Techron+Valve Adjustment=Low Gas Milege?

[fitz]

Is this normal? About a month ago I was getting 21 to 24 mile per gallon. Then three weeks ago I got a valve adjustment and the gas mileage went down to 19. Before my last fill up I put some techron in my tank to clean the injectors and now I got 15 miles per gallon. Wha's Up with this? The techron made the engine run quieter but 15 mpg? Today's fill up cost me $40.00 and might only last me a week at best with my commute.

Are these two things related to the poor gas mileage?

Any suggestion or comments are appreciated...Ron Fitz

[cstreit]

If your injectors were clogged and you were running lean, the techron may have cleaned them out and allowed more/better fuel flow?

You didn't mention what car this is from.

[cowtown]

Did the shop that did the valve adjust set your mixture as well? What other service did they do?

[fitz]

Ooops, I forgot a few details...Sorry.

Cstreit, The care is an 88' 911 cab. with 102,000 miles. I was also wondering same thing about the techron and better fuel flow. Also, I usually don't race the car at stop lights or stomp on the pedal every chance I get, (especially now that gas is getting more expensive).

Cowtown, thanks again for reponding to another of my post. To answer your question the only other thing the shop did was replace the oil temp sensor because of an oil leak. Other then the temp sensor and valve adjustment that all that's been done. The other thing I plan to do next month is to replace the O2 sensor based on my last post about a slightly rough idle.

One thing that is really cool is that the engine valves seem to run alot quieter after the techron. Before they would be a little noise after being in traffic for a while.

Does techron boost the octane of gas?

Thanks for the replies.....Ron Fitz

[ChrisBennet]

Maybe the gas formula itself has changed? Seriously.
-Chris

[Superman]

Oh yeah? Well:

Techron + Valve adjustment + mixture adjustment (if possible on a Carrera) + ignition system checkup/adjustment = maximum performance and fuel economy.

[stlrj]

Could the rough idle and poor mileage be caused by a bad plug?

Cheers,

Joe
86 Carrera

[fitz]

Joe,
thanks for the suggestion but I just changed the plugs, cap, and rotor less than a 1000 miles ago. The rough idle has been there since I bought the car a year ago. I think it might be the O2 sensor, especially after reading Wayne's book. As far as I can see with the receipts from the po the O2 sensor has not been change for 75K+. Wayne recommends every 30K. So, I think it's long over due. Once I change the O2 sensor I'll reply back to let you all know if it takes care of my problem.

Thanks for the reply Joe...Ron

[jeff m]

A faulty O2 sensor will cause lower gas mileage.
Once a car is warm/hot a signal is sent to the ECU to ruduce the fuel metering.
You could check that the wire hasn't fallen off.
Jeff

[stlrj]

From my experience, a bad 02 sensor will not cause a rough idle, poor mileage...maybe.

How old are your ignition cables?


Joe

[fitz]

Jeff and Joe,
Thanks for the info. I checked the O2 wires and the are fine. The ignition cables I think are as old as the engine. I usually replace ingnition cables on my cars soon after a 100K just to keep good pep in them. However, I priced the porsche cables and Oooch! $$$ I have to wait a little while to replace them.

Thanks again...Ron Fitz

[MotoSook]

Don't buy the plug wires from the dealer! Heck I think I've only had to go to the dealer for two parts since I've owned my car (8yrs)! I just don't like getting raped with a smile from the counter person.

Buy from Pelican, and if you can't get it from Pelican in a rush there are other sources.

[1fastredsc]

Magnecors are reasonably priced and very good quality, might think about that as far as wires are concerned. Our host sells them. And a bad o2 sensor can cause bad gas mileage seeing that the o2 sensor adjusts the mixture under all conditions except WOT.

[thomschoon]

I use Techron a couple times of year in each of my cars, it usually kills the mileage for the tank it is added to and gets better from there. I also change the fuel filter after adding the Techron because it seems to clean out the tank a bit also.

Check your mixture and double check the valve adjustment

[Dan Owens]

Ron,

I'm not sure what checking the o2 wires mean but I don't think just looking at them will tell you anything. The o2 sensors are only good for about 30 to 50k and then should be replaced. It can make a huge difference in performance if the o2 sensor is bad. Also if your plug wires are as old as the car you may want to replace those some time too.

[stlrj]

There's a real easy way to tell if your OEM Beru ignition cables are any good and that's by spraying some water on them while the engine is idling. If it sputters and dies, your cables are history.

You can do this test on any non Porsche and the engine will keep purring. I know because I regularly degrease my Oldsmobile and Grand Caravan at idle with no change in rpm or smoothness at all.

I got rid of my Beru wires in favor of a set of Autolites designed for a 96 Dodge Intrepid which came with the long spark plug ends that fit perfectly in my 86 3.2 and degreasing my engine at idle is no longer a problem.

I wonder if Magnacores would be able to pass the water test as well?

Cheers,

Joe

[1fastredsc]

They pass, or at least they did on my 944. Only thing though is the outside insulation is silicon meaning that you have to keep them away from gasoline.

[fitz]

Wow,
Thanks for all the great advice. I've ordered the O2 sensor today and will try next month to order new cables. Joe, I never knew about the water test for Porsche cables. I'll try that this weekend.

1fastredsc, if I get the magnacores will I have to be concerned about them and the gasoline issue? or are they safe and good quality to use?

Thanks again guys...Ron Fitz

[Formerly Steve Wilkinson]

Magnacores, and their end fittings, are the best-quality wires you can get for a 911. Just don't spray gasoline on your engine...

Stephan

[stlrj]

never knew about the water test for Porsche cables

I think we've all been through the water test whenever we drive through a downpour/ carwash or plow full speed though 3" of standing water.

Unless, of course, if you have a garage queen...

Joe