Stops in traffic and stop lights

Hi Mike and welcome back:

Can you remind me what was already done? Also, is there a misfire or checking light staying on?

Let me know.

Joe

Hi, Joe, thanks for welcome back but really don't want to be here. smile. Yes, Engine Check light is always on. A recent mechanic of a long list of mechanics said it has several sensor problems; oxygen sensor, water sensor, crank sensor, and they changed crank sensor for one in my trunk, and changed spark plugs from NGK to Denso. But, they were getting expensive so I asked for my car back. It starts great, runs great but then when it gets warm it tries to stop in traffic and at stop lights. Thanks for any help at all. Mike

Hi Mike:

Honestly, it sounds like it could be related to the coolant temp sensor. Basically, the sensor tells the computer the coolant's actual temperature. Based on that info, the computer determines what fuel/air ratio is needed. Here is denotative description of the sensor.

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Engine coolant temperature sensor
The Engine Coolant Temperature (ECT) Sensor provides an input voltage to the ECM relating to coolant temperature. The ECM uses this input signal along with inputs from other sensors to determine injector pulse width and ignition timing. As coolant temperature varies the ECT Sensor's resistance changes. The change in resistance results in a different input voltage to the ECM. When the engine is cold, the ECM will operate in Open Loop cycle. It will demand slightly richer air/fuel mixtures and higher idle speeds until normal temperatures are reached.

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Basically the same as what I said but with a lot of technical jargon. lol With that in mind, if the computer thinks the temp is too cold, it will change injection timing and air fuel ratio. For example, if the coolant is 195 Degree F and the computer thinks it's -40 degrees F, it will make the mixture too rich (too much gas and not enough air) causing the engine to run poorly or stall. Considering that, it will also lead to other codes such as misfire (new plugs), O2 sensor faults and so on.

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What to do...
The easiest way to check if that is the case is by using a live data scanner. With the scanner, one can actually see what the sensor is telling the computer and determine if it is correct or not.

Also, the sensor can be tested to see if it is good by checking checking resistance. Basically, you take the sensor, place it in a specified temperature liquid and check if it provides the correct resistance. (see pictures 1 and 2)

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If I was there, I could check it for you in under five minutes, but. Also, if you have access to a live data scanner, check the sensor's readings when the problem is happening. When it is cold, the system runs in what is called a closed loop and the readings may be a false positive.

Based on everything you mentioned, I have a feeling this is causing the problem. However, I could be and have been wrong in the past. lol But this is my first suspect.

Let me know if this helps. And by the way, I understand you would rather not have to be here for obvious reasons. LOL However, it's nice to hear from you again.

Take care and have a great Christmas.

Joe

Thank you very much, Joe. I wrote to you this time because you always go into lots of great detail, and it helps immensely. Sure appreciate it. Joe, I don't have a scanner and also I will probably have to wait until after Christmas to get much done, but I will check those things you have mentioned one of these days and get back with you. Merry Christmas to you and your family and have a great new year. Mike in Panama

You are very welcome and I will watch for your reply.

Merry Christmas to my friend in Panama.

Joe

Hey, Joe. Hope you and your family had a great Christmas, we did. My 2002 Kia Rio is worse now. A mechanic ran a scan for $25.00 and said it had three codes. didn't tell me the numbers but said one was crankshaft code, camshaft code, and oxygen sensor code. He changed the spark plugs from NGK to Denso, and when I got it back it still would shut off in traffic after getting warm. Oh, he didn't change any of the sensors mentioned before. However, two other mechanics came to work on the car to change the valve cover because it was leaking oil near the belt for the alternator and so they stopped that but with a silicon seal. Also, they sprayed the throttle body and also the IAC valve. Took a while to crank with the spray in IAC but then took off good, but eventually when motor got warm started idling bad and shut off several times so they turned the little screw by the throttle body and at first got better then started crapping out worse. They had spent most of the day on the car out looking for used parts for the IACV and valve cover, and so I told them to go home and we will try later in the week or tomorrow or sometime. That's where we are, Joe. Nothing good to report. Mike

Mike:
Thanks for getting back to me. I wish you had better news, but feel you are on the right track.

However, bad crankshaft or camshaft position sensor could be the problem. Have they further diagnosed those codes? Often times a crankshaft position sensor will cause a stalling as they warm up. What happens is the copper wiring in the sensor will expand as the vehicle gets hot causing a loss of signal. Take a look through this link and let me know your thoughts.

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

If I don't hear from you, have a great New Year's

Take care,
Joe

Hi, Joe. That crankshaft sensor presentation was very good. Helped me understand more about the system. Thank you. For now it is running so so and getting by, so when it belches I will write more again. Thanks, Joe. Your pal in Panama. Mike

Mike:
Take care and let me know if you run into problems.

Joe

Well, Joe, it is now April, and doing it again. Stalling at signals and in traffic. I changed the IAC Valve and it ran better for 4 days, then back to same old stuff so the e-bay seller is sending me another one, and will get it in a few days. Meanwhile, I changed the temperature sensor and it still stalls after getting warm. Strange problem.
Mike

Welcome back, Mike:

When you remove the IAC, make sure it is clean inside where it mounts. If there is anything blocking the airway, it will cause the stalling.

Now the warmer temps still have me confused. Has the check engine light ever come on?

Joe

Hi, Joe, welcome back. Yes, Joe, the engine check light is always on for five years now. I have changed a lot of stuff and it never goes out. Only when I disconnect battery for a while and reconnect, but then comes back on after a while. Not much to go on Joe, and I bought a scanner and can't get it to work on this car. It has a plug but says there are 3 codes, but I can't see them. Confused in Panama. Mike

Can you upload pictures of the scanner indicating there are codes? I may be able to help you figure it out.

