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Glowing Catalytic '98 Explorer 4.0L V6 SOHC 16V (VIN E)

archer973

Well-Known Member
Joined
January 31, 2014
Messages
112
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City, State
Mt. Vernon, WA
Year, Model & Trim Level
1998 Ford Explorer XLT
History: Vehicle on road traveling about 45 MPH when several backfires occurred accompanied by fireballs from the exhaust. A compression test indicated a timing chain had slipped causing low compression in all right side cylinders. Towed home and placed in garage for 10 years. I acquired the vehicle and started an engine rebuild--ongoing spare time project chronicled in my thread 1998 Explorer XLT Resurrection. I recently reinstalled the engine which runs fine, but I observed the right side catalytic converter is glowing red hot.

An initial online search into this problem revealed the most common cause is unburned fuel in the engine exhaust or a plugged catalytic converter. A compression test of the engine indicated all the valves were closing, so I concluded the catalytic was plugged and ordered a new one. $170 dollars later, I still have a glowing catalytic converter. I spent a couple of hours yesterday reviewing other threads here and in other forums looking for a solution to the problem. Most of the threads contained many suggested solutions, but very few of the threads come to a conclusion, i.e., "I fixed it. This was the problem." So I am starting this thread focused on this problem alone and will follow through until I have a fix and posted the answer for others.

One suggestion I found is that the exhaust could be plugged further downstream from the catalytic, so I disconnected the muffler from the new catalytic. After starting the engine, it took longer, but eventually the catalytic started glowing again so I am back to thinking unburned fuel in the exhaust.

I am not ruling out I made a mistake somewhere in my rebuild that could cause this. Lots of hoses and wires unattached and reattached. New gaskets. Some new parts, some old ones, and some from a wrecking yard. My next step is to test the oxygen sensors and plug wires. Hoping I will receive some good tips from others here.
 



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My 2 cents would be to download Forscan (free) on your laptop and you then can see your O2 sensor response, fuel trims, any misfires as well as all your other sensors. You will need an elm 327 adapter which allows you to connect your Obdii plug to your laptop. I know you have checked but are you 100% sure your plug wires are going to the correct plugs... I have to ask, sorry.
 






stuck open injectors?

Your glowing cat indicates a rich exhaust. The problem seems to be only on the passenger side. That eliminates sources that would affect both sides (i.e. MAF sensor, fuel pressure). When fuel injectors sit unused for more than a couple years they are unreliable. Normally, they stick closed because that is their unused mode. However, it is possible one or more could have opened and then stuck that way after you returned the vehicle to operation.

Another possibility is no spark on the right bank. The unburned fuel could be burning in the cat. When I rewired my wiring harness to install the supercharger I omitted the power source for the left bank of the fuel injectors. The engine started easily and idled normally but had no power.
 






Thank You crunchie_frog & 2000StreetRod

My 2 cents would be to download Forscan (free) on your laptop and you then can see your O2 sensor response, fuel trims, any misfires as well as all your other sensors. You will need an elm 327 adapter which allows you to connect your Obdii plug to your laptop. I know you have checked but are you 100% sure your plug wires are going to the correct plugs... I have to ask, sorry.

Hi crunchie_frog. Thank you for your input. I've often wondered if anything like the elm 327 adapter existed, but didn't look into it. I've often used a scanner rented from Autozone, but I have an adapter on order now thanks to your input. Bluetooth compatible and interfaces with Torque App on an Android as well as laptop software. Sounds fun. The reviews on the one I ordered sounded good.

And no need to apologize for asking about the plug wire connections. Sometimes the obvious is what is overlooked. However, the plugs are wired correctly and I rechecked this again today while checking the wire resistances.

Your glowing cat indicates a rich exhaust. The problem seems to be only on the passenger side. That eliminates sources that would affect both sides (i.e. MAF sensor, fuel pressure). When fuel injectors sit unused for more than a couple years they are unreliable. Normally, they stick closed because that is their unused mode. However, it is possible one or more could have opened and then stuck that way after you returned the vehicle to operation.

Another possibility is no spark on the right bank. The unburned fuel could be burning in the cat. When I rewired my wiring harness to install the supercharger I omitted the power source for the left bank of the fuel injectors. The engine started easily and idled normally but had no power.

Hi 2000StreetRod. Good information. I have to admit that I spent time today checking the MAF sensor because I didn't think through the symptoms as you did. I appreciate your insight and will remember this reasoning in the future.

The engine has been running well, but no load applied so it may not have power as you described. I will check for spark on the right bank tomorrow. I checked my plug wire resistances today. Four were within spec, but two on the right bank were > 2x spec. Could this be the problem? I will replace them, of course, but wondering if I have found the problem here.

Concerning the injectors...If I can hear them clicking using a stethoscope could they still be stuck open? That was the process I followed in the Haynes Manual.
 






