how to adjust a/f mixture?
12-26-2002, 01:01 PM
#1
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Car Info: 1998 Chevy S10... lowww
how to adjust a/f mixture?
non subaru related, but:
my suburban is running really really rich. at best it should be getting 10-13 mpg in its condition. right now its getting about 3. i was told i needed to change the a/f mix, but no one ive talked to knows how to do that on a FI car, but they know how on a carbuerator.
anyone here know how to do that? if your in the area, id like to get it done today.
pm me if your available.
my suburban is running really really rich. at best it should be getting 10-13 mpg in its condition. right now its getting about 3. i was told i needed to change the a/f mix, but no one ive talked to knows how to do that on a FI car, but they know how on a carbuerator.
anyone here know how to do that? if your in the area, id like to get it done today.
pm me if your available.
12-26-2002, 02:33 PM
#3
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Car Info: 96 Chevy Impala SS, 06 GMC 2500HD (former 02 WRX)
What year is the suburban, and what motor does it have?
The answers to your question vary WIDELY depending on the answers to the above 2 questions
The answers to your question vary WIDELY depending on the answers to the above 2 questions
12-26-2002, 03:10 PM
#4
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Originally posted by Impala SS AutoX
What year is the suburban, and what motor does it have?
The answers to your question vary WIDELY depending on the answers to the above 2 questions
What year is the suburban, and what motor does it have?
The answers to your question vary WIDELY depending on the answers to the above 2 questions
12-26-2002, 06:59 PM
#6
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Car Info: 96 Chevy Impala SS, 06 GMC 2500HD (former 02 WRX)
OK : does it have Throttle Body Injection or a 4-barrel Quadrajet? I THINK that the 89 350's all had TBI by then (I know the car ones all did), but am not 100% sure....
Assuming it is TBI, here are several things to looks at :
1. How old is the O2 sensor? If it's more than a couple of years or 10-20 K miles, replace it. Also, if it is an "off" brand, replace it with an AC Delco (i.e. the parts store ones are CRAP).
2. Are there any exhaust leaks (i.e. cracked manifold, bad gaskets, bad pipes, etc)? If so, fix them as they can throw off the A/F.
3. How old is the fuel filter? If not pretty new, change it.
4. How old are the plugs/wires/distributor?
5. What kind of shape are the two injectors (in the throttle body) in?
6. Is the EGR valve new? If it's got much age, change it.
7. If above doesn't solve it, I'd get a compression test and make sure the motor isn't just "toast" in the first place
This isn't a guaranteed fix, but should all put you on the right path.
Assuming it is TBI, here are several things to looks at :
1. How old is the O2 sensor? If it's more than a couple of years or 10-20 K miles, replace it. Also, if it is an "off" brand, replace it with an AC Delco (i.e. the parts store ones are CRAP).
2. Are there any exhaust leaks (i.e. cracked manifold, bad gaskets, bad pipes, etc)? If so, fix them as they can throw off the A/F.
3. How old is the fuel filter? If not pretty new, change it.
4. How old are the plugs/wires/distributor?
5. What kind of shape are the two injectors (in the throttle body) in?
6. Is the EGR valve new? If it's got much age, change it.
7. If above doesn't solve it, I'd get a compression test and make sure the motor isn't just "toast" in the first place
This isn't a guaranteed fix, but should all put you on the right path.
12-26-2002, 07:05 PM
#7
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Originally posted by Impala SS AutoX
OK : does it have Throttle Body Injection or a 4-barrel Quadrajet? I THINK that the 89 350's all had TBI by then (I know the car ones all did), but am not 100% sure....
Assuming it is TBI, here are several things to looks at :
1. How old is the O2 sensor? If it's more than a couple of years or 10-20 K miles, replace it. Also, if it is an "off" brand, replace it with an AC Delco (i.e. the parts store ones are CRAP).
2. Are there any exhaust leaks (i.e. cracked manifold, bad gaskets, bad pipes, etc)? If so, fix them as they can throw off the A/F.
3. How old is the fuel filter? If not pretty new, change it.
4. How old are the plugs/wires/distributor?
5. What kind of shape are the two injectors (in the throttle body) in?
6. Is the EGR valve new? If it's got much age, change it.
7. If above doesn't solve it, I'd get a compression test and make sure the motor isn't just "toast" in the first place
This isn't a guaranteed fix, but should all put you on the right path.