Let me know,
Joe

Thanks, Joe. Give me a few days. Mike

Not a problem. Take care.

Joe

Joe, just checked car for codes, says it has three codes as follows:
P1500 DTC definition not found.
P0740 Torque converter clutch circuit
P0740 Gear 3 incorrect ratio
But, I tried to look at real time when I was driving and could not do it. This is a new Konnwei Scanner, and I have tried everything without much luck. Mike

Welcome back:

The P1500 is a speed sensor issue which is most likely causing all the problems related to the transmission. To diagnose the problem, you will have to do some checking. I have attached a diagnostic flow chart related to the code. If you can follow it, great. If you can't, let me know. Also, let me know if there is something on it you can't read.

Take care and let me know what you find.

Joe

Hi, Joe. The first thing I noticed on your flow chart is that Number one is bad. My speedometer has not worked for about two years, and a guy I know on the Kia Forum said he had the same problem, same car year, model, and mfg. He found out it was a bad connector going to the speedometer, but I have asked about three mechanics to try and track it down, and none of them has done it or maybe don't want to, don't know. So, that is a problem for sure. Mike

Welcome back:

Honestly, I feel confident that is exactly what it is. Are you able to follow the flow chart to determine the cause the speedometer issue?

Let me know.
Joe

No, Joe. But, I think it is probably the connector or wires to connector, but that would not cause my idle and engine shutting off in traffic, would it? Mike

No, it really shouldn't.

I am going to change the IAC Valve tomorrow I hope, and let you know about the idle afterwards. Thanks for all. Mike Soon, my friend.

Let me know what happens. Also, make sure where it mounts on the throttle body that everything inside that you can see is clean.

I will watch for your reply.

Joe

Can't do it today, Joe, maybe tomorrow. Mike

No problem, Mike. I will watch for your reply regardless. Let me know if you run into trouble or have questions.

Take care,
Joe

Hi, Joe. I changed the IAC Valve yesterday and waited to write until I drove it a little bit today. It is idling better, accelerating better and so far has not shut off on me in traffic or at a stop sign. However, the last time I changed it the car ran better for four days and then reverted to the same old stop in traffic and at stops. So, I want to try a few more days to see how it acts in a week or so. Thanks for your help. Mike

Welcome back:

That is good news. Did you check to make sure there was no dirt where it mounts to the throttle body? Actually inside the TB? Also, is the wiring good.

I'm asking because of the last time. If it happens again, it could be a bad connection or dirt.

Let me know after a few days if there is a change. I will keep my fingers crossed for you.

Joe

Hi, Joe. Cleaned everything when disassembled with MAF cleaner, including throttle body, holes with a q-tip, and MAF. also surface where IACV mounts, new gasket which came with the IACV, and it ran good yesterday but idled high when i got back so turned the idle screw out until it almost shut off, and then back in until it almost shut off and back out a little. Today, started great, ran great but when I went over a speed bump, the motor quit running. So, have another problem now? Shoot. This car is going to take me out. It is the worst car I have ever had in 24 cars in 79 years of my life. And, it was idling a bit high again after driving today, so I am going to turn the little screw again and tighten the stop nut on the screw.
Mike

Welcome back:

Did it restart after it stalled?

Joe

Yes, Joe, it restarted immediately and ran okay to my house. So, must be an intermittent connection or wire to the coil or somewhere in ignition. What do you think? Mike

Welcome back:

Mike, I agree. What I would try to do very carefully is this. First, get a rubber glove so you don't get shocked on any of the ignition wires. With the engine running and very, very carefully, move the wiring around on the ignition components. Just make sure to keep your hands away from any moving parts such as a belt or fan. See if you can recreate the issue by doing that.

Let me know.

Joe

Pardon me for not writing sooner.
I replaced the IACV that the seller on e-bay sent me for free because I told him that the first one worked good for 4 days and then started having problems.
Well, this one is better, but I have another problem.. You know this car, has a mind of it's own. Now, when going over some speed bumps, depending on how high, speed, etc., the motor shuts off some times, not all the time. Still have not purchased a rubber glove to try what you previously recommended to move the wires around near the coil pack to see if I can duplicate the stall out. That is where I am right now Joe. Trying to also see if can purchase a new Chevrolet Aveo with air, auto transmission. Mike

Welcome back, Mike.

If a speed bump is causing it to stall, I suspect it is a bad connection at some point. Does it always start right back up for you?

Good to hear from you. Let me know.

Joe

Yes, Joe, it always starts right back up, and runs okay until another speed bump or big hole in the road. Thanks for writing back. Have a good Sunday. Mike

Welcome back:

What I think needs done is via a live data scanner, check what is called freeze frame data. That may indicate what failed when the car actually stalled. It's a thought.

Take care and you have a good Sunday, too.

Joe

Hi, Joe. I bought a scanner a couple months back from E-Bay and I can not do a freeze frame, tried it many times. Can not even see live data, must be the model of my car. Don't know. Have a good one. Mike

Hi Mike:

Does the scanner have the capability? The car does. It may be the type of scanner. Let me know.

Joe

The scanner is a KONNWEI, Model KW808. Can you check it and see if you think it has the capability? Thanks. Mike

Hi, Joe, please check this site. Good review of my scanner I bought, but feedback from users indicates it is not as good as advertised and problems with it. Please let me know if you think it can do freeze data.
https://theeffectiveguide.com/konnwei-kw808-reviews/

Welcome back:

I read through the link and it should read live data and freeze frame information. By any chance, do you have access to a different scanner that we can use to test if there is a problem with the vehicle? Since it is reading codes, I see no reason why the other options wouldn't work.

Let me know.

Take care,
Joe