So I installed a new TPS from Auto Zone and modified it with a set point of 0.71 volts at run position. The old one was fluctuating badly.

Problem is I went down in MPG's from 15.2 average to 8.1.........WTF

Put the old one back in that was set at 0.68 and now is running at 0.62 and I'm back up to 13.8.........WTF

I'm going to set it down to 0.68 if I can but don't see the fix. When installed without the mod the new one was 0.56 so what do ya guy's think???????????

 

BTW........... Elevation is 4320 and temp right now is around average 26 F

 

Yes Hydra the issue your having can very well be as the TPS along with other sensor tell the PCM how much gas to give the engine.
Note this is a performance mod

 

Ya, but the OEM I set at .68 without modification and ran great until it started fluctuating.

The new one was set to the up by only .03 with noticable smoothness although power seemed to lower a bit. I have reset the PCM nd let it re-calibrate each time. I accually think the new TPS is a problem because of fuel settings.

I did however notice as I was testing the output temperature of the T-stat on the neck with a thermocouple with my multimeter and was getting readings all over the place and noticed small sparks between the thermocouple and the neck grounding out. I'm going to get into it further to insure a proper grounding.

That TPS has got to be bad. Question is can someone test theirs with the mod and see aproxemently how much voltage is output about 1/4 throttle. I am thinking it's reading to fast fooling the MAP although with that much fuel one would assume a CEL would trip.

Really thinking I need to put everything back together and take that POS back!

 

I've not had any luck with modifying the TPS.

When I modded the factory TPS, I thought I noticed a difference in the peppiness of the throttle. 4 months later, it went out with the DTC fault code ofr TPS voltage. I bought a new one from O'Reilly's and installed it and everything was great. Then I got the itch to mod that one. Modded it, and the mileage went South just like you had posted and I noticed no throttle improvement at all. Bought a 3rd and left it alone. Haven't had an issue yet.

 

Ok,

So I bought a new multi meter (a real nice one) and checked it and was at .68 so I increased it to .71 and ran a bottle of heat into the tank. I HATE PUTTING ANYTHING IN THE FUEL PERIOD! I thought that maybe I had ice in the lines or something?????

Anyway I took it for a drive and had about 250 miles on it sense the change out and about 5 miles after the final set point was achieved and the gas mileage went back to normal???????

I just ran 100 miles down to the city at 80 MPH and 75 mph back and got 14.858 mph for the round trip. At 80 mph I average 11.4 and at 70 mph I average 15.2 mph so as I look at these numbers I am in disbelief. If I average to normal what will be I will see a noticeable increase of fuel mileage by at least 1 mpg.

Can't wait to do a final couple of tests!

 

What kind of meter did you pick up? I got a Fluke 117 the other day as well as a boatload of craftsman tools for when I am ready to go to work in the diesel industry this summer.

 

Blue Point FTW

70 mph is that magical speed for me as well. Till i get back into the city, then my mpg is "WTF..."

 

The multimeter is a 10709 from ETEK. I picked it up at Walmart for around $20 bucks and it has everything.

I have the 392 rear gearing and 31X10.5 LT15 tires.

 

Sounds good. I can't wait until I can afford a lab scope. The one I want is about $3000 though.