Terrible Fuel Mileage

[dusty76]

I bought my Typhoon while i was deployed thinking it only needed a head gasket. 4 bent rods and two gand later, it runs great. But, the fuel economy is dismal. The best I have gotten so far is like 14.6 mpg on a tank. I commute about 110 miles a day to school and it is all interstate. I kept finding little things for the first few weeks, but none of them affected the mileage. I have fixed all of the vacuum issues, verified the egr operation, etc. It runs like a top, but the gas mileage is just killin me. I bought a 4 banger s10 to commute in, but I can't justify this thing gettin the same mileage as my 1970 GTO, well almost the same. By the way, I only run shell 93 octane and I built a datalog cable, but I can't seem to get it to work yet. Thanks in advance.

 

[--SyTy Jim--]

Re: Terrible Fuel Mileage

Hey, welcome to the forum and thank you for your service to our great country! :tup:


Yeah, the trucks are horrible on gas. If you looking for any sort of fuel economy, these bad boys are on the bottom of the list. Get yourself a Honda to go to school and such. Use the Typhoon for cruising and hanging out.

The most you MIGHT get on a perfect day may be 17 MPG on the highway.

Jimmy

 

[aasltmike]

Re: Terrible Fuel Mileage

Hey, welcome to the forum and thank you for your service to our great country! :tup:


Yeah, the trucks are horrible on gas. If you looking for any sort of fuel economy, these bad boys are on the bottom of the list. Get yourself a Honda to go to school and such. Use the Typhoon for cruising and hanging out.

The most you MIGHT get on a perfect day may be 17 MPG on the highway.

Jimmy

I've done 20.5 on the interstate going to Texas from Georgia right after I bought my Ty. After my engine rebuild, the best I've managed is in the 14's. SyTy Jim is right...they're gas hogs, but a lot of fun! :tup:

 

[Ruddell]

Re: Terrible Fuel Mileage

I had someone riding in the Ty ask me how it was on gas. I said its pretty bad, esspecialy when I stand by putting Huskys 94 Premium in it. They started to tell me how much gas gets burned when accelerating, and laying off would help. I put him in his seat right after he said that. Gotta love driving Typhoons.

 

[gkrcr882]

Re: Terrible Fuel Mileage

Power = fuel, and SyTys are no exception. Even N/A 4.3s are pigs.

 

[Beavis]

Re: Terrible Fuel Mileage

You can put a block under your gas pedal or maybe move the seat back a few notches. Either way will reduce gas comsumtion because you wont be pressing it as much. The best I ever got was 19 mpg at 60-64mph avg with very light throttle.

 

[dgoodhue]

Re: Terrible Fuel Mileage

How do you drive on the highway? If you drive like Grandma you should get 18-19 mpg on the highway. If your driving like grandma and getting 14mpg, you have some issue that need to be addressed. This year my Sy was getting 14-15 mpg on the highway most of the year, because i was in boost tuning and my torque converter wasn't lockinging up, I think the best I did with out the Torque converter locking up was 17mpg, In the past I have gotten 19-20mpg taking it easy on the highway.

 

[92TYPHOON937]

Re: Terrible Fuel Mileage

i have gotten 20mpg highway in my 92 but thats doing the speed limit and takin it easy

 

[dusty76]

Re: Terrible Fuel Mileage

I drive pretty reasonably, because I want the fuel mileage to be good. I use the cruise and go between around 65 and 75, but more towards 65 to 68. I figured out how to get the cable i built to test good in tunerpro rt v5, but i couldn't get any data still today. A guy I know told me that you should never reuse a knock sensor because they get damaged removing them, to which I said "rubbish." I would just buy the cable, but thats another 70 bucks and i see these 2 transistor ones working everywhere.

 

[SYCLONE#1531]

Re: Terrible Fuel Mileage

I got 100 miles out of my last tank!! just cant seem to keep my foot out of it!!:roll::rant:

 

[Quickstop [UK]]

Re: Terrible Fuel Mileage

4-8 mpg here

 

[qbnkiller]

Re: Terrible Fuel Mileage

I was able to average 15.9MPG on E85 with a TH400 on my trip to Homecoming last year. I can tell you that a sound driving strategy (no boost launches and keep the speed below 65 in my case) are as important as the tune itself.

 

[BoostedSUV]

Re: Terrible Fuel Mileage

I never got better than 15-16mpg with my stock engine build. With my built motor I'm lucky to get 14mpg.
I drive it easy but most of my driving is not on the highway.

 

[aasltmike]

Re: Terrible Fuel Mileage

4-8 mpg here

OUCH! I thought I had bad mileage...

 

[Quickstop [UK]]

Re: Terrible Fuel Mileage

yeah, it's rich in cruise and I have size 13s

Not a healthy mixture. Damn fun to drive though.

 

[dusty76]

Re: Terrible Fuel Mileage

I understand it isn't a prius, but I don't think that 18 to 20 mpg seems unreasonable. I have done plenty of looking around and that seems to be the average for a stock truck. Last night, i downloaded datamaster and my cable checks out ok, but it won't recognize the ECU it says, what gives!

 

[mattw]

Re: Terrible Fuel Mileage

I use to get 20-21 on trips in my Ty if I drove nicely. That being said you should be getting similar if everything is working properly and you are keeping your foot out of it.

Have you checked all of the basics like:

tire pressure
alignment
torque converter locking
4th gear working properly
fuel filter
air filter
etc...??

 

[dusty76]

Re: Terrible Fuel Mileage

I did find tonight that the egr diaphragm doesn't hold vacuum. It does move when you hold the rpm up in park. when i put a mighty vac on it, it drops from 20" vacuum to 0" in about 5 seconds. My thought is that it pulls all of the timing wi\hile cruising if the egr isn't allowed to flow enough. the diaphragm stays pulled, but the vacuum all goes away. this isn't normal, is it? The other thing is that it pulls to the right in the steering wheel, but I wouldn't think that would drop the fuel economy 25%.