97 5.0 issues

[SuperGordo]

Yep that’s one reason I want to pull the intake. I have no clue what they did or didn’t do. They could have left rags stuffed in the intake manifold for all I know. But it pulls great vacuum and I haven’t found anything really hacked up aside from the cats being removed.

Something else I just thought about. My Ex had a fuse blown that powered the oxygen sensor heater circuit. Ran like crap, replaced the fuse and it was much better. I don't know the exact fuse number at this moment. It was in the interior fuse panel.

 

[iajet]

New member, first post. I’ve tried searching for this extensively before posting my own thread.

Ok, I just purchased a 1997 EB 5.0 AWD w/ 156k miles that had a miss. Thinking I could fix it easily but I’m at a loss. Also I am using AutoEnginuity software to look at all of my OBD2 info.

The explorer is mostly stock but I found that the cats have been removed. Everything else is completely stock. The previous owner did a lot of stuff and sold it because he couldn’t get the miss fixed. I did a compression test yesterday, all cylinders were 150-160 psig, verified the proper autolite plugs, plug gap, wires were routed to the right spot on the new coils. By the way he already replaced both coils, all plugs, wires, MAF sensor, injectors, and 1 (bank 2 upstream) O2 sensor.

The engine runs horrible, low erratic RPMs, almost no power, in closed or open loop. All of my STFT and LTFT are really high, O2 readings are high, which if I understand correctly indicated a lean condition and adding fuel. And the O2 graphs are cycling up and down and not flat lined so they’re working. But when I pulled the plugs they were nearly dripping with gas and sooted up. What is going on here??

I had a similar issue not too long ago and the culprit was the EGR vacuum solenoid. Good luck

 

[lugnut1009]

I had a similar issue not too long ago and the culprit was the EGR vacuum solenoid. Good luck

How was the vacuum solenoid causing this issue? Vacuum leak in the valve or keeping the EGR open all the time? I already tested the EGR and verified at different time the vacuum solenoid valve was open or closed.

 

[iajet]

How was the vacuum solenoid causing this issue? Vacuum leak in the valve or keeping the EGR open all the time? I already tested the EGR and verified at different time the vacuum solenoid valve was open or closed.

The valve was constantly open.

 

[Joe Dietz]

LugNut,
Give this a go, since the truck has had some fiddling with, is there a chance the left 02 sensor is in the right side exhaust and visa-versa? I only ask as when I did a Mustang motor swap into my first gen exploder, it barely ran...like the computer was fighting itself. Suggest that you double check that wiring? I know its a long shot... ;-)

Be well,
Just Joe

 

[Jsck5466]

New member, first post. I’ve tried searching for this extensively before posting my own thread.

Ok, I just purchased a 1997 EB 5.0 AWD w/ 156k miles that had a miss. Thinking I could fix it easily but I’m at a loss. Also I am using AutoEnginuity software to look at all of my OBD2 info.

The explorer is mostly stock but I found that the cats have been removed. Everything else is completely stock. The previous owner did a lot of stuff and sold it because he couldn’t get the miss fixed. I did a compression test yesterday, all cylinders were 150-160 psig, verified the proper autolite plugs, plug gap, wires were routed to the right spot on the new coils. By the way he already replaced both coils, all plugs, wires, MAF sensor, injectors, and 1 (bank 2 upstream) O2 sensor.

The engine runs horrible, low erratic RPMs, almost no power, in closed or open loop. All of my STFT and LTFT are really high, O2 readings are high, which if I understand correctly indicated a lean condition and adding fuel. And the O2 graphs are cycling up and down and not flat lined so they’re working. But when I pulled the plugs they were nearly dripping with gas and sooted up. What is going on here??

vacuum leak probably the intake manifold .. i had the same problem on my 97 explorer 5.0 that's my best guess ..

 

[XploderPhil]

Have you checked the barometer PID to make sure the ecm doesn't think it's at 12,000ft? A dirty MAF sensor can cause all kinds of lean problems.
The ECM uses the air flow reading to estimate a barometer reading.

 

[lugnut1009]

Have you checked the barometer PID to make sure the ecm doesn't think it's at 12,000ft? A dirty MAF sensor can cause all kinds of lean problems.
The ECM uses the air flow reading to estimate a barometer reading.

I have, the barometric pressure was right at 14.7 and the MAF sensor is clean and seems to be working correctly.

 

[lugnut1009]

A stuck lifter would make noise that you can hear from ten feet away - not to mention that the affected cylinder would have low compression. Before tearing into anything I would check for separated tone ring on the harmonic balancer. I am looking at one as I am writing this and can see that the double-wide gap is centered at about 25deg BTC. If you see it more than a few degrees away from that spot, you found the problem.

Looks right to me?

 

[FATK]

New member, first post. I’ve tried searching for this extensively before posting my own thread.

Ok, I just purchased a 1997 EB 5.0 AWD w/ 156k miles that had a miss. Thinking I could fix it easily but I’m at a loss. Also I am using AutoEnginuity software to look at all of my OBD2 info.

The explorer is mostly stock but I found that the cats have been removed. Everything else is completely stock. The previous owner did a lot of stuff and sold it because he couldn’t get the miss fixed. I did a compression test yesterday, all cylinders were 150-160 psig, verified the proper autolite plugs, plug gap, wires were routed to the right spot on the new coils. By the way he already replaced both coils, all plugs, wires, MAF sensor, injectors, and 1 (bank 2 upstream) O2 sensor.

