1998 Explorer XLT Resurrection

[archer973]

2 Short Road Tests

I've taken it on the road twice. The first was just an around the block at 15 mph. The engine felt strong, but I wasn't really putting it to a good test. I noted a rattle in the undercarriage I want to locate and fix, and there was a shudder in the steering during the sharp right turn into my driveway, but that might have been because of the road surface.

The second road test was about a mile in length and I got it up to 60 mph. Acceleration was good--plenty of power. Temp stayed at mid range. The catalytic didn't start glowing. Not sure if I felt that shudder in the steering again or not. If it was there, it wasn't as noticeable, so not sure what to think. I'm hoping it's the road surface, but I fear I might be wrong. Haven't been able to find what is rattling yet either.

I'm planning a longer drive down to British Camp and back, about 30 miles round trip, before I call it done.

 

[archer973]

Still not finished

I've made a few trips to town and while the engine runs great I am once again getting codes for lean mixture on both banks (P0171 & P0174) and one for the IAC (P1506). I've tested for vacuum leaks--none. I've cleaned the injectors, the MAF sensor, the intake air temp sensor, all oxygen sensors, the IAC, and cleaned and tested the TPS. I've seen some improvement in acceleration, but still get the codes. Before doing all this cleaning, the engine idle was high and would occasionally drop low, but it idles at about 850 constantly now.

I've searched this forum and others looking for answers, but everyone that has started threads about this problem never finish the thread and no solution is given. So I'm looking for help and I have a few questions.

1) When watching the sensor readings on a diagnostic scanner while the engine is running at idle, what should I see for the MAF, Timing Advance and Throttle?

2) What is the vacuum operated valve mounted on top of the intake manifold behind the IAC? It is some type of butterfly valve and I think it balances the manifold, but I cannot find anything about it's function or what it is called. Could it contribute to this problem?

3) Where is that rattle in the undercarriage coming from? I've searched and can't find its source. (I'm not really expecting someone to try to answer this question.)

I'm open for suggestions. I am putting this vehicle into service while I try to find the solution to this problem unless someone thinks that is a bad idea. Let me know.

 

[archer973]

One question answered

I already wrote part of this entry once but now that I've come back I see that it isn't posted. Can't find it anywhere so don't know what happened. Anyway...

I found the answer to my question about the valve. It's callout number is 9G463. It is part of the Variable Intake System Assembly along with the IAC valve. While the engine is at idle, this butterfly valve separates the two sides of the manifold. When engine rpm increases and vacuum increases, the valve turns 90 degrees and the manifold will now act as a single unit instead of two units at idle.

When at idle, the throttle plate is closed so the air passes through the IAC which controls the flow rate. The output of the IAC port splits the airflow to the two sides of the manifold that are separated by the butterfly valve.

OK, I removed this unit from the manifold and found that a lot of gunk had collected in the bottom of the IAC output port. I cleaned the port and both of the airflow channels then reinstalled it. But I could see that this probably would not fix the lean condition. The airflow would be impeded which would cause a rich condition instead.

I started the engine and I no longer had a consistent 850 rpm idle. The idle was low and varying up and down. Figuring that this cleaning made a big difference in airflow, this would mean the PCM has to relearn the operating settings. So I shut down and disconnected the battery to allow the PCM to forget everything it had learned. After reconnecting later, the engine still idled poorly. After it was fully warmed up I went for a test drive and monitored the engine with a diagnostic scanner. About 1/4 of the way into my drive, the P0171 code returned, but the P0174 code did not return until I was almost home again. The P1506 code did not return. At the end of the drive, engine idle was constant, but high.

I'm thinking I need to remove the upper intake manifold again and thoroughly clean it. There is a spray cleaner on the market for cleaning coated manifolds. Will purchase that for this task. I'm still hoping for input from others out there.

 

[2000StreetRod]

Variable intake system

. . . 2) What is the vacuum operated valve mounted on top of the intake manifold behind the IAC? It is some type of butterfly valve and I think it balances the manifold, but I cannot find anything about it's function or what it is called. Could it contribute to this problem? . . .

