1993 ford explorer bogging down, transmission noise?

[Bboy]

Alright so I recently bought this 1993 ford explorer sport, 4.0, 5 speed manual, odometer says 80k miles so I'm guessing 180k, I drove it home and it could barely hold 65 mph and just felt like it was bogging down, whenever starting off in first gear it felt like it was about to stall (almost like if you start something it 2nd or 3rd gear) should also mention that when driving it doesn't seem to want to go above 3000 rpms unless you downshift hard which is why I thought it was an engine thing but it revs fine, it had 3 check engine codes, my brother has them written down and is out of town so I'll get those when he gets back, 1 was about the maf sensor, one was a bank 1 lean, and the 3rd was something about the coil pack.

The guy we bought it from said his mechanic said it needed fuel injectors on the passenger side (said he didn't know how it was running because all 3 weren't working) we paid $500 for the thing so we weren't about to go spend money on actual nice injectors so we bought some junkyard ones and put them in and it seams to be running better and we reset the code and the only one to stay so far is 157 (maf sensor)

Now for the weird part, when ever you're runs reving it while sitting there it seems to rev fine maybe a slight hesitation but not as much as when it's in gear, when you release the clutch while just idling you can hear a almost cluncking noise from the transmission (when not in gear) and to test if this was happening while driving I put it in 4 low and with no throttle went through the gears and every gear made this noise. After changing the fuel injectors it still wants to die when starting off and it still doesn't want to go over 3000 rpms when driving.

We also through in some motorcraft spark plugs and wires and a different coil pack from the junkyard (we also tested a brand new motor craft coil and it ran the same) we put in a maf from the junkyard because the previous owner put in a Chinese brand one and it made no difference (the junkyard one could be bad as well so that's something we might look into)

Sorry that that was all over the place, I'm wondering if it's possible that yes the engine isn't running perfect with that maf sensor but also if the transmission is bad and causing extra drag because it seams to rev fine but when it's driving in gear it doesn't like going up in rpms. It's like the clutch is bad but it's not slipping if that makes sense
I had a video of both reving in so you can see it does that fine and driving it so you can hear it clunk through the gears but it won't let me upload them so sorry
Any advice is welcome and helpful

 

[ChildIdenticant]

Please provide the codes. Btw, a "Chinese brand one" of something may be the best of the best available. Some damn fine products can come out of china. "Made in China" does not hold the same meaning it did in mid 90's .
$500 for a ?80k manual sport is a good deal on any day except screwday.
again, let's start with those codes. and please consider not throwing parts at it.
I don't think I have ever seen those wheels on a 93 sport.

It's just necessary to mention at this point btw, check the capacitors on the pcm.

Purple cars are dope , yo.

 

[Bboy]

Please provide the codes. Btw, a "Chinese brand one" of something may be the best of the best available. Some damn fine products can come out of china. "Made in China" does not hold the same meaning it did in mid 90's .
$500 for a ?80k manual sport is a good deal on any day except screwday.
again, let's start with those codes. and please consider not throwing parts at it.
I don't think I have ever seen those wheels on a 93 sport.

It's just necessary to mention at this point btw, check the capacitors on the pcm.

Purple cars are dope , yo.

Yeah I tried messaging my brother but I think he's outside of service, as soon as I have the codes I'll let you know, I hate "throwing parts" at things but in this cast I checked the fuel injectors and it appeared at least 2 maybe 3 weren't working and the spark plugs were autolites which I've heard don't run the best in these engines, as far as the "Chinese" maf it's doesn't have any brand on it and I've had a few like that in some other Ford's that didn't work so I was basing it off that.
Didn't realize the capacitors we're a problem for the ford explorer, definitely will check them, had an f150 a while back that had that kind of issue, should have thought about that.
And yeah the purple is pretty cool and the wheels look nice, look like some later 90s explorer/ranger wheels

 

[Fix4Dirt]

if you unplug the maf does it run better? sounds like an issue under load. i wonder if its something fueling related? just speculation at this point however

 

[Bboy]

if you unplug the maf does it run better? sounds like an issue under load. i wonder if its something fueling related? just speculation at this point however

Unplugging the maf sensor doesn't change anything which is kind of weird, could be like a fuel pump issue or something where it's not getting enough fuel. Could that be how it killed multiple fuel injectors at the same time?

My brother got back to me with the codes we started with 157, 215, 172. And since clearing the codes the 157 has come back but we haven't driven it much at all so the others could still come back but I don't know yet.

 

[~X~]

157 is a MAF code.
172 is lean O2 sensor & 215 is a coil fault.

If you decide to clean the MAF sensor, check the intake tube for cracks. Mine were cracked in the accordion section close to the battery. It's a common problem, you can't expect it to run right if it's getting unmetered air.

