new timing chain?

[adwriter73]

my '94 xlt has 76K miles and has been idling below 500 rpms when cold or when a/c is on. the "check engine" light goes on and off. usually comes on during acceleration. i had the codes read at it said "IAC is at maximum learning capacity". Autozone said it is my timing belt/chain. I have new plugs and wires, so I doubt it is that. Any other possibilities? Or is it the timing?

 

[MrShorty]

What was the code number? I can't pick that one out on my code list, and am wondering if they gave you a bad code description. If you don't remember, pull the codes yourself. See tests at www.dalidesign.com/hbook/eectest.html
Timing chain doesn't fail very often on this motor, and the EEC-IV system doesn't have any way to directly know if it's bad or not. There isn't enough information in a single trouble code to tell us the timing chain is bad.

 

[adwriter73]

Code was 416, I believe. But I'm looking in my Haynes Manual, and that isn't even listed. His reference manual was different. All codes aside, here is what I know it is doing. Idle runs below 500 rpms until it has warmed up for about 5 or 7 minutes. The other day, the temperature guage jumped back and forth from normal to really hot. I pulled over several times to keep the engine from overheating. The "check engine" light goes on and off during driving. It is guaranteed to come on when I accelerate hard.

 

[Billy177]

sounds like a bad tps but try setting the base idle first

 

[MrShorty]

I don't believe 416 is a valid code; I don't see it in any of my EEC-IV code lists. Was that what the good folks at Autozone told you, or did you pull that code yourself? If that's what Autozone told you, my advice would be to go out and pull the codes yourself.

 

[adwriter73]

416 was what Autozone told me. Today--not sure if it's related--my Explorer started, I backed it out, stopped, then it died and took 5 tries and a bit of throttle to get it to stumble to a very rough start.

 

[Deldawit]

code 0416 is listed on fords trouble code definitions as "Secondary air injection switching valve B circuit open" . good luck fixing it......

 

[Deldawit]

code 0416 is listed on fords trouble code definitions as "Secondary air injection switching valve B circuit open" . but that is listed as an obd 2 code