Around Christmas time I bought my son a 1990 F-150 to drive. He is 17 and it seems to suit him well.

It has the I6 and an automatic.

After the holidays, I put in a new rotor, distributor cap, plug wires (which looked to be the original ones), and plugs.

The air filter was fine.

Changed the oil and filter and off he went. It was running very well. Very smooth.

A week ago the lower radiator hose blew a hole. My son knew that something was wrong and got the truck off to the side of the road and called me.

I had it towed home and replaced both the lower and upper radiator hoses.

Ok, now for the problem. It is generally running rough at idle. Seems to get down the road just fine, but at a stop it acts like it wants to die, but never has.

I took it out for a drive with him this evening and the Check Engine light came on. We stopped by AutoZone and they read 4 different 2 digit codes.

The trouble codes are

32 - EvP voltage below closed limit.
56 - TOT (transmission operating temp) sensor circuit ground failure specific to your engine.
64 - air charge (ACT) sensor ground or open.
67 - the neutral switch/ manuel trans lever/ A/C input signal either open, grounded wiring.

In addition, I'm hearing a shrill squeeking like the belt is slipping (which may be the case) after the truck warms up. I'm certain that antifreeze was sprayed throughout the engine compartment including the the belt. Perhaps that damaged the A/C compressor as well.

I can check the fuel pressure if you think that might help.

Your advice is appreciated.

Hunt4Fun

 

You have a good start. What not to do is as important as what to do at this point. Don't start swapping parts to see what helps. Do learn to test parts before you swap them.
You would do well to read this thread:
https://www.ford-trucks.com/forums/s...d.php?t=299857
You will be doing many of the tests mentioned in that thread. You need to learn the abbreviations and visit some of the sites linked to in that thread. Know these terms: KOEO, KOER, continuous memory.

This is a link to the advanced search here on this site, learn to use it:
https://www.ford-trucks.com/forums/search.php

This thread addresses the code 32:
https://www.ford-trucks.com/forums/s...d.php?t=301211

 

Good advice. I learned the hard way on that one once or twice, but I've been very methodical lately.

Code 56 (Trans temp too high) tells me that my suspicions about the condition of the tranny fluid are confirmed. I had planned to have it flushed soon or at least drain it myself.

On this vehicle if I drop the pan and drain the tranny, will I be draining all of the fluid or just a portion of it?

 

Pretty sure you have a drain on the converter. Is it an AOD transmission?

 

Sorry, I have not been underneath of the truck looking at the tranny as yet. It's pouring down rain in Indy today, so I opted to gain as much info as I can today and then get started tomorrow.

Thanks for the heads up on the other threads. I'll read them this evening.

KOEO - Key On, Engine Off
KOER - Key On, Engine Running

I've done a couple of searches, but did have much luck. Now I know enough to do some good ones. I'm a web developer so searching is a natural.

Thanks for the help. I'm often over on www.f150online.com for my 2000 truck. This is my first experience with the older body style. I really like the 90 truck. It's in great shape, but it does need a little TLC.

 

Generally it is better to start with the lower number codes and work your way up. Check out that last link in my first post. Fefarms gives a method to check your EVP wiring back to the computer.

Did you get the codes immediately after the water hose incident or immediately after the tune-up? Did you wash the engine after the hose incident?

When you read about the tests to get codes, read about the wiggle test also. (continuous monitor mode) Also read about how to clear codes.

Do you have a vacuum pump and a volt/ohm meter?

 

Yes, Fefarms had some good things to say. I printed that message and will take it out in the garage with me tomorrow.


Did you get the codes immediately after the water hose incident or immediately after the tune-up?

I had the codes read last night, so it wasn't just after the tune up or the radiator hose blowout. Does it make sense then to reset the computer completely and then handle the codes that come up one at a time?

Did you wash the engine after the hose incident? Yes, the engine was wiped down, but we did not wash it as the temps have been too low until just this week

When you read about the tests to get codes, read about the wiggle test also. (continuous monitor mode) Also read about how to clear codes.

Do you have a vacuum pump and a volt/ohm meter? I have a volt/ohm meter and have used it many times. I'm going to go ahead and get the vacuum pump at AutoZone later this week. It sounds like a must for troubleshooting a number of issues.

I also have a Haynes manual for the truck in front of me. The one for my 2000 has served me well.

 

You need to identify whether these are KOEO codes or memory codes. If they are memory codes, I would clear the codes and see how long it takes them to come back, if at all. Check all of your grounds.

Code 32 -- possible bad EVP
Code 56 -- the transmission oil temperature circuit is open, or the sensor is bad. It isn't saying anything about the condition of the oil. The computer thinks the resistance reading of the circuit is "unreasonable".
Code 64 -- ACT sensor input unreasonable. Bad sensor, bad grounds, shorted wire
Code 67 -- make sure you turn the A/C and defroster off before running a KOEO test
Otherwise, possible MLPS problem (sensor on side of transmission)

Code 64 is the one most likely associated with rough running at idle. Code 32 is a possible indication of a stuck open EGR valve (which will cause idle quality problems) but the computer appears to think the valve is closed, not open.

There is a Ford TSB regarding "chirping" of the serpentine belt. Supposedly there is a different pulley available to stop the noise.

 

I saw this in the duplicate thread and it sounds like a good observation. It may be a good idea to check all of your grounds between engine, trans, body, computer, and battery. Clean the battery terminals.

Now I see fefarms and MBdiagMan already said the same thing.

Check the grounds physically and with the meter.

 

You guys are great. Thanks so much for the responses. I'll be looking into the problem this week. If it takes me a few days to get back to you, I will, but I may be working on it for that long.

The three day weekend might help as well.

Take care,

Hunt4Fun

 

I thought the charging system was bad, and maybe it still is. The voltmeter gauge on the truck goes all the way to the right above the 18 indicator. That can't be good. But I checked the voltage with the truck off and it was at 12 and then about 13-14 with it running.

 

Keep thinking false readings. It looks like your error codes may be due to false readings by your sensors. The false reading by your volt gauge backs up this theory and may be due to the same cause. Check grounds.

 

Sounds like a plan. I need to change out the heater core tomorrow, but with the length of the truck I can shut the garage door. Give the single digit temps we are expecting, it might take me a couple of days to get it fixed up.