VIS Conversion

The lever should move easily when the linkage to the vacuum motor is disconnected.

 

[archer973]

Thank you 2000StreetRod

The lever should move easily when the linkage to the vacuum motor is disconnected.

Thank you! Interesting thread at the link you provided. While I had the valve out, I tested it and it operates smoothly. After cleaning & re-installing it, I observed its operation when I gunned the engine. It quickly flips 90 degrees like it should at higher rpm.

 

[archer973]

It might be done

I was futzing around in the garage and found an insulator that I didn't know where it came from. Thinking it might go somewhere under the hood of this beast, I started looking for a place to put it--maybe tape it to the firewall. No. Look some more. Lo and behold, down low under the battery, a hose not connected where it should be. My brain immediately said, "Hmm. That doesn't look right." This was surprising since my brain rarely speaks to me.

I don't know what this thing is, but it has two hoses connected to it. One with a white plastic retainer and the other green. The green one, connects to the upper doohickey on this wazzit, was just hanging there. After connecting, I started the engine and had a very nice idle at about 1200 rpm, cold. Slowly the idle dropped to about 650 while I monitored the diagnostic scanner. And it purred at 650. I've stopped for lunch. Mrs. Archer needs to go into town and I'm going to take her and use this as a test drive. Will post the results later.

Oh, I do have another intermittent problem that has come up three times. Occasionally, I will try to start the car and nothing happens. All the console lights are on, car in park, foot on the brake, turn the key and nothing-no starter motor. The first time this happened, it started on the third or fourth try. The next time, maybe twenty tries before it started. Then it didn't happen again for several days until yesterday. I was ready to put it back in the garage and it wouldn't start. I left it for awhile and when I came back, it started first try. BTW: The "Theft" light is not blinking rapidly. I'm thinking maybe an intermittent starter relay. Hard to track down intermittent problems.

 

[2000StreetRod]

fuel vapor management valve

. . . down low under the battery, a hose not connected where it should be. . .

That's the fuel vapor management valve.
Looking down (ignore red arrows):

Looking up:

Edit: Ford calls it the evaporative emission canister purge valve.

 

[archer973]

re: fuel vapor management valve

That's the fuel vapor management valve.
Looking down (ignore red arrows)

Thank you, again, 2000StreetRod! I felt like you would probably identify this puppy for me. I'm not sure when the hose came loose. I know it was connected at one time and for awhile I was not having the P0171/P0174 codes. I think it might not have been fully snapped/locked into place or maybe I knocked it off when I was re-installing the gravel shield in that wheel well.

Took it for a test drive and it ran very well into town and back. No codes after I got back home and this was a longer test drive than the last few that resulted in codes. The no-start problem occurred once, but it started the second time I turned the key. However, I also detected a new rattle--more of a rumble. It occurs at very low rpm. Now that the idle is lower than it has been before I am hearing something that is resonant at this lower frequency. It's from the rear of the car. I haven't started looking for it yet. The other rattle I have been hearing appears to be stuff inside the muffler, probably debris from when the backfires & fireballs occurred ten years ago.

 

[anti eloi]

rumble

Exhaust System - Boom/Grunt/Groan/Moan/Vibration
Article No.
98-21-1

10/26/98

NOISE - "BOOM/GRUNT/GROAN/MOAN" - DURING IDLE WITH ENGINE HOT OR COLD - 4.0L SOHC VEHICLES

VIBRATION - DURING IDLE WITH ENGINE HOT OR COLD - 4.0L SOHC VEHICLES

LIGHT TRUCK: 1997-99 EXPLORER, MOUNTAINEER

This TSB article is being republished in its entirety to include additional Figures, additional symptoms and to include 1999
model year vehicles and Mountaineer.

ISSUE
A vehicle vibration may be present during a hot or cold idle condition and/or an audible "boom/grunt/groan/moan" may be
present between 700-800 rpm during a cold engine start and low vehicle speed. This concern may be more noticeable on left
turns. This may be caused by exhaust system vibration when the engine firing frequency lines up with a resonant frequency of the exhaust system.

