CEL after 10 mins of running....how to diagnose?
 

Hello--
My CEL comes started coming a few days ago. It comes on about 10 mins of driving. Once I shut her down and restart, CEL goes off. After I drive for 10 mins it comes back on.

Things I've done to engine right before this started to occur...

1. Changed plug wires, dist cap, rotor
2. Replaced air filter and PCV filter
3. Removed batt cables (pos and neg) to install chemical pads under terminals.
4. Changed oil and filter (synthetic 10W/30 - FL-1HP filter).
5. Initial drive to test run vehicle, (turned off OD to test OD functionality as I never turned it on/off since I purchased a few months ago)

During the initial drive, after all above was performed, is when this started.

What can this be? I do not have an OBD I to check codes

Thanks!

I have this same problem, mine is due to an o2 sensor that i cant get unstuck... it comes on after a few minutes because certain sensors need to be warmed up. O2 sensors need to be warmed up as well as a few others

How can you be sure it is an 02 sensor? why not replace as opposed to trying to get unstuck? BTW...how do you get it unstuck?

I know its bad haha. Long story... lets just say water damaged. And by stuck i mean stuck in the bung on the exaust pipe. Pb blast, an acytelene torch and an 02 socket and still cant the dang thing outta there to replace it:(

I believe you can jump a couple of pins and be able to pull the codes, or purchase a code reader. iirc mine wasn't expensive.

However I would check over everything you touched, leaned on or took off. It could be as simple as a vacuum hose getting knocked off.

I checked all hoses and all around engine but did not see anything out of place

Quit guessing what is triggering the CEL.....

Warm up the engine then do this: How to run a Self Test

List the codes, by number and when they were displayed, here. We can help you decode them.

Most likely you should get three digit codes. 3 Digit Code Definitions

You have to run the self test to retrieve DTC info. No reason to load the parts shotgun more than once.....

LMAO. never heard that one before but so true.

I want to laugh too....what does this mean?

You're kidding, right?

This is the name for the all too common approach to repair work that involves the replacement of parts with out any real thought or diagnostic process....in the case of a "shop" it is often the most profitable route...ranks right up there with the "wallet flushing" and "pad slappers"....So instead of spending the effort to make the repair "you" hypothetical of course....just "load" the shotgun with a few parts and pull the trigger! You might get lucky and actually "fix" it.
Most times DIY folks just don't have the info (service info, wiring diagrams, code setting criteria etc.) tools or knowledge to really dig in and make the repair themselves. That's where forums like this come into play...lots of priceless info here for anyone that can find it.

Take care.

They can be a real fight! Sometimes to get it done I just cut the harness at the O2 sensor and drop the pipes. Hit the offender with an impact and see what happens next. Most don't break off.....they give up before that.:) Running with a stuck O2 isn't good for the long term health of the engine. Hard on cats or pistons.

Thanks! That's what I thought, but I wanted to be sure. I'm not the shot gun type and prefer to diagnose correctly.

You are in the minority.
Take care.