1997 Blazer...service engine soon light is on also...this thing sucks gas...


Dano2
02-08-2005, 11:43 AM
Hi, Im a newbie to this board and to the 97 blazer we bought about 7 months ago. Excellent condition, drives nice.
However after many trips to the gas station it looks like this thing eats gas like there's no tomorrow. I'm scratching my head at this because you see people driving these things like they are sports cars. We estimate its getting about 10-12 miles in the city, it was better on the highway.
Does this sound right? I called a Chev dealer, talked to a service guy, he said depending on the gear ratio, he had one the same year, gas sucked he said, couldn't do much about it, however on another year the gear ratio being different his other one got better mileage. Any truth here? and how do I find this info out? Any other suggestions on this gas guzzler?
Also just this morning the service engine soon light came on, another thing to piss me off:) Can you diagnose this yourself with those gadgets you can buy? or best off taking it in? thanks for any info...

regards....dano2

scholzee
02-08-2005, 12:18 PM
I have a 96 2dr 4x4 and with 75 % highway 25 % city I get a steady 18.5 mpg in the summer. In the winter with my remote start and 4x4 use same type of driving I have not seen lower than 15 mpg. The only time I can even come close to 10-12 is with my plow on, 4x4 in use and plowing. Something is wrong and Autozone can read the code for free but do not buy anything from there yet, post the code here and some people will try to guide you in the right direction.

Skeeter6755
02-08-2005, 12:35 PM
Hi, Im a newbie to this board and to the 97 blazer we bought about 7 months ago. Excellent condition, drives nice.
However after many trips to the gas station it looks like this thing eats gas like there's no tomorrow. I'm scratching my head at this because you see people driving these things like they are sports cars. We estimate its getting about 10-12 miles in the city, it was better on the highway.
Does this sound right? I called a Chev dealer, talked to a service guy, he said depending on the gear ratio, he had one the same year, gas sucked he said, couldn't do much about it, however on another year the gear ratio being different his other one got better mileage. Any truth here? and how do I find this info out? Any other suggestions on this gas guzzler?
Also just this morning the service engine soon light came on, another thing to piss me off:) Can you diagnose this yourself with those gadgets you can buy? or best off taking it in? thanks for any info...

regards....dano2


Since you have a "Check Engine" light, it is best to go to Autozone and get the codes read for free. Come back here and post the exact codes, not what "they" say it is.

Dano2
02-08-2005, 02:28 PM
Since you have a "Check Engine" light, it is best to go to Autozone and get the codes read for free. Come back here and post the exact codes, not what "they" say it is.


There are not any Autozones in my area but found a store that will do the code check. I will let you know what it is asap. Thanks for the replies. Also, I wanted to mention, the service engine soon light just started this morning, but the bad gas mileage has been going on since we had it, is there going to be anything I can do about the gas mileage or could there be something actually wrong with the engine that gives it terrible gas mileage?

thanks....

BlazerLT
02-08-2005, 02:37 PM
Get the code number please, the EXACT code.

Also, might be time to do a proper tuneup.

Dano2
02-10-2005, 01:26 PM
Get the code number please, the EXACT code.

Also, might be time to do a proper tuneup.


OK, so before I got a chance to get the code checked out, the service engine soon light went out and has not come back on since yet.
Untill it does I guess I cannot get that checked out right? Any suggestions on the poor gas mileage? tune up? any thing else I can do to improve the gas? thanks...

blazee
02-10-2005, 01:51 PM
The code is stored for a while after the light goes out.

BlazerLT
02-10-2005, 02:30 PM
OK, so before I got a chance to get the code checked out, the service engine soon light went out and has not come back on since yet.
Untill it does I guess I cannot get that checked out right? Any suggestions on the poor gas mileage? tune up? any thing else I can do to improve the gas? thanks...

The code will be stored in the computer's memory.

You don't have to have the light on to get the codes.

Go get the codes scanned and come back here with the actual number.

Do not do anything until you do that.

Dano2
02-10-2005, 02:53 PM
The code will be stored in the computer's memory.

You don't have to have the light on to get the codes.

Go get the codes scanned and come back here with the actual number.

