Well my 97 SE 5 sp has 124k on it now, and I'm wondering if the knock
sensor is bad. Supposedly fuel economy goes down because of it. What
highway mileage do you get? How much mileage did you get back when you
replaced your knock sensor?
Under these conditions, I recently got 24mpg highway: 93 octane fuel,
low altitude, no a/c, cruise control, 55-75mph.
Dave
Tony Kujawa - 27 Sep 2004 18:09 GMT
> Well my 97 SE 5 sp has 124k on it now, and I'm wondering if the knock
> sensor is bad. Supposedly fuel economy goes down because of it. What
[quoted text clipped - 4 lines]
>
> Dave
Maybe. On my 91 w/ 105K I'll get 28-30 at 60 w/o air on. But bump it up to
75 with the air on and it will dip down to 25.
E. Meyer - 27 Sep 2004 18:37 GMT
On 9/27/04 9:38 AM, in article cj98qp0tg5@news2.newsguy.com, "David
Geesaman" <dgeesamandontspam@yahoo.com> wrote:
> Well my 97 SE 5 sp has 124k on it now, and I'm wondering if the knock
> sensor is bad. Supposedly fuel economy goes down because of it. What
[quoted text clipped - 4 lines]
>
> Dave
24 is too low. You should be getting around 28. Run a few more tanks of
gas through it to make sure that one time wasn't a fluke.
The knock sensor sets a code, but does not light the light. You might try
swinging by your local AutoZone and see if they will read out codes for you.
David Geesaman - 27 Sep 2004 19:34 GMT
> On 9/27/04 9:38 AM, in article cj98qp0tg5@news2.newsguy.com, "David
> Geesaman" <dgeesamandontspam@yahoo.com> wrote:
[quoted text clipped - 13 lines]
> The knock sensor sets a code, but does not light the light. You might try
> swinging by your local AutoZone and see if they will read out codes for you.
I hadn't done many strictly highway trips lately, so if I get the chance
again I will compare numbers. On my daily commute (60% highway), I still
can't get over 21mpg no matter how light footed my driving is. It also
seems low for summer driving without AC.
You know, I've been meaning to do that, but you're right I need to
really check. I had a knock sensor code this summer that I assumed was
caused by the other codes, but if it has reappeared that would explain it
all. (Funny, the plastic cover on the ECU has a new home under my drivers
seat, and I think it will remain there permanently).
Dave
Codifus - 28 Sep 2004 14:23 GMT
>>On 9/27/04 9:38 AM, in article cj98qp0tg5@news2.newsguy.com, "David
>>Geesaman" <dgeesamandontspam@yahoo.com> wrote:
[quoted text clipped - 28 lines]
>
> Dave
Before you assume the knock sensor, have you thoroughly eliminated all
the basic stuff? Like:
air filter
feul filter
spark plugs
tire pressure
Once those items are checked, then I'd go to the knock sensor.
Also, when a car gets old, rust and corrosion on the ground contacts can
have an effect on how well the ECU is reading everything from the O2
sensors to the MAF etc. I would also consider cleaning all the ground
contact or invest in one of those kits that gives you more ground
contacts on the car. But this would be a very last resort suggestion.
CD
David Geesaman - 28 Sep 2004 14:51 GMT
> Before you assume the knock sensor, have you thoroughly eliminated all
> the basic stuff? Like:
[quoted text clipped - 3 lines]
> spark plugs
> tire pressure
These were done recently at the 120k tuneup. Good ideas.
> Once those items are checked, then I'd go to the knock sensor.
> Also, when a car gets old, rust and corrosion on the ground contacts can
> have an effect on how well the ECU is reading everything from the O2
> sensors to the MAF etc. I would also consider cleaning all the ground
> contact
Good idea - I will do this. The car has significant terminal corrosion
(the green powder) on the negative terminal of the battery. Is this
related?
> or invest in one of those kits that gives you more ground
> contacts on the car. But this would be a very last resort suggestion.
Invest, no, waste. The way to do it is to buy 8ga amp wire from a
stereo shop and make your own kit for $15. The folks who make those
grounding kits have quite a racket going.
Dave
Codifus - 28 Sep 2004 18:59 GMT
>>Before you assume the knock sensor, have you thoroughly eliminated all
>>the basic stuff? Like:
[quoted text clipped - 15 lines]
> (the green powder) on the negative terminal of the battery. Is this
> related?
Clean those, that won't hurt, and there are other ground connections on
the car, like one on the cam cover.>
>>or invest in one of those kits that gives you more ground
>>contacts on the car. But this would be a very last resort suggestion.
>
> Invest, no, waste. The way to do it is to buy 8ga amp wire from a
> stereo shop and make your own kit for $15. The folks who make those
> grounding kits have quite a racket going.
That's an even better idea:)
> Dave
CD
David - 27 Sep 2004 21:23 GMT
> Well my 97 SE 5 sp has 124k on it now, and I'm wondering if the knock
> sensor is bad.
Do a code scan. Knock sensor doesn't trigger the CEL. Also, I'm told
spurious knock sensor codes are common. Scan, if you have the code,
clear, drive, then scan again.
