Couple of Questions: 98 4.0L - Ticking, and Cruise Inop

[91RS]

Hello all, I'm trying to help a friend out with their 98 Explorer with the 4.0L SOHC engine. I'm a GM guy, so I don't know a whole lot about the nit picky stuff of Fords. This truck has a couple of issues I'm not sure about. First, on a cold start or after the truck sits a little while it makes a hellacious noise on startup (kind of like the noise the engine makes on the first start up after the oil is drained) and then it'll make a rattling/ticking type of noise. It looks like the timing chain tensioner may need to be replaced from what I've found here so far, but I doubt that's related to the noise on initial startup (low oil pressure?). I think I'm hearing some valvetrain noise as well though. He told me he thought he had the tensioner adjusted a while back, but I'm not sure it is adjustable? The other problem is the cruise control does not work, is there a common failure item for this? He told me a light used to come on the cluster when the on button was pressed, but now it doesn't. I'm not sure if there's a light or not, my grandma's Cougar does not turn on a light until the cruise control as actually activated, not when the system is turned on, so I'm kinda confused. This truck hasn't had the recall harness installed for the brake switch, it did have the plug disconnected, but the system still doesn't work even when I plugged it back in to test it.

This truck has 181k miles on it and they need this truck to make it from Atlanta to Dallas, and then his wife will fly back and forth and just drive it around there. He's most worried about this noise causing some sort of issue on the trip. Any help with these problems would be greatly appreciated. Thanks!

 

[jlsparky7]

What weight oil is he running? Thicker oils tend to make the tapping louder. Also what oil filter? Make sure its one that doesn't allow drain back. Fram sucks.

Try running some seafoam in the oil incase it is a sticky valve.

With 181k the tensioners are probably worn pretty bad.

 

[dogfriend]

Re: Cruise control inoperative - If the SCDS (the recalled switch on the master cylinder) is actually shorted, then the cruise control won't work. When this happened to mine, when you tried to engage the CC, the light in the dash would come on for a fraction of a second and then go back out again. The solution is to replace the SCDS (secondary cruise control deactivation switch).

 

[91RS]

What weight oil is he running? Thicker oils tend to make the tapping louder. Also what oil filter? Make sure its one that doesn't allow drain back. Fram sucks.

Try running some seafoam in the oil incase it is a sticky valve.

With 181k the tensioners are probably worn pretty bad.

I'm not sure what oil is in it, but I saw the oil filter from up top and its just a white can so I'm sure it's a really good quality piece. I think I saw an oil change sticker on the floor, so I'll go look at that a little later and see if it says what oil. Maybe I just need to throw an AC/Delco or Wix filter on it and see what happens.

Re: Cruise control inoperative - If the SCDS (the recalled switch on the master cylinder) is actually shorted, then the cruise control won't work. When this happened to mine, when you tried to engage the CC, the light in the dash would come on for a fraction of a second and then go back out again. The solution is to replace the SCDS (secondary cruise control deactivation switch).

I'm not sure if the light even did that. I was trying to drive though, so I may not have noticed. I wish I would have brought home my DMM so I can test that switch. With the mileage on this truck, I wouldn't be surprised if that switch is shorted.

 

[dogfriend]

I'm not sure if the light even did that. I was trying to drive though, so I may not have noticed. I wish I would have brought home my DMM so I can test that switch. With the mileage on this truck, I wouldn't be surprised if that switch is shorted.

Make sure the SCDS isn't leaking brake fluid. Mine was. The red top switch is the original which got recalled. The replacement switch has a black top.


http://www.explorerforum.com/forums/showthread.php?t=164279&highlight=cruise+control

http://www.explorerforum.com/forums/showthread.php?t=168572&highlight=Cruise+control

http://www.explorerforum.com/forums/showthread.php?t=163990&highlight=recall

 

[91RS]

Alright, I believe this one is red. If that switch is replaced, does the brake system need to be bled? The oil sticker that was on the floor was old, so it isn't any help.

 

[dogfriend]

Alright, I believe this one is red. If that switch is replaced, does the brake system need to be bled?

I didn't have to bleed mine. I think you are ok unless the level in the master cylinder got too low because of the switch leaking.

 

[91RS]

Well, I brought my DMM home today. I'm thinking right now that the servo is bad. I cannot get the cruise light to light up for anything (I tried the thing with holding off and turning on and off the ignition to read the codes in it). It's got power and ground, and the wiring for the on and off switches is good. The switch on the master cylinder is working properly and the brake pedal switch works since the brake lights work.

 

[dogfriend]

This might help you in troubleshooting the servo:

 

[91RS]

Yes, that does help, though the pin numbers are backwards in that end view. I just went and made sure, I am getting voltage from both brake pedal switches at the servo connector. The only wire I've not verified at that connector is the VSS wire, but if the speedo works I don't see why it wouldn't be working. Though I think I can manually turn on the indicator bulb by grounding the indicator, I tried putting power to that wire and got nothing.

 

[dogfriend]

Some more schematics:

 

[91RS]

Where are the tensioners located? The picture I pulled up in Alldata looks like they screw into the engine somewhere and I shouldn't have to take the front cover off. Is this correct?

 

[Walldingo]

I have a similar problem... 97 EX 2x4 4.0L V6 - tripping 0720 (output shaft speed sensor) O/D flashing, no 5th gear or overdrive, 2-3 flare.
1. Found VSS wires nicked so I cut and crimped - Speedo still works, Still tripping 0720
2. Replaced speedo gear to adjust to correct speed - speed fixed but still tripping 0720
3. Replaced VSS - Speedo still works, Still tripping 0720
4. Adjusted Bands - Speedo still works, Still tripping 0720
After reading as many post as i can find and working with Brooklyn to get these steps all done I believe I have a wire/short issue? In several posts and manuals I read the following:
1. Check Pin 3 and 6 for the VSS
2. Radio gets VSS for Auto Vol Control (AVC)
3. Box is located behind the stereo
My questions:
1. Where is the connector/box that has pins 3 and 6 i should test to ensure I have continuity from the VSS to the far end?
2. Is it possible a short in the Stereo (occasional pop in the speaker and rare AVC changing the vol to Max for no reason) VSS signal is the culprit or just related to a bad VSS signal? Looking at dog friends diagram I think so...

 

[dogfriend]

I looked at pages 130-1, 130-2 & 130-5 (Radio) for the 679 circuit GY/BK but I don't see it on those pages. I don't know where to look for the pins 3 & 6 - are they possibly talking about the VSS itself?