OK : does it have Throttle Body Injection or a 4-barrel Quadrajet? I THINK that the 89 350's all had TBI by then (I know the car ones all did), but am not 100% sure....
Assuming it is TBI, here are several things to looks at :
1. How old is the O2 sensor? If it's more than a couple of years or 10-20 K miles, replace it. Also, if it is an "off" brand, replace it with an AC Delco (i.e. the parts store ones are CRAP).
2. Are there any exhaust leaks (i.e. cracked manifold, bad gaskets, bad pipes, etc)? If so, fix them as they can throw off the A/F.
3. How old is the fuel filter? If not pretty new, change it.
4. How old are the plugs/wires/distributor?
5. What kind of shape are the two injectors (in the throttle body) in?
6. Is the EGR valve new? If it's got much age, change it.
7. If above doesn't solve it, I'd get a compression test and make sure the motor isn't just "toast" in the first place
This isn't a guaranteed fix, but should all put you on the right path.
1. im not sure about the O2 sensor, ill find out.
2. the exhaust has problems. we replaced the gasket at the head and header awhile ago, and should be good still. however, the weld at the cat side of the muffler is completely gone, so if the piping wasnt sticking into the muffler it would hang. the muffler also had lots of holes in it, which were successfully patched.
3. fuel filter was replaced about 1 1/2 weeks ago.
(i work at an express oil change shop)4. probably originals.
5. how will i know whats good and bad? i have done a FI cleaning service on it about 1k miles ago i think. maybe a bit more.
6. EGR valve? damn i feel dumb now, i dont know what that is or where to find it.
7. where can i get a compression test done, and what tools does it take? (im also in an Intro to auto service class at school)
thanks for your help, ill try and take pics of the mentioned parts tommorow if i dont get called into work early.
12-27-2002, 10:37 AM
#8
Phil,
You almost describe the same situation I had with my jeep. One thing I don't know if you mentioned. Is the Cat converter original? Mine was totally clogged with over 175k miles. I had it swapped out and undid all the tweaks to the FI system thinking that was the problem and everything got better.
I know you are getting crappy gas mileage, but how is the overall performance. You mentioned the exhaust sounded lile a lawn mower..... My 2cents, since it sounded so close to home.
bill
You almost describe the same situation I had with my jeep. One thing I don't know if you mentioned. Is the Cat converter original? Mine was totally clogged with over 175k miles. I had it swapped out and undid all the tweaks to the FI system thinking that was the problem and everything got better.
I know you are getting crappy gas mileage, but how is the overall performance. You mentioned the exhaust sounded lile a lawn mower..... My 2cents, since it sounded so close to home.
bill
12-27-2002, 05:57 PM
#9
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Originally posted by byoung
Phil,
You almost describe the same situation I had with my jeep. One thing I don't know if you mentioned. Is the Cat converter original? Mine was totally clogged with over 175k miles. I had it swapped out and undid all the tweaks to the FI system thinking that was the problem and everything got better.
I know you are getting crappy gas mileage, but how is the overall performance. You mentioned the exhaust sounded lile a lawn mower..... My 2cents, since it sounded so close to home.
bill
Phil,
You almost describe the same situation I had with my jeep. One thing I don't know if you mentioned. Is the Cat converter original? Mine was totally clogged with over 175k miles. I had it swapped out and undid all the tweaks to the FI system thinking that was the problem and everything got better.
I know you are getting crappy gas mileage, but how is the overall performance. You mentioned the exhaust sounded lile a lawn mower..... My 2cents, since it sounded so close to home.
bill
12-27-2002, 07:30 PM
#10
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I know the original will not be cheap. You could probably pick up an aftermarket cat for way cheaper. EGR is the exhaust gas recirculation valve which redirects some of the exhaust gas back into the combustion chamber to insure that all the fuel is being burned. I'm sure impala can elaborate on the location of it on your motor, but if you understand what it does you can probably find it yourself. They're not too expensive.
12-27-2002, 08:00 PM
#12
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$42.80 for the valve and 50 cents for the gasket. just get a new one and save yourself the trouble. 
BTW, its called www.google.com
BTW, its called www.google.com
12-27-2002, 08:58 PM
#13
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Originally posted by Steppin Razor
$42.80 for the valve and 50 cents for the gasket. just get a new one and save yourself the trouble.
BTW, its called www.google.com
$42.80 for the valve and 50 cents for the gasket. just get a new one and save yourself the trouble.
BTW, its called www.google.com
haha
thanks, but i meant for the cat.