# Helppppp. Love this truck but don't understand what's wrong.



## Edwin82 (Oct 30, 2015)

It is a 94 k5 blazer, 5.7 4x4. Just did major ignition tune up and changed oil switch. It takes off VERY slow, once it's going to accelerates fine, just the initial start is bad, oil gauge goes crazy, but I think it just needs a sending unit, possibly. Don't think it's the heads cause there's no knock or tick. I'm thinking it's either oil pump or fuel ignition issue. What do you guys think??


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## NE GA Pappy (Oct 30, 2015)

if it is the oil pump, it will show up real quick.  as in parts scattered all over the highway showing up.  You need to find someone who works on vehicles that understands engines and issues and quit trying to figure out something you obviously have no clue about.   Sorry to be so blunt, but you have no idea about how engines work and run.


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## Edwin82 (Oct 30, 2015)

NE GA Pappy said:


> if it is the oil pump, it will show up real quick.  as in parts scattered all over the highway showing up.  You need to find someone who works on vehicles that understands engines and issues and quit trying to figure out something you obviously have no clue about.   Sorry to be so blunt, but you have no idea about how engines work and run.



No need to apologize, unfortunately in this world of crooks and thieves I can't just take it to anyone cause as you know a lot of mechanics can be pretty messed up, I'm trying to get an idea of what the problem can be to head to the right direction. I can go anywhere and they can say it's one thing and it be a completely different thing. So as you know this isn't cheap stuff, so I'm hoping maybe someone on here might know these engines well and can lead me in the right direction. ??


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## NE GA Pappy (Oct 30, 2015)

Edwin82 said:


> It is a 94 k5 blazer, 5.7 4x4. Just did major ignition tune up and changed oil switch. It takes off VERY slow, once it's going to accelerates fine, just the initial start is bad, oil gauge goes crazy, but I think it just needs a sending unit, possibly. Don't think it's the heads cause there's no knock or tick. I'm thinking it's either oil pump or fuel ignition issue. What do you guys think??



Ok... 

here is what it boils down to...

1.  who did the major tune up?  Slow Joe You Know, or a mechanic?

2.  what the heck is an oil switch?  do you mean the sending unit? and if you mean the sending unit, why do you later ask if it could be the sending unit?

3.  What do you mean by "takes off very slow".  That it is slow to accelerate, or that it doesn't crank easily?

4.  Heads don't knock or tick.  Rods knock. Crankshaft could have a knock. Pistons can slap, and valves can clatter, but I guess what you are saying is that the engine is not making any funny noises.

5.  can't be an oil pump issue, or the engine would be making all kinds of noise, and you would soon lock it down.

6.  there isn't such a thing as fuel ignition.  There is ignition and there is fuel.  2 separate systems.  It might be a fuel issue, it might be an ignition issue.  

7.  you are going to give much more descriptive explanation of the symptoms.  Does it have any MIL lit?  Is it MFI or TBI fuel system?  does it have stock exhaust system? does the exhaust system get overly hot?  

Get the idea?  you are going to have to be much more educated on how engine and their systems work to even get started on finding the issue.


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## Edwin82 (Oct 31, 2015)

NE GA Pappy said:


> Ok...
> 
> here is what it boils down to...
> 
> ...




Cool, well I can give all the info I know and hopefully someone can work with that. 

1. A friend did the tune up, he's more of a Japanese car guy but still a fairly good mechanic from what a few people have told me, I just rather let someone who really works on Chevys continue the work. 

2. He called it an oil switch, I thought it was a different part that's why I kept saying I think it needs a sending unit. You are right, same thing. All the research I've done says that it is the main reason the oil gauge usually goes crazy, it was changed, but continues to move around. 

3. By "takes off slow" I'm meaning at a red light going to green it takes it a little while to build up the strength to get up to 20mph. Once it reaches there's it accelerates with no problem. 

4. I thought heads did indeed knock if the lifters were bad, again my bad. 

6. There is no fuel ignition, you are absoutely right, I miswrote that. 

7. I'm not sure what kind of fuel injection it is, I looked all over the truck and couldn't find what kind it was. 

8. I'm hoping this can help alittle more


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## marcusperdue (Oct 31, 2015)

994 should be tbi.  Tbi looks like a 2 barrel carburetor with an injector in each barrel.  Get the timing checked those trucks are bad about distributor gear wearing enough to jump time


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## safebuilder (Nov 1, 2015)

Try Gary Smith Masters Garage in Athens....old school and straight up good guy.


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## NE GA Pappy (Nov 1, 2015)

it could be a combination of things.   Do you have any test equipment to check it out?  Tools like a VOM and timing light?

did this start all at once, or over time?  Why did you have the tuneup done? ie, was it running rough or bad mileage?  Does it have an MIL lit?

These truck also had a knock sensor that the wires would get burned and short out and it would CensoredCensoredCensoredCensoredCensoredCensored the timing on them.  


