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Rough idle complaints

 
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Old 11 Sep 2012, 02:29 am
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Default Rough idle complaints

Evening all.

I am still not happy with the way The PT idles, it just seems rougher at times then I think it should be. So I've done a little research I thought I'd pass along. It seems that the late 90' and early 00's four cylinders from almost every manufacturer have consistent complaints of rough idle. One of the things that caught my eye was the increased use of Ethanol in today's fuels. They say 10% in my area and that is soon to be increased to 15%, but testing over the years has shown that the amount of Ethanol is typically greater than what is stated. That said, you ask "so what"?

How an engine performs, including idle is dependent on a correct air to fuel ratio. This ratio also affects emissions and fuel mileage. This is called the stoichiometric ratio and is different for different fuels.

A simple explanation of this is the stoichiometric ratio of a reagent (fuel) is the optimum amount or ratio where, assuming that the reaction proceeds to completion:
All of the reagent is consumed,
There is no shortfall of the reagent,
There is no excess of the reagent.

The following is the correct ratios for several fuels:
Unleaded 14.7:1, Methanol 6.5:1, Ethanol 9.0:1, Propane 15.7:1. Studies showed that 4% Ethanol provided the best idle. Idle quality is diminished as Ethanol is increased becoming poor when approaching 20% or more.
Diesel engines were originally designed to run on peanut oil, 8.0:1

I have tried fuel at several different stations in my area. I was surprised to find that it did make a difference in idle quality, where I bought fuel. None of us can know what the Ethanol percentage is in the fuel we are buying, and apparently there is some variation between brands. Swapping where you fill up may make a difference for those of you with a rough idle.

Ron
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Old 11 Sep 2012, 02:54 am
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Default Re: Rough idle complaints

FWIW, for the past 2500 miles I've been using Ethanol Free (E-free) gas in my PT. About 2 tanks ago I recently started using E-10 again because our local Costco just opened a new gas station and the $.45 difference is fairly big. This is basically a MPG comparison experiment but anyway...

My idle characteristics have not changed.

Still rougher than I want. Could be the mods by the previous owner, though...was hopin' it was the fuel...
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Old 11 Sep 2012, 07:16 am
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Default Re: Rough idle complaints

The rought idle i've had to deal with was in a SRT4. The culpret was a broken balance shaft. The owner of the car chose to cut the chain and let it fly.
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Old 11 Sep 2012, 07:35 am
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Default Re: Rough idle complaints

Quote:
Originally Posted by Badglas View Post

I have tried fuel at several different stations in my area. I was surprised to find that it did make a difference in idle quality, where I bought fuel. None of us can know what the Ethanol percentage is in the fuel we are buying, and apparently there is some variation between brands. Swapping where you fill up may make a difference for those of you with a rough idle.

Ron
have you seen this list? Ethanol-free gas stations in the U.S. and Canada
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Old 11 Sep 2012, 01:16 pm
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Default Re: Rough idle complaints

Quote:
Originally Posted by rob342 View Post
Hey rob. Yes I have seen this list. I was hoping to find a station in my area. There is 1. Now all I have to do is load my PT on a barge in Lake Springfield and float over to the marina. the only place in my area that is available.

Thanks for the info.

Ron
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Old 11 Sep 2012, 01:32 pm
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Default something of interest

The Barrel
Unbranded vs. branded gasoline: Is there a difference?
By Alison Ciaccio on August 23, 2010 3:25 PM | No Comments | No TrackBacks
Gasoline by any other name still smells as sweet.

When it comes to branded and unbranded gasoline what comes out of the refinery from BP, Exxon or Citgo, may not be the same product that consumers think they are getting at the branded pump.
While all gasoline sold in the US has to meet quality standards, the farther you get from the refinery, the less likely you are to know where your gasoline comes from, said Jeff Lenard, vice president of communications at the National Association of Convenience Stores, or NACS.

While some retail stations promise gasoline from Shell, the unbranded gas station down the street could also be selling Shell gasoline, but at a cheaper cost to consumers.

