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jmdomini

Converting a 2008 Malibu Classic/2007 Malibu V6 3.5L?

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My supercharged Scion tC has about the same story.  About E60-E70 is the best blend for me.    Non-FFV vehicles need to be experimented with to find the suite spot.  I mix one gallon regular to 4 gal E85 and all seems to be happy.  Any higher than that I notice P0171 (running lean codes) which stop after I dilute back down with regular gas.  Considering I would have to use 91+ octane normally, I'm ahead with E60-70.

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Sorry to hear the news as well.  I went back to some earlier threads and noticed you mentioned 'pinging' on E85, but not on lower level blends - which would actually have lower octane, and presumably you heard nothing on regular gas as well (which would have very low octane)?  You also mentioned $2200 in additional repairs?  Curious what that involved and if it was anything related to the failure?

 

As for the failure itself, it would be hard to tell without actually examining the engine and failed parts.  You mention the pings happened while accelerating from a stop light.  This is where pre-ignition (as opposed to detonation) tends to take place.  Pre-ignition usually starts from a sharp edge or chunk of carbon somewhere in the combustion chamber.  This creates a 'hot spot' which can light the fuel before the spark plug does and tends to happen at low speeds under load.  Detonation tends to happen at high speeds/high load and is more of a heat/pressure relation. E85 is much more resistant to detonation than gas due to higher octane, though it is similarly susceptible to pre-ignition. 

 

If the car is known to use oil, or has leaking intake gaskets - particularly on 'V' engines where oil can get sucked out of the valley and into the combustion chamber - this can set up conditions for pre-ignition by coating the combustion chamber in a layer of carbon / ash which get hot and light the fuel.  So if the 'additional repairs' were  things like intake gaskets, honing the block, piston rings, or other oil control issues, the engine might have an oil control problem which further increases the possibility of pre-ignition.

 

My best wild guess over the internet:  Given the millions of flex fuel vehicles and thousands of gas>E85 conversions which operate trouble free, I don't think the fuel itself would be the main cause.  I suspect you possibly had a chronic pre-ignition problem with gas.  It's likely the pre-ignition on gas wasn't as severe, or happened at an engine speed where it wasn't audibly detectable.  Adding the E85 leaned out the fuel mix and likely made the existing problem worse. 

 

You mentioned the plugs were 'eroded'.  I believe most plugs in late model cars should be good to 100,000 miles with minimal wear.  So the erosion is definitely a sign something is wrong.  But the plug erosion from pre-ignition is also not going to show up after a few tanks of fuel or a few noted 'pinging' events.  This is going to take 1000's to 10,000's of miles to develop.  So again, this doesn't seem to have a direct relation of the fuel causing the failure, but could have pushed an engine already having troubles over the edge.

 

Anyway, hope everything is back together and running well.  If you decide to give E85 another go, I'd highly recommend some type of conversion box or doing other modifications to give the proper fuel flow and AFR's.  I'm not a huge fan of the 'PSI' (pour some in) method.  While it works fine under closed loop operation, starting the engine or going under heavy loads can put the ECU in open loop which means the fuel is being delivered based on a set of values pre-programmed for gasoline - which further means E85 is much too lean.  E85 has enough extra octane it will usually survive these lean conditions and most people don't go WOT very many times, if at all.  But if you are a moderate to performance oriented driver, live in hilly terrain, or have other reasons for spending more time at larger throttle openings, you might be pushing these boundaries.  Modifying the fuel system to deliver the proper AFR's on E85 will ensure a long/happy engine life, more power and possibly a bit more fuel economy as well.

 

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Corey,

I think you're on to something here. Two of the conditions that you mentioned were present, a slight issue with burning oil (about a quart between oil changes) along with heavy carbon buildup. Actually carbon buildup has been a long running issue with this car. So I'd say it's quite possible that what happened was pre-ignition and it could have been going on for some time to a lesser extent unnoticed.

 

Replacing the upper and lower intake gaskets were a give and covered by the power train warranty, the extra charges were for cleaning off the carbon deposits, piston work (rings I assume), fuel injectors, flushing the oil and coolant system and some other unrelated repairs (transmission and power steering).

