fountain

I'm having a little issue with my cel being on. At first it was low on power and weak feeling. I cut the cat off and that seemed to help with the power being low. I thought that may fix me, but it came back on.
at the time I was having power issues, I checked the air filter and it had a big black smut spot(powdery, not oil) in the middle of it. That's where I was thinking that the cat may be clogged and it was backing up back into the air box. I then checked the temp and the manifold was about 700 and cat 400.

Now with the cat off and the o2 sensor appearing to be visibly in good shape, I'm not sure what my trouble may be. I'm leaning towards the mass air meter on top of the air box.

Have any of you seen this before? Any ideas?

scope103

I think CEL means "check engine light." So you're supposed to check the engine, not chop up the exhaust system or "look" at the O2 sensor.

More specifically, CEL represents about 19 different states (codes) on our very simple trucks. So far as I can tell from your post, you never checked which code your truck is trying to tell you. Do that first. http://web.archive.org/web/201211190...85diagnosi.pdf

fountain

You are correct, I havent checked the code. Power was low and with the manifold that hot and the converter half of that temp, I knew it was clogged or clogging up. That was my first and cheapest route, so I went with it.
Two weeks ago, it died going down the road and has been in the shop since..new distributor. I just got it back yesterday and drove it this morning. The light came on about 3 miles into my ride.
It seems to come on more so in the mornings than evenings. That's got me thinking its air related and something to do with moisture in the air.

with help on checking the codes, I will hopefully narrow that down

fountain

There's no other way to check the codes on this thing other than that?

scope103

There is no other way to do that on this thing.

fountain

That looks mighty confusing to me.

do you have to check in both normal mode and test mode?

scope103

No.

Put the paperclip between E1 and TE1, turn the key to ON, count the flashes. If you stop for a cup of coffee in the middle, it will take you about 2 minutes.

fountain

Looking at counting the flashes and pauses is what's confusing me. It doesn't look hard to do perse, but the counting looks confusing. I need to go do it and just see what I come up with

Spread5150

I just did this yesterday for the first time. it will go


blinkblink.... blink blink blink blink ..... that's 14
then it will do the next one if there is one.

Or it will repeat that again if its the only one.

fountain

Ok, just checked the codes..and I have no clue how to decipher it now. I counted the blinks and even wrote them down, but I cant find anything on that pdf that looks similar. There may be multiple codes. Total flashes we 19

is there any way I could video this and text it to some of you to help me figure out what's wrong?

scope103

Post it to youtube and post the link here.

Spread5150

fountain

RJR

Looks like 12, 13, 41 and 52.

12 and/or 13 sometimes come up if you've cranked the engine a lot without it starting, so they may be bogus. 41 is the TPS, 52 is the knock sensor. Both of those are likely legit. I'd clear the codes by pulling the EFI fuse (in the fuse box under the hood, passenger side), and then run the truck for a few trips and see what comes back.

Code 52, no signal from the knock sensor, is most likely the cause of your symptom of low power. The ECU isn't hearing from the knock sensor, so it retards timing significantly to prevent engine damage. That will definitely reduce power. There are several lengthy threads on this forum about solving knock sensor problems.

scope103

12 and 13 are traceable to the replacement distributor (could be a bad connection -- don't forget, the codes point to a SYSTEM, not just a part).

41 is probably a bad wiper in an end-of-life TPS. Not a matter of the setting. Still, easy to check for with an ohmmeter.

52 is the explanation for the low-on-power and hotter than normal manifold. When the ECU loses contact with the knock sensor, it dramatically retards ignition timing to save the engine. Retard timing => runs like a dog.

Good luck!

fountain

Ok, I disconnected the neg and let it reset everything. I just drove it home and the cel came back on. I'm going to go back and check it now and see what it does.
I got a new distributor and that got me up and running again. Now to chase down the little gremlins its giving me.

if it is the knock sensor, whats the deal there? Replace it?


what's more important...is how did you decipher all those codes????

fountain

Ok. Now, I have a series if 5 steady blinksthen a payse6, and 2 blinks.

scope103

Ah Jeez, fountain. Do I have to hold your hand? The same link I provided to tell you HOW to get the codes, LISTS all the codes, their explanations, and "most likely" cause.

But use the "cause" carefully; the manual was written back when our trucks were new. ECU problems could crop up (that's really the last possibility now), but the sort of wear and tear we have wasn't considered.

So with code 52, the MOST likely cause is not the knock sensor itself, but the "pig-tail" that connects the sensor to the harness right above the injectors. It's in a hellish environment and eventually fails. You need to remove the intake manifold to access the pigtail, so no one will criticize you if you just go ahead and throw in a new knock sensor as well.

But I would be remiss to not mention that it is very difficult to directly diagnose the operation of the knock sensor. Some have found they needed to also replace the shielded wire part of the harness upstream of the pigtail.

Good luck!

RJR

OK, it's like this:
b=blink
.. = short pause
.... = longer pause.

After the initial quick flash (don't know what that was all about) the pattern in your video was
b..bb....b..bbb....bbbb..b....bbbbb..bb
which equals 12 13 41 52

The first and second digits of each code are separated by shorter pauses (..), while the actual codes are separated by longer pauses (....)

If you had let it go longer, the whole pattern would have repeated after an even longer pause.

RJR

That says code 52 is back. As scope says, you'll need to tackle the knock sensor/wiring. Not fun, but it's the only way to get your truck running right again.