Do not do anything until you do that.

ok, will do, thanks, and by the way your black blazer is killer looking...

BlazerLT
02-10-2005, 03:12 PM
ok, will do, thanks, and by the way your black blazer is killer looking...

Hey, thanks a lot! :D

Labor of love.

Dano2
02-11-2005, 04:18 PM
I am going to try and get the code checked out this weekend. In the meantime what is all I need to do a tune up myself besides plugs and wires? thanks...thought while I was the store I might get what I need since I have no idea when the last time this thing was tuned....

BlazerLT
02-11-2005, 04:48 PM
AC Delco Platinum Plugs
Ac Delco Wires
Fuel Filter
PCV valve
Air Filter

Maybe service your transmiision with new fluid and filter and then replace your transfer case and differential fluids.

Dano2
02-11-2005, 05:30 PM
kool, thanks....

BlazerLT
02-11-2005, 06:49 PM
Make sure you use ONLY AC Delco Plaitnum plugs and gap them to 0.060

Dano2
02-12-2005, 10:05 PM
Make sure you use ONLY AC Delco Plaitnum plugs and gap them to 0.060

ok, so I spent today doing the tune up.
-PCV valve, replaced, easy
-air filter, easy job
-oil and oil filter while I was at it.
-AC D Plugs and wires, here I had some trouble

Got all the wires and plugs in except one plug, the middle one
on the driver side. Seems the steering wheel drive shaft or whatever
you call it is directly in the way, I found I can get the plug socket on
it reaching through the wheel well but there is only about 1/2 inch clearance and no way to get the wrench on it. How in the heck do you
get that one out??? I couldn't do it, so its still in. Is there a special tool to buy?

No for the gas filter, I disconnected it alright. Mine has a black bracket around it, it wouldnt slip out of it, I found a small screw with my hand just above it , removed it, but that did nothing, is there a secret there as well? all in all everything else I got done.

Tomorrow Im going to go get that code checked and post it.

If anyone has the solution for my above problems please let me know...my hands and arms are so sore....thanks again...dano

BlazerLT
02-12-2005, 10:51 PM
You will beed some extensions and a flexible elbow to get the middle plug out.

The fuel filter bracket comes out as a whole thing.

What about the cap and rotor?
You will see where it holds onto the brake lines above it. You take the whoel thing out, then swap in the new filter, then install it back in.

Dano2
02-12-2005, 11:51 PM
You will beed some extensions and a flexible elbow to get the middle plug out.

The fuel filter bracket comes out as a whole thing.

What about the cap and rotor?
You will see where it holds onto the brake lines above it. You take the whoel thing out, then swap in the new filter, then install it back in.
Ah, so I need to like un-snap the brake lines above it out of the bracket? then take the whole thing out? it sounds like?
Does a 1997 have cap and rotor?
I have a flexible elbow, no way it would fit, must be another one that does? do you take your wheel off to get at it? thing is, my plug socket it so long, not much room left to get anything in......need to try again I guess....

BlazerLT
02-13-2005, 12:21 AM
Ah, so I need to like un-snap the brake lines above it out of the bracket? then take the whole thing out? it sounds like?
Does a 1997 have cap and rotor?
I have a flexible elbow, no way it would fit, must be another one that does? do you take your wheel off to get at it? thing is, my plug socket it so long, not much room left to get anything in......need to try again I guess....

Yea, the vracket is kinda like the ones holding your spark plug wires in order along side the engine. Feel around, you will feel where they rest in a groove in the bracket.

You will just have to gently push them out one by one.

Yes, of course a 1997 has a cap and rotor.

The elbow can get on, you need to try harder and yes, take the tire off if it will help you gain access.

Dano2
02-14-2005, 12:25 PM
OK, I still need to get a cap and rotor, thought maybe it was electronic one.
I called Chev and they said I may need to remove a screw to move the steering column our of the way to get to that one plug, that sounds scary...
-Will try and replace the fuel filter tonite...thanks...wish me luck....maybe my ratchet is too big or the sparke plug socket is too big...????

blazee
02-14-2005, 01:59 PM
The first time I changed mine, I didn't have the right tools. So I used the Spark Plug socket and put a 19mm wrench on the end of the socket. It was a pain in the ass, but it did work.

