No power and bogging.

[dshaw340]

Hi ADMIN 1, me again. I'm the guy that had the 'Won't Start' issue. Well the car is still running but now there is a different problem. I took it out for a test drive and found that no matter how much gas you give it, she won't hardly get above 30MPH. If you coax it enough maybe 45MPH but that's with letting the gas off and back on again in order to try and get it to shift into a higher gear.

Here is the wierd thing, I disconnect the IAC and she runs like a champ. I guess it's fine like that but I am trying to sell the car and I would like to have it up to snuff before doing so.

So not wanting to spend $130 for a new IAC I went to the junk yard and got a used one for $20 but it is still doing the same thing. My dilemma is that I do not know whether the used one I got is buggered or if there is something that works with the IAC that might be no good. Is it possible to check these things with a meter? I notice there is a spring loaded shutter inside one of the valve ports. On the one I got from the junkyard it moves quite freely while the old one is kind of sticky.

[Admin1]

I really doubt its your IAC causing your concern. The IAC only allows air to get in the engine when the throttle is closed. If it is bad will cause the car not to idle. Do you have a http://www.myhyundaiforums.com/Pictures/SeviceEngineLight.jpg on? It kinda sounds like a TPS concern. Also did you ever have your MAF sensor off? If so make sure its on right.

[dshaw340]

I really doubt its your IAC causing your concern. The IAC only allows air to get in the engine when the throttle is closed. If it is bad will cause the car not to idle. Do you have a http://www.myhyundaiforums.com/Pictures/SeviceEngineLight.jpg on? It kinda sounds like a TPS concern. Also did you ever have your MAF sensor off? If so make sure its on right.

The check engine light comes and goes. Why does the car run good with the IAC disconnected?

Is the MAF the thing attached to the boot between the air filter and the intake? If so, I never touched that.

How can I check if the TPS is okay? I disconnected it a while back when I was trying to fix the starting problem and it would hardly run until I plugged it back in.

[Admin1]

Sense you have did all these repairs have you pulled the negative on the battery? You might try that as well. If you were disconnecting stuff an letting it run then plugging stuff back might of confused the PCM. With out a scantool its hard to test the TPS. Some have disconnected the TPS an if it runs better it is bad. I know this works on an Elantra but not sure on a Accent.

[dshaw340]

Sense you have did all these repairs have you pulled the negative on the battery? You might try that as well. If you were disconnecting stuff an letting it run then plugging stuff back might of confused the PCM. With out a scantool its hard to test the TPS. Some have disconnected the TPS an if it runs better it is bad. I know this works on an Elantra but not sure on a Accent.

Actually I disconnected the positive on the battery and let it sit for about 10 minutes and pressed the brake for about 30 seconds ( I read somewhere that you had to do that to completely discharge the capacitors in the ECU).
Should I be disconnecting the negative? I then started the car and the first time I pressed the gas it revved up fine but the second time I pressed the gas it only revved to about 3000RPM and stayed there.

[Admin1]

When its running at 3000RPM disconnect the TPS. See if it goes down. I bet if you run codes you will get a P0121 code... Possible the IAC could cause this concern but most of the time it will not cause any drivability concerns. Just idle problems.

[dshaw340]

When its running at 3000RPM disconnect the TPS. See if it goes down. I bet if you run codes you will get a P0121 code... Possible the IAC could cause this concern but most of the time it will not cause any drivability concerns. Just idle problems.

I'll try doing that tomorrow.

Sorry to be repetitive but why does it run good when I unplug the IAC?

Also, what does the P0121 code pertain to?

[Admin1]

So if you disconnect the IAC an test drive the car it runs ok? Does it bog down like it was?

[dshaw340]

So if you disconnect the IAC an test drive the car it runs ok? Does it bog down like it was?

Yes, I test drove the car with the IAC disconnected and it ran fine. No bogging.

[Admin1]

I think you found it. That is a odd one. But whats really odd is the used one will not work either... Did you try cleaning yours out with some brake clean/carb clean?

[dshaw340]

I think you found it. That is a odd one. But whats really odd is the used one will not work either... Did you try cleaning yours out with some brake clean/carb clean?

Yes I did clean it with carb cleaner but still it does the same thing. Maybe I just got a bad one from the wrecker? Not that that hasn't happened before. I once replaced a master cylinder with a new one and it turned out the new one was faulty too. What a head scratcher that was.

[dshaw340]

Yes I did clean it with carb cleaner but still it does the same thing. Maybe I just got a bad one from the wrecker? Not that that hasn't happened before. I once replaced a master cylinder with a new one and it turned out the new one was faulty too. What a head scratcher that was.

Just for grins I went to another wrecker and the guy was kind enough to let me try it before buying it. So I grabbed both the IAC and the TPS and replace both. Same bogging problem. I unplug the IAC and it runs fine. The only problem with doing this I noticed is that the cooling fans don't come on. What's with that? Another puzzle to the problem? I'm thinking of removing the IAC from the manifold and plugging it into the connector and then put a cap over the manifold holes.

[Rallyman]

I wouldn't think the IAC should have any relation to the cooling fan operation. It is just allowing air into the engine at idle since the throttle plate is closed.

