Several Questions

[Locruid]

So my friend recently got a 93 Explorer and she's having a bit of trouble with it. My experience goes to Nissan Hardbodies, LT1 based cars, 5.2 and 4.7 Mopar Engines and International/Powerstrokke Diesels so I arrive here in hopes of some assistance.

First off the victim is a 1993 Explorer 6cyl. Absolutely positively stock down to the paper filter. I was hoping to find some service manuals or maybe some advice on what could be wrong. I pretty much know how to troubleshoot but don't have the recommended tolerances by Ford. Also ya'll would be very knowledgeable on what typically goes wrong on these vehicles and the proper troubled part. So without further ado......

When it's cold it doesn't like to shift. But once it warms up it shifts just fine. I know the Trans was rebuilt about 3 yrs ago. Fluid looks great and doesn't have any discolorations. We just did a fluid filter change. Was doing it before and after.

Runs rich and sluggish. Piss poor mpg. I'm thinking the Temp Sensor might be misreading and preventing closed loop operation. Was hoping someone had a trick on testing this? Or Ford's Tolerances. No Engine light

Fuel gauge keeps bouncing. Read correctly most of the time but does bounce everywhere. Short? Gauge? Float assembly?

Speedometer Bouncing. Are these electronic or cable based? If Electronic would the Speed sensor cause any other symptoms?


Thanks in advance everyone. If you have questions on my knowledge with the before-mentioned vehicles I have feel free to ask lol.

 

[Anime]

If you want service manuals, they are easy to come by, factory service manuals are on ebay all the time for just a few bucks. They were worth it when they were hundreds of dollars, they're even more worth it now. You can also get Haynes/Chilton's manuals for cheap, too.

As for the transmission, the A4LD automatics have their share of issues. I'd guess maybe some thicker fluid was used to stop a transmission leak, or perhaps the wrong fluid was used at some point? These take Dexron III / Mercon fluid, and going to thinner fluid like Dexron VI or Mercon V isn't always a good idea. Same with certain "universal" synthetics, sometimes they are too thick or too thin. Best bet is usually to stick with some kind of the new "Dex/Merc" fluids.

The easiest fix for sluggish performance is cleaning the Mass Airflow Sensor. Use electronics cleaner or carburetor cleaner and make sure it's clean clean clean. It's a good idea to clean the throttle body while you're at it and all the moving parts around it.

Fuel gauge is probably the float assembly, or could be an issue with the gauge or its electronics that slow down the reading.

Speedometer bouncing is the cable getting hung up on the sheath. The other end needs to be pull out of the transmission/transfer case and then you can pull the instrument cluster, pull the cable out, and re-lube it with whatever it looks like it has on there, either graphite or grease. There is spray-on graphite that makes the job easier than trying to pour graphite into the sheath.

 

[arco777]

When it's cold it doesn't like to shift. But once it warms up it shifts just fine. I know the Trans was rebuilt about 3 yrs ago. Fluid looks great and doesn't have any discolorations. We just did a fluid filter change. Was doing it before and after.

Runs rich and sluggish. Piss poor mpg. I'm thinking the Temp Sensor might be misreading and preventing closed loop operation. Was hoping someone had a trick on testing this? Or Ford's Tolerances. No Engine light

Fuel gauge keeps bouncing. Read correctly most of the time but does bounce everywhere. Short? Gauge? Float assembly?

Speedometer Bouncing. Are these electronic or cable based? If Electronic would the Speed sensor cause any other symptoms?

Trans: The governor is likely your problem. It is located at the tail end of the transmission and gets sticky from wear and crud in the trans fluid. Regular fluid changes can help, or install a lower mileage governor. Sonnax makes a heavier governor weight that helps as well.

Running Rich: Check for possibly a faulty MAF sensor. Swap in a spare and see what happens. You can also clean the one you have if there is gunk on the sensor wires. Remove the two screws holding the sensor electronics to the body and check the tiny resistor wires. If they are cruddy, clean them with electronics cleaner. I would not recommend brake cleaner or carb cleaner, as they could damage the elements.

Fuel gauge: The sender (in-tank) is probably fine if it reads correctly, but there is an anti-slosh module in the gauge cluster assembly that should keep the needle from bouncing. I believe it is easily removable from the cluster, you could probably swap in a junkyard module.

Speedometer bounce: The speedometer is cable driven. Check for a speedometer cable that needs lubrication, is binding up due to a sharp bend, or damage/wear to the gear on the end of the cable or its counterpart inside the transmission (2wd) or transfer case (4wd). Another possibility is that the speedometer drum inside the gauge has warped, but this is less common.

 

[Locruid]

Thanks everyone I'll check it all out this weekend!

I'll snag a new cluster just in case as I'm heading to the JY this weekend anyways.

 

[MrShorty]

In addition to the other great advice. "By the book" diagnosis of most fuel mixture issues on these suggests starting by checking fuel pressure (see the fuel pressure mini-diary thread started by Glacier991, I think it is in the Under The Hood forum here). Don't forget to check the vacuum line to the FPR for gas, indicating a ruptured diaphragm in the FPR.