Can you chip a car to run on regular instead of premium?

[glenn31792]

I have a Nissan Maxima that requires premium. Can I chip it or have it programmed to run on regular?

 

[gremlin]

I have a Nissan Maxima that requires premium. Can I chip it or have it programmed to run on regular?

why does it require premium?? if its not a sports car or built engine run it on reg. if it does not spark knock then rock on

 

[glenn31792]

It says to run it on premium. The valves clatter on regular gas.

 

[gremlin]

It says to run it on premium. The valves clatter on regular gas.

ya the noise you hear is spark rattle. call your dealership and see if they can adjust the octane rating. on our older fords it was an adjustable peramiter

 

[ShoerFast]

It says to run it on premium. The valves clatter on regular gas.

Just a guess, but thats not the valves clattering.

Most closed-loop feed-back engines have a way of telling how effective the ignition timing is. Knock sensors being the most common, others use an adiptive memory system that remembers what worked well in the past by doing a few minor test to see were the engine runs best.

I have no idea what your Nissan uses, but it's my bet that something is on the cusp of working?

When dose the engine make the most noise?

(My first guess is under a heavy load? my second guess is rev-ed up, like right before it needs a higher gear?)

 

[gremlin]

Just a guess, but thats not the valves clattering.

Most closed-loop feed-back engines have a way of telling how effective the ignition timing is. Knock sensors being the most common, others use an adiptive memory system that remembers what worked well in the past by doing a few minor test to see were the engine runs best.

I have no idea what your Nissan uses, but it's my bet that something is on the cusp of working?

When dose the engine make the most noise?

(My first guess is under a heavy load? my second guess is rev-ed up, like right before it needs a higher gear?)

correct info. the noise he hears when using low grade is predetonation caused by the low octane fuel igniting too fast for the preset timing

 

[ShoerFast]

correct info. the noise he hears when using low grade is predetonation caused by the low octane fuel igniting too fast for the preset timing

That, and or it's under-fueling under load?

The processor should be able to take care of it.

It would be a fun system to dial in a little more fuel-rail pressure.

Had the privelage of working on a few dynos, and seen how baty processors can get when the injector dwell can't keep up with the fuel requirements.

WOT should back any timing off,,,,,, bring on the RMP's it should bring it back up. Short change it on fuel and it's all over the place.

80% - 90% injector dwell and .3 volts off an O2 sensor,,,,and yes, one h311-of-a rattle.

Glenn, is this a new problem? Or has it eased into a problem?

Making the fuel filter the first place to 'guess' and the pump and regulator second, in order of cost.

 

[OilHead]

What is your coolant temp? Was it doing this last winter on rainy days ? Return hose temp measured with infered when symtoms occour. Is there 10% ethenol corn squezzins in the mix ?

 

[glenn31792]

Thanks for all the replies.
Nissan says to run it on priemum. I don't know if its because of high
compression or what. Being Fi I expected it to adjust somewhat.
I might run the tank down and put regular in it and disconnect the
battery for an hour. I hear that this will get the computer to reset
and adjust for altitude and things. Who knows it might do something.

It has made the noise since day one. So I have always used premium.
Sometimes you can get away with filling 1/4 tank with regular.
Car now has 60k miles on it.
Temp has always been the same.

 

[gremlin]

good idea to disconnect battery and reset KAM

 

[goblin]

I've had a 2.3L fuel injected Ford engine that has done the same thing since the day I got it (1989). It runs perfect on Premium, OK on the middle grades, and downright lousy on 'regular' grade (low octane), knocking and pinging to beat the band.
If I remember correctly, the owner's manual did state that if the engine knocks or pings excessively you should increase the octane of the gas that you are using.

I figure that some engines prefer premium gas just like some people prefer premium beer, while other people will drink anything.....and enjoy it.

 

[gremlin]

I've had a 2.3L fuel injected Ford engine that has done the same thing since the day I got it (1989). It runs perfect on Premium, OK on the middle grades, and downright lousy on 'regular' grade (low octane), knocking and pinging to beat the band.
If I remember correctly, the owner's manual did state that if the engine knocks or pings excessively you should increase the octane of the gas that you are using.

I figure that some engines prefer premium gas just like some people prefer premium beer, while other people will drink anything.....and enjoy it.

ha good post and true as well

 

[OilHead]

If that engine has a vacuum advance pot on the distributor pull off the hose & plug it. It will then limit the total advance & detonation should go away so you can run regular fuel. Miles per gallon may suffer & it probably wont rev out as high. Make sure the coolant antifreeze is clean w a 50 50 mix.

 

[joecool85]

You can "chip" a car to run on damn near any octane, so yeah, you could retune it to run on regular. You won't get as much hp though. The only thing keeping you back might be compression. If you have 10:1 or less compression you should be able to run regular (87 octane), any more than that and you're going to need premium (91+ octane) no matter what the tune.

