Only during cold weather, the car idles strangely. I live in Florida, so cold for me (and the car) is something in the 50s or lower. If I've just started the car after it's been sitting a while, it will idle up near ~2,000 for 5 seconds, drop down a bit and then pulse back up to 2,000. It'll do this over and over again for some time. If I've driven somewhere and I park and let it idle, it will often idle very low, the the point where it shakes a bit and feels like it might cut off. It never does, but it seems close.

--

A few years ago, after I was quoted over $600 dollars to replace just the front struts, and ended up doing it myself for a fraction of that cost, I decided to start trying to work on my car myself.

Looking for advice on where to start to diagnose/fix this problem. The car has been so incredibly dependable that I've been quite complacent with some things. Very little has been done with the engine, fuel system, etc. What I listed at the beginning of the post is nearly all that's ever been done to it. So with that in mind, where should I start?

Thanks in advance.
 
First step with no check engine light, I'd check the fuel pressure.
 
Question: When you rotate the tires yourself, are you also balancing and aligning? I don't see how that can be done at home.

asechrest said:
Car: 2003 Toyota Corolla, 215k miles, manual transmission

My auto experience: rudimentary DIY stuff -- oil change, tire rotations, serpentine belt replacement, front struts replaced, brake jobs. I have a nice floor jack and tools. I know very little else about cars.

Issue: Only during cold weather, the car idles strangely. I live in Florida, so cold for me (and the car) is something in the 50s or lower. If I've just started the car after it's been sitting a while, it will idle up near ~2,000 for 5 seconds, drop down a bit and then pulse back up to 2,000. It'll do this over and over again for some time. If I've driven somewhere and I park and let it idle, it will often idle very low, the the point where it shakes a bit and feels like it might cut off. It never does, but it seems close.

--

A few years ago, after I was quoted over $600 dollars to replace just the front struts, and ended up doing it myself for a fraction of that cost, I decided to start trying to work on my car myself.

Looking for advice on where to start to diagnose/fix this problem. The car has been so incredibly dependable that I've been quite complacent with some things. Very little has been done with the engine, fuel system, etc. What I listed at the beginning of the post is nearly all that's ever been done to it. So with that in mind, where should I start?

Thanks in advance.
Click to expand...
 
Sounds like trothle position sensor to me. Wen is cold the auto choke is engaged
If position sensor is out of aligment or just failing you would rough idle and jumping rpms
 
Most likely the cold start enrichment is gummed up due to lack of use in the FL weather.
 
spiderweb said:
Question: When you rotate the tires yourself, are you also balancing and aligning? I don't see how that can be done at home.
Click to expand...
No, just rotating. The Corolla calls for a simple front-to-back rotation, with no swap to the other side. The car stays in reasonable balance/alignment, though I'm sure it couldn't hurt to get it tweaked at the shop.
 
Surging can also be due to a vacuum leak. Along with what everyone else has thrown at you that should pretty well cover everything that can go wrong with a car. Hehe
 
spiderweb said:
Question: When you rotate the tires yourself, are you also balancing and aligning? I don't see how that can be done at home.
Click to expand...

There is no need, both those issues are separate from rotating tires. Once a wheel is balanced, it will be balanced regardless which position it is placed in. As for alignment, this is completely independent of the wheel.
 
I'd check the coolant temp sensor. They often die without throwing codes.

-Rich
 
Henning said:
Typically there is a 5th injector nozzle, clean or replace it.
Click to expand...

Dude, it's a 2003 Toyota Corolla, not a 2014 Chevy Impala. There is no 5th injector, the ECU enrichens the mixture by telling the injectors to pulse more and longer. There is no separate cold start enrichment that could get gummed up either.

