She doesn't like cheap drinks ....

[DJM/78]

So for the first time since I bought my truck , I wanted to see how my truck would run on 85 octane fuel .

 

Now she's mad at me , its like taking a supermodel to Taco Bell for a first date ..

 

Anyway , loss of power is amazing , stutters through low RPM's and forget 5th , worthless ....

I'm guessing its the fuel because she started running that way as soon as I put it in there .

 

What octane are you guys running and yes I know , it looks like I'll be going through the fuel system and all the vac. lines as well .

Even better I'll be doing it in the snow this weekend .... yea ... :dunce:

[Pete M]

as you found out, 85 is too low. 87 is the minimum required octane. :thumbsup:

 

You should be able to dump in a can of octane booster into the tank to get back to the proper rating.

[kro10000]

Most octane booster is a scam, when they say increases octane 7 points it means from 87 to 87.7, apparently NOS increases by 40 points, but I have no experience, id get a gallon of race fuel

[XXLMJ]

I live in Indiana and i don't think i have ever seen 85 before. Is that something new? I believe our pumps start at 87-89-91or92. Or did you mean E85?

[mrsinister]

south dakota was all ethanol and 85-87-91. it sucked.

[DJM/78]

Yeah its E 85 , I knew I shouldn't have done that ..... :doh:

 

Lesson learned . I guess I'll run 91 in it from now on .

[MJ is dead]

south dakota was all ethanol and 85-87-91. it sucked.

 

I don't know where in SD you were, but I've lived there my entire life and have never seen 85 octane, unless of course you meant E85. As far as ethenol goes, its only a slight additive in our 87 octane here. Everything else is good ole petrol. I've been running the partial ethenol 87 in my past 3 vehicles. I don't notice any problems with it :thumbsup:

[kro10000]

Ok now thats completely different, i would drain out the tank and flush out the system IMMEDIATELY, E85 is highly corrosive, and will cause permanent damage to fuel system components

[kro10000]

The problem isnt the octane, E85 is about 100 octane, it is 85 percent alchohol, but the fuel system needs to supply 30% more fuel, and the system isnt capable of doing that, also wrong programming

[DJM/78]

The problem isnt the octane, E85 is about 100 octane, it is 85 percent alchohol, but the fuel system needs to supply 30% more fuel, and the system isnt capable of doing that, also wrong programming

 

OK , so if there is only about a quarter tank left , I could just add some REAL octane booster and some fuel system cleaner and

flush the rest of that out before adding better fuel ?

 

What fuel system cleaners and products do you think would work best for a 4.0 HO with 200k on it .

 

I've been hesitant to put any eng. flushes or fuel system cleaners in it for fear of something really coming loose in there and

clogging or damaging something more important .

[kro10000]

I would try to siphon out as much fuel as possible from the tank, and fill up with 87 octane fuel, I never recommend octane booster, id use either chevron techron inj cleaner or sea foam

[kro10000]

But you NEED to get the E85 out of the system ASAP, right now its eating away at everything in the system. But I don't think I've made myself clear, If you did in fact put in E85, than octane isnt your problem. E85 has way more octane than what the engine was designed for, and theres nothing immediately wrong with that. The reason you have no power now is that the fuel system isnt capable of supplying the necessary volume of fuel to the cylinders, and even if it could, the ECU has no idea what to do, it is calibrated for gasoline not an alcohol based fuel.

 

But once you have siphoned out the system and filled with regular 87 octane, I would just flip the key on a couple times to clear the lines of the E85, instead of firing it up.

[DJM/78]

But you NEED to get the E85 out of the system ASAP, right now its eating away at everything in the system

 

Yeah ! its coming out when I'm done with work .

 

Thanks

[Pete M]

I've seen 85 octane fuel for sale on my travels out west.

[jimoshel]

I run nothing but 85 octane in all my vehicles. Airplanes excepted. In the Harley I notice a difference between 85, 87 and 90 but not enough to pay the higher price.No problems of any kind. There is a difference between E85 and 85. E85 get it out of the system. The Ethanol eats rubber hoses, gaskets and seals.

