Mystery "Check Engine" light

I run w/out cats and have no codes. Could be a wiring/connector problem. The page I copied has tests for that as well.

JL

ps- How about an email addy?

<font size=-1>[ This Message was edited by: FasterDamnit! on 1/17/03 1:39pm ]</font>

Geez--it just occured to me that even if the computer can read the neutral switch proble, that circuit wouldn't trigger the 'check engine' light, would it?

Looks more and more like a bad oxy sensor wire--maybe grounding out against the body or something...
[addsig]

Just a couple of thoughts........

Yes, the neutral start switch can cause the MIL to illuminate. I just discovered this while rebuilding the transaxle in my son's Ford Probe.

This may be a stretch..... but did you use any types of silicone gasket sealers during your rebuild? I remember that back when computer controls were justing coming into automotive use, Permatex had to reformulate their entire line of silicone sealers because the gases generated from the curing process were giving O2 sensors fits. Now most automotive sealer manufactures state that their product wil not affect O2 sensors right on the package.

Just my 2 cents.

JO
[addsig]

Bigdog--I didn't know that about the sealers--that's good info! The machine shop who did the build are pretty respectable, so I doubt they used obsolete sealants. And, they knew it was going to be an EFI engine, so I'm sure they thought of that. But if the problem persists, I will go back to see them (for the 3rd time!).

I've narrowed the problem down to the wiring which comes off the left side o2 sensor--if the ignition is on and I reach under and wiggle the wiring, the 'check' light comes on. It must be a short somewhere between the sensor and the computer--grounding out somewhere along the body or exhaust... The search continues...
[addsig]

I thnk you've got it. There is actually a "wiggle" mode diagnostic you can put the EEC into that lets you go a wiggle wires and connectors and it will flash when one has a problem. Since it's late I will have to post the instructions tomorrow.

g'night!
[addsig]

I had the same problem, cold weather, light acceleration, and that damn light comes on.

I got an EGR code, and it turns out the EGR valve had a rip in the seal.

Disconnect the vacuum line, and ive never had a problem since. (just remember to plug any vacuum lines you take off.) The solonoind valve might have been leaking as well, causing the valve to move, but the problem was solved, im happy with it.

Trial and error worked for me.
tyi

_________________
If you can't hear it before you see it, its not worth driving!

<font size=-1>[ This Message was edited by: nicepony on 12/11/03 5:20am ]</font>

<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font size=-1>Quote:</font><HR></TD></TR><TR><TD><FONT SIZE=-1><BLOCKQUOTE>
On 2003-12-10 17:18, nicepony wrote:
I had the same problem, cold weather, light acceleration, and that damn light comes on.

I got an EGR code, and it turns out the EGR valve had a rip in the seal.

Disconnect the vacuum line, and ive never had a problem since. (just remember to plug any vacuum lines you take off.) The solonoind valve might have been leaking as well, causing the valve to move, but the problem was solved, im happy with it.

Trial and error worked for me.
tyi

_________________
If you can't hear it before you see it, its not worth driving!

<font size=-1>[ This Message was edited by: nicepony on 12/11/03 5:20am ]</font>
</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>

Try disconnecting the battery cables overnight to erase any bad memories that may have been established in the system..Ever have a bad dream and wake-up okay??? AL

You can always do what my old boss did... fix it at the dash with a piece of black electrical tape.[img]/phpBB/images/smiles/icon_wink.gif[/img]

Mine has been on in the truck for the past 90,000 miles due to a "glow plug monitor circuit" code. I swear if the Pelican had a check engine light, it would go on too[img]/phpBB/images/smiles/icon_bs.gif[/img]


[addsig]

I have the same problem with my 95 5.0. Thanks for all the suggestions. Thas been very helpful. Whats the easiest way to pull the codes from the engine. I've got a cheap code reader from Walmart, bit i have not used it yet. All it does is flash. Is there an easier way?

Thanks,
Chris