Good point! Thanks, I forgot to mention that. The way I figured out which plug was which was by turning the ignition to run(I didn't start the engine) and stepped on the gas. The first connector I unplugged was the wrong one and the TPS remained at 0. The correct plug is very difficult to see.
Edit: The correct plug is the lower one.
You mean the connector to that little teeny RC looking motor? I was expecting something at least the size of 1/2 a beer can. That little golf ball sized thing is telling my 1.9L engine to idle faster and rob me of what, maybe 400 RPM and the subsequent GPH?!?!?!?!
I got a Mitchel On-Demand CD manual for Saturns for 10 bucks on Ebay, and I can't find any reference to this motor at all .
EDIT : Or is it actually an "idle control valve" like so :
I saw some postings and some mentions but not too much on IAT resistors. Almost everytthing on the net is about more power not fuel economy. I apologize if this has been beat to death years ago.
I just went for the gold. I put in the lowest resistance that the computer would accept without setting a code for Intake Air Temp out of range and compared that with a 10k resister. Here is a little range of experiments and the intake temp I see on the Scangauge. I just used the nominal values of the resistors rather than measuring them. A co-worker tried to tell me about these "chips" a year ago or so and I just totally discounted it. This is darn near the stuff of urban legends. These resistors are 99 cents for a pack of five at Radio Shack. I have never done so much so cheaply before in my life. This is on my 2001 Saturn SL.
10k ohm IAT 28 F
940 ohm IAT 198F
136 ohm IAT 233 F this is two 68 resistors in series.
068 ohm IAT 279 F set an out of range code.
I did an ABAB experiment on the same 8.5 mile loop trying to drive identically. The lights did not cooperate 100% but I judge the experiment valid. The two runs with the 10k ohms were 43.3 and 44.1 mpg. The two runs with the 136 ohms were 61.0 and 63.9 mpg. The average speeds ranged from 29-31 mph. The difference between the average mpg's is 18.75 mpg giving an increase of 43%. The 10k ohm resistor was a slight handicap as the actual temp was 40 F. It was not far off since when I filled up yesterday my tank average was 46.2 mpg and this is just a little better than the 43.7 average of the two 10k runs.
I then went out on the freeway and made a 16 mile total loop at 60 mph and got over 60 mpg without any engine off coasting. I just drove easy. I did a bit of idle coasting on the last bit coming home as I could see the average was at 59 and wanted to break 60 mpg.
This morning I did the trip to work starting with a cold engine, I did not need to go to work it is just a familiar route. Against the slight grade and more than slight wind I made 53.8 mpg to work on the freeway at 61 mph. There was no drafting. The instantaneous mileage was between 55 and 60 mpg. I never shut off the engine but reset the current trip at work and started home. I came home on secondary roads so I could drive slower and pulse and glide with the wind to my back. By the time I got to near 1/2 way home my average was 112 mpg. I then lost a bit on as the lights would not turn green until I triggered them myself in the light Sunday morning traffic. I had to get into 2nd gear at several lights. At the stop sign at one road I botched the takeoff and lost about a mile per gallon. I only mention this because the trip home averaged 99.6 mpg. Darn it all anyway. The round trip averaged 70 mpg at an average speed of 40 mph. Here is the "today" summary:
40 mph ave
My car obviously has a sensor that tells it when I am in fifth gear. The instantaneous mileage makes a distinct jump now when I hit fifth gear. Something beyond the usual expected with a shift. I can accelerate decently on a slight upgrade at 40 mph in 5th gear and get 50-60 mpg during the acceleration. This does more than just adjust the timing. I can watch the timing and while it changes some with the resistor the change is not that great and something else is going on. Some think it leans the engine out but it is running closed loop. My current theory suggests EGR. I have run engines lean and ruined one turbo 2.3 Ford engine running it lean. This does not feel lean. Drivability is not suffering in the least. I am excessively short shifting to get into fifth gear as soon as I can because I see the immediate benefit.
The only aero mods to my car are blocking the grill and removing the spoiler. I have not even proven that removing the spoiler is a good thing.
This is pretty unbelievable. Nothing will be really confirmed until more distance passes and I have to fill up and check the calibration again on the Scangauge. Last check was within 0.5% yesterday. I hope this is for real. It sure looks that way. I suspect that the exhaust temp is probably not warm enough to keep the catalytic converters on line. Just speculation at this point.
If someone else was writing this I would not believe it either.
I copied this over to the experiments page. That is probably a better place for it.
To illustrate the penalty a cold car exacts on FE potential...
In an earlier post I reported 61.0 mpg (US) for one round trip I've been doing almost daily this month. This was on a cold car (actually, 2 hrs EBH) @ -16C ambient.
Today I did that same round trip @ -6C with the car fully warmed up, from other errands, and managed 80.2 mpg (US).
It's not strictly apples to apples because of the ambient temp difference, but worth noting. I think the absolute best result I've seen for this round trip with the car cold was in the neighbourhood of 70 mpg - but I couldn't find the post.
Don't forget I've got pretty much ideal traffic conditions. On top of the fact that traffic is hardly heavy here to begin with, I make a point of not driving at "peak" times. So most of the time I can do whatever I want with nobody to piss off.
And my average speed for this round trip was pretty low - like 21 mph.
It's basically aggressive P&G in 2nd & 3rd gears, 25-60 km/h, rinse, repeat. (May not apply directly to your car - remember my gearing's taller now).
EDIT: and this evening I pretty much hit all the lights perfectly.
The stars were aligned.
EDIT2: also I think this is a 17km round trip. So the potential's greater. Your 3 mile trip is a killer. Gotta get on your bike when the weather warms up