 

[TedJ]

The EEC-IV relies heavily on the MAF signal. They do not run well at all without a maf signal. At best it is a limp home. Torque converter lockup is inhibited and it runs very rich/low power. If you are getting the MAF code, fix that first. Before replacing it, make sure the intake tube from the MAF to the throttle body is sealed up completely, including the crankcase vent. It has to be 100% sealed, all air must go thru the maf. The rubber seals commonly turn to dust. Take the MAF out of the housing and verify nothing has bypassed a crappy air filter and gotten stuck in it.

 

[FredDoug]

Good morning y’all,
This is an update to the post from my brother's earlier post that is just above.

Unfortunately, I must admit I have begun throwing parts at it as I know I very much shouldn't. Of course it hasn't fixed the issue so I'm back to the forums for some help.

Quick background if you don't want to read everything above:

I have a 1993 Ford Explorer that has just no power….. most of the time. When we purchased it the guy said he’d replaced the O2 sensors and hollowed out the cat (he didn’t need to pass emissions) and his mechanic had told him to replace the fuel injectors but he’d decided he just didn’t want it anymore. See the old forum for more details.

Codes we started with: 157, 215, 172

Immediately replaced the spark plugs and wires. And got 'new' junkyard coil pack and fuel injectors.
Then we cleaned and then replaced the maf and soldered a new connector end in
I cleaned the intake tube and sealed 2 small holes in the accordion section near the engine with gasket maker, checked for other leaks and didn't find any in the tube.
Replaced the air filter and pcv valve.
I confirmed the cat was hollowed out.
Unplugging the MAF sensor also seems to have no effect on power.

ONTO THE UPDATES:

One random day I decided to replace the fuel pump and fuel filter hoping that was the problem.
As I was driving it to a friends house to work on it, it suddenly had full power, easily accelerated to 60mph and felt like there were no problems. After turning it off and on again to see it it was magically fixed by the power of waiting, it was back to the bogged down self it was before. We replaced the fuel pump and filter and did an oil change. Took it for a test drive and it now bounces back and forth from having regular power and being able to accelerate to being bogged down. Much more often it's bogged down though.

I only get the chance to work on it on the weekends so forgive me if I can't check things as soon as a suggestion is made. This next week is spring break though so I'll have extra time then. I added fuel cleaner to the fuel to see if that may help and I currently plan on doing a MAF sensor test, checking for a vacuum leak again, and fuel pressure test next. It currently doesn't have a check engine light.

 

[DaSovietPotato]

Good morning y’all,
This is an update to the post from my brother's earlier post that is just above.

Unfortunately, I must admit I have begun throwing parts at it as I know I very much shouldn't. Of course it hasn't fixed the issue so I'm back to the forums for some help.

Quick background if you don't want to read everything above:

I have a 1993 Ford Explorer that has just no power….. most of the time. When we purchased it the guy said he’d replaced the O2 sensors and hollowed out the cat (he didn’t need to pass emissions) and his mechanic had told him to replace the fuel injectors but he’d decided he just didn’t want it anymore. See the old forum for more details.

Codes we started with: 157, 215, 172

Immediately replaced the spark plugs and wires. And got 'new' junkyard coil pack and fuel injectors.
Then we cleaned and then replaced the maf and soldered a new connector end in
I cleaned the intake tube and sealed 2 small holes in the accordion section near the engine with gasket maker, checked for other leaks and didn't find any in the tube.
Replaced the air filter and pcv valve.
I confirmed the cat was hollowed out.
Unplugging the MAF sensor also seems to have no effect on power.

ONTO THE UPDATES:

One random day I decided to replace the fuel pump and fuel filter hoping that was the problem.
As I was driving it to a friends house to work on it, it suddenly had full power, easily accelerated to 60mph and felt like there were no problems. After turning it off and on again to see it it was magically fixed by the power of waiting, it was back to the bogged down self it was before. We replaced the fuel pump and filter and did an oil change. Took it for a test drive and it now bounces back and forth from having regular power and being able to accelerate to being bogged down. Much more often it's bogged down though.

I only get the chance to work on it on the weekends so forgive me if I can't check things as soon as a suggestion is made. This next week is spring break though so I'll have extra time then. I added fuel cleaner to the fuel to see if that may help and I currently plan on doing a MAF sensor test, checking for a vacuum leak again, and fuel pressure test next. It currently doesn't have a check engine light.

I think that it is your MAF sensor connectors/wiring. Normally when the MAF sensor is unplugged the engine goes into "limp mode" which severely reduces power, and if no change is noted it would indicate that the MAF sensor is constantly disconnected. The on/off nature of the power bog also seems like a symptom of a loose wire in the system.

 

[FredDoug]

I think that it is your MAF sensor connectors/wiring. Normally when the MAF sensor is unplugged the engine goes into "limp mode" which severely reduces power, and if no change is noted it would indicate that the MAF sensor is constantly disconnected. The on/off nature of the power bog also seems like a symptom of a loose wire in the system.