[james750]

In Colorado, 85 octane (NOTE, not E85) fuel is sold at all gas stations, I never run anything different in my MJ, and it runs fine. It's an altitude thing. Taken from Wikipedia, "United States, in the Rocky Mountain (high altitude) states, 85 AKI is the minimum octane, and 91 AKI is the maximum octane available in fuel. The reason for this is that in higher-altitude areas, a typical naturally-aspirated engine draws in less air mass per cycle due to the reduced density of the atmosphere." This is also why my MJ runs like crap here in CO vs at sea level.

 

If you did put E85 in it, Then there's a problem. E85 will destroy your fuel pump, can eat away at your lines, and can also cause damage to plastic tanks. I would recommend removal and replacement of the fuel IMMEDIATELY to prevent further damage.

[DJM/78]

It says it was 85 , I don't know ?

 

It was just the standard low grade gas , but just as soon as I put it in there I lost tons of response and power .

 

I've never seen this big of a difference between the 85 87 before ...

 

I've been running 87 in it since the day I got it , figured I'd change just to see how it ran .

 

Guess I'm just a dumb@ss .

[kro10000]

Ok in that case it was probably just regular low grade gas, not E85. In that case id fill her up with some premium gas, and that should fix your problem, and always go with at least 87 from now on

[jimoshel]

I'm starting to think you just got a bad tank of gas. I find it hard to believe that you would use E85 (yellow and black label, Pump seperated from others, etc) instead of 85. Either way you still need to drain and flush your system. When you drain it, let it sit awhile, Impurities, water etc will separate and maybe give a clue what happened. And smell it. You can smell the dif between 85 And E85,

[DJM/78]

yeah , I'm still going to check everything else too .

 

I knew if I tried putting anything other than 91 in my race bikes , they just won't run , but man this made a huge difference .

Its almost like something is plugged or a spark plug or wire isn't firing right .

Which I'm going to look at tonight , in the cold and dark , on the rocks ... :nuts:

 

Thanks

[DJM/78]

Alright , last night I went through and cleaned my fuel system with some Techron fuel cleaner and some Lucas fuel system cleaner

and lubricant . Replaced the fuel filter and threw some 87 back in the tank .

 

Cleaned of the spark plug prongs and checked all the plug wires .

 

Drove it last night and this morning for a while and it runs allot better , not perfect but I'll take it as it comes .

She's still a little cranky but starts right up and I've got some of my power back .

 

What impressed me was the Lucas Oil stabilizer and the cylinder head lubricant/fuel system cleaner worked good .

Took out some of the knocks out of the valve train too .

 

I think my truck just doesn't want any thing lower than 87 ... :huh???:

 

91 is too high up here , no difference in power from the 87 fuel .

[Pete M]

I know your truck doesn't want anything less than 87. There's not enough octane in 85. Octane is the big difference between the different gasses. More octane means the fuel can take more punishment before pre-detonating and so the timing can be advanced more and make more power. Less octane means less power (or much worse in the case of high performance engines).

[kro10000]

Well in all actuality, you should actually lose power running 91 octane. Higher octane fuels burn cooler, and are less likely to predetonate. This allows for higher compression ratios and or advanced timing which both help to make power. If your engine has neither of these than the cool burning ways of 91 octane will actually hurt power a little. Many newer performance cars are designed to run on both regular and premium and gain power with premium. This is because they utilize knock sensors to detect pinging and so advance or retard timing as necessary.

 

(I do not believe the renix system is desgined to do this, regardless of the knock sensor)

[james750]

I don't see why your truck would run like crap on 85 but mine has been running fine on it for years now. Maybe I'll try 87 at the next fill up. For it to run as badly as it is with 85 it really makes me wonder if you had E85 in the tank.

[Pete M]

It's possible that the renix era trucks are more resilient to a drop in octane than 91+. :dunno: Lots of variables involved here.