Dano2
02-14-2005, 02:17 PM
The first time I changed mine, I didn't have the right tools. So I used the Spark Plug socket and put a 19mm wrench on the end of the socket. It was a pain in the ass, but it did work.

Good idea, the only thing I can think of why I didnt try that is that maybe my spark plug socket doesnt' have a nut shaped end on it, I will have to go look when I get home.
I see you have a 99, mine is a 97 and gets terrible mileage, like around 12 in the city, what is yours like? A guy in the parts at the local chev dealer said it has alot to do with the gear ratios and that there is not much I can do about the gas mileage, except buy a different blazer with different gear ratios...that would be bad:( we have had it for only about 7 months...

blazee
02-14-2005, 02:39 PM
I would suggest you buy the right tools...using the wrench was a real pain in the ass, I only did it because I didn't want to have to finish later. If you look in your glovebox there is a list of RPO codes (three digit codes that tell everything equipped on the vehicle) on a sticker. The code GU* is your gear ratio, look and tell me what this code is and I will tell you your ratio.(the star will be replaced by a number)

I currently get 20 city and 26 highway. Mine is above average. Chevy says they get 18 city and 25 highway.

blazee
02-14-2005, 02:46 PM
Can you smell gas? What does your temperature gauge show when it is completely warmed up? (stuck thermostats are common on these things, when they stick the vehicle doesn't warm up enough for the computer to enter closed loop, this causes a drop in fuel economy.)

Dano2
02-14-2005, 02:54 PM
have not ever smelled any gas, I will warm it up tonight and check temp gage along with what the gear ratio is....so would the gear ratio make a huge difference in gas mileage?

blazee
02-14-2005, 03:07 PM
Gear ratio would affect gas mileage, but not enough to drop your economy down to 10 - 12 mpg. If you have a low gear ratio, it would contribute to your problem, but wouldn't be the sole issue.

**EDIT**

Now that I think about it, I believe mine has the lowest gear available. So the affect of gear ratios on these vehicles is probably minimal.

Dano2
02-15-2005, 11:48 AM
OK, here is what my gear ration says=GU6
As far as heat, I drove it home last night checked the temp gage, it was reading just below the first mark,like 100 and something.
So, so far I have left to do is a new cap and rotor....what else could be the cause of poor mileage on this thing...thanks...

blazee
02-15-2005, 11:58 AM
Your ratio is 3.42 that is the same as mine. I believe it is the most common.

The temperature gauge being that low is a sign of a stuck thermostat. That is contributing to your fuel economy problem.

Dano2
02-15-2005, 02:58 PM
ah, interesting, well, I can try installing a new one, how hard or easy is it to get to? done em before just not on a blazer...

blazee
02-15-2005, 03:07 PM
Get the 192/195 degree thermastat, make sure it comes with the gasket.

Fairly easy. 20 minutes max.

1 drain 1 gallon of coolant.(drain it into a jug and you can reuse it)

2 The Thermostat is located in the housing where the upper radiator hose connects to the intake. Remove the two bolts in the housing.

3 Remove the old thermostat

4 Drop in the new thermostat

5 Put the two bolts back in.

6 Refill the coolant. (not all of it will go back in, you have to keep it topped off over the next few days as the air is worked out)

Dano2
02-15-2005, 03:31 PM
excellent, sounds easy, thanks...hope this can help cure my gas station blues...thanks....

blazee
02-15-2005, 03:40 PM
It should definitely help.

blazee
02-15-2005, 03:43 PM
You still need to investigate the check engine light though.

BlazerLT
02-15-2005, 03:46 PM
Yes, get the check engine light scanned at autozone for free.

Also, remember to replace the thermostat housing gasket when you swap in a new one. It won't come with the stat and is separate.

blazee
02-15-2005, 03:48 PM
The one I got at NAPA came with it, so check the box before you buy one.

Dano2
03-14-2005, 03:30 PM
I'm Back....and happy to report way better gas mileage after replacing the thermostat.
I still need to replace the fuel filter. That thing was a bugger to get out last time I tried it.
What are the tricks to getting that thing out? thanks....