Plug Wires and Oxygen Sensors

I inspected & tested my plug wires today. Two of the wires on the right side were over two times the rated resistance value for their length. I'm wondering if this is the source of my problem and will order new ones.

I uninstalled the oxygen sensors and tested them using a method I found in a Youtube video: Oxygen Sensor Test. Using a propane torch to heat the sensor while monitoring the voltage on the sensor, I concluded my sensors are OK. I also probed the heater, which he doesn't do in the video. I read four ohms on both heaters. Based on my past experience with heating elements and many other similar devices, I think this is probably a good value.
 






Problem May be Fixed

I reinstalled the oxygen sensors this morning, but just before installing the downstream sensor, I noticed it rattled and I was able to see some debris through one of the vents. Wondering if that is causing a problem when gases are rushing through the vents, something I couldn't duplicate in my test yesterday. I'm planning to get another at Pick-n-Pull next time I'm in that area.

I also tested for spark on all right side cylinders--no problems. I should also mention here that yesterday as I tested the resistance of the plug wires, I also used a pair of pliers to apply slight pressure to each plug end connector before reconnecting. I could then hear it click as it made a solid connection.

I ran the engine while watching the catalytic and it did NOT start glowing, but...

The engine is overheating. I'm not going to discuss this problem here as this thread is dedicated only to the glowing catalytic problem. This will be added to my other thread, 1998 Explorer XLT Resurrection.

After everything cools down, I will reconnect the muffler and run it again while watching the catalytic. Mrs. Archer will monitor the temp gauge to shutdown before it overheats.
 






Still Glowing

I reattached the muffler and did another engine run. After quite awhile, the orange glow returned, but on the other hand, the engine didn't overheat. Tomorrow I will remove the muffler and upend it and shake it to see if I can dislodge any debris. If I shake anything loose, will reinstall and try again.

I know that removing the muffler requires either cutting the mounts or using an air chisel to remove them. I have some idea about cutting them and reusing without additional expense. Will share if my ideas work, but if anyone has already removed and reinstalled a muffler on an Explorer, I would appreciate you input.
 






Muffler OK

After disconnecting the muffler from the catalytic pipes I decided to try something my wife suggested before I cut the muffler hangers. I used my shop vac to blow air through the muffler to see if it was clogged. There was good air flow so I am guessing it isn't plugged and is not causing the catalytic to overheat. I now have two items on my list that may be the source: the downstream oxygen sensor rattles and has debris in it and two of my spark plug wires have higher resistance than they should.

I've ordered new plug wires off Amazon. I expect them to arrive Tuesday. I am also going to Pick-n-Pull that day to get an oxygen sensor. I don't expect to do anymore work on this till Wednesday.

I'm still open for other suggestions of things to check.
 






O2 sensor wiring problem?

The PCM cycles the AFR between slightly rich and slightly lean based on the pre-cat O2 sensor output voltage. Its possible that a wire from the PCM to the sensor could be broken or shorted to the chassis resulting in no voltage fluctuation. If the PCM "thinks" the AFR is lean it would continue richening the AFR until it reaches a pre-set limit from normal. However, usually when the limit is reached a lean condition DTC is set.
 






Thank You 2000StreetRod

The PCM cycles the AFR between slightly rich and slightly lean based on the pre-cat O2 sensor output voltage. Its possible that a wire from the PCM to the sensor could be broken or shorted to the chassis resulting in no voltage fluctuation. If the PCM "thinks" the AFR is lean it would continue richening the AFR until it reaches a pre-set limit from normal. However, usually when the limit is reached a lean condition DTC is set.

Thanks, 2000StreetRod! While I am on my trip to the big city Tuesday, I will stop at Autozone and rent a diagnostic scanner so I can monitor the O2 sensors live. I'm hoping I will be able to do that with the ELM327 adapter I ordered, but I'm renting the real thing because I know I can do it with that.
 






Problem Solved and Thread Summary

This problem has been solved. In his first post, 2000StreetRod came close to guessing the problem--the fuel injectors. He thought that one or more might be stuck open causing too much fuel to be injected which would not be burned in the cylinder and would burn in the catalytic. The fuel injectors were the problem, but not because they were stuck open.

crunchie_frog suggested I buy an ELM-327 chip to monitor the fault codes. I did and using it I found the problem. The logged fault codes, P0171 and P0174, indicated both banks were running lean, not rich. This calls for cleaning the fuel injectors, which 2000StreetRod had suggested.

After cleaning all six injectors, the engine is running good and the catalytic did not start glowing even with the muffler attached. The fault codes are no longer being logged. The problem was fixed before replacing the plug wires or oxygen sensor and only the injector cleaning had been performed.

