SURGING IDLE,CK.ENGINE LIGHT ON

[EX-SPORT]

97 EXPLORER SPORT,CK ENGINE LIGHT CAME ON A COUPLE OF DAYS AFTER STARTED SURGING AT IDLE WHEN A/C OR HEATER IS ON.TECHNICIAN AT A DODGE DEALER SHIP RAN A CODE SCANNER ON IT & CAME UP W/H CODES PO 171 & PO174.ANYBODY GOT ANY IDEAS WHAT THESE ARE,I'M PRETTY MECHANICALLY INCLINED & DO A LOT OF MY OWN WORK SO I HOPE THIS IS SOMETHING I CAN FIX.THIS IS MY FIRST POST HERE SO I HOPE YOU CAN HELP,THANKS.OH YEAH,IT HAS THE 4.0 SOHC ENGINE,SORRY.

 

[leebo]

I'd like to start off by giving you a hand on your purchase on the Explorer and welcoming you to the site. I'm sure you'll love them both.

As for the codes....I don't know. I would start though by checking your MAS sensor. It's an easy fix that seems to be common in most explorers. Attached to your air-box there is a sensor. Remove that by using a "security" screwdriver. You may need to get this part at Napa or somewhere like that. Take off the sensor and spray some carb cleaner on the tiny "light bulb" looking parts on the sensor. Let it dry and reinstall. This sensor seems to get dirty easly on the explorer and the cleaner seems to do the trick. You can also go to the "explorer tips" page and get some more info on this.

 

[Robert]

Originally posted by EX-SPORT
97 EXPLORER SPORT,CK ENGINE LIGHT CAME ON A COUPLE OF DAYS AFTER STARTED SURGING AT IDLE WHEN A/C OR HEATER IS ON.TECHNICIAN AT A DODGE DEALER SHIP RAN A CODE SCANNER ON IT & CAME UP W/H CODES PO 171 & PO174.ANYBODY GOT ANY IDEAS WHAT THESE ARE,I'M PRETTY MECHANICALLY INCLINED & DO A LOT OF MY OWN WORK SO I HOPE THIS IS SOMETHING I CAN FIX.THIS IS MY FIRST POST HERE SO I HOPE YOU CAN HELP,THANKS.OH YEAH,IT HAS THE 4.0 SOHC ENGINE,SORRY.

Exact same story as my '97 late last year. Surging idle, P0171 & P0174 codes. Turned out to be my lower intake manifold o-rings were leaking. It is somewhat common (enough to warrant a TSB# 99-10-4). Be sure and replace the gasket between the upper and lower intake manifolds as well.

 

[EX-SPORT]

thanks leebo & robert i REALLY appreciate the help from you guys!robert,did you change the o-rings yourself,how hard was it if you did & also did it surge all the time like a vacuum leak or just when it was under load(a/c or heater on) leebo i'll also look at the mass air sensor while i'm checking stuff thanks again,i'll let you know what i find

 

[Robert]

Originally posted by EX-SPORT
thanks leebo & robert i REALLY appreciate the help from you guys!robert,did you change the o-rings yourself,how hard was it if you did & also did it surge all the time like a vacuum leak or just when it was under load(a/c or heater on) leebo i'll also look at the mass air sensor while i'm checking stuff thanks again,i'll let you know what i find

No, I have a Warranty Gold extended warranty so I let them cover it. I took it to my regular mechanic and he charged my warranty company about $133. That was for $14 in parts, the rest in labor. He had about 3 hours in it, but there were several gaskets leaking (lower intake manifold o-rings, IAC valve gasket and VIS gasket). Everytime he put it back together, he heard another leak. Ford would have been about double the price. If you are competent in mechanics, it probably wouldn't be too difficult. I would have done it myself, if I didn't have the warranty. I diagnosed the problem myself since Warranty Gold told me that if the reason my Check Engine light was on turned out to be emmissions related, they wouldn't pay for it since it is one of their exclusions. I bought an OBD II scanner and read the codes myself. I then located the TSB and under the troubleshooting steps, it states to inject propane around the lower intake manifold while monitoring the short-term fuel trims on banks 1 & 2. If you see a sudden change when the propane is added or removed, you have a leak. I bought a $10 propane torch at Wal-mart that worked great. It let me put the propane right down to where I suspected the leak was. My fuel trims changed by a huge margin whenever I had the propane near the leak. I don't remember if they went up or down though. I felt the torch was much safer than trying to balance my barbeque's propane tank with one hand and opening the valve with my other hand and holding the hose between my teeth. Anyway, once I confirmed the leak, I called Warranty Gold again and told them what I found and asked them if they covered it. They said that if I took it to an ASE certified shop and they diagnosed the intake manifold gasket was leaking that they would cover it. That is when I took it to my mechanic.

Also, it didn't surge too badly, and only while sitting there idleing. Whenever I listened under the hood and blipped the throttle, I was certain that I was hearing a loud hiss. The first time the light came on, I disconnected my battery. The light only stayed off for about a week. I checked my codes before the light came back on and it had set a pending code so I knew it was just a matter of time before it came back on.

 

[EX-SPORT]

i talked to the local ford dealer yesterday about it & they said they weren't sure what those codes were for but i called the service manager there that i'm friends w/h & he said he was about to give me a call,it seems he & the mechanic we talked to, later got together & remembered that tsb because the mechanic had done several of them.he was supposed to fax me the tsb but i guess he got busy & didn't get to.where did you get you're obd tool i have one for the eec-iv systems but not obd.again thanks for all the help & i'll let you know how it turns out.

 

[Robert]

Send me an e-mail and I'll fax you the TSB. I got the OBD-II scanner at a place called Checker Auto Parts (CKS Auto). It is an AutoXray scanner (www.autoxray.com). It did not work for monitoring the fuel trims though. In the real-time monitor mode, it showed -100% for my short and long term fuel trims on both banks. When the code got set though it did have the correct fuel trim at the time the code got set. AutoXray is located about 1/4 mile down the street from my work so I contacted them thinking I had a defective scanner. They let me borrow their multi-thousand dollar professional scanner for a week to troubleshoot with. What I found out was that whenever I used the professional scanner in Generic OBD-II mode, it performed the same as my scanner. If I put it in OEM specific mode, it would let me monitor my fuel trims in real time. They are supposed to be offering an upgrade to OEM specific tests in November, but the other things that they have released were always several months behind so I'm not looking for it any time soon. Works great for pulling the codes and monitoring most engine functions in real time though.

 

[EX-SPORT]

i got the tsb today the serv.mang.faxed it about 6pm yesterday & i got it this morning i'm going to do it friday night & saturday so let you know how it goes.thanks for the tip on the obd tool i may get one.