Lots and lots of information needed to start.  I still would recommend that you find a reliable shop and pay someone who know what he is doing.  You can throw parts at it all day and still have the same issue at the end of the day.


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## 7Mag Hunter (Nov 1, 2015)

Catalytic converter..........


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## Gaducker (Nov 1, 2015)

Edwin82 said:


> No need to apologize, unfortunately in this world of crooks and thieves I can't just take it to anyone cause as you know a lot of mechanics can be pretty messed up, I'm trying to get an idea of what the problem can be to head to the right direction. I can go anywhere and they can say it's one thing and it be a completely different thing. So as you know this isn't cheap stuff, so I'm hoping maybe someone on here might know these engines well and can lead me in the right direction. &#55357;&#56397;&#55356;&#57339;




That makes me want to tell you whats wrong with it, I tell you what.  Crooks and thieves?

You could work on it for days going back and forth or you could take it to a shop where folks do this kinda work everyday for a living and prob get out for less than 2 hours labor plus parts.


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## Edwin82 (Nov 1, 2015)

Gaducker said:


> That makes me want to tell you whats wrong with it, I tell you what.  Crooks and thieves?
> 
> You could work on it for days going back and forth or you could take it to a shop where folks do this kinda work everyday for a living and prob get out for less than 2 hours labor plus parts.




Understood, there are crooks in thieves in every aspect of business, not all shops have trust worthy people. Fact of life. Not everyone is that way but unfortunately some are. That's why I'm trying to figure out what it can be from someone expirenced OR pointed in the direction of someone that people on here might know or get engine work done by.


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## Edwin82 (Nov 1, 2015)

safebuilder said:


> Try Gary Smith Masters Garage in Athens....old school and straight up good guy.




Cool, I live in Snellville, it's not too far at all. Thank you!


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## cullyhog (Nov 2, 2015)

Sure it is not transmission related? Sounds like it is not starting in first gear. Manually shift it to first and see if it accelerates.


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## Lukikus2 (Nov 2, 2015)

7Mag Hunter said:


> Catalytic converter..........



X 2

Sounds like it's a stoppin' up. It'll do it everytime.


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## Stroker (Nov 2, 2015)

At 308K original miles my 92 K5 Sport Blazer done the same thing, it was the catalytic converter.


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## Edwin82 (Nov 2, 2015)

I just got a new catalytic converter done to pass emissions maybe 2 weeks ago


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## GoldDot40 (Nov 2, 2015)

Edwin82 said:


> I just got a new catalytic converter done to pass emissions maybe 2 weeks ago



And when did it start acting up? Before or right after the catalytic converter swap? Before or after the tuneup?


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## NE GA Pappy (Nov 2, 2015)

Bassquatch said:


> And when did it start acting up? Before or right after the catalytic converter swap? Before or after the tuneup?



We have lots of questions, but no answers.  I guess we didn't bring the right magic wand to wave over the truck and make it all well over the emmernet.


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## GoldDot40 (Nov 2, 2015)

NE GA Pappy said:


> We have lots of questions, but no answers.  I guess we didn't bring the right magic wand to wave over the truck and make it all well over the emmernet.



That's why I was attempting to dumb it down so maybe he could help us understand. Not everyone comprehends  mechanical lingo. Baby steps....


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## NE GA Pappy (Nov 2, 2015)

Gee, I thought my questions were pretty well at the bottom of the simple barrel.


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## Edwin82 (Nov 2, 2015)

Bassquatch said:


> That's why I was attempting to dumb it down so maybe he could help us understand. Not everyone comprehends  mechanical lingo. Baby steps....



Sorry for not responding faster, but can't really be on the phone while at work. It's kinda been happening since I got the truck maybe 3 weeks ago. As soon as I bought it I could tell it needed a tune up, so I got one done, went to go get emissions and it didn't pass, it said I needed a cataliyic, so got that done. Then noticed the oil gauge was going crazy so I sent it to get fixed, even though it still moves some. After really driving it about 25 miles is when I noticed how bad the acceration process was and that's where I'm at now. From buying the truck to driving it those 25 miles last Friday it had only been driven maybe 10 miles total. That's why I really didn't know much about what the truck was doing.


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## Edwin82 (Nov 2, 2015)

NE GA Pappy said:


> Gee, I thought my questions were pretty well at the bottom of the simple barrel.



Yeah, you've been dumbing it down for sure, thanks! ??


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## NE GA Pappy (Nov 2, 2015)

Edwin82 said:


> Sorry for not responding faster, but can't really be on the phone while at work. It's kinda been happening since I got the truck maybe 3 weeks ago. As soon as I bought it I could tell it needed a tune up, so I got one done, went to go get emissions and it didn't pass, it said I needed a cataliyic, so got that done. Then noticed the oil gauge was going crazy so I sent it to get fixed, even though it still moves some. After really driving it about 25 miles is when I noticed how bad the acceration process was and that's where I'm at now. From buying the truck to driving it those 25 miles last Friday it had only been driven maybe 10 miles total. That's why I really didn't know much about what the truck was doing.