BlazerLT
03-14-2005, 06:54 PM
I'm Back....and happy to report way better gas mileage after replacing the thermostat.
I still need to replace the fuel filter. That thing was a bugger to get out last time I tried it.
What are the tricks to getting that thing out? thanks....

How old is it?

Dano2
03-15-2005, 11:25 AM
Its a 97. Also, as far as the thermostat. I have noticed since I put the new one in. Once it warms up the gauge goes to 210 then backs off down to just a little over the 1st quarter mark like 150 or something like that, is this normal? thanks again...

dridley
04-15-2005, 04:22 PM
Dano,

From what I have read it sounds like the upstream O2 sensor is getting weak and that is what caused the SES light to come on.

Did you ever get the codes read? If your Blazer has more than 80K I would change the upstream sensor. You might be suprised at the difference in mileage.

Dano2
04-15-2005, 04:26 PM
Is the upstream sensor something I can replace myself and how hard is it? what kind of $$ does this thing cost. And no, I never got a chance to have the codes checked.

blazee
04-15-2005, 04:48 PM
Don't replace anything until you get the codes scanned, there are lots of things that will make the light come on.

dridley
04-15-2005, 06:19 PM
A weak 02 sensor will decrease mileage. It should be replaced around 80k. I gained 4mpg hwy by replacing mine and there were no codes thrown to the computer. Here is the instructions. The upstream one is BEFORE the cat converter. Autozone has a loaner 02 removal tool that you can use.


REMOVAL PROCEDURE

CAUTION : The Heated Oxygen Sensor (HO2S) and the Oxygen Sensor (O2S) use a permanently attached pigtail and connector. Do not remove this pigtail from the Heated Oxygen Sensor. Damage or the removal of the pigtail or the connector could affect the proper operation of the sensor.

NOTE : Take care when handling the HO2S and the 02S. Keep the in-line electrical connector and the louvered end free of grease, dirt, or other contaminants. Also avoid using cleaning solvents of any type. Do not drop the H025 or the O2S. Do not roughly handle the HO2S or the O2S.

NOTE : When the engine temperature is below 48C (120F), the Heated Oxygen Sensor (HO2S) may be difficult to remove. Excessive force may damage the threads in the exhaust manifold or the exhaust pipe.



Disconnect the negative battery cable.
Remove the electrical connector by releasing the locking tab.
Carefully back out the heated oxygen sensor you are replacing.
HO2S Bank 2 Sensor 1(1)
Catalytic Converter (2)
HO2S Bank 1 Sensor 3 (3)
H025 Bank 1 Sensor 2 (4)
HO2S Bank 1 Sensor 1(5)
INSTALLATION PROCEDURE

NOTE : A special anti-seize compound is used on the Heated Oxygen Sensor (HO2S) threads. The compound consists of liquid graphite and glass beads. The graphite tends to burn away, but the glass beads remain, making the sensor easier to remove. New, or service replacement sensors already have the compound applied to the threads. If the sensor is removed from an engine and if for any reason it is to be reinstalled, the threads must have anti-seize compound applied before the reinstallation.



Coat the threads of the oxygen sensor with anti-seize compound GM P/N 5613695 or the equivalent if necessary.
Install the sensor. Tighten
Tighten the sensor to 41 Nm (30 lb. ft.) .
Install the electrical connector.
Connect the negative battery cable.

blazee
04-15-2005, 06:25 PM
As I said before, don't replace anything until you get the codes scanned. There is no reason to waste your money guessing before you know what the problem is.

blazee
04-15-2005, 06:37 PM
Dano,

From what I have read it sounds like the upstream O2 sensor is getting weak and that is what caused the SES light to come on.


The O2 sensor is a probability....along with a hundred other things, that could set the MIL. What exactly about his post makes you think that it is the problem?

dridley
04-15-2005, 07:12 PM
The O2 sensor is a probability....along with a hundred other things, that could set the MIL. What exactly about his post makes you think that it is the problem?


Because it happened to me. At today's gas prices it is well worth it.

