MPG dropping - Page 2 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


1987-1991 Parley with regards to your 1987 to 1991 Bonneville, Olds 88 or Buick Le Sabre Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

Reply
 
 
 
Thread Tools Search this Thread
Old 10-26-2004, 03:42 PM   #11
Senior Member
True Car Nut
 
Join Date: Apr 2004
Location: Three Oaks, Michigan
Posts: 4,879
Thanks: 0
Thanked 0 Times in 0 Posts
opensourceguy is on a distinguished road
Default

Oh yeah, forgot about the GX3, but I don't know my gear ratio.. i'm too lazy to clean out the trunk and look at the RPO codes. However, I know I have enough power to chirp the tires from a dead stop, and have 1400rpm runs at 55. I think that is the perfect combination.


-justin
opensourceguy is offline   Reply With Quote
Old 10-26-2004, 04:41 PM   #12
Senior Member
Posts like a 4 Banger
Thread Starter
 
Join Date: May 2004
Location: Minnesota
Posts: 118
Thanks: 0
Thanked 0 Times in 0 Posts
therealscu03 is on a distinguished road
Default

Quote:
Originally Posted by padgett
Are you keeping any sort of mpg records ? Could be something as simple as turning the a/c on. However if you have not changed your habits, something else has. Could be ignition, could be clogged injectors, could be O2 sensors, with fall coming on it could be a stuck thermostat.

Are there any trouble codes ? Is the block learn multiplier (BLM) reading high ? Is the system in closed loop ? All things needing to be checked to answer your question.
The a/c heat is only on the lowest setting when i am driving on the interstate. So i dont think its that, and if any of habits have changed its been not **** canning it every time i accelerate b/c of the MPG issue, so its not that. I dont know much about thermostats but i do know that the other day my temp went up to like 220 or so and i slowed down to pull over but then it went down??? WTF!? I have been using injector cleaner every time i change my oil. I am going to change the o2 sensors. I have absolutely no fricken clue what the BLM is, please enlighten me.
Thanks
therealscu03 is offline   Reply With Quote
Old 10-26-2004, 06:21 PM   #13
2x4
Member
Posts like a V-Tak
 
Join Date: Jul 2003
Location: S/W Michigan
Posts: 93
Thanks: 0
Thanked 0 Times in 0 Posts
2x4 is on a distinguished road
Default

I made up a better air intake for mine, that helped a lot. Since I made that it gets about 2mpg more than using the stock intake/air cleaner combo.

I just used a cone K&N air cleaner, a 3" wide pvc pipe and a rubber elbow. I had under $40 wrapped up in the whole thing, it pays for itself in no time. Not the prettiest thing, but its very functional! I average 21-23mpg (city/hwy mixed driving) and thats with 241K on the odometer.
2x4 is offline   Reply With Quote
Old 10-27-2004, 02:23 AM   #14
Senior Member
True Car Nut
 
rjolly87's Avatar
 
Join Date: Jun 2003
Location: Las Cruces, NM
Posts: 6,857
Thanked 298 Times in 246 Posts
rjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant future
Default

u use duct tape on it? has the drop been gradual, or sudden.
rjolly87 is offline   Reply With Quote
Old 10-27-2004, 09:49 AM   #15
Junior Member
 
Join Date: Aug 2002
Posts: 0
Thanks: 0
Thanked 0 Times in 0 Posts
Custom88 is on a distinguished road
Default

Quote:
Originally Posted by opensourceguy
Oh yeah, forgot about the GX3, but I don't know my gear ratio.. i'm too lazy to clean out the trunk and look at the RPO codes. However, I know I have enough power to chirp the tires from a dead stop, and have 1400rpm runs at 55. I think that is the perfect combination.


-justin
you have the 2.97 Gear ratio.
Custom88 is offline   Reply With Quote
Old 10-27-2004, 01:05 PM   #16
Senior Member
Posts like a Camaro
 
padgett's Avatar
 
Join Date: Jul 2003
Location: Orlando, Florida
Posts: 872
Thanks: 0
Thanked 0 Times in 0 Posts
padgett is on a distinguished road
Default

"i do know that the other day my temp went up to like 220 or so and i slowed down to pull over but then it went down??? "

Sounds like a sticking thermostat and may be sticking open as well. If sticks open and coolant temp drops under 146F, the engine will go into open loop operation (poor mpg) Can get heat even at 110F.

