Hi all,

I've read this forum in the past but I'm new to join so I apologize in advance if this is miscategorized.

I was driving to a trailhead last weekend and hit a creek crossing too hard. Maybe a foot and a half deep, but water splashed pretty high. Immediately after leaving the water I heard like a gear stripping sound, I knew the danger so I shut it off right away. A guy who claimed to have been a mechanic was driving by and I explained my situation; he said he was more worried about my electricals (distributor) than my intake. Either way, I checked and dried that, the battery, and the intake and filter and drove it with almost no problems (but the occasional cough) for another 5 miles or so out of the hills, but it started coughing real bad when climbing the hills out to the main road. It got so bad I called a tow back to town before I could get to it. By this point, the check engine, check oil, and battery lights were all on. Probably didn't help that I was pretty low on gas but I know I had about 40-50 miles range left and I did check oil and coolant. The truck wasn't leaking noticeably, or more than usual.

I was able to start it in my driveway and pull engine codes. Still ran rough, bogging every now and then, but I got the following:
114: Air charge temp sensor voltage high or low (by the way, where is this located?)
10: Cylinder #1 has a problem
157: MAF fault, low voltage
543: fuel pump secondary circuit fault.

Battery voltage was steady above 12V when off and 15V or so when running.

A few days later (it's been raining a lot and I don't have a garage) I was able to go out and check again, and ran more tests after adding a gallon of 91 and some HEET (methanol additive?), my latest theory being that maybe water got in the fuel tank or lines. I pulled the plugs, which looked black but normal-ish.
I messed it up worse by dropping the MAF while cleaning it, so I have a new one shipping in any day now. Anyhow, ran some tests and got the following:

Key-on Engine-Off Test:
10 ,157, 543
Key-on Engine Running Test:
998 (failure mode), 157 (MAF is the sensor that failed)

The engine ran but would bog down every now and then or run off-balance and just wouldn't run well. Smelled like it was rich.

This being said, what steps should I take to get this thing back to normal? I plan to replace the MAF, the Intake Air Temp Sensor, fill the tank if I can get it to run all the way to the station, dump the rest of the bottle of HEET in to clear out any water... Maybe replace fuel pump?

TL,DR: I drove my '94 through a creek too fast, it got wet. Now it runs real rough and gives me error codes for the MAF, ACT, cylinder 1, and Fuel pump 2ndary circuit.

Thanks for any help you can offer.

 

Welcome to the forum

1994 Ranger with 4.0l OHV engine will have an EEC-IV computer using 3 digit OBD1 codes

List is here: OBD-I Diagnostic Trouble Code (DTC) Applications - Ford 3-Digit Codes

114 IAT(intake air temp) sensor out of range, it is located on upper intake drivers side mid-engine
2 wire connector

There is no 10 code, all will be 3 digits

157 MAF sensor circuit low

543 Fuel pump secondary circuit fault, when fuel pump is on it sends 12volts to the computer to confirm it is indeed on, getting 12volts at least.
This is called secondary circuit because primary is actual fuel pump getting power.

From your description my guess would be the computer got water in its connector, that would explain all the codes, including the 10 code.
Computer is in engine bay but kind of hidden down next to the drivers side fender
Look on drivers side firewall and down, where all the wires go, thats where computer is located

Unhook battery FIRST!!!!

Video here might be helpful: www.youtube.com/watch?v=zw4ODEs_xrw

You are checking for water intrusion and corrosion on the connector, so get a good look at it

If you want to pull out the computer just to check it, you can open the top, it is out of warranty now, lol, and have a look at the circuit board.

Should look like this: Ford EEC-IV

Now if you look at the wiring diagram on that page you will see pins 25, 26, and 27 are together AND... 25 is IAT, 26 is 5volts for IAT and MAF, and 27 is MAF, water here would effect both sensors
pin 8 is secondary fuel pump circuit connection

Di-electric grease is used inside connectors like these, point of using di-electric grease is that it DOES NOT conduct electricity, so you DO NOT want it on or inside the pins, they DO need to conduct electricity.
It is used around connectors to prevent water intrusion, so use best judgement if you add any

Spark plugs should NOT be black, very light brown means clean burn and correct air/fuel mix.
Blackish color means Rich burn, change BOTH O2 sensors if they have more than 150k miles on them, MPG gain will pay for the sensors in a year