With the engine running, I'd try looking around the fuel pressure regulator to see if he can hear any hissing sounds that would indicate a vacuum leak. Try wiggling the vac. line coming out of the FPR. Try pulling the oil fill cap with the engine running to see if it gets worse or stays the same. It should get worse (because you create a massive vac. leak when you pull the cap)
 
MSPAviator said:
Dude, it's a 2003 Toyota Corolla, not a 2014 Chevy Impala. There is no 5th injector, the ECU enrichens the mixture by telling the injectors to pulse more and longer. There is no separate cold start enrichment that could get gummed up either.

With the engine running, I'd try looking around the fuel pressure regulator to see if he can hear any hissing sounds that would indicate a vacuum leak. Try wiggling the vac. line coming out of the FPR. Try pulling the oil fill cap with the engine running to see if it gets worse or stays the same. It should get worse (because you create a massive vac. leak when you pull the cap)
Click to expand...

Even the old K-Jetronic systems from the 60s used an extra nozzle for cold start enrichment IIRC.
 
I would find the forum for the make, model and generation of the car, and ask there.

Toyota Nation maybe:
http://www.toyotanation.com/forum/133-corolla-forum/

Edit: I searched their forum for that generation for corolla, specifying cold start and idle, and I a got a reasonable number of hits. I opened just one of them, and somebody who complained of rough idle after start was answered by a chorus of posters advising to spend $10 on a specific gasket and see if that solves the problem. This is the wonderful utility of the type-specific forum.
 
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I'm not familiar with the exact hardware set used by Toyota. But...

Vacuum leak at fuel pressure regulator is not out of the question.

Possibly throttle position. More likely an issue with sludging around the throttle plate or (if it has one) in the air bypass valve that controls the idle speed. Note: Some throttle bodies contain a coating that is sprayed around the throttle plate to get it to seal to the throttle body when it is closed - don't clean that off.

I would start by getting a manual for the vehicle.
 
The first thing I check with almost any cold-weather problem is the Coolant Temp Sensor. They often go bad in ways that prevent the ECU from throwing a code.

The CTS (or ECTS, for Engine Coolant Temperature Sensor) is just a thermistor. Unless it reports a resistance of infinite or none, the ECU may just accept the reported resistance as representing the coolant temperature, even though the CTS is not reporting accurately. Or to put it another way, the CTS can malfunction in a way that "fools" the ECU, and which can cause all sorts of performance problems as the ECU tunes itself to an incorrect temperature.

CTS malfunctions are common enough and easy enough to diagnose that it's worth checking early on in the diagnostic process, especially for temp-related issues, and even more especially if there's no OBD2 code accompanying the problem. You can monitor the CTS resistance with a scanning OBD2 reader, but if you don't have one, you can also check it with a common ohmmeter. Here's how.

1. With the engine cold and not running, find and disconnect the CTS.

2. Connect an ohmmeter to the CTS. Black to ground (engine block, or the ground wire on the sensor, if the sensor connector has two wires).

3. Set the ohmmeter range higher than 2500 ohms if your ohmmeter is not auto-ranging. (This will probably mean setting it at Rx10K, but your ohmmeter may vary.)

4. Check the resistance. I don't know the exact numbers for Toyotas, but typically the resistance on a cold ECTS should be in the ~2000 ohms neighborhood.

5. Leave the ohmmeter connected (watch the wires!), start the car, and let it warm up. Monitor the resistance. The resistance should smoothly decrease as the car warms up, usually settling in the ~200 ohm neighborhood when fully warm.

Note that the car most likely will run like crap while the CTS is disconnected, and it will throw a code and light the MIL. This should clear itself once the CTS is reconnected, although it may possibly take a drive cycle or two on some cars. I don't know about the Toyota.

-Rich
 
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Retired auto mechanic here with about 6 years of experience at a Toyota dealer. 2003 did not have the illustrious 5th nozzle.