 

Still not fixed right, first cold start of the day it sounds like running water in the heater core. Also I had filled up the tank with premium gas the day I picked it up and it ran great. Well, had to fill it up today and regular gas is now up to $4.29 :o in my area so I wasn't going to spring for premium. It's not liking 87 octane, idling rough and feels like it lost quite a bit of power.  :(

 

Dan-As far as I know the gaskets are silicone rubber on this engine. I immediately though if the Dex-Cool fiasco with blown gaskets though. GM claims that this is no longer an issue however, that said not sure I believe them.

 

As for the failure itself, it would be hard to tell without actually examining the engine and failed parts.  You mention the pings happened while accelerating from a stop light.  This is where pre-ignition (as opposed to detonation) tends to take place.  Pre-ignition usually starts from a sharp edge or chunk of carbon somewhere in the combustion chamber.  This creates a 'hot spot' which can light the fuel before the spark plug does and tends to happen at low speeds under load.  Detonation tends to happen at high speeds/high load and is more of a heat/pressure relation. E85 is much more resistant to detonation than gas due to higher octane, though it is similarly susceptible to pre-ignition. 

 

If the car is known to use oil, or has leaking intake gaskets - particularly on 'V' engines where oil can get sucked out of the valley and into the combustion chamber - this can set up conditions for pre-ignition by coating the combustion chamber in a layer of carbon / ash which get hot and light the fuel.  So if the 'additional repairs' were  things like intake gaskets, honing the block, piston rings, or other oil control issues, the engine might have an oil control problem which further increases the possibility of pre-ignition.

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That is a real bummer jmdomini ! The 3.5L in our 3 FFV company cars ('06, '07' 08 Impalas) have had none of those issues and range from 188,000 miles to 230,000 miles now. Engines not even touched except for a mouse attack on injector wires on the '06 when it was parked outside in the fall (I live in the woods so fall can be bad that way). They are FFV's and have run e85 nearly 100% of the time (only time they are fed gas is when we are repairing gas pumps and need to flow test them).

 

I have a feeling if we tore them down we would find virtually 0 carbon.

 

One addtional source of pre-ignition can be protruding tip/ fine wire electrode types- are the plugs OEM?

 

That gurgling water in your heater core bothers me- they did not get all the air bled off the top of the engine potentially causing hot spots/ inaccurate temp sensor inputs have have some nasty results. OR- you still have a head gasket/head problem. Make sure they get a look at this or are at least aware of it. A cooling system test may be in order.

 

Lifted heads/blown head gaskets are not uncommon in the performance world where compression or boost is pushing the envelope - especially when combined with too much/too little fuel and wild timing. ---BUT--I have not seen this otherwise outside of MAYBE in a friend's non-FFV Yukon where he slammed e85 in full blast and drove it hard (as he always drove)- even on that one the real cause was not clear.

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Using E85 in non-FFV vehicles is a do at your own risk proposition.  I'm running E70 now with no CEL and no-performance hit at 75 K miles on a supercharged Scion tC.  The supercharger kit replaces the stock fuel injectors with higher flow ones, plus an ECM flash which has a much wider trip capability.  Thus I would expect my engine to be able to handle higher ethanol concentrations than the standard 2.4 L Toyota engine.  I would love to see a complete list of what is changed in an FFV versus non-FFV where the models are almost identical like a Chevy Malibu for example.  The fleet ones are FFV and the standard ones aren't.

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" I would love to see a complete list of what is changed in an FFV versus non-FFV where the models are almost identical like a Chevy Malibu for example."

 

In general, the FFV "version" receives different software (fuel mapping) than the non-FFV.  Hardware changes may include larger (greater capacity)  fuel injector and fuel pump. 

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Dropped off the car at the dealer last night, they spent most of the day working on it today. Just got it back a little while ago. Seems to be running well knock on wood. Won't know for sure until morning when this engine is cold if the gurgling is resolved, they said there was air trapped in the engine and they spent a good two hours purging it out though. Seems to me they should have done that when they originally put everything back together.  ???

 

Outlaw1, it did have OEM plugs in it. Another completely non-ethanol related question, as I noted carbon buildup has been a long running problem with this car. Well before it started burning oil (or at least enough for me to notice). Is there anything that actually works to keep deposits at bay? I typically will pickup a bottle of Gumout Fuel System Cleaner at Farm and Fleet about once a month and throw it in the gas tank. That clearly hasn't accomplished a dang thing however.

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...air trapped in the engine and they spent a good two hours purging it out though. Seems to me they should have done that when they originally put everything back together.  ???

