QuestionOk the resistance values of the old idle actuator is as follows. One of the set of pins read: center to each outside pin 28.5 ohms. The other set of pins center to each outside is, 28.5 ohms on one side and open on the other side to center. I hope this helps. I will set the idle as you have explaned and awaite your reply on the above resistance checks, in hopes that you have another possible solution. Thanks
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Sir I checked the Idle control motor as you suggested and it was bad. One side was open. I got a replacement one and tested it all of the readings were 29 ohms. I verified no evidence of coolant in the throtle body and replaced the control motor. This along with seting the idle has helped for a smoother idle but the car still dies when put in gear. It also still drives fine when going down the road until you let off the gas and come towards a stop it dies. Next sugestion please.
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The 97 sonata has no check engine failure. Has the new TPS and is set as you recomended. The car still starts a little hard but starts and goes to about 1500-1800 rpm. Once heats up a little it goes back down to 1000rpm. Not a problem I can adjust this. But it is hunting for proper RPM. It starts running up and down from about 1500-1000 rpm. And when put in gear it dies. Now on the hunting problem I did pull the plug for the MAF and the idle smoothed out high but better. It still dies when put in gear. Does it seem that the MAF is bad? And what could cause it to die when put in gear? Also if you hald the gas and break when put in drive you can drive it up and down the road and the shifting is good and dirves good. HELP!
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The hunting you describe occurs when the idle is too high and the ECM cannot lower it enough by using the idle actuator. The stalling in drive is consistent with the actuator not being able to raise the idle enough, but can be caused by other problems as well.
The reason the hunting stopped when you disconnected the air flow sensor probably has more to do with the fact that the ECM entered a backup mode than anything else. The air flow sensor is one of the major sensors used by the ECM to help determine fuel injector on-time. If the air flow sensor were not working properly, I'd expect a check engine lamp or a problem with the way the vehicle drove (aside from the stalling). Furthermore, the air flow sensor used in your car is *very* reliable. I can count on one hand the number I've had to replace, and the majority of them were damaged by overvoltage rather than being a problem that was the fault of the sensor itself.
I think the next place to look is the idle actuator. I doubt the issue is your base idle adjustment, since you have both a stalling issue and a hunting issue. If you unplug the idle actuator (in the bottom half of the throttle body), you'll see two rows of three pins each. Use your ohmmeter to test the resistance from the center pin to each of the outer pins in both rows. Each of the four resistances should be about 30 to 35 Ohms. Significant difference from this indicates the idle control actuator is faulty.
Additionally, if the electrical test shows a faulty idle control motor, you should inspect the throttle body for evidence of coolant. One of the causes of failure is coolant leaking into the idle actuator. If this has happened, you'll also need to replace the gasket between the two halves of the throttle body.
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Okay. Good job so far.
At this point, it's important to verify that you're setting the idle properly. Actually, you're not really setting the idle but rather a base amount of air bypass through the throttle. Prior to beginning the procedure below, please follow up with how you've been adjusting the idle if significantly different that the procedure I've given below. Since I assume you don't have access to a scan tool, the procedure I give will be a little different than what's listed in the shop manual.
1. Start the car.
2. Turn off all accessories.
3. Allow it to run with the until the radiator fan cycles on and off.
4. Attach an inductive tachometer to one of the plug wires. It's reading will likely be double the actual rpm due to this vehicle's use of a waste spark ignition system. Verify by comparing with the tachometer on the dash.
5. Loosen the air bypass adjustment screw until the engine rpms are 100 rpm greater than the listed idle on the underhood sticker.
6. Gradually tighten the screw until the engine rpm is within 25 rpm of the target idle speed. If the coolant fan is running, wait for it to stop.
7. Tighten the screw another 1/2 turn.
Additionally, I'd like to know the bad resistance value(s) from the old idle actuator if you can tell me. That will help me determine the likelihood that you may have a problem with your ECM.
I'm also starting to think that you may have an uncommon issue with this vehicle. One of the things that makes this difficult for me is that I cannot feel your vehicle stall. A good technican can, in most cases, feel the stall occur and determine whether the issue is with the idle control system or with the way the engine or transmission is otherwise operating. At the very least, I wouldn't recommend replacing any more parts unless you can show they are defective. There are many, many possibilities as to the problem, and we've already eliminated most of the more common ones. Once we run out of idle-related things to check, it may be a good idea to have the car professionally diagnosed by a good driveability technician. Although this will cost some money, it's probably better than guessing at low probability causes. Hopefully, your feedback to the above questions will help lead me to your issue, but I think we're probably approaching the time when someone with a significant amount of driveability experience needs to feel the problem occur and check the car with a scan tool.
AnswerOpen circuit indicates low likelihood of ECM damage. A short circuit, on the other hand, would have indicated almost certain ECM damage.
If resetting the idle doesn't fix the issue, presuming you weren't attempting to adjust the idle by adjusting the throttle cable, then I think the next step would be to take it to a good driveability shop like previously mentioned. At this point, we've checked the things that can affect idle control, and I'd need to feel the problem and read the scan tool data to be of much more assistance. And, of course, I cannot do that via this forum.