I would start with a simple throttle body service. take off the hose from the intake to the engine. open the throttle plate and spray away with some carb cleaner. if i were to take anything off, i would take the Idle Air Control motor off and clean that passage out. its purpose is to bypass air around the throttle plates to maintain idle speed. note that you will most likely have to hold the throttle to the floor while cranking it over to put the computer into "clear flood" mode to restart the engine.

i really shy away from trying to give car advice on the internet because i tired of arguing with all the armchair quarterback experts but i couldn't help myself with all the bad information on this thread.
 
Capt. Geoffrey Thorpe said:
I'm not familiar with the exact hardware set used by Toyota. But...

Vacuum leak at fuel pressure regulator is not out of the question.

Possibly throttle position. More likely an issue with sludging around the throttle plate or (if it has one) in the air bypass valve that controls the idle speed. Note: Some throttle bodies contain a coating that is sprayed around the throttle plate to get it to seal to the throttle body when it is closed - don't clean that off.

I would start by getting a manual for the vehicle.
Click to expand...

Just to add to this... If you clean the throttle body or anything else in that neck of the woods, use only a carb / fuel system cleaner. Products like WD40 and others that leave films might mess up the O2 sensors.

As an aside, on a car with that many miles, cleaning the throttle body and the associated passages isn't a bad idea in any case. Accumulated deposits can mess with the physics and adversely affect performance and fuel economy.

On some cars you can do a good job with carb cleaner, a rag, and a toothbrush without actually removing the throttle body. On others, you need to take it off to give it a good cleaning, so make sure you have a new gasket on hand. I don't know about Toyotas specifically.

-Rich
 
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Putting a fuel pressure gauge on most modern cars takes about 30 seconds. If you have a fuel pressure regulator problem the fuel pressure won't be right, if you have a fuel filter problem the fuel pressure won't be right, if you have a fuel pump problem the fuel pressure won't be right.

If you have good fuel pressure you can pretty much eliminate all those items.

Do not just randomly start replacing parts people mention on the internet. Figure out what is wrong and fix it.

If you stop by an auto parts store most will scan for codes for free, you can also borrow the fuel pressure tester if you leave a deposit usually.

The gasket mentioned in the Toyota forum is a good possibility also, I believe it is an intake gasket, I would spray starting fluid around this gasket with the car running, if rpm changes while spraying you have an intake leak.

Engines need more fuel compared to air to run when cold or breathing cold air, this is where the problem lies. The question becomes is it a monitoring problem or an adjusting problem. The computer monitors via sensors, coolant temp and intake air temp are players in this. The computer also adjusts by increasing the pulse width to the injectors (on longer) or using another enrichment device, mentioned 5th nozzle not present on this car. Most cars of this vintage do not monitor fuel pressure, the computer assumes it is good. I like to start there because it's quick, easy, and eliminates lots of possible causes.
 
Also you should be on your second set of plugs, and that's about the time the O2 sensors start failing as well.

I had a 2000, manual transmission. I put 215,000 on it and it was the best car I've ever owned. I wish I still had it.
 
Idle air control valve. They get sticky and surge. Take it off, spray it down liberally with carb cleaner, and get in there with a small brush and get the gunk off it. Most likely it's not a plunger type but a rotary, and it's been turning in a very small arc because the car isn't cold. When the temp sensor demands more idle air, the valve motor tries to force the valve wider and finally overcomes the resistance, then it sticks too far open, and the ECU calls for it to close down, and it overshoots in the other direction.

The temp sensor is also suspect, but it usually won't cause surging, just rough running when cold, but it could happen.

<edit: I looked back and Jaybee mentioned it already in the body of his post>

<edit again: I just looked it up, and it's the type that can't be cleaned by hand. Locate the elec plug to the valve, with the engine cold take that plug off, and start the car, you may need to open the throttle slightly. With the elec plug off the IAC, hold the throttle steady and see if it surges. If it does, look elsewhere. If it stops, repl the IAC>
 
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spiderweb said:
Question: When you rotate the tires yourself, are you also balancing and aligning? I don't see how that can be done at home.
Click to expand...

If your shop is billing you for an alignment every time you get your tires rotated, you've been had.