I don't know what the climate is like at this time of year where you are but the cooling fan in my Sonata rarely comes on during winter here since the ambient temperature is cold.

[dshaw340]

I wouldn't think the IAC should have any relation to the cooling fan operation. It is just allowing air into the engine at idle since the throttle plate is closed.

I don't know what the climate is like at this time of year where you are but the cooling fan in my Sonata rarely comes on during winter here since the ambient temperature is cold.

I am in Seattle and it was about 55 today. I noticed the engine was running into the red so I put a paperclip between two of the connectors of the IAC plug and the fan kicked on.

This should be an easy fix but it is befuddling.

[Admin1]

I am in Seattle and it was about 55 today. I noticed the engine was running into the red so I put a paperclip between two of the connectors of the IAC plug and the fan kicked on.

This should be an easy fix but it is befuddling.

Oh so you crossed over the IAC plug an the fan came on? Now on the IAC there are three wires. Witch two did you cross? Sounds like you found your ECT(Engine coolant temp sensor) If you cross it over the fan will come on. If your ECT is bad it can cause a "Bog" concern. Its been awhile but are any of the connectors there the same? Could they be swapped?

[dshaw340]

Oh so you crossed over the IAC plug an the fan came on? Now on the IAC there are three wires. Witch two did you cross? Sounds like you found your ECT(Engine coolant temp sensor) If you cross it over the fan will come on. If your ECT is bad it can cause a "Bog" concern. Its been awhile but are any of the connectors there the same? Could they be swapped?

Attached is a picture showing the plug disconnected from what I think is the IAC valve. (Actually from the HMA service they call it the ISC acutator or Idle Speed Control Actuaotr) You can see the two terminals I jumped to turn the fan on.

Also, there are no other connectors that could have been swapped.

I was thinking that maybe the IAC is really like a choke on a carburetor only it measures the temperature of the air/fuel mixture and this information is used by the ECM to adjust the mixture for cold starting. If the mixture is too hot, the IAC can also turn the fan on just like the ECT does when the coolant gets too hot. At one point I took what I think is the IAC off the intake and inside one of it's ports is a kind of shutter valve. I turned the key on and plugged it into the connector and I could see the shutter move. Maybe it's not opening all the way which is causing it to bog at 3000RPM

[Admin1]

What you are doing is Jumping 12 volts to the PCM side. I'm not to sure why it turns the cooling fans on but it cant be good to send 12v to the PCM there. Test the center wire(Green) an see if you have 12v. I did some checking an the Idle Speed Actuator only controls idle. Its not like a choke. The Engine Coolant temp sensor acts like a choke. When it sees then engine cold it will adjust fuel as needed. Check an see if your 12v are there. Also if so try unplugging the MAP(Manifold absolute sensor) sensor an see if changes anything? Also do the same with the MAF(Mass Air Flow). :mmph: Got me scratching my head! LOL

[dshaw340]

What you are doing is Jumping 12 volts to the PCM side. I'm not to sure why it turns the cooling fans on but it cant be good to send 12v to the PCM there. Test the center wire(Green) an see if you have 12v. I did some checking an the Idle Speed Actuator only controls idle. Its not like a choke. The Engine Coolant temp sensor acts like a choke. When it sees then engine cold it will adjust fuel as needed. Check an see if your 12v are there. Also if so try unplugging the MAP(Manifold absolute sensor) sensor an see if changes anything? Also do the same with the MAF(Mass Air Flow). :mmph: Got me scratching my head! LOL

So duh, where is the ECT located?

[dshaw340]

So duh, where is the ECT located?

I think I found the ECT. Is it under the intake manifold and screwed into the block? It looks like there are three wires going to it. I get 10 volts on the blue and 5 volts on the orange.

The MAP sensor is the one right in the middle of the intake correct? There are four terminals and from left to right I get 5.6, 5.0, 5.0 and 0 volts,

It looks like the 1.6DOHC does not use a MAF but just the AP sensor. No wonder I couldn't find it.

There are three wires going to the IAC. The middle one is 12 volts and the two outside ones are 3.6volts each

[Rsquared]

That sounds like the ECT. If you have the 1.6 I'm pretty sure you only have a MAP. The 1.5 has a MAF.

[dshaw340]

That sounds like the ECT. If you have the 1.6 I'm pretty sure you only have a MAP. The 1.5 has a MAF.

Do the voltage measurements of the ECT sound correct?

I unplugged the MAP and id does the same thing. ie bogging

[Rsquared]

Go to the fuel system section of your service manual and check page FL-33. Trust me, it'll be easier than me trying to explain it to you.:D

Yours is a '01 correct? And, it sounds like you have the 1.6 DOHC, so ignore the picture with the ECT by the alternator. That must be the 1.5 .

[dshaw340]

Go to the fuel system section of your service manual and check page FL-33. Trust me, it'll be easier than me trying to explain it to you.:D

Yours is a '01 correct? And, it sounds like you have the 1.6 DOHC, so ignore the picture with the ECT by the alternator. That must be the 1.5 .

I don't have a service manual.

[Rsquared]

You do now. Check you pm's.

[Ausom Accent 9]

You do now. Check you pm's.

U R 2 :good:

[nutzy21]

hey what happened did you get your car fixed, i have the exact same issue