98 blazer Questions

[Jsdirt]

Sounds alot like mine lol. I won't put a wrench on this thing unless I absolutely have to. Going to need it's 4th set of brake lines (that I know of - may be on it's 6th for all I know) pretty soon. Started leaking last winter during the last storm. Hasn't completely blown out yet, which is amazing. I try to go light on the pedal. As long as I don't drive it over the cliff pushing snow, I'm good.

[Doug Rosewood]

Found a new issue..so the vents are stuck blowing air at me, the dial doesn't change air flow..any ideas?

[Jsdirt]

Either a blend door problem, or a vacuum leak in the dash, or under the hood somewhere. Check the connection to the orb (vacuum canister) inside the driver's side fender up towards the firewall. You'll see the vacuum line going to it. If not, you'll need to find and connect it.

 

Several Blazers I've worked on, this orb wasn't even connected. It's fun trying to get your fingers in there - might need a pair of angled needle nose pliers to make it easier.

 

Blend door problems are also common on this generation. That job is much less fun ...

[Doug Rosewood]

Well service engine soon light came on today. I'm guessing an o2 sensor took a shit

[Jsdirt]

Could be anything, really. Get a code reader on there and let's see what you've got.

 

Remember that whatever code it's showing doesn't mean that that particular part failed - could be any number of things that cause that code to be stored.

[Doug Rosewood]

Yeah, I have a buddy with a scan tool. I just guessed o2 sensor seeing as the truck runs fine, just seems to got a little thirstier fuel wise. Tail pipe also looks like it's been burning oil for awhile

[Doug Rosewood]

pulled trouble code "P0171" for a lean bank condition...blazers idles and drives fine, but it was unholy hot outside and I was driving it rather hard..any ideas?

[Jsdirt]

On a '98, I'm willing to bet it's intake gaskets. If they've never been changed before, the OE gaskets were galactically craptastic - complete garbage. Pretty much guaranteed to leak. They were made of plastic, and broke in several places. Just awful.

 

See if you can see the ECT (engine coolant temperature) in the freeze frame data on the scan tool. If it's not 180° or higher, it's probably the intake gaskets leaking - they will leak bad when cold, and sometimes fix itself with a little heat.

 

I'd also double check ALL the vacuum lines - the rubber GM used in those years was horrendous. I remember my hands being jet black from rubber hoses that were just disintegrating just by touching them, on a '00 model 9 years ago. Was like black chalk. What a mess ...

 

To check the intake gaskets, wait until the next morning when the engine is cold, and get a squirt bottle of water - a plastic soda container with a hole pierced in the cap works well, since you can really dump the water on fast. Pour the water on the gasket surface of the intake / cylinder head. You'll hear it getting sucked in, and the idle speed will change a bit.

[Doug Rosewood]

Thanks for the reply, every once in awhile I will get a mild whiff of coolant when its sat all night but not always. Like I said it idles and drives fine. I hopped in it tonight and drove to work (flipped the key and off I went with no warm up) and it ran fine. My buddy cleared the code, to see if it comes back..do you think they could of potentially been a fluke? also I've noticed it runs a little warmer then it did when I first got it, I figured with it being close to 100 degrees outside that it was normal..

[Jsdirt]

Usually lean codes are pretty accurate. Any lean condition will get worse in cooler weather (air is more dense), and that's compounded by the fact that metal also contracts with cold (if it's indeed a gasket issue).

 

With winter coming, you'll probably find the leak with cooling ambient temps. A gasket leak will get much worse, especially at cruise (usually will throw a P0300 due to lean misfires) - you'd feel it skip a bit at cruise, but at idle or full throttle, it will run normally. If it's a leaking vacuum hose, weather won't change the problem much.

 

Forgot to mention that an exhaust leak upstream of the upstream sensors can cause lean codes too. Could also try cleaning your MAF and see if anything changes.

[Doug Rosewood]

The exhaust leak is quite possible. From day one it's had exhaust rattle and you can hear it lurch and pop after start up. The light did flip on while cruising on a bumpy rural road while going 70 lol.

[Jsdirt]

That'll do it - just like driving on a Massachusetts highway.

[Doug Rosewood]

So far CEL has stayed off, it's gotten pretty cold here during the night, and it hasn't ran any different..

[Jsdirt]

It's possible it could've just been a batch of fuel with high ethanol content. Wouldn't be the first time that's happened. Hopefully it stays off.