I just have a couple things I wanted to ask......I have a 94 S10 Blazer 4.3 (W), 2 door, 4x4.

First question, I changed my oik today to find that it seemed very runny and smelled of gas. I just got the Blazer so I don't know how long it's been since the last oil change. It runs great but what could cause this?

Second question, as I am driving at highway speeds, occassionally I will get a loud vibrating noise, almost like a tire going flat at first. As I slow down, the noise will get louder then make a clunk noise. After the clunk, the noise goes away completely. As I said before it runs and drives great for a 94. What could cause this noise?

 

First, does it smoke at all? Startup, all the time, any time?


second, sounds like a u-joint is bad

 

Yeah it starts up everytime, all the time though, when it is cold and hasn't been ran that day it takes a couple cranks to start. It never smokes! I do turn the key and let the fuel pressure build up before I crank. Sometimes it takes pumping the gas a couple times to get it to fire. Once it is warm it fires right up without even letting the pressure build.

I never thought of it being a u-joint! They all feel tight. Could it possibly be the wheel hub?

 

You should test that fuel pressure, there is only one way to get the gas into the oil, and thats a leaking CPI injector or related components. It starts out like that but the symptoms will get worse.

I would be inspecting your 4WD and front axles, I wonder if the 4wd is not disengaging, or the axles boots are in a bad way? Should inspect that front end and see whats going on.

 

I agree check the fuel setup on what you said.


Sometimes a bad u joint will cause a clunking noise as long as its seized then once it breaks loose will act fine. I've seen them act all kinds of ways before, hard to tell over the net.

Most of the time if its in the front end you will be able to feel it in the steering wheel. If it shakes real bad then clunks and the shaking goes away that would point a finger there.

 

It sounds like I need a fuel pressure gauge....is the injector hard to change? What about the "nut kit"? What should the fuel pressure be?

I think the noise in the front end is the auto locker in the hub.....I'm going to check it out today. But, the front differential was low, I added a quart of gear oil and haven't had the noise since. So that may have been my problem.....

 

I had a similar problem on my 89 4wd. During hard acceleration (mostly on the freeway) I would get a sudden loud noise like a tire going flat or something bad going on in my front end, and it would stay until I slowed to around 20 or so . Turned out to be a bad (leaking) vacuum switch in the transfer case partially engaging the 4wd under high vacuum. Try to shake the 4wd selector when the noise happens, you should be able to disengage the 4wd if a vacuum leak engaged it partially.

 

Thanks Wazzledoozle....that is EXACTLY what mine is/was doing? I filled the front differential and haven't heard it since so I do think it deffinately has something to do with the 4wd. I'll keep your suggestion in mind and try that if it happens to do it again....Thank again!!!