Its good to get them balanced at the same time though.
 
Assuming no check engine light, car runs smoothly when driving and gets good MPG.

First thing I would do is unplug the IAC as mentioned above. Although I'd just start it when cold, let it idle and then yank the plug off (assuming its doing the surging routine) if it quits then the IAC is the problem. If you buy the service manual (you should) there will be a procedure for testing the IAC.

Your IAC is one of the silly rotary types that is $150. Check rockauto.com for a replacement. Usually they have the best prices.

My #1 advice to you is to buy the factory service manual printed by Toyota. They are probably $50-100 but its an invaluable resource. Don't **** around with the $25 manuals you see at autozone, get the real deal.


PS On a car with that many miles I would suggest you change the transmission fluid (manuals always get this overlooked), spark plugs and coolant. You might consider doing the waterpump as a preventative maintenance thing if you think it is original. Follow the service intervals in your manual.
 
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asechrest said:
Car: 2003 Toyota Corolla, 215k miles, manual transmission

My auto experience: rudimentary DIY stuff -- oil change, tire rotations, serpentine belt replacement, front struts replaced, brake jobs. I have a nice floor jack and tools. I know very little else about cars.

Issue: Only during cold weather, the car idles strangely. I live in Florida, so cold for me (and the car) is something in the 50s or lower. If I've just started the car after it's been sitting a while, it will idle up near ~2,000 for 5 seconds, drop down a bit and then pulse back up to 2,000. It'll do this over and over again for some time. If I've driven somewhere and I park and let it idle, it will often idle very low, the the point where it shakes a bit and feels like it might cut off. It never does, but it seems close.

.
Click to expand...

Spouse's Saturn (2002) does the same thing --- and has most of it's life.

Usual suggested maintenance is to replace the TPS (Throttle Position Sensor).
Been done before, but problem returned later. Could be the FADEC central controller as well; but cost is such that we are anticipating boat-anchoring the Saturn for a Fusion instead
 
kgruber said:
I'd start with pulling the codes.
Click to expand...

Poor idle when cold?

No no no no no.

START by looking for vacuum leaks, taking a look at the inside of the air bypass valve (or at least the ports on both ends), and that the idle switch on the transmission works. Then check the timing and base idle and verify the coolant is full and not fouled.

If your basics are not known good, you'll get false codes.

Most of the time, faulty idle is either a dirty air bypass valve or a vacuum leak, or the idle switch is stuck open and the computer thinks you're in gear. If it's the first, clean it with "sensor safe" (non chlorinated) intake cleaner. B-12 chemtool works fine.
 
Comanche flyer said:
Sounds like trothle position sensor to me. Wen is cold the auto choke is engaged
If position sensor is out of aligment or just failing you would rough idle and jumping rpms
Click to expand...

A TPS is trivial to test and should never be changed just by guessing. It is also unlikely to cause a temperature sensitive fault.

It's just a potentiometer. Get an ohmmeter and look for dead spots.

And if the TPS throws a code, you do NOT know the TPS is at fault. You have to assume the wiring is good to make that diagnosis, which is never a given.
 
Henning said:
Even the old K-Jetronic systems from the 60s used an extra nozzle for cold start enrichment IIRC.
Click to expand...

Most modern multiport fuel injection doesn't. You have precise control over the injector pulse width, so it is not necessary to make an additional injector.

Just like you don't have choke plates anymore either. It's an electronic bypass valve.

I think a vacuum leak is substantially more likely.
 
asechrest said:
No, just rotating. The Corolla calls for a simple front-to-back rotation, with no swap to the other side. The car stays in reasonable balance/alignment, though I'm sure it couldn't hurt to get it tweaked at the shop.
Click to expand...

OK thanks. I was really curious as to how it could be done at home!
 
Henning said:
There is no need, both those issues are separate from rotating tires. Once a wheel is balanced, it will be balanced regardless which position it is placed in. As for alignment, this is completely independent of the wheel.
Click to expand...

