iRV2 Forums

iRV2 Forums (http://www.irv2.com/forums/)
-   Trailer Towing and Tow Vehicles Discussion (http://www.irv2.com/forums/f45/)
-   -   Warning concerning sparkplugs (http://www.irv2.com/forums/f45/warning-concerning-sparkplugs-131327.html)

HSVcamper 07-23-2012 06:10 PM

Warning concerning sparkplugs
 
My tow vehicle is a GMC 2500 with an 8.1 L V8 (496 cui). Last trip it struggled up moderate mountains so when I got home I replaced the plugs which were in Real Bad condition...! The ceramic surrounding the platinum electrode was broken on 5 plugs and one even had some missing half ceramic...! I think the ethanol in the gasoline caused this. This truck only has 42k miles on it and has only towed my 5er about 7k miles.

Perry White 07-23-2012 06:21 PM

Your detonating the engine. What gears in the rear end?

Mr_D 07-23-2012 06:30 PM

I don't think you can blame the ethanol for this. We've had gas with 10% ethanol around here for over 10 years and I haven't heard of any detonation problems from it.

mrv8outboard 07-23-2012 06:47 PM

GM has a long running TSB about drivability concerns and top tier fuel. The detonation is destroying your spark plugs and you engine.

cb1000rider 07-23-2012 07:40 PM

Ethanol rates out near 100 octane. An EFI motor should self-protect (knock sensor) against detonation... Check motor specific forums and let us know what you find.

ron4jon 07-24-2012 12:22 PM

First of all, are any of you automotive engine design engineers? My profession before I retired, from Boeing, was a missile defense engineer. Prior to that I was employed as a design engineer as a NASA contractor. The engine is not pinging, nor have I ever run it at high RPM. When it needs to kick down to a lower gear I let up on the gas peddle so that it doesn't rev higher than 3200 rpm - in other words I treat my equipment well. This truck is "pure stock" and has never been modified. It has a 4.10 rear end so that it's tow rating in high.

I'm in my 60s and have driven for a very long time (51 years) and owned many GM cars and trucks including two Corvettes which I raced. I have rebuilt engines and transmissions and everything associated with cars or trucks including 4 wheel drive systems from end-to-end.

The spark plugs were made by Delco and were the proper part number. So unless any of you are engine engineers who have designed and/or rebuild engines, I still think I have a better opinion than what has been provided so far.

My posting is directed to other owners of RVs or trucks with GM 496 engines. I would like to receive a constructive reply from these owners to see if they have had this similar experience. This engine type and manufacturer is installed in several class A and C motor homes as well as pickups, both Chevy and GMC.

I am trying to be helpful to these other owners as well as to find out what "Really" caused this issue.

Midniteoyl 07-24-2012 01:04 PM

But.. your still wrong. You are having a detonation issue, and its not from ethanol, which is a higher octane than gas.

Now, you could be having this issue due to heat, like maybe wrong heat range on the plug or improper heat removal from the plug to to the head, which is where I would start.

NFlcamper 07-24-2012 01:07 PM

Wow! He should know his equipment with those credentials.
What year truck, and where did that trip go? Wonder if fuel mix up at a filling station occur? Maybe someone dropped E85 in the wrong holding tank? Is your truck E85 compatible? Has someone else gone through that area and now experiencing similar woes? Other ideas?

I have a GMC with the 5.3 and recently changed the original plugs at 145000 miles. I know, late, but they looked good for the mileage! I tow at capacity of my truck and appreciate any heads up about something that may destroy it.

ron4jon 07-24-2012 02:06 PM

I'm not a chemical engineer and I don't know for sure but I have read that ethanol burns at a higher temperature than gasoline. So, that is why I suspect the 10% ethanol blend, while the engine is under a load pulling our 8k lb 5er, caused the sparkplug's ceramic to fail.

One thing I failed to add to my post: This truck has an Allison 5 speed transmission which has a "Trailer Haul" mode that is selectable via a push-button switch on the gear selector lever. I always drive this truck in the Trailer Haul mode while pulling my 5er or my utility trailer or my in-bed truck camper. This mode provides a higher rpm up-shift and delays the torque converter lockup well as downhill "engine braking" assist. The engine is in the lower 2000 rpm range while driving on Interstate roads in the mid 60s mph range. I monitor the engine and transmission temperature gauges as well all other gauges and I haven't seen anything occur out of the ordinary. Actually, I'm surprised that the transmission temperature is never very high.

Here in northern Alabama and southern Tenn., "straight" gasoline without ethanol is very hard to find, and especially while traveling within 100 miles of here. So, up to now, I have been using what is readily available, which is 10% ethanol blend without a concern. Now I have lingering concerns.

I belong to the gmfullsize.com forum and so far no one there has posted a similar thread. I will take digital photos of my plugs and post them there is see if someone has experienced similar issues.

ron4jon 07-24-2012 02:16 PM

No - this truck is not E85 compatible.

The suggestion that someone dumped E85 gas in the wrong tank may be a good possibility. I am sure I didn't get gas from an E85 labeled pump. I mainly use this truck around town while working on Habit For Humanity construction and I haven't noticed any major performance change except this last trip up to Nashville, TN.

And, there's another question in mind: I've read somewhere that ethanol blended gas has a "lower" energy producing potential therefore, you actually get lower gas mileage using the blended gas than using "straight" 100% gasoline.

Are there chemical or automotive engineers out there that can set me straight on this? Maybe I have been misinformed.

Arch Hoagland 07-24-2012 02:16 PM

I had a 2003 GMC P/U with the 8.1 and Allison transmission. I also have a 2004 motorhome with the 8.1 and Allison.

I put about 45,000 on the truck and have 60,000 on the motorhome and haven't run into your problem so far.

I've burned everything in the motorhome while going around the country, including 85 octane which was all I could get in the midwest.

It will be interesting to see how your new plugs hold up. Keep us posted.

chief02 07-24-2012 02:19 PM

News flash>>>>> when you post on here you get replys. Maybe not what you want to hear, but non the less you will get them. No need to give the responders a tongue lashing

Perry White 07-24-2012 02:36 PM

If you want to know about engines, ask Mike Canter. He works on real engines (FORD)

ron4jon 07-24-2012 02:38 PM

Quote:

Originally Posted by Arch Hoagland (Post 1254187)
I had a 2003 GMC P/U with the 8.1 and Allison transmission. I