diagnosing two engine codes 15/17

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My check engine light came on today on the way to work, and then again on the way home. It comes on, and goes off by itself after a couple minutes. After 30 minutes of searching I finally just started grounding all the wires. (One worked! pic below)

At first I got a code 15, and 17, checked with haynes and it says oxy sensor for both. The oxygen sensor was replaced about 1500 miles ago (bosch unit) when I b6 swapped, and the connector had come apart, so I put it back together, reset the codes (removed - battery cable and pressed brake petal for 10-15 seconds.) Checked and no codes, started the car, it idled for about 3 minutes and the check engine light came back on, so I checked it and it's only doing code 15 right now, but I haven't driven it so 17 might come back.


The car has idled high since I swapped, and as of last week you can hear a misfire. I attempted to fix the high idle a couple days ago by adjusting the idle set screw down 3/4 of a turn, it still won't idle less than 13-1500. I got out the stethascope and it sounds to me like all the injectors are clicking. So where to check next? I don't have a fuel pressure gauge.


how to check codes, WRONG PIC!

http://www.fordfestiva.com/forums/sh...ad.php?t=17417

stickied post with alot of -now dead- links

http://www.fordfestiva.com/forums/showthread.php?2155-Festiva-Aspire-REPAIR-amp-HELP-***README***

Cool idea, where do I find these resistors?

http://www.fordfestiva.com/forums/showthread.php?31418-Is-there-a-way-to-check-for-engine-fault-codes-with-a-volt-meter&highlight=engine+codes

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Update, spark plugs in order 1-4. These were brand new NGK V-Powers ~1500 miles ago. Cap and rotor button were also new.

Also should probably mention that the temperature gauge hasn't been going up around half the last couple weeks, it's progressively been warming closer to the C mark. Now it's within 1/8" of the first C mark and it's been there for a couple days. Plenty of coolant in the radiator.

[ckiesman]

thats what mine look like on the stock b3. lets see what anyone says.

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Cap and rotor button. /for some reason I can't edit a pic into the last post? Hasn't been 20 minutes.

[WmWatt]

I think you are supposed to hook up a digital mulimeter to the O2 sensor to check the voltage it's sending to the computer. If it's out of range the computer sets the check engine light.

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^

just did that, reading chapter 6-10 in the haynes manual it said it would set code 15 if the sensor is reading less than .7V @ 1500 rpm. So I hooked the positive wire to o2 sensor wire, and negative to chassis bolt, got .513-.61x, and after a few minutes when the car should have been warm it went from .4xx-.6xx, never higher than .6....

Could a bad thermostat constantly circulating fluid cause the engine to run so cool that the sensor doesn't warm up like it should?

[bravekozak]

The EGO sensor can be affected by:
1. fuel quality
2. air cleaner and duct system
3. fuel delivery system
4. ignition system

The test consists of three parts:
1. EGO input voltage to ECA
2. EGO voltage check
3. EGO sensor sensitivity check

Good luck.

[TominMO]

You should probably have the battery cable off for more than 15 seconds to clear the codes. More like 15 minutes to be sure. And I'm curious, why did you mention pressing on the brake pedal? (Edit: found out why: to kill off any residual current)

Code 15 is a dead O2 sensor. Code 17 indicates (not very specifically) an issue within the ignition or fuel system.

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I started the car up this morning and it had a bad miss, way more pronounced than it had been. Popped the hood and turned the idle screw back to where it was, then 1/4 turn clockwise to get the idle back down a little. Problem still persisted and the idle was really jumpy within a couple hundred rpm. I could he's something clicking, sounded like it was comming from the disty cap, I jiggled the wires and shocked myself. (Were new wires, cheap tho) got out the stethascope and the clicking was more audible over by the coil, the plug wire itself about an inch out from the coil...so I ripped the plug end off a spare wire an swapped it for the coil wire, problem went away.

Drove it 14 miles into and around town, there's still a miss, gets worse with engine load, but the check.engine light hasn't come back on yet.

[TominMO]

That would take care of the 17 code (ignition issue), but the 15 should be dead O2 sensor.

[fastivaca]

...gets worse with engine load, but the check.engine light hasn't come back on yet.

This makes me wonder if you have a ground issue. Had something similar happen on mine, it would miss when under load going up a hill. I discovered that the bracket that is attached to the front corner of the cylinder head at the thermostat end was loose. This has a number of ground wires attached to it as well as the throttle cable and plug wire clips. Tightened up the bolt and the issue was solved.

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