JeepForum.com

JeepForum.com (http://www.jeepforum.com/forum/)
-   YJ Wrangler Technical Forum (http://www.jeepforum.com/forum/f12/)
-   -   Low idle 4.0 after rough ride (http://www.jeepforum.com/forum/f12/low-idle-4-0-after-rough-ride-1504359/)

General Purpose 04-04-2013 11:19 PM

Low idle 4.0 after rough ride
 
As as soon as I am on a rough road or any kind of flexing MY RPM drop at idle. It does not stall just sounds like it sucks wind and hovers around 200 RPM. I can hear my throttle body whistle, As soon as I give gas it is OK. As soon as I let off. It is back to low RPM almost stalling. Probably tomorrow it will be OK again at some point in the day. Vacuum?? Fuel pump from all the bouncing around? Why would my TB make noise? Anyone have a similar issue?

rawk hard xj 04-04-2013 11:21 PM

Loose vacuum line somewhere. Like one on the throttle body.

Que89YJ 04-05-2013 11:47 AM

Clean your IAC and throttle body and check your codes on any low idle. A vacuum leak will usually cause a high idle. The TPS or MAP could be suspect, but IAC and codes first.

General Purpose 04-07-2013 10:01 AM

Quote:

Originally Posted by Que89YJ (Post 15251444)
Clean your IAC and throttle body and check your codes on any low idle. A vacuum leak will usually cause a high idle. The TPS or MAP could be suspect, but IAC and codes first.


you called it. I had to replace the IAC, it was pooched. Jeep runs good now. only issue now is I am still throwing codes. Voltage is to to high 15 volts. but alternator reads normal voltage, could be a ground to the ECM?

Que89YJ 04-07-2013 10:10 AM

Did you reset the ecu by disconnecting the battery for 10 seconds?

General Purpose 04-07-2013 06:26 PM

Yes I did. Just the voltage is registering 15 volts after the ecm.

Que89YJ 04-07-2013 08:10 PM

15 volts is not a full field so you aren't going to blow anything up. Normal is 14.5 to 14.9 so you are barely high and I am surprised it throws a fault. I know this is a stretch but are you sure you have the right alternator in there. For an obd 1 your voltage is regulated by the ecu. You need to pull the alternator and get out tested.

General Purpose 04-07-2013 10:04 PM

Quote:

Originally Posted by Que89YJ (Post 15263060)
15 volts is not a full field so you aren't going to blow anything up. Normal is 14.5 to 14.9 so you are barely high and I am surprised it throws a fault. I know this is a stretch but are you sure you have the right alternator in there. For an obd 1 your voltage is regulated by the ecu. You need to pull the alternator and get out tested.

Good plan I will do that. thanks for all the help. I will post what I find. I know the alternator has never been changed in the 16 years I owned it. well as far as I remember I never changed it. :confused:

Que89YJ 04-08-2013 07:15 AM

If you have owned it that long then it is probably the right alternator. Some people swap in an internally regulated alternator and it will function fine but you get the 41 fault and a little worse fuel economy.


The time now is 03:13 PM.

Powered by vBulletin Version 3.8.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.