 

[OilHead]

I am guessing the engine is fuel injected . If your talkin about chipin the car then assume its computer controlled. In any case if the O2 sensor is lazy, crumed up or out of calibration then it will cause this. So how old is the O2 ?

 

[ShoerFast]

You can "chip" a car to run on damn near any octane, so yeah, you could retune it to run on regular. You won't get as much hp though. The only thing keeping you back might be compression. If you have 10:1 or less compression you should be able to run regular (87 octane), any more than that and you're going to need premium (91+ octane) no matter what the tune.

Yep!

And to comply with NOx emissions, there is a good chance that it's not above 9.5:1 comp.

Chopping the base timing might also help, along with erasing the memory (disconnecting the battery) Remember to touch the disconnected neg. cable to the pos. cable to kill any capacitor or other system back-up it might have.

I will still stand on there being a problem. With stock cylinder heads needing premium to live. There just way to de-tuned to meet emissions to cause the need for that much octain to control the flame/pressures.

Most systems look at the throttle position, manifold pressure, engine temp, and RPM first, and then look at the O2 , knock-sensor and ambient temp, before re-tailoring the base for air-fuel ratio and timing curve.

If the base curve, (distributor position/inginition-trigger) is too far advanced, there will be a problem.

If the fuel-rail/injectors can not meet the demand, you might be able to trick it with a better quality fuel, but your bandaiding the real problem, and the engine could be doing a better job for you.

 

[ShoerFast]

I've had a 2.3L fuel injected Ford engine that has done the same thing since the day I got it (1989). It runs perfect on Premium, OK on the middle grades, and downright lousy on 'regular' grade (low octane), knocking and pinging to beat the band.
If I remember correctly, the owner's manual did state that if the engine knocks or pings excessively you should increase the octane of the gas that you are using.

I figure that some engines prefer premium gas just like some people prefer premium beer, while other people will drink anything.....and enjoy it.

Working with the SVO and Rapideo groups in early 89 . The best fix for those early processors was to take the fuel regulator and a 10MM 1/4" Snap-on deep-well socket and trial and error, compress the fuel regulator 'shorter' to increase the fuel delivery pressure. (compressing the case put more pressure on the release spring)

Trusting memory here, but your looking to go from 36#'s of line pressure to about 40#'s .

That old Pinto engine, along with others were hard to clean up, making them too clean was the problim, everything dialed into the base (the PROM) was too lean and lazy.

There been 400HP test done with Fords 2.3 and Mopar's 2.2L's

 

[OilHead]

Yep & if the egr valve is clogged up & or the vac signal is not present after it has warmed up crusin then that could be the cause also. It lowers the peak combustion temp & aids in reducing spark knock.

 

[joecool85]

I will still stand on there being a problem. With stock cylinder heads needing premium to live. There just way to de-tuned to meet emissions to cause the need for that much octain to control the flame/pressures.

You'd be surprised. There are a handful of n/a cars that aren't performance cars, but the way they are tuned from the factory they run like poop on regular gas. Nissan makes a few cars like this. I wouldn't be surprised if the car is in perfect shape.

 

[ShoerFast]

You'd be surprised. There are a handful of n/a cars that aren't performance cars, but the way they are tuned from the factory they run like poop on regular gas. Nissan makes a few cars like this. I wouldn't be surprised if the car is in perfect shape.

Would not be surprised at all,,,,but it still is not right. Your use of the word 'perfect shape' is far different then mine.

A very large percentage of the work I did was correcting factory (stock) problems.

Meeting EPA regs and oxygenating fuels is an evil as well.

The saplings old Pinto engine was a good example......

That old Pinto engine, along with others were hard to clean up, making them too clean was the problem, everything dialed into the base (the PROM) was too lean and lazy.

There been 400HP test done with Fords 2.3 and Mopar's 2.2L's

I have a lot more respect for Nissan's and Toyota's then anything the Big-3 ever built.

The trick, in my opinion, is making it run with this stuff that call gasoline any more. Tier II and E85 fuels don't help. And cost us billions of dollars.

The reason I sort of leaned toward the possibility it may be a fuel ratio problem, if I may?

Is the fact that todays fuels are at best only 85% of what 'gas' should be.

Simple math, it takes 130% more fuel (with this cheap-stuff) to get the same power, and yes, it will make an audible rebellion.

Back in da day, they took 87 octane fuel and blended MTBE and other fun stuff to make 100+ octane fuel. It cost less, ran better.

Now, they take 93 (or so) fuels, dump in chet engines don't need or like, and come up with 87 octane fuels.

You need more to get the same.

On that note, gas is hitting an all time high, but to grab the next higher nozzle still cost about a dime a step-higher.

Making 93 octane (for a few pennies more) more bang for the buck,,,,,,,,,
But that improvment would only be made if it is a sound runner to start with. (not needing the octane to improve a fault)