That's what I was thinking, I replaced the connector so maybe I need to look at the wiring. Does someone have a diagram or experience doing that? I haven't played with wiring much.

 

[FredDoug]

Today I did a maf test on the sensor and got back numbers in what I think is the normal range. It has 12v power, is grounded, and the sensor return wire when idling (1000rpm) is 1.18v and steadily increases to about 2.2 at 4000rpm. I then took it for a test drive. It’s still bogged down super bad. First and second gear rev normally without much power/acceleration. Third gear doesn’t rev above 2500 rpm no matter what. I unplugged the maf on the way back and it drove the same except sometimes in second gear it would gain power and acceleration easily almost like it exited limp mode for a few seconds. Now it would seem the maf is probably failing to return this data to the pcm. I also disconnected the pcm to check the pins and the connector and all that looked fine. (Pin 14 and 15 are maf sensor wires I believe)

What’s the other wire (not grd, hot, or return) in the maf? And whats it supposed to read? Or should it be tested?
Now should I think it’s a wire problem between the maf and the pcm or is it a pcm problem? Any help would be appreciated

 

[FredDoug]

Update: I tested the maf wiring right outside the pcm and I was getting nearly identical numbers (maybe a tiny tiny bit smaller) to what I was getting by back probing the maf sensor. I also saw a video about listening to the fuel injectors to check if they’re firing, so i did that and they all sounded like they were functioning. Is there a way to test the pcm at this point? Or is there something else to look into? All ideas welcome

 

[Project91Jp]

I'm totally new to explorers but I had a hyundai do the same thing.
I replaced the map sensor, iac, and tps all at once. One of them did the trick, lol.

I read elsewhere, it could also be a bad fuel pump relay.

Good luck

 

[FredDoug]

Update: I ended up deciding to do a compression test because I saw some things that said that might be the issue. I have the specific readings but it doesn't terribly matter because they all ended up from 100-120 psi which is above the recommended 100psi and within 75% of each other which I believe is the requirement. From what I've seen around it sounds like a healthy psi would be closer to 150-160 range for this engine but correct me if I'm wrong. All them seemed to hold the pressure though once I got the compression tester on tight enough.

I put some oil in one cylinder because that's how a lot of people said to test if it is a ring or a valve problem. It had no effect on the psi which I believe would mean it's a valve problem. I ran out of time to test all of them with oil but the real issue occured when I put it back together and started it up again. It was spewing white fumes out the exhaust which I think was just the oil burning out right? The white fumes stopped after a minutes. But then after running for a few minutes and triple checking and having my dad check that I put all the spark plug wires back where they should be, it was running horribly and would stall when pressing on the gas and we had a hard time even moving it around the yard. Before the compression test I could drive it around town albeit it was very slow accelerating and didn't have a high top speed. Anyone have ideas of what I could've forgot to plug in or possibly dislodged or did wrong? I'd like to get it back where it was before purchasing an iac or tps or continuing the search.

 

[ChildIdenticant]

Anyone have ideas of what I could've forgot to plug in or possibly dislodged or did wrong? I'd like to get it back where it was before purchasing an iac or tps or continuing the search.

Spark plug wires. Quadruple check them if you didn't pre label. Very easy to be convinced they are correct and be wrong.

The new and temp smoke would be the oil you used to test for compression increase, yes. Odd that you wouldn't see at least some gain.

While it won't fix any of your issues, you may want to check to see how strecthed out the throttle cable is. Might improve things a bit.

Codes change at all?

 

[FredDoug]

I'll triple check the plug wires again tomorrow. I'm using this diagram, it's right isn't it? It's the same I used when I replaced the wires I believe.

How would you check if the throttle cable is stretched? And is there a way to tighten it?

The light wasn't on last time I checked but I'll check again and see if there's any stored codes.

 

[ChildIdenticant]

The throttle body butterfly doesn't react correctly, inhibits power. The fix is → Zip tie the extra cable slack near the pedal. May even get you more honest compression numbers.
That is the correct firing setup. Still, recheck. I have the pasted to my hood and had still gotten it wrong a couple times. Not the only one. It's the most likely suspect by the change after the diagnostic you performed unless you supported your weight directly on a harness connector (or possibly crossthreaded a plug or 2).

 

[Turdle]

Have you removed the pcm and cracked it open for a look?

 

[Josh P]

Does it run differently cold vs warmed up?

 

[ChildIdenticant]

Regarding comment by user:Turdle (I assume), The computers have been suffering from leaking catalytic capacitors since at least 2006 (lincolns and fords and mazdas) . I think there be only between 1 to 3 caps accross all pcms. Not entirely sure though.
When those caps fail it is a severe issue. Repairable though. The biggest hassle is the conformal coating unless a unique trace rot instance has occurred..