JimV - 28 Sep 2004 03:12 GMT
> Well my 97 SE 5 sp has 124k on it now, and I'm wondering if the knock
> sensor is bad. Supposedly fuel economy goes down because of it. What
[quoted text clipped - 4 lines]
>
> Dave
That's probably a couple MPG low and at 124K the knock sensor is
probably gone, but check the codes to be sure (and then reset and check
again in a day or two). If it's no longer working it won't make any
difference if you run 87 or 93 and will lack the punch it used to have.
Dave Stone - 28 Sep 2004 07:07 GMT
> Well my 97 SE 5 sp has 124k on it now, and I'm wondering if the knock
> sensor is bad. Supposedly fuel economy goes down because of it. What
[quoted text clipped - 4 lines]
>
> Dave
I usually get 26mpg or better with no AC at 75-85 mph on my interstate
commute. This on a 97 auto running 89 octane. I'm surprised by
that because my luck with this car has not been great otherwise.
E. Meyer - 28 Sep 2004 15:17 GMT
On 9/28/04 1:07 AM, in article 10lhvtc834t7scb@corp.supernews.com, "Dave
Stone" <n=> wrote:
>> Well my 97 SE 5 sp has 124k on it now, and I'm wondering if the knock
>> sensor is bad. Supposedly fuel economy goes down because of it. What
[quoted text clipped - 8 lines]
> commute. This on a 97 auto running 89 octane. I'm surprised by
> that because my luck with this car has not been great otherwise.
That (only 26) could be because you run it on 89. It wants 91. Your knock
sensor is constantly in action.
Dave Stone - 29 Sep 2004 03:51 GMT
> On 9/28/04 1:07 AM, in article 10lhvtc834t7scb@corp.supernews.com, "Dave
> Stone" <n=> wrote:
[quoted text clipped - 14 lines]
> That (only 26) could be because you run it on 89. It wants 91. Your knock
> sensor is constantly in action.
I ran 93 for the first few months I had the car and noticed it got about the
same mpg. The EPA highway rating on it for the auto trans was 27, right?
E. Meyer - 29 Sep 2004 05:13 GMT
On 9/28/04 9:51 PM, in article 10lk8qb6t3l2d72@corp.supernews.com, "Dave
Stone" <n=> wrote:
>> On 9/28/04 1:07 AM, in article 10lhvtc834t7scb@corp.supernews.com, "Dave
>> Stone" <n=> wrote:
[quoted text clipped - 20 lines]
> I ran 93 for the first few months I had the car and noticed it got about the
> same mpg. The EPA highway rating on it for the auto trans was 27, right?
EPA was 21 city/28 highway for the automatic, 22 city/27 highway for the
manual.
My '97 automatic always got 28-30 on the highway.
TY - 28 Sep 2004 07:22 GMT
I had my knock sensor replaced in my '99 SE 5SP with 75K and the gas mileage
and performance did improve. I currently get about 22 MPG in suburban
Chicago driving and 26-27 highway.
> Well my 97 SE 5 sp has 124k on it now, and I'm wondering if the knock
> sensor is bad. Supposedly fuel economy goes down because of it. What
[quoted text clipped - 4 lines]
>
> Dave
Mouse - 06 Oct 2004 17:56 GMT
> Well my 97 SE 5 sp has 124k on it now, and I'm wondering if the knock
> sensor is bad. Supposedly fuel economy goes down because of it. What
[quoted text clipped - 4 lines]
>
> Dave
1996 Max SE. 5 Speed. 82K.
So I did a test (yesterday). Woodland Hills (LA area) to San Jose, CA.
Freeways. 341 miles. 5 hours 15 minutes. Average speed 64.95. Fuel
consumed 12.248 gallons.
27.8 mpg.
Cruise control most of the way, set at ~75. Air conditioning on about 1/2
the time. Some stop and go at the start (Ventura Freeway) for about 5
miles. Some 45 mpg towards end (10 miles) behind two slow trucks on
highway 152. There is a 4,000 rise for the Grapevine (and descent), and
another ~1500 rise and descent after leaving interstate 5. 91 octane
premium (Mobil).
1 drive through for food, 1 pit stop (quick).
Cheers,
M
mynetsig@yahoo.com - 07 Oct 2004 21:27 GMT
The knock sensor does not affect gas mileage at all. Not in my case
anyway.
I know for a fact that my sensor is bad. Instead of replacing it, I
simply switched to regular gas and have been running with regular gas
for more than a year now. NO engine knock at all.
Last week I make a round trip from Houston to Lake Charles and back.
Total over 430 miles, mileage is 28.5mpg. Mine is a 95 SE with manual
transmission, 198Kmiles on the odometer.
Doghouse Riley - 08 Oct 2004 12:10 GMT
> Well my 97 SE 5 sp has 124k on it now, and I'm wondering if the knock
>sensor is bad. Supposedly fuel economy goes down because of it. What
[quoted text clipped - 4 lines]
>
> Dave
About the same as everyone else -
99 Max SE 5 speed
Highway 27-29
City 23-25