Also what is up the the controlling attitude? 02 sensors are meant to go bad. A weak sensor will NOT throw a code but suck gas like there is no tomorrow.

OBDII is not the end-all-be-all of the car world. Things go wrong that don't throw a code.

blazee
04-15-2005, 07:27 PM
Because it happened to me. At today's gas prices it is well worth it.

Also what is up the the controlling attitude? 02 sensors are meant to go bad. A weak sensor will NOT throw a code but suck gas like there is no tomorrow.

OBDII is not the end-all-be-all of the car world. Things go wrong that don't throw a code.

Yes O2 sensors go bad, but they shouldn't be replaced just for the hell of it. There several ways that the ECM can detect problems with the O2 sensors and can even detect slow sensors. His code could be caused by an O2 sensor, but there are a lot more things that it could be. I don't have a controlling attitude, I just don't want this guy wasting his money replacing things when there are no signs that they are the problem.

In your recent thread, you were about to replace the computer because you had a blown fuse. Computers go bad, too. but it would have been a waste of money for you to replace a good one.

BlazerLT
04-15-2005, 10:37 PM
Because it happened to me. At today's gas prices it is well worth it.

Also what is up the the controlling attitude? 02 sensors are meant to go bad. A weak sensor will NOT throw a code but suck gas like there is no tomorrow.

OBDII is not the end-all-be-all of the car world. Things go wrong that don't throw a code.

This is a blind assumption.

Please don't tell people to randomly replace sensors when we don't know the true root cause of an issue.

The codes will tell all if the SES light is on.

JA no Y
04-24-2005, 11:45 PM
I have a 95 Blazer that has the same problem with the middle plug on the drivers side. I had to dissconnect the steering colum to get to that plug. Its relativly easy to do. Just folow the colum down to the plastic cover over the connecting joint and remove the cover. There should be 1 bolt you have to remove to loosen colum to be able to slide back off the joint. You can then lift the colum and get to the plug through the inner fender. Just keep your steering wheel locked so you don't turn the wheel and get it off center. Otherwise your steering wheel will not be straight.

Dano2
05-08-2005, 10:07 PM
Ok guys Im finally back to this post. So I did have to replace the thermostat as stated earlier in this thread, it was bad. It boosted my gas mileage a little bit, but it still doesnt seem that great. I got the codes read for free at a local Shucks auto place, no error codes were detected. So what else can suck the gas, someone mentioned oxy sensors...any suggestions? thanks Dano

rlith
05-09-2005, 07:45 AM
Did you ever replace the cap and rotor? Do you ride around with the AC or defroster on? I would look to 02 sensors as they can start going bad without throwing a code...Have you checked your fuel pressure? Have you checked your tire pressure? Air filter? When you did your new plugs, did you just stick them in or did you properly gap them to .060? How are you measuring your miledge?

Dano2
05-09-2005, 12:16 PM
Lets see:
-Have not replaced cap and rotor yet.
-No we don't use the a/c much nor the defrost.
-Have not checked fuel pressure, how do you do that? and what does that affect things?
-Tire pressure, not checked lately, looks ok though, but yes I know I need to check it regularly.
-Put in new air filter.
-Put in new Plugs and wires, and did gap them properly.
-We took the mileage when we filled up last time, after I replaced the thermo, its around 18 in the city.

rlith
05-09-2005, 12:39 PM
18 city driving is pretty good... That's about average...As to fuel pressure, if you have low fuel pressure that would mean there is a leak in the injector system which would chew up gas, but as I said, 18 is pretty damn good.

JC327
05-09-2005, 08:53 PM
The first time I changed mine, I didn't have the right tools. So I used the Spark Plug socket and put a 19mm wrench on the end of the socket. It was a pain in the ass, but it did work.

This is what worked for me. Yep, pain in the ass, but it works.

Gotta be careful not to slip and break the connector off the temperate sensor. Don't ask me how I know that... at least it's a really cheap part.

BlazerLT
05-12-2005, 01:17 AM
Cap and rotor will definitely help.

If the check engine light is on, there will be codes. i don't know why they couldn't see them.

Also, clean your MAF.

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