Drove home for lunch and ended up with an engine code 23, 32, 45. That was a IAC, EGR, and O2 sensor. It immediatly struck me that I may not have re-connected the IAC sensor back up last night. I checked and it was not. So, I hooked it up, disonnected the battery neg cable to reset the computer again. Reconnected the battery and drove it back to work with no engine light coming on. I'm hoping it stays this way. But, there is still that possibility that a 32 is still occurring...

 

That "fine black mist", I'm sure you know is carbon. If you can have someone rev the engine like you did, and hold your finger over the hole and release it when you feel pressure build. You might be able to dislodge some loose carbon.You can also take your vehicle to a shop or you can do it (not sure of your capabilities) and run some "GM top engine cleaner" (that's the actual name) and run it through your intake via one of the large vacuum ports on the upper plenumn. Or what we used to do at the dealer was to start and run the engine to normal operating temp. and get a funnel with a hose to the throttle body and dump as much of the cleaner into the throttle body as you can until it stalls and then stop! Let it sit for about 20 min. and then start the engine, it might be a little hard to start at first but it will and then be ready for LOTS of white smoke out the tail pipe. It will go away, but it is burning all the cleaner and carbon that it has washed away. Let me know

 

Well, let me say I am at most a "wanna be mechanic" no real background with this until maybe last year when I pulled a fuel pump on my jeep.

Yea, I figured that I would be able to actually capture some of the pellets or loose carbon as we revved the engine. I think it didn't work because the engine was not hot, or at normal operating tempature... Like I say we only did it a few times, not nearly enough for the engine to warm up.

EGR valve code came back on again. I'm going to try your "GM top engine cleaner" this weekend...There is obviously carbon buildup still in there...

 

Have you had any luck with this? Are you getting a puff of black smoke at the pipe when you rev it suggesting you're running too rich from another problem with engine management or maybe a dribbly injector? Has your economy dropped off a lot suggesting you're running too rich. Seems like you're making a lot of carbon, even for an older engine. How were the plugs when you pulled them, carboned up alot or looking pretty normal? Was just one of the plugs heavily carboned like you had one cylinder with a problem?

 

Still no luck, it just seems to have degenerated back to being a problem. It's making a knocking sound pretty bad, not sure how else to describe it, I picture a valve that is moving without firing. Or something like that...

The fuel pump does not hold it's 60 psi anymore, it goes there on engage, then drops to about half that if I don't start the engine. If I do start the engine it's struggling, The fuel pump reads back up in the high 50's however, but the engine is not running well, and there is that knocking.
Would the fule pump be causing this noise, isn't it supposed to hold steady at 60psi after engage?

I took the EGR off again and did find carbon pellets holding it open. I've checked the plugs and wires and the front right wire had come off, needed a little squeeze with pliers to fit better, but I didn't break it, however this was after the engine had started running rougher.

 

By the way,
the plugs looked to me to be normal, I mean they were coated, but not unusual looking at far as that goes. A couple of the plug wires were split and looked to be in worse shape than the plug itself.

I haven't notice black smoke, but like I say, right now it's not sounding good enough to leave running for very long, however when I did run it last it didn't seem to be smoking. Other than the initial lot's of white smoke from the Sea Foam application I did. Now I've changed the oil again since then...

 

I have the same problem with my 94 4x4. After reading the rest of the posts it is more than likely the O2 sensor, but I have a mystery hose that I can't figure out were it goes. While I was replacing the plugs and wires I came across a hose just dangeling next to the engine. Its on the passenger side of the engine compartment right next a big black ball. There is a larger hose that has two smaller hoses that tee of the end. One goes back behind the motor the other I don't have clue as to what its supposed to hook up too. Any suggestions?

Thanks
Geoff

 

Possibly Brake booster vacuum hose? Don't really know without looking (and probably don't know if I was looking, without coming back here and asking an expert). If it seems to be a vacuum hose I'd try and locate a spot on the engine, passenger side valve cover back end that may be missing a connecting hose. I'd also suggest figuring out what one end is connected to if possible, that may answer where the other end needs to go. Of course you probably have looked, or you wouldn't have asked on here...

Also, I highjacked this thread a week or so ago. I would suggest you start a new thread concerning this subject with a clear subject line about the mystery hose. I think this thread is about used up and getting away from it's original intent.

 

Hey all,

It's been a while since my first post on this thread, and I wanted to give an update.... From looking at the thread add-ons, it looks like others have similar symtoms, but possibly different circumstances...

The Blazer ('95 4-Door 2WD) - still runs a bit rough... and gas mileage is suffering. Also, this last weekend, I noticed a definite lack of power when pulling a SMALL trailer with camping gear. The trailer is light enough when loaded to move around the driveway by hand - and is a pretty lightweight trailer... but it was all the blazer could do to keep up to 70 MPH with traffic. I had the pedal floored to get up to 65-70 MPH.

I changed the plugs again today (it was last March they were changed, if I recall correctly) - and noticed the following...

The plugs on Cyl's: 1, 3, and 5 are nice looking.. a brownish color to them... However the plugs pulled from 2, 4, & 6 are ALL carbon fouled. Is there something common to the passenger side of the engine that would cause an incomplete burn on those 3 cylinders? I've checked to make sure the spark-plug wires/boots are firmly in place on the plugs... and all seems okay with that route...

Also removed & cleaned out the EGR valve.. no change there, except a bit quieter - since I used some gasket sealer to hold the copper gasket in place when I put the EGR valve back on.... But my main concern would be to find out what's common to the passenger side of the engine to cause an incomplete burn in those cylinders, and thus carbon fouling the plugs...... (Cyl's 2, 4, &6). Any ideas?

Thanks,
Rex S.
'95 S10 Blazer 2WD 4Dr



[IMG]local://upfiles/1011/AA145F77FA4D44449F4151D7DE34F664.jpg[/IMG]

 

Well, refer to the following link for the fix to my rough idle, etc, etc.... I've got the parts on order, and expect them in this week for a "like new" ride again... Yaay!!!

Rex

Injector Replacement