ACTION

Install a Y-brace. The brace limits the vertical bending motion of the exhaust system and reduces the possibility of an
objectionable vibration. Refer to the following Service Procedure for details.

SERVICE PROCEDURE

1.Reprogram the Powertrain Control Module (PCM) with the latest calibration. Refer to TSB 98-1-18.
(Do not reprogram 1998 vehicles built after 2/14/98.) The new calibrations limit the amount of time the vehicle will spend
in the critical rpm range.

2.Neutralize the exhaust system as per the 1998 Explorer Workshop Manual, Page 100-04-29.

3.Install a new pressure Power Steering Hose (F87Z-3A719-JA). Isolate the metal lines on the steering assembly (use rubber hose).
Refer to Figures 1 and 2

4.Install the new exhaust brace. The top "Y" portion of brace attaches to two (2) bolts at the bottom of the
transmission bellhousing per the following process:

a. Install the Y-Brace (F87Z-5K249-AA) and hand start bolts in transmission bellhousing.

b. Attach to the left catalyst converter brace using a 2" U-bolt (F87Z-5A231-BA). Hand start the U-bolt nuts.

c. Torque transmission bellhousing bolts to 30 N.m (22 lb-ft).

d. Torque the U-bolt nuts to 40 N.m (30 lb-ft).

Obtain an Authorized Modifications Decal (FPS 8262 - obtainable through DOES II, 25/pkg) and list the date,
dealer number, and summary of modifications performed. Select a prominent place adjacent to the Vehicle
Emission Control Information Decal suitable for installing the Authorized Modifications Decal.
Clean the area, install the decal, and cover it with a clear plastic decal shield.


PART NUMBER PART NAME

F87Z-5K24S-AA Y-Brace
F87Z-5A231-BA U-Bolt
F87Z-3A71S-JA Power Steering Hose

OTHER APPLICABLE ARTICLES: 98-1-18

SUPERSEDES: 98-15-14

WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage


OPERATION DESCRIPTION TIME

982101A Install Service Parts 1.0 Hr.

982101B Reprogram Powertrain 1.5 Hrs.
Control Module (PCM) And
Install Service Parts

DEALER CODING
CONDITION
BASIC PART NO. CODE
RECAL 42

OASIS CODES: 403000 608000, 608400, 702300, 703000, 703100

 

[anti eloi]

rumble

Call a Ford Dealer and give them your VIN # and see if you have already had the PCM re-programing.

As far as the Y brace.....good luck finding one.
I am just going to make my own and use a heavy duty muffler clamp.

 

[archer973]

Thank You anti eloi

Call a Ford Dealer and give them your VIN # and see if you have already had the PCM re-programing.

As far as the Y brace.....good luck finding one.
I am just going to make my own and use a heavy duty muffler clamp.

Thank you anti eloi! Very good information. I think I will go along with you and make some type of brace to fix this problem and I will call a dealership tomorrow.

 

[archer973]

Resurrection Complete

I just put this vehicle on my insurance and am going to start driving it on a regular basis. I just finished programming two new keys for it using my ELM 327 adapter and Forscan software on a laptop with Bluetooth capability. I didn't write about that in this thread, but I covered it in another of my threads: Glowing Catalytic '98 Explorer. That info got placed there because another person in that thread told me about the Forscan software and key programming.

I still have the occasional rumble in the exhaust system that I need to fix and still get a FuelSys2 error that I hope to fix soon, but neither of these items keep the vehicle from running fine. The tires on it are probably 15 to 20 years old so I need to replace those the first time I take it off-island.

This has been a long running thread that I've used to talk about my progress so it is more of a blog than a helpful thread. I plan to create a new thread where I will extract the useful information and condense it into a useful format for others. When that is done I will add a link to it.

Before closing--Thank you to all of you that helped by sharing your knowledge! Throughout this project, you guys have been encouraging and provided inspiration. I've tried to always thank each individual after they posted helpful comments. I hope I didn't miss anyone. To all of you--this salute is for you!