I am guessing that the PCM, after sensing a lean condition, was enriching the fuel mixture too much which caused too much fuel to be unburned and passed into the catalytic. I'm not totally satisfied with that explanation. If anyone has more insight, please share.

Next post--How I cleaned the injectors.
 






How I Cleaned My Fuel Injectors

Having never cleaned fuel injectors before, I turned to the internet for some DIY help. I googled "DIY cleaning fuel injectors" and watched a few Youtube videos and read a few other posts. I used ideas from two videos and came up with my own method. The two videos are: how to clean fuel injector! DIY and Improvised fuel injector cleaning with a battery and... a bullet. It might be helpful to watch these videos to understand my method explained below.

Tools I used: shop vise, air compressor turned down to 15 psi output, blow gun, a clean rubber tip from a grease gun fitting, two lead wires with small alligator clips on each end, a 9 volt battery, and GUMOUT® CARB/CHOKE & Parts Cleaner (referred to as parts cleaner in the process below).

Process:

1. Clamp a fuel injector vertically in the vise, outlet pointed down. Do not over tighten to prevent damage to the injector.

2. Attach one of the lead wires to one of the injector's terminals. Attach the other end to either of the battery terminals. It isn't necessary to worry about polarity.

3. Attach the second lead wire to the second injector terminal, but do not attach it to the battery. Practice tapping this lead on the open battery terminal. You should hear the injector click each time you tap.

4. Force the rubber grease gun tip onto the blow gun outlet.

5. Hold the blow gun vertical with outlet pointed down. Using a spray tube on the parts cleaner spray can, fill the body of the blow gun by inserting the spray tube into the blow gun inlet and slightly depressing the spray can nozzle to allow the parts cleaner to trickle out of the can.

6. After the blow gun is full, continue to hold it vertically while attaching the hose from the air compressor. Don't forget to have the air compressor output turned down to about 15 psi.

7. Press the rubber tip of the blow gun against the injector inlet and squeeze the blow gun trigger. (When I did this, I had a perfect seal--no spray leaking at the injector inlet.)

8. Tap the open lead wire on the open battery terminal. Each tap should result in a spray of parts cleaner through the injector. Continue tapping until the blowgun is empty.

9. I don't know if it was necessary, but after I emptied the blow gun, I refilled it and emptied it through the injector again.

This process solved the problem I was having. I didn't mention in my previous post, I backed this Explorer out of the garage today. The first time it has moved under its own power since 2005. Didn't street test it, backed down the drive and back to the garage a few times. Transmission works and the brakes work. More to be added in my other thread - 1998 Explorer XLT Resurrection.
 






Re: Forscan

My 2 cents would be to download Forscan (free) on your laptop and you then can see your O2 sensor response, fuel trims, any misfires as well as all your other sensors. You will need an elm 327 adapter which allows you to connect your Obdii plug to your laptop.

Hi crunchie_frog. I want to thank you again for your suggestion about the elm 327 adapter, but also Forscan. When I bought the adapter several weeks ago, I focused on the Torque app for my smartphone because all the ads for these adapters mentioned it. A couple of days ago I was rereading this thread and saw that you had also recommended Forscan. Well, I downloaded it to my wife's laptop, the only computer we have that has bluetooth transmitters. But we learned that those aren't working. But, there is a Forscan app that I downloaded and it has so much more analysis capabilities than Torque. That helped solve a problem with PATS that I was having.

Quick question: I received only one key for this vehicle. I read that Forscan on a computer can program additional keys into the PCM. Have you ever tried this and if yes do you have any tips/advice for me when I try it?

Thanks again! :salute:
 






Hi Archer, yes I recently used Forscan to program a second key for two vehicles, a 99 and 2000, starting with just one key. First, get a quality transponder key ( I used Stratec 597602 H72PT blank from Amazon). Then get it cut by a locksmith, not lowes, Home Depot, Walmart...). For some reason they do not do an adequate job for cutting transponder keys (ask me how I know).
You will need to download the latest version from forscan and then Google forscan pats programming. You will need to get a temporary license from them, (free) but you have to give them your email. I have received no junk mail from them after doing this. You will use the timed sequence for reprogramming. So, the nervous step is you have to erase your original and only key and then reprogram it and the new key. I will have to go back and check my notes and correspondence I had with forscan and I can tell you exactly what the steps are and post them for you. I considered pulling my vehicle into the parking lot of a local locksmith that does pats programming before doing this but, my confidence it would work won out. Saved me ~ $150 by doing this myself, plus the nice feeling you get by winning at "beat the dealership".
 






Then get it cut by a locksmith, not lowes, Home Depot, Walmart...). For some reason they do not do an adequate job for cutting transponder keys (ask me how I know).

