Flonker

I just bought an '05 about 3 weeks ago and I have been monitoring my mileage and I feel like it's awfully low. 12-15mpg is what I'm seeing.

I've only recently learned about pcm flash, and I apologize if this info is already out there but I couldn't seem to find it in the stickied Flash thread, but I'm not sure if this is really just something that applies to '04 productions or if it's something I can/should consider looking into with an '05.

Are all the issues resolved by these PCM flashes already corrected in the '05 by default or can I consider this as a potential resolution?

RIWWP

iTrader: (2)

A) Yes, 2005s have the possibility of not being on the latest factory flash.

B) You would need a dealer to hook up to the ECU To find out if the correct flash has been performed

C) You will pay for the diagnostic and reflash at this point (you are outside of the powertrain warranty)

D) The updated flash is largely for engine health, and will not "fix" your mileage.

E) Your mileage issues will be a cause of one or more of the following:
- Failing compression (power loss for more throttle usage, unburnt gas getting pushed out)
- Failing cat (power loss for more throttle usage)
- Ignition coil failure (fuel not being burnt, power loss)
- Plug wire failure (fuel not being burnt, power loss)
- Plug failure (fuel not being burnt, power loss)
- MAF fouling (improper fuel injection amounts constantly trying to be corrected)
- Eshaft sensor fouling (incorrect fuel and ignition timing)
- vacuum leak (renders MAF data incorrect)
- O2 sensors failing (ECU isn't properly trimming the fuel)
- Right foot used too much or not smoothly

In short, anything that makes the car lose power, have a hard time burning what you are injecting, or make the ECU have trouble seeing what the engine is actually running like.

Flonker

thank you very much. this is helpful. gives me several places to look as I may not have known where to begin otherwise.

How much could I expect a flash to cost and is there any possibility that it would at least HELP with the mileage in any way if not "fix".

RIWWP

iTrader: (2)

The cost should be under $200, but the dealer fees change regionally. You should be able to find a basic service list for whatever dealers you have in range, look for the item Electronic Diagnostic (may be worded differently). That fee is likely what they will charge for the hookup, and if they JUST do the reflash, it's probably not going to be anything additional. Probably. They might add a separate charge.

If they do the full "low power" complaint TSB that is usually linked to the reflash, then you can be looking at quite a bit more, as it can run >4 hours of shop time, decarb, various testing, etc...


Any mileage benefit that the flash can have is due to point #1, engine compression. However, if compression loss is your problem, the flash won't fix it. The main impact here is the flash injects more oil to assist with the lubrication of the seals to help slow down seal wear from the start. Once wear has occurred though, you can't just put it back without an engine rebuild. And wear accelerates the more it wears, due to the hot gases blowing through the gaps. Much like the tiny leak in a dam can wear it's way bigger and bigger until it's a flood through a massive hole.

If you are within the 8yr 100k warranty on the engine, taking it in for a compression test might be a better way to go, rather than the reflash. However, there are other items you can check/fix for free or dirt cheap, or are needed maintenance items anyway. Work on those first.

Flonker

I wonder, are worn seals covered by the warranty or only when they become completely destroyed?

I'm assuming moat of the items in your original list may be what you're referring to as cheap to check or fix. I will certainly look into these before resorting to warranty and dealer related solutions.

I appreciate your input.

RIWWP

iTrader: (2)

Doing anything with the seals requires an engine rebuild. Look at some pics of an engine in 'exploded view' to grasp why.

The warranty covers the entire engine block. Housings, plates, rotors, and seals. The only way to tell if the seals are failing is with a compression test. And it doesn't tell which seals are failing or why.

However, if your engine is still running smoothly and you have low compression the seals are just worn. Destroyed seals will make your engine "lumpy" and barely driveable due to all the internal damage it would cause. At the time of the event you would have felt the destruction, and possibly even heard the seal bits rattling through the exhaust. This would also destroy other seals in the process from the debris. At this point, you wouldn't be able to start it, and would only be able to keep it running with LOTS of throttle usage and keeping the RPMs higher than ~7,000 (enough natural compression to keep firing at that point, depends on which seals are still intact). Though all the air and fuel you are dumping in is largely getting wasted in combustion, as most of the combustion would be occurring in your exhaust, superheating the entire exhaust system to the point that it glows bright red and starts catching your car on fire unless (in theory) you can keep at high enough speed for the air flow to make enough of a barrier to the heat. If you hunt around you can find people on here that had multiple apex seal failure at once (usually from one seal taking out additional seals), and kept it driving, but the exhaust heating up lit their car on fire when they came to a stop. Usually the rear bumper.


Nothing you have mentioned suggests any of this.

Start with vacuum leaks, sensor cleaning, cat checking, etc...

Flonker

that sounds nice and expensive since I'm probably toward the end of my 8 years

zoom44

dirty oil, dirty air filter, bad thermostat, wrong tire pressure and on and on and on. there are like 35 items of maintenance which can cause lower than expected mpg.

here http://www.fueleconomy.gov/feg/factors.shtml
http://www.edmunds.com/fuel-economy/...a-ratings.html

alnielsen

iTrader: (4)

You may already have the up-to-date flash. Look for stickers under the hood. They were suppose to have been applied when it was updated. Some dealers ran out of the stickers, so the lack of one (or more) doesn't mean that you don't have the latest one either.