help passing inspection

[MSHarnett]

I have a 97 (OBD II) and need help passing emmisions. I'm pretty sure I'll pass a sniffer test, but they hook up to the computer instead. My check engine light is on for code 42, I guess it has something to do with the fuel level sending unit. Anyway, they said if the light is on, it doesn't pass. Whats the big deal, its just a fuel guage. Unless that code means something else, can someone please help, I'm already past my inestion date, last month, eek.

[XJ_ranger]

check engine is a part of the system that lets a person know that there is something wrong with the engine. Most of the sensors are fuel/emissions related... and i guess they figure that there must be something wrong that isnt the fuel sending unit...
all i know is that my ranger failed because the CE light was on.

[XJJPR]

If the light is on for something minor and then something major happens that will pollute big time they want that light to come ON for you to check. So if it is always on you'll never know if something new is wrong.

Not sure of that code, but it must have a problem with the system if it is on. I'm sure it wouldn't trip a code for something that doesn't need attention!

hinkley

[MSHarnett]

OK, this is everything that code 42 means. Anyone have any clues on how to figure outhow I can narrow this down?

An open or shorted condition detected in the auto shutdown relay circuit.

- or -

An open condition detected in the ASD relay output circuit.

- or -

An open or shorted condition detected in the fuel pump relay control circuit.

- or -

An open circuit between PCM and fuel gauge sending unit.

- or -

Circuit shorted to voltage between PCM and fuel gauge sending unit.

-or -

No movement of fuel level sender detected.

[jldiaz]

Change the ASD & fuel pump relays and disconnect the battery for a minute to clear the codes. Start and see if your MIL stays off.
If not, check the wiring & connectors to the fuel pump, clear the codes & check the MIL again.
Aren't there any other symptoms? Does your fuel gauge work allright? Any problems starting?

[MSHarnett]

I have replaced the ASD relay, it did nothing. I have not changed the fuel pump relay though. The Jeep runs fine, starts fine but does do something funny once in a while. After I start it and drive away, within the first 200 meters or so, the engine bogs down, then I hear a cluck and it runs fine for the rest of the day, its really wierd.

The fuel guage is wacked out sometimes, but the fuel light works normal.

[Timber]

Originally Posted by MSHarnett

After I start it and drive away, within the first 200 meters or so, the engine bogs down, then I hear a cluck and it runs fine for the rest of the day, its really wierd.

I have this exact same problem with my '99, but my CE light hasn't tripped.

[jldiaz]

-Fuel gauge wacked sometimes: intermittent connection.
-Relays Click

Just a theory:
The PCM shuts the system down via the ASD Relay, probably due to a short. Then after a while it reactivates the system and the relay clicks. Does this only happen on a cold engine? The short doesn't repeat itself in a while and everything seems to be fine.

The Fuel pump and the Gauge sending unit share one same connector close to the pump. I'd check this and the lines from there on forward for possible shorts.

[MSHarnett]

Sometimes it'll do it when the engine is hot. It'll go away in about a week, but if I reset the computer, say after changing a sensor or something, it'll start doing it again.

I will check the electrical lines, maybe put some di-electric on any of their connectors. The guage has been wacky since I bought the Jeep. I took it back, the dealer fixed it under warrenty, then it happened again 6 months later. I said the hell with it, I don't need a guage, haha. I guess it's causing more headaches then I thought.

Thanks for all the help.