'94 Explorer 4.0L Rough Idle , Error codes 181, 186, 189 - Ford Truck Enthusiasts Forums

Explorer, Sport Trac, Mountaineer & Aviator 1991-1994, 1995-2001, 2002-2005, 2006-2010 Ford Explorer

'94 Explorer 4.0L Rough Idle , Error codes 181, 186, 189

Thread Tools Search this Thread
Old 08-16-2002, 12:56 PM
TC56 TC56 is offline
Freshman User
Thread Starter
Join Date: Jul 2002
Location: USA
Posts: 25
TC56 is starting off with a positive reputation.
'94 Explorer 4.0L Rough Idle , Error codes 181, 186, 189

Reply With Quote
Old 09-09-2002, 01:06 PM
scharble scharble is offline
New User
Join Date: Sep 2002
Posts: 2
scharble is starting off with a positive reputation.
'94 Explorer 4.0L Rough Idle , Error codes 181, 186, 189

My '94 Ford Explorer 4.0L has a rough idle (shakes) and occasionally the check engine light came and went off. Code 181 Adaptive Fuel Rich limit Reached Right Side, Code 189 Adaptive Fuel Rich Limit Reached left side, and Code 186 Injector Pulse width high

I've cleaned the MAF Sensor, Replaced the Plugs, replaced the PCV valve, tightened the lower intake manifold, and installed a new Fuel Pressure regulator. Still a rough idle. Could it be the O2 sensors?

Any Ideas? :-(
Reply With Quote
Old 09-09-2002, 04:23 PM
Dialtone Dialtone is offline
Elder User
Join Date: Aug 2001
Location: South Texas
Posts: 932
Dialtone is gaining momentum as a positive member of FTE.
'94 Explorer 4.0L Rough Idle , Error codes 181, 186, 189

[updated:LAST EDITED ON 09-Sep-02 AT 04:29 PM (EST)]One common cause for a rough idle or failure to maintain idle speed is the Idle Air Control valve. It can stick and not step open/closed properly under PCM control. You can remove it and clean with spray carb cleaner.
The codes you gave are continuous memory codes that indicate both sides of engine seem to be running lean and the PCM can no longer compensate for the lean condition by varing the injector pulse height/width. It is curious that no codes for O2 sensor lean condition was set also. Assuming you have O2 sensors on both left and right sides of engine, it is less likely that both O2 sensor failure is the source of the problem (but not impossible)
You may be on the right track, but I would make sure to rule out some things first as follows.
1. Clear PCM and run both key on engine off tests and engine running tests to rule out a sensor problem first. Repair any codes given in these tests first and foremost. Work on only the first code given, then re-run test again from scratch.
2. Remove and block all vacuum ports at the tree on intake manifold to check for unaccounted for air in intake system. (most especially the power brake booster). Also check the air duct between MAF and intake for opening which may be letting air in system after MAF.
3. Run a fuel pressure test with both the engine off and running. With key on engine off, pressure in the fuel rail should be 35-40 PSI, Engine running and regulator vacuum line on should yield 30-35PSI. Goose the throttle and make sure pressure is maintained at minimum pressure level. If it drops significantly, suspect a restriction in fuel system (Fuel filter) or fuel pump in tank.

If all above looks OK then try this to simulate an Open Loop running test. (Cold engine startup and run)
1. Clear the PCM again.
2. Disconnect lead from Temp Sensor to PCM to simulate cold engine.
Take a short test drive and see how engine performs. If OK then lean to O2 sensors in closed loop. (This may set a code but you can ignore it for now) If not OK the you definately have an air or fuel related problem. (Just because you cleaned the MAF sensor does not mean it is measuring airflow properly)

Don't forget to check the Throttle Pos sensor also, It can cause some really wierd results. Clear PCM EACH time you change any emissions related component.
Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
**** bradphx 1973 - 1979 F-100 & Larger F-Series Trucks 61 04-27-2017 01:22 AM
Can someone explain this to me? 1987 - 1996 F150 & Larger F-Series Trucks 11 03-09-2016 01:40 PM
ooops Aerostar 5 01-14-2015 04:16 AM
... miko6810 Modular V10 (6.8l) 9 06-04-2014 07:14 AM
DPSE Roachfood 1987 - 1996 F150 & Larger F-Series Trucks 3 03-11-2002 11:21 PM

Go Back   Ford Truck Enthusiasts Forums >

181, 189, 40, 49l, 95, code, e350, explorer, ford, idle, rich, rough, shakes, starting, trouble

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump

All times are GMT -5. The time now is 06:45 AM.

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.