OK, I'll bite. How do you know? Actually I think that was a rhetorical question. But I appreciate the warning. I was intending to do it at Ace Hardware. I guess I will rethink that. I purchased keys through Amazon also, don't remember the exact brand off-hand and the keys are out in the garage. Bought two key fobs also. That was the problem I was having with PATS. I couldn't get the system to go into the mode for reading them. Forscan was showing a PATS error. I read somewhere that one way to reset was to turn the key in the driver's door to the left then to the right, but that lock wouldn't turn. Thinking that might have something to do with the PATS error, I removed the door trim panel, unjammed the mechanism and reset the PATS. Next attempt to record the key fobs worked exactly like the book said. And the PATS error is gone.

I told my wife yesterday that we would have to erase the only key we have from the PCM in order to read in the new keys. She said maybe we should take it to a dealer and let them do it. I told her I am going to take it to a dealer but I will park in the parking lot and try to program them myself. She thought that was a good idea. But I like your idea of doing it at a locksmith instead. I'm sure they would be cheaper than a dealer if I have to ask for their help.

Looking forward to your next post. Would really appreciate your notes on this, but there isn't a big rush. No place in my little community to have the keys programmed so I will wait till a later date to take the car off the island and to the mainland to do all this. Don't want to have to pay ferry fees for a tow vehicle if I mess up and have to take it to a good locksmith.

Thank you for your quick response to my query!
 






yes, it was a rhetorical question. but I ruined a pats/transponder key at home depot, they cut it but I had to jiggle it to make it work, for some reason they cannot cut it well. Took another key to a locksmith, took all of 5 seconds and it was a perfect fit. Read online that others have had similar issues with transponder keys at lowes, home depot, etc.

For the programming, you need forscan 2.2.5 version. You will need to get a temporary license from them, you can google and find it. Once you connect forscan, select the service procedures (has the wrench image) then select pats programming and start procedure by hitting the "run" arrow. Select erase and program keys, you will have to wait 10 minutes and then it will instruct you to cycle the key and insert the second key, just follow along with what it asks you to do. I had no issues with this, as I said, I did two different vehicles, 99 and 2000 (mountaineers/explorers).
 






Success!

For the programming, you need forscan 2.2.5 version. You will need to get a temporary license from them, you can google and find it. Once you connect forscan, select the service procedures (has the wrench image) then select pats programming and start procedure by hitting the "run" arrow. Select erase and program keys, you will have to wait 10 minutes and then it will instruct you to cycle the key and insert the second key, just follow along with what it asks you to do. I had no issues with this, as I said, I did two different vehicles, 99 and 2000 (mountaineers/explorers).

Hey crunchie_frog! I owe you a big-time thanks for help and encouragement. You are the one that told me about Forscan and then encouraged me to program my own keys. I just finished the process a few minutes ago. The actual programming went very smoothly, getting prepared for it wasn't.

First, I had to take my blank keys to be cut. We live in a remote community on an island in Puget Sound, WA. So I took the keys with me on one of my jaunts off island, but I forgot to take the original. That delayed the preparations until a second trip off island which occurred last Friday. Found a locksmith who works out of his home--low overhead--and he charged me $5 to cut both blanks. Tested them when I got back home and they turned the key cylinder fine. But we had another problem to overcome. My wife's laptop is the only computer we have with bluetooth but apparently it's transmitter or receiver doesn't work because it can't find nearby bluetooth units, not our smartphones or the ELM adapter. Yesterday she had to go to another of the islands. She works for an engineering firm in the islands and the office is on a different island--she works out of our home. While at the office she borrowed her boss' laptop. I got hold of it last evening, installed the software, got a temp extended license and studied the forums about this. Like I say, the rest was easy, just followed the on-screen instructions, erased all codes, re-programmed the one original key I have and then one of the new ones. Afterwards I used the two-key process in the owner's manual to program the third key.

And now, we just added the car to our insurance. Thanks for your help by sharing your knowledge with me! :salute:
 






Good for you. Sounds like you are lucky to have a good partner there in your wife. Forscan also helped me diagnose some dirty fuel injectors and it really is a neat tool to have in your tool box. You can also get an elm 327 cable instead of Bluetooth. I think I got mine for less than $10 on eBay or Amazon.
 






Good for you. Sounds like you are lucky to have a good partner there in your wife. Forscan also helped me diagnose some dirty fuel injectors and it really is a neat tool to have in your tool box. You can also get an elm 327 cable instead of Bluetooth. I think I got mine for less than $10 on eBay or Amazon.

Yes sir, Mrs. Archer is one of a kind and I am very lucky and blessed to have her.

I'm just beginning to figure out Forscan. It seems to have much more capability than the Torque App for working on this vehicle. Now for my other projects I need Geoscan, Astroscan & Pathfinderscan. Then to help my son's out I need Cherokeescan, etc.

Thanks for the idea about a cable. I will look into that since it would be cheaper than having someone repair the laptop.
 



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