Thanks for the info. I guess the reason I associate the three actions is because whenever I have the tires rotated, a balance is included at the shop where I take my car, and I also request an alignment.
 
spiderweb said:
OK thanks. I was really curious as to how it could be done at home!
Click to expand...

You can do criss-cross rotations at home using the spare tire and a jack. But it's a PITA.

Many tire shops will do free rotations and balance if you buy tires from them. Though the balance should stay good if the alignment does, and the alignment should stay good if you're not hitting curbs constantly or just beating the crap out of your suspension.
 
dell30rb said:
If your shop is billing you for an alignment every time you get your tires rotated, you've been had.

Its good to get them balanced at the same time though.
Click to expand...

The shop has been including the balancing, and has been billing me for an alignment--but I've requested the alignment.

I may be oversensitive, but I always notice the slightest pull to one side or the other by the time I go in for a rotation.
 
spiderweb said:
The shop has been including the balancing, and has been billing me for an alignment--but I've requested the alignment.

I may be oversensitive, but I always notice the slightest pull to one side or the other by the time I go in for a rotation.
Click to expand...

I'd suggest giving your suspension and steering a thorough inspection. If the alignment is moving around, something isn't right. Maybe a broken bushing, worn tie rod end, etc.

Though alignment shops almost universally underestimate how well you can feel a pull. It's been years since a shop has gotten an alignment done to my satisfaction on the first try.
 
asechrest said:
Car: 2003 Toyota Corolla, 215k miles, manual transmission

My auto experience: rudimentary DIY stuff -- oil change, tire rotations, serpentine belt replacement, front struts replaced, brake jobs. I have a nice floor jack and tools. I know very little else about cars.

Issue: Only during cold weather, the car idles strangely. I live in Florida, so cold for me (and the car) is something in the 50s or lower. If I've just started the car after it's been sitting a while, it will idle up near ~2,000 for 5 seconds, drop down a bit and then pulse back up to 2,000. It'll do this over and over again for some time. If I've driven somewhere and I park and let it idle, it will often idle very low, the the point where it shakes a bit and feels like it might cut off. It never does, but it seems close.

--

A few years ago, after I was quoted over $600 dollars to replace just the front struts, and ended up doing it myself for a fraction of that cost, I decided to start trying to work on my car myself.

Looking for advice on where to start to diagnose/fix this problem. The car has been so incredibly dependable that I've been quite complacent with some things. Very little has been done with the engine, fuel system, etc. What I listed at the beginning of the post is nearly all that's ever been done to it. So with that in mind, where should I start?

Thanks in advance.
Click to expand...


Clearly you need a preheater for your car.
 
spiderweb said:
Thanks for the info. I guess the reason I associate the three actions is because whenever I have the tires rotated, a balance is included at the shop where I take my car, and I also request an alignment.
Click to expand...

No problem doing it, it's not a bad idea to check the balance every now and then since sometimes wheel weights come off. Unless I see a wear issue in the tires, have drive ability issues, or have been hitting big potholes/running on rough roads, I won't bother with alignment at tire rotation, at change of tires is frequent enough. More than likely they are rolling it on the rack and finding everything in spec.
 
MAKG1 said:
I'd suggest giving your suspension and steering a thorough inspection. If the alignment is moving around, something isn't right. Maybe a broken bushing, worn tie rod end, etc.

Though alignment shops almost universally underestimate how well you can feel a pull. It's been years since a shop has gotten an alignment done to my satisfaction on the first try.
Click to expand...

Thanks for the advice!
 
spiderweb said:
The shop has been including the balancing, and has been billing me for an alignment--but I've requested the alignment.

I may be oversensitive, but I always notice the slightest pull to one side or the other by the time I go in for a rotation.
Click to expand...

Like Henning I get an alignment with a new set of tires, and don't mess with it unless something comes up that requires it.

I do get my tires re-balanced with every rotation.
 
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