HELP! Check engine light - Loss of power

[bennelson]

Thanks 2000mc!

I was able to get that to work! I saw how to do it on the older connector, but couldn't find any info on this odd year with the OBD2 style connector!


Once I jumpered those pins and turned the truck on, the check engine light flashed once, then twice, and repeated that three times.

Then it flashed 3 times and two times and repeated that pattern three times total, then started the 1,2 1,2 1,2 ... 3,2 3,2 3,2...

It's my understanding that the truck is giving me the codes for 12 and 32.

According to Troublcodes.net Trouble Codes OBD & OBD2 Trouble Codes and Technical info & Tool Store. By BAT Auto Technical :
code 32 means
"32 EGR open command did not change the fuel mixture when the command was given during off idle operation. EGR opening should cause the mixture to be slightly richer because of the low oxygen content of exhaust gas."

So what the heck is an EGR? What's it do? And how do I fix it?


And what about the error code 12? It's not listed on that page!


EDIT: In a list of generic GM OBD2 codes, it says 12 is diagnostic mode and that 32 covers:
BARO sensor circuit(carb models)
EGR circuit(injected models)
MAP sensor(open)

I think we can eliminate the BARO as my truck is fuel injected.

[bennelson]

Currently reading through my Haynes S10 repair manual.

Apparently the EGR (exhaust gas recirculation) is an emissions thing, designed to reduce pollution and make my truck not work right.

The book says the EGR valve is controlled by a vacuum control solenoid valve. That's a remotely operated electronic switch/valve, right?

The book also says that the duty cycle time for that valve is controlled by the computer using info from the ECT, VSS, and IAT sensors.

Does that mean that the problem could be one of the other sensors? If it was, wouldn't it give another error code in the flashing check engine light?

The book also said to check for leaky/bad vac hoses and noted that some models use a BACK-PRESSURE-TYPE EGR valve.

A back-pressure valve might have problems working right if there is something wrong with the exhaust system, right?

Earlier, some people made comments about a possible plugged up catalytic converter or similar problems.

Is all this connected? Is it starting to make sense to anyone?

Learning as I go...

-Ben

[bennelson]

I have potential bad news.

In inspecting the engine, I see wetness oozing from what looks like the spot between the head and the rest of the engine.

The coolant in the expansion tank looks dirty.

Do I have a leak in the head gasket, causing the oil and coolant to mix, and cause these other problems?

[2000mc]

12 is something like no camshaft position sensor signal or something like that... they all show it as a current code when the engine isnt running

the egr...well youre pretty much going to have to diag. that. sensors not directly related to the egr system i would consider unlikely causes. more likely would be the valve itself, vacuum leak in the hoses controlling the egr, solenoid, or it seems like theres a egr temp sensor , atleast on some, blocked passages...

head gasket leaks could cause a laundry list of problems...

[Ford Man]

Originally Posted by bennelson

I have potential bad news.

In inspecting the engine, I see wetness oozing from what looks like the spot between the head and the rest of the engine.

The coolant in the expansion tank looks dirty.

Do I have a leak in the head gasket, causing the oil and coolant to mix, and cause these other problems?

If I was concerned about the head gasket I'd refill the cooling system with 50/50 water anti freeze solution and watch it for a few days, if it lowers the coolant level within a few days I would be very suspicious of the head gasket, but before jumping to the conclusion it's the head gasket check to make sure you don't have any leaks around the radiator cap, thermostat housing, in the radiator, or leaking radiator hoses/heater hoses. Another thing you could do is drain the oil and check for coolant in the oil. Have you noticed excessive steam from the tail pipe? If so that's probably the engine burning the coolant. Another forum I am a member of is www.gassavers.org there are several pretty knowledgeable people there that might have some suggestions too.

[3dplane]

Ben!
You are dang right assuming theyare all connected.
And that is why it's not easy to fix over the internet.
Regardless of the type of EGR valve used if it is vacuum controlled it will not be able to operate with a clogged CAT (or muffler)because the engine is unable to produce enough vacuum.
How hard is it for you to disconnect the exhaust?(rust etc). Seriously that would be the easiest way to find out. By the way a stuck closed EGR valve will not effect drivability.
A stuck open EGR will only effect the way the engine runs (like crap) at low rpms. And that is actually one way to see if the EGR passage is clogged or not to open the valve (either manually on the old or command open with the scanner on newer) and if the engine dies from idle,all is good.
I'm just going by your simpthoms description.
Barna

[bennelson]

Oh No!

These same loss of power symptoms are back!

I had to come back here and dig around to find this thread to see what I ever did as a solution to the problem!

There never was one?
It seems the problem just sort of cured itself seven months ago when it was an issue.

I do seem to remember sort of a rattle going on before all this started again. I think the sound was from the catalytic converter!?!? Could a "clogged cat" do that?

[Christ]

Clogged/burned cat could cause serious loss of power, overheating, etc..

Disconnect your exhaust before the cat, fire it up, and rev'er up a bit... see if it stops that from happening.

If it does, remove the cat completely, and shine a light through it. You should be able to faintly see light at the other end. Do it in a dark place, so you'll see better. Shake the cat while it's off... if anything rattles, it's bad, unless the rattling noise is just the heat shield.

[bennelson]

OK, we have finally reached a conclusion on this whole mysterious issue.

My last comment on this was a few weeks ago.
I just got back from a trip, then had to run off to the MREA Energy Fair, and have been busy since then.

Right before taking off for the energy fair, I quick went to work on my exhaust system.

After 20 minutes of wacking, slashing, and whatever else I could do to get the exhaust, muffler, and catalytic converter off there, I had the muffler in my hands and it made a rattling noise!

Want to guess what was inside?

Here's a hint:


Apparently, a couple of chunks of catalytic converter broke loose and then wedged themselves inside the intake end of the muffler. Notice that the once piece at least has the holes going the right direction, but the other is at a right angle!

This must have been the equivelant of a potato in the tailpipe!

I still need to completely remove the cat and replace it with some plain straight pipe to keep any more chunks from breaking off and getting into the muffler again.