The engine runs horrible, low erratic RPMs, almost no power, in closed or open loop. All of my STFT and LTFT are really high, O2 readings are high, which if I understand correctly indicated a lean condition and adding fuel. And the O2 graphs are cycling up and down and not flat lined so they’re working. But when I pulled the plugs they were nearly dripping with gas and sooted up. What is going on here??

Did you disable the Bank 1 and bank 2 O2 sensors after the non existent CATs? Also remove the DTCs for those O2 Sensors. This way your fuel trims should reference the 2 existing O2 sensors. I would expect to see a noticable improvement. Sometimes people just take the CATS off and expect a miracle to happen when it comes to performance. They don't realize it is all tied together in the program. Best of luck.

 

[lugnut1009]

I don’t know how to turn them off, but I’ve had luck using the non-foulers in the past on secondary O2 sensors to keep the CEL off for them. They’ve pretty much stayed at zero, but with it running so rich I’m not sure how hot the exhaust is getting to help them operate.

Anybody have a wiring diagram for this one? I haven’t had any luck finding one. All of the links are either dead or expired.

 

[1998Exp]

Looks right to me?
View attachment 423813

Yes. Time to look elsewhere. A timing chain that jumped a tooth? Don't know if that would still allow correct compression. Anybody?

 

[EB4X]

Maybe your ECM is failing.. ?

 

[lugnut1009]

Well I’m not giving up. I have a Can-am Spyder in my shop right now I have to finish work on for a lady before I can get it inside and really tear into it, but unless someone has another area to inspect or test I’m pulling the intake and valve covers for a proper inspection.

 

[lugnut1009]

Maybe your ECM is failing.. ?

How would I know this or test for it? I do have some interior lights that don’t work but marked that up to a faulty headlight switch or dimmer. I read where some people were pulling and opening the ECM and found burnt resistors or capacitors. Guess it can’t hurt.

 

[CDW6212R]

The PCM would be the last possibility to have faults, the transistors etc. But it's more likely someone before left some issues behind, wiring damage etc.

My 98 truck has a hard miss which came from bad gas creating corrosion that filled the sock at the pump. A lean code came but was after a long time and replacing a bunch of parts, including coils that was one new Accel coil that failed. So I thought I had found the miss, and my bet is the lean condition hurt the valve seats. I haven't had time to work on it since then.

Keep at it, working through other's problems is big trouble.

 

[410Fortune]

You guys these 5.0 with hollow or Mia cat primary converters will run fine for the most part. Every once in a while a code
May show up for catalyst efficiency but it still runs smoothly
I feel like there is an underlying issue here, not the missing cats causing this problem

 

[samo_finest]

New member, first post. I’ve tried searching for this extensively before posting my own thread.

Ok, I just purchased a 1997 EB 5.0 AWD w/ 156k miles that had a miss. Thinking I could fix it easily but I’m at a loss. Also I am using AutoEnginuity software to look at all of my OBD2 info.

The explorer is mostly stock but I found that the cats have been removed. Everything else is completely stock. The previous owner did a lot of stuff and sold it because he couldn’t get the miss fixed. I did a compression test yesterday, all cylinders were 150-160 psig, verified the proper autolite plugs, plug gap, wires were routed to the right spot on the new coils. By the way he already replaced both coils, all plugs, wires, MAF sensor, injectors, and 1 (bank 2 upstream) O2 sensor.

The engine runs horrible, low erratic RPMs, almost no power, in closed or open loop. All of my STFT and LTFT are really high, O2 readings are high, which if I understand correctly indicated a lean condition and adding fuel. And the O2 graphs are cycling up and down and not flat lined so they’re working. But when I pulled the plugs they were nearly dripping with gas and sooted up. What is going on here??

I think its getting more gas than need.. i would recommend to check the fuel system..

 

[1998Exp]

New member, first post. I’ve tried searching for this extensively before posting my own thread.

Ok, I just purchased a 1997 EB 5.0 AWD w/ 156k miles that had a miss. Thinking I could fix it easily but I’m at a loss. Also I am using AutoEnginuity software to look at all of my OBD2 info.

The explorer is mostly stock but I found that the cats have been removed. Everything else is completely stock. The previous owner did a lot of stuff and sold it because he couldn’t get the miss fixed. I did a compression test yesterday, all cylinders were 150-160 psig, verified the proper autolite plugs, plug gap, wires were routed to the right spot on the new coils. By the way he already replaced both coils, all plugs, wires, MAF sensor, injectors, and 1 (bank 2 upstream) O2 sensor.

The engine runs horrible, low erratic RPMs, almost no power, in closed or open loop. All of my STFT and LTFT are really high, O2 readings are high, which if I understand correctly indicated a lean condition and adding fuel. And the O2 graphs are cycling up and down and not flat lined so they’re working. But when I pulled the plugs they were nearly dripping with gas and sooted up. What is going on here??

Something is telling me that the previous owner removed the cats because they were plugged. Is this engine burning a lot of oil? Are you sure that the soot you see on the plugs is not burned oil?

 

[lugnut1009]

Something is telling me that the previous owner removed the cats because they were plugged. Is this engine burning a lot of oil? Are you sure that the soot you see on the plugs is not burned oil?

Well the compression test was good and when I pulled the plugs they were dripping with gas. So pretty sure it’s just flooded. But I guess I’ll find out eventually.