Are you sure it wasn't the O2 sensor and not the catalytic converter?  there is not really a test to tell you if the converter is bad.  Either it is open and the catalyst is working, or it is plugged up with carbon and junk from burning oil or overly rich fuel mixture.

If you could go back and start with the questions and answer them, it would help trying to figure out what is happening.  

Does it have oversized tires on it?


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## Edwin82 (Nov 2, 2015)

NE GA Pappy said:


> Are you sure it wasn't the O2 sensor and not the catalytic converter?  there is not really a test to tell you if the converter is bad.  Either it is open and the catalyst is working, or it is plugged up with carbon and junk from burning oil or overly rich fuel mixture.
> 
> If you could go back and start with the questions and answer them, it would help trying to figure out what is happening.
> 
> Does it have oversized tires on it?




To be honest, no I don't know if it's the o2 sensor. After I failed emissions I was told that the test results indicate it's the catalytic, so I went to a muffler shop and they told me it was the same thing. So I had it done and it passed emissions. So could it be a o2 sure, I don't know. 

As for the tires size right now it's got 275/75/r16


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## badger (Nov 3, 2015)

cullyhog said:


> Sure it is not transmission related? Sounds like it is not starting in first gear. Manually shift it to first and see if it accelerates.



I would be looking at this first in the absence of other drivability symptoms.


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## Edwin82 (Nov 3, 2015)

badger said:


> I would be looking at this first in the absence of other drivability symptoms.



I will definitely try this, but the engine doesn't rev when trying to accelerate. It feels like it boggles some before actually having the force to really take off


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## OmenHonkey (Nov 3, 2015)

Fuel Pressure? Maybe a new fuel filter would help? Most shops won't replace them during a "Tune-Up" They should but usually don't unless it's requested.


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## Edwin82 (Nov 3, 2015)

OmenHonkey said:


> Fuel Pressure? Maybe a new fuel filter would help? Most shops won't replace them during a "Tune-Up" They should but usually don't unless it's requested.



To be honest, I'm really thinking that might be it. As obvious I'm no mechanic, but I'm thinking it might be not getting enough fuel on take off.


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## GoldDot40 (Nov 3, 2015)

That's likely a TBI (throttle body injection) engine. They are fairly notorious for fuel system issues that can/will cause some of your symptoms. One of the most common and also most overlooked problems is the pressure regulator will be bad and nobody thinks about it. It's easily replaced if you have any type of basic hand-eye coordination. Look it up on YouTube. 

But I'd highly recommend finding a reputable repair shop and let them diagnose and repair it.


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## Edwin82 (Nov 3, 2015)

Bassquatch said:


> That's likely a TBI (throttle body injection) engine. They are fairly notorious for fuel system issues that can/will cause some of your symptoms. One of the most common and also most overlooked problems is the pressure regulator will be bad and nobody thinks about it. It's easily replaced if you have any type of basic hand-eye coordination. Look it up on YouTube.
> 
> But I'd highly recommend finding a reputable repair shop and let them diagnose and repair it.



Cool man, I appreciate it. Been doing some reader has on good shops around here and looks like I'll be taking it to ace auto repair in griffin Friday. Hopefully it's not too bad.


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## Edwin82 (Nov 3, 2015)

Research *


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## 660griz (Nov 5, 2015)

Timing is a critical issue. Verify that your timing is correctly set;
Fuel pressure is not adequate for proper operation, make sure that there is no contamination in the tank or your fuel filter is plugged. A plugged fuel filter may be an indication of a contaminated tank.
Bad ground to the block, insure that the surface that you are making the connection to on the block is clean and making a positive connection.
Your O2 sensor may be contaminated, bad or not properly installed in the exhaust.


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## Stroker (Nov 7, 2015)

I went from 265 to 275 tires on my 92 K5 Blazer and they hurt both acceleration and towing, but then it's got 308K on original motor and transmission.


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## Eudora (Nov 8, 2015)

If you are in Snellville, the BEST GM mechanic is there too.  
Calvin Nabors Automotive Inc  Address: 1255 Old Snellville Hwy, Lawrenceville, GA 30044  Phone770) 972-5469
I have been in the parts biz for over thirty years and have called on garages in 28 states, and this is where I take my GM.  No sign out front.  Behind his home.


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## chadf (Dec 8, 2015)

Have you put into 1st gear manually yet ?


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## mattech (Dec 8, 2015)

So if its in park, will it quickly redline?

I wouldn't stress the oil guage, I've had several people tell me thier gm oil gauge jumps, especially while towing.


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## divinginn (Dec 8, 2015)

How fresh is the gas? I had one driving me crazy one time I got from my brother in law,turned out the gas was several years old.


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