I like STANT Superstats - 59848 (not discontinued, U$7.49 at Pep Boyz) : 180F for "C" or "L" 3800 and don't forget a new O-Ring
padgett is offline   Reply With Quote
Old 10-27-2004, 02:15 PM   #17
Senior Member
Posts like a 4 Banger
Thread Starter
 
Join Date: May 2004
Location: Minnesota
Posts: 118
Thanks: 0
Thanked 0 Times in 0 Posts
therealscu03 is on a distinguished road
Default

I'll add that to the list of things. I have to start getting this stuff done before the snow flies. Changing the thermostat is a fairly easy job?
therealscu03 is offline   Reply With Quote
Old 10-27-2004, 03:43 PM   #18
Senior Member
True Car Nut
 
rjolly87's Avatar
 
Join Date: Jun 2003
Location: Las Cruces, NM
Posts: 6,857
Thanked 298 Times in 246 Posts
rjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant futurerjolly87 has a brilliant future
Default

yeah, really easy. its as simple as taking out the engine, pulling off the heads, and dislodging the old thermostat with a suitable explosive. no big deal really though, i think u just remove that thing that the top radiator hose connects to the block with <2 bolts i think> bang it off with a hammer and block of wood, theres your thermostat, pop it out, scrape gasket off <must be all, or u can brake the piece> new gasket and thermostat in, bolt and torque it down, see if it leaks. no leaks, no problem. just be sure to keep an eye on the temp to confirm thermostat function, and also learn new behavior. tada!!!!
rjolly87 is offline   Reply With Quote
Old 10-27-2004, 04:11 PM   #19
Senior Member
Posts like a 4 Banger
Thread Starter
 
Join Date: May 2004
Location: Minnesota
Posts: 118
Thanks: 0
Thanked 0 Times in 0 Posts
therealscu03 is on a distinguished road
Default

thats what i thought i would need to do to get that bad boy off. ill get that done tomorrow, let you guys know how it goes.
therealscu03 is offline   Reply With Quote
Old 10-27-2004, 05:08 PM   #20
Senior Member
True Car Nut
 
Join Date: Apr 2004
Location: Three Oaks, Michigan
Posts: 4,879
Thanks: 0
Thanked 0 Times in 0 Posts
opensourceguy is on a distinguished road
Default

rjolly: That is a general description of how to change a tstat. Here is a more detailed explaination, for all to share, and read with their kids in front of the fireplace .

You let the car sit OVERNIGHT, then pull the upper radiator hose, on the block, you will see the tstat housing, it has ONE bolt [strange, yes, PITA, yes, leads to problems later on, yes], it is an 11mm bolt, you will need a box head wrench of that size, or a universal joint of that size. I used a box head with a cheater bar [approx 2ft in length]. To get the housing off.. you need to take the biggest box head wrench you have, wrap around a shop towel or two [more if just reg. paper towels]. and shake that sucker for all you are worth.. pull up, left, right, down, whatever it takes. Mine was a PITA. Once you have that off, you will have two rubber o-rings.. one around the diameter of the housing, and one in between the tstat and housing. You will need to replace the one around the housing.. the other one is fine. But when replacing the one around the housing, you need to get one that is TIGHT around the housing. Mine had about 4mm play around the housing, and of course the housing wouldn't go back on like that. Once you have that all squared away, put the tstat on the block [NOT on the housing like you probably pulled it from when removing]. Take a small hammer and long flat screwdriver, and make sure the housing is fully secured on the intake, and there isn't ANY space left. Once that is done, bolt it up, put on upper radiator hose, and IMO flush the cooling system.

Was that long enough for you? Hope so, because that is what it takes.


-justin
opensourceguy is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
The MPG Post to end all MPG Posts mkaake 1992-1999 24 05-05-2005 03:25 AM
Why dropping the clutch isnt good on FWD vehicles (Saturn) Spiral General GM Chat 4 04-16-2004 05:32 PM
Wal-Mart dropping BulldogSecurity stuff? acg_ssei Audio (and aftermarket electronics) 5 03-03-2004 11:12 AM
Just dropping the front by an inch? Bassplayincrowe Performance, Brainstorming & Tuning 4 02-24-2004 08:04 PM
RPMs dropping at 50-70 MPH 74747474 1992-1999 10 10-06-2003 11:49 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 01:04 AM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.