The process from refining to pipeline shipment to storage starts with a specific brand and ends with a mix of gasoline from several different producers.

"All gasoline that comes out of refineries that has met governmental standards is then shipped via a pipeline where it is then put into a wholesale terminal of about 3 million gallons," said John Eichberger, vice president of government relations at NACS.

From there the gasoline gets mixed with product from other refiners and then shipped through another pipeline to a storage facility.

At that point, said John Eichberger, vice president of government relations at NACS, there is no way to tell which gasoline was produced by which refiner.

"I don't think retailers in the US can say with certainty where their fuel comes from," said Lenard.

At Valero, spokesman Bill Day said that much is true.

"It is true in that gasoline is a fungible commodity," said Day whose company owns and operates almost 1,000 branded stations in the US. "But there are certain detergent packages, added at the end, that make it brand specific. But it doesn't necessarily mean that the gasoline that is for sale at a branded station was made by that refinery."

What partially sets apart branded versus unbranded gasoline is the detergent or additive package that is injected into the gasoline before it heads to the branded station, claiming to aid in automobile performance.

Chevron boasts its Techron patented additive that the company says reduces the accumulation of deposits in fuel injectors and on intake valves, and minimizes build-up of deposits in the combustion chamber. In short, it will help your vehicle perform better.

But with added incentives in the gasoline, also comes added price.

Unbranded gasoline that heads to stations like US Gas also receives the detergent or additive package, albeit a generic one that is regulated by the government. But with price at the forefront, more retailer store owners are making the move to unbranded stations as consumer's eye price over performance.

"The brand right now is price," said Lenard. "The brand may come back if the brand can offer consumers something other than price."

Valero's Day said their gas stations do not offer a patented "value-added" detergent package to their gasoline.

"We have distribution agreements and add proper packages at the rack but we don't have specifically branded additives," said Day. "All of those packages add to price and Valero competes on price, not marketing."

Retail gasoline station owners in New Jersey are encouraged to make the change from branded to unbranded, said Sal Risalvato, executive director of the New Jersey Gasoline-C-Store-Automotive Association.

"There has been a transition over the past five to six years," said Risalvato, referring to many retailers switching to unbranded gasoline stations. "We encourage it because [the gasoline] can be bought and sold cheaper. Branded and unbranded is all the same stuff."

The question of branded versus unbranded came to the forefront following BP's massive oil spill in the gulf when angry consumers pushed to boycott BP products.

"All gasoline gets co-mingled at the rack before it goes to the pump," said Risalvato." If you boycott BP you are hurting the small businessman. You could then drive down the street to an unbranded station and pump BP gasoline without knowing it."

Around 50% of Risalvato's nearly 1,500 membership is now made up of unbranded retailers versus around 30% unbranded 10 years ago.

"There was a time 20 to 25 years ago when you could tell the difference of whose gas was whose but today you can't because of how fungible the product is," Risalvato said. "It is the nature of the business today."
Categories: Oil spills, Refining
Tags: BP, gasoline
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Old 11 Sep 2012, 01:39 pm
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Default Re: Rough idle complaints

my rough idle is caused by 4 things

Bad camshaft sensor, bad crankshaft sensor, bad Idle air control and bad throttle position sensor :-p
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Old 11 Sep 2012, 06:20 pm
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Default Re: Rough idle complaints

In California a number of years ago, we used to switch to a 10% ethanol blend in the winter (I have no idea why). Then the summer blend was switched back to 100% gasoline. Now, of course, we have 10% ethanol all year long.

The thing I noticed immediately was that the 10% ethanol blend did not smell as rank as the old pure gasoline. So that was okay by me. However, the Subaru I had at the time--a 1.8 ltr engine--would get 35 MPG on the highway. But when the 10% ethanol was added, I went to 27 MPG on the highway. That was a hefty drop, so I re-checked at each fill-up, and sure enough, I had lost a whopping 6 to 8MPG when the gas changed over to the cleaner-burning blend.

I suppose the cleaner air was worth it, but somehow it felt like we had been forced to rob Peter to pay Paul ....

Tim
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