 

... Is there anything that actually works to keep deposits at bay?...

 

2 hours to purge air?  Wow - if they are that incompetent, I don't know that I would take the car back there!  Maybe they were just pulling your leg to make it sound like the worked hard??  :)  Either way, this 'air' situation is something to keep an eye on.  Modern cooling systems should almost be 'self purging'  They are designed so the air has a pretty easy way to work back to the filler neck as coolant is added.  Plus the overflow bottle should allow air to escape when the engine warms, then pull coolant back in when it cools.  Over a few hot/cold cycles the system should purge itself of any tiny amount of remaining air.  Then, once the system is 'solid' with coolant, the overflow is just catching expanding coolant and returning it to the engine as it cools.

 

If you're continually 'getting air in the system' it can mean a couple of things...1) the hose to the overflow bottle is cracked/broken.  The air escapes when the engine warms up, but when it cools and should start to pull in coolant, it pulls air through the broken hose instead.  2) the head gasket is leaking compression gas into the cooling system.

 

Either way, I'd keep an eye on the coolant overflow reservoir for the next couple of days.  The engine should naturally exchange air for coolant over a few hot/cold cycles and the level could drop. Keep it topped up to the proper level so the purge process can continue.  If you happen to see bubbles in the tank coming from the overflow hose while the engine is running, that is a bad sign - the head gasket is leaking into the cooling system.

 

As for keeping carbon at bay, E85 works!

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On some systems the temp sensor sits up high and if so a clue for air in the system will also be very erratic temp readings as air pockets pass over it. As Corey and I have stated- if this continues, they may not have got the head sealed (provided as Corey said0 the hose is good and you keep the coolant reservoir to the correct level.

 

Did they clean/flow injectors? Were they fouled? ---one product that is OTC that I would use (most I would not) is Chevron Techtron to clean fuel injectors. Can you get at the plugs that were on the problem bank? --if so you may want to pull them and read them for heat and deposits--compare the 3 you can get to to see if all are equal or if you see differences.

 

How much oil use have you had at 3,000 miles after an oil change? (1 quart?)

 

What oil is being used? (Viscosity, brand, and mineral/synthetic blend/full synthetic?)

 

Oil change interval?

 

Normal drive cycle? (city, rural hwy, mixed- and most importantly- run time)

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...air trapped in the engine and they spent a good two hours purging it out though. Seems to me they should have done that when they originally put everything back together.  ???

 

... Is there anything that actually works to keep deposits at bay?...

 

2 hours to purge air?  Wow - if they are that incompetent, I don't know that I would take the car back there!  Maybe they were just pulling your leg to make it sound like the worked hard??  :)  Either way, this 'air' situation is something to keep an eye on.  Modern cooling systems should almost be 'self purging'  They are designed so the air has a pretty easy way to work back to the filler neck as coolant is added.  Plus the overflow bottle should allow air to escape when the engine warms, then pull coolant back in when it cools.  Over a few hot/cold cycles the system should purge itself of any tiny amount of remaining air.  Then, once the system is 'solid' with coolant, the overflow is just catching expanding coolant and returning it to the engine as it cools.

 

If you're continually 'getting air in the system' it can mean a couple of things...1) the hose to the overflow bottle is cracked/broken.  The air escapes when the engine warms up, but when it cools and should start to pull in coolant, it pulls air through the broken hose instead.  2) the head gasket is leaking compression gas into the cooling system.

 

Either way, I'd keep an eye on the coolant overflow reservoir for the next couple of days.  The engine should naturally exchange air for coolant over a few hot/cold cycles and the level could drop. Keep it topped up to the proper level so the purge process can continue.  If you happen to see bubbles in the tank coming from the overflow hose while the engine is running, that is a bad sign - the head gasket is leaking into the cooling system.

 

As for keeping carbon at bay, E85 works!

 

I have to disagree that most modern cooling systems are designed so they are self purging, in fact the opposite is often true as the cap on the surge/expansion tank is often mounted lower than the top of the engine. Because of this lots of cars have very specific methods for the initial fill and bleed procedure and often note that "extreme engine damage can occur" if the procedure isn't followed and air is trapped in the system. On some of those systems it can take a lot of time to fully bleed the system as you need to warm it up and then let it cool subsantially before opening the system and adding the remaining coolant and in some cases it needs to be done multiple times. Of course it's not 2 hours of actual work it's just waiting for the engine to cool.

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