Hello all,

2005 2.3 durtatec


For a long time now I have had a drop of idle RPM when I am coming to a stop. It does not happen every time I come to a stop but fairly often. I have checked for vacuum leaks and did not find any. I have replaced a while a ago the ICV and that helps it a lot but it still does it. I have kept up with the PCV valve replacements but did not use OEM just what I got off of Rock auto. I am considering getting a OSS sensor that gives the vehicle speed as I think it may be because of that not working at low speeds as well as it should. I do not have any issues with the speedometer. It is more of a nuisance than a problem, but I would rather not have it. I have researched that when the RPMs are held high while the car is moving and in neutral for emissions. Do other folks with the duratec have this issue. Could it be my PCM? I want the little truck to drive perfectly and other than this little issue it does.



Thanks for the input.



BOB

 

Manual or automatic?

Do you have an OBD2 reader, if not get one, Bluetooth ELM327 is under $15, APP is $5
You need to look at Live Data to figure this out

I assume you mean you replaced IAC(idle air control) Valve, which is a good idea but test first
After engine is warmed up and idling unplug the 2 wire connector on IAC Valve
Engine RPMs should drop to 500 or so, engine may even stall, it means Computer was controlling IAC Valve and IAC Valve is working, and there are no vacuum leaks
If idle stays the same then either computer is not controlling IAC Valve or IAC Valve is not working or there are vacuum leaks

I also assume this is not an issue when engine is cold and has a higher idle, only happens after warm up?
Computer should run Choke Mode on cold start, high idle and rich fuel mix
If no high idle on cold start then computer issue or IAC issue

2.3l Manual trans should have warm idle of 750 or so, automatic 800-850

When coming to a stop in a manual vehicle you of course can push the clutch in to disconnect engine from transmission
In an automatic the torque converter needs to "automatically" unlock so engine doesn't stall, now you can shift to Neutral when stopping to see if engine still stalls, if it still stalls then not a torque converter issue

TPS(throttle position sensor), this tells computer when your foot is off the gas pedal and that it should take over idle
On OBD2 reader key on engine off, foot off the gas pedal TPS should show 17-19%, gas pedal to the floor, 90-92%
20% and higher driver is considered to be in control of RPMs
under 20% then computer is

 

Hello All,

Thanks Ron for the reply,

It is a manual transmission and the issue occurs during warm operation. I tested the ICV when warm and the rpm was about 600. I also sprayed around with starter fluid and no signs of a vacuum leak.



I think that I will try an Motorcraft PCV valve as I had replaced it before with what rock auto had but I do not think it was OEM. That may affect it a bit.



I tested it by driving with the transmission OSS unplugged and the issue did not occur so I do think that it is related to vehicle speed by either the sensor or the PCM. It may just be a normal nuisance but I don’t like it and I want my baby ranger to be perfect.



I did replace the TPS not too long ago and have it at idle at .98 V so I think that is good.



Thanks for the help.



BOB

 

Have you cleaned the throttle valve recently? If not, I would try it. It is easy and cheap. Some air is supposed to slip by the cracked throttle. A build up of junk can reduce the air and slow RPMs. The old computers didn't adjust for a dirty throttle body as well as today's do.

 

Thanks for the advise,

I have heard that these throttle bodies should not be cleaned. I have cleaned mine in the past so I may have already damaged it. There issome kind of coating that can be damaged.

I am willing to do that again as long as it is the right thing to do.

Thanks

 

PS
I did have to modify the TPS a bit to get the volt reading correct. I made the holes a bit bigger so I could spin it a bit further. I am not sure if I should have put an OEM in there and adjust the set screw or my method. I do think that the one I put in was OEM. I could buy another one and leave as it is and adjust the set screw. I was trying to avoid adjusting the set screw if possible.

Thanks again,

 

I have never heard of problems cleaning throttle bodies, but I can imagine trying to spray them clean might be a problem. I have not yet cleaned the Ranger throttle body as it is fairly low miles, but I have cleaned a couple other cars with good results. I used the spray on a rag manipulated by a finger technique.

 

Hello All,

I have replaced the PCV and that did the trick. I must have not installed it correctly last time as it was not snug enough on the little grommet. This time I took off the off the oil separator and replaced the gasket. That seemed like a good idea as the old one seemed tired. Now I do not get a surging idle where it hunts for the right rpm. It has not been so long so it is still learning but it seems much better. Too bad it is such a PITA to get off but it was worth it. I suggest that you just remove the separator and clean it out and change the gasket if has never been done. Next time I will change out the vacuum hose as it is old too. I am pleased to fix it but saddend that I caused the problem in the first place. It's funny how the Ranger is just like all of the problems that I solve for myself.

Thanks

BOB