spark plug help

[tomjt714]

Anyone have any clues as to why the 1,2 and 3 cylinders of 4.0L carbon the plugs while the 4, 5 and 6 cylinders are perfect? Doesn't seem to affect performance or mileage, but I seriously hate check engine light being on. I've checked/cleaned MAF and IAT, replaced TPS, no help. Possible fuel rail problem? (Air and fuel filters changed) Any info greatly appreciated.

Thanks for the time.
tomjt714

 

[MrShorty]

Have you pulled codes? Gut feel is that bank is running rich due to a bad O2 sensor/wiring or something.

 

[Anime]

If you've got a CEL, definitely pull the codes rather than throw money at the problem hoping to figure out what it is. You can get an Innova Equus #3145 Ford Code reader online for ~$25 shipped, or many auto parts stores will use code readers to read your engine codes for free.

Since it's one-sided issue, I'd agree with the O2 sensor, the 93-94's have one oxygen sensor for each side of the exhaust in the Y-pipe, and a faulty sensor on one side could be compensating for a lean condition that doesn't exist, resulting in a rich mix and plugs getting gunked up.

 

[tomjt714]

Thanks for the tips, especially for the code scanner. Been looking for an Obiwan Kenobi I for some time, all that I can find are OBD II with I capability for 200 bones. TOO much. Can't even find a I version on Ebay. I'll get the 25.00 version and see what's up.

Again, thanks for the tips.
tomjt714

By the way, Auto Zone and Advance only have scanners for OBD II (1996) and newer. Leastways that's how it is here in BFE.

 

[Anime]

A few of the more expensive scan tools that can read OBDI with a supplied or available adapter might be a good idea if you have both older and newer vehicles, rather than multiple scan tools for each one.

There are several of the Equus readers on ebay, but they are the older models that use flashing lights to indicate the codes. The 3145 is the best and most recent, giving you the codes straight out as digital numbers. Sure beats counting flashing lights.

The parts stores used to offer the same OBDI readers, but they aren't big sellers anymore. The online prices are better, anyway.

 

[MrShorty]

Thanks for the tips, especially for the code scanner. Been looking for an Obiwan Kenobi I for some time, all that I can find are OBD II with I capability for 200 bones. TOO much. Can't even find a I version on Ebay. I'll get the 25.00 version and see what's up.

Again, thanks for the tips.
tomjt714

By the way, Auto Zone and Advance only have scanners for OBD II (1996) and newer. Leastways that's how it is here in BFE.

FWIW, all that is "required" to get codes from your '94 is a paper clip. I won't say you shouldn't buy one of those code readers -- some people find it easier. But it is far from "necessary." If you're interested in this option, review the sticky threads in the EEC-IV forum.

 

[doonze]

FWIW, all that is "required" to get codes from your '94 is a paper clip. I won't say you shouldn't buy one of those code readers -- some people find it easier. But it is far from "necessary." If you're interested in this option, review the sticky threads in the EEC-IV forum.

Yep, I got a paperclip I keep in the glove box just for this purpose. It's a little bit of a learning curve to learn "how" to read the codes, but so far I've been able to pull em every time. Once you've done it a couple of times you'll just scratch your head and wonder why you ever wanted a code reader to begin with....

By the way, I know of myself and at least one other person on here who wasn't able to get O'Reilly's OBDII reader with the OBDI adaptor to work on our trucks. Just won't read, at all, but I can pull codes just fine with a paper clip.

 

[tomjt714]

Problem solved!?!?
After being pointed in the right direction (O2 sensor) and employing the highly expensive and complicated paperclip code reader I did in fact get an O2 fault code. After careful observation of said O2 sensor it was found to be in extreme unscrewed position, could have removed with fingers only. Anyhoo, tightened the bugger up, cleared codes and we'll see what happens. May still have to replace as I don't have a clue as to the affect of all the clean air surely being sucked past the @!#* thing.

Thanks for the tips folks!
tomjt714

 

[Anime]

The paper clip method is nice for cheap and when you're in a pinch, but I'll gladly pay $25 for the ability to get a boatload of codes in a flash rather than wait for 10 minutes...and get a digital readout. Miscount just one flash with the lights and you're looking in the wrong direction.

Theres no real "effect" on the O2 sensor from being loose, the system just saw it as an air leak, and it likely changed the sensor reading enough to indicate a lean condition.

Nice that it was such a cheap and easy fix.