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Pontiac Grand Prix Fuel System

46 messages,  Last post on Nov 15, 2009 at 5:27 PM

You are in the Pontiac Grand Prix Forum.

What is this discussion about? Pontiac Grand Prix, Fuel System, Sedan

Messages Page 1 of 5

#2 of 46 Dod and mpg by dribs15

Dec 30, 2005 (8:24 am)

well my heavy foot city mpg is up to 13.2 at 1100miles-would love to end up getting 15+...maybe in time.
 
also, i travel on rte 295 in s. jersey same stretch every day when i go to work and few times i've tried cruise control at 80mph (b/c of the posts seen here), sometimes DOD has definitely kicked in b/c i'm getting at least the upper 20's and maybe higher (can't remember) mpg, while other times it's lower, but i've noticed more wind resistance.
 
chats1 sorry about your hum, but mine is not loud and goes off as soon as you turn the car on too...maybe it is onstar.

#3 of 46 Re: Dod and mpg [dribs15] by rayainsw

Dec 30, 2005 (8:47 am)

Replying to: dribs15 (Dec 30, 2005 8:24 am)
“also, i travel on rte 295 in s. jersey same stretch every day when i go to work and few times i've tried cruise control at 80mph (b/c of the posts seen here), sometimes DOD has definitely kicked in b/c i'm getting at least the upper 20's and maybe higher (can't remember) mpg, while other times it's lower, but i've noticed more wind resistance.”
 
In the interest of science (ahem) I tried an experiment this AM on the way in to work.
 
Since the traffic was (much) lighter than usual, I was able to set the cruise at 80 for a few minutes. Twice.
 
Although there is no “DoD On” indication like there is in the Impala SS, my observations are that even the slightest incline \ upslope (Interstate upslope on I85 just north of I285 and just south is likely less than 1%) will dramatically reduce the instant MPG – from 28 – 30 on level or (very) slight downslope to below 20 MPG.
 
As always, YMMV.
- Ray
Wishing my every commute could be this light, traffic-wise . .

#4 of 46 Re: Dod and mpg [rayainsw] by tjrgxp

Jan 23, 2006 (9:55 pm)

Replying to: rayainsw (Dec 30, 2005 8:47 am)
Also drive 295. New GXP 2006. Have gotten 25 mpg on 295. Have averaged near 23 in a week with mixed hwy/city driving. Have gotten as low as 18 mpg also. Car is black and is very hot looking. Two problems so far - 1) Thermostat bypass hose on top of engine was gashed open by the pulley (maybe a poor factory installation). Dealer fixed and repositioned. Hose was hard to get. Came from lansing Michigan. Was without car for three days with onlt 1000 miles on engine. 2) No automatic dimming rearview mirror is a disappointment and a downgrade from my 1999 GTP. Owners manual says it is an option. Well, what model do they put it on, if not the GXP? No mention of that option in the book. Nevertheless, my GXP is all that they say it would be. Love it. Too bad GM is cheaping out without telling the buyer. Watch out for your bypass hose. Tjr GXP

#5 of 46 Re: Dod and mpg [tjrgxp] by bob97

Jan 24, 2006 (11:14 am)

Replying to: tjrgxp (Jan 23, 2006 9:55 pm)
I also miss the auto-dimming feature – my guess is that it interfered with the microphone pickup for Onstar. But my biggest problem with the rearview mirror is how much of the front view it blocks.

#6 of 46 Re: Dod and mpg [bob97] by sigfulsig

Jan 24, 2006 (9:13 pm)

Replying to: bob97 (Jan 24, 2006 11:14 am)
The good news about the rear view mirror is that it takes up so much of the view that when I mount my GPS (Garmin Nuvi 350) under it, I hardly notice the difference.

#7 of 46 DOD by smallegan

Jul 19, 2006 (3:25 pm)

Does anyone know if there is a way to verify that your DOD is activating? I drive the GXP pretty hard and I am just wondering at what point it activates?
 
-Ryan

#8 of 46 Re: DOD [smallegan] by dblduce

Jul 20, 2006 (5:52 am)

Replying to: smallegan (Jul 19, 2006 3:25 pm)
Ryan,
 
I read that a good way to verify when the DOD turns on is to put your information display on 'Instant MPG'. That way, you can watch your actual miles per gallon usage as you drive. I have tried this on the highway. Normally it is around 19-24, but after a few minutes if the road stays level you can tell it has turned on because the MPG starts going up to around 30 or more. I think it has to be running at a constant speed for a set amount of time before it kicks on.

#9 of 46 Re: DOD [dblduce] by rmozol

Jul 21, 2006 (7:13 pm)

Replying to: dblduce (Jul 20, 2006 5:52 am)
That's good to know. I always watch that screen, but probably not for long enough.

#10 of 46 Re: DOD [dblduce] by gxpjoeyp

Jul 22, 2006 (1:49 am)

Replying to: dblduce (Jul 20, 2006 5:52 am)
I would like to know too,on the Impala ss and the monte carlo ss there is a dummy light that comes on the dash when it is running 4 or 8 cyl. why did gm put that light on those 2 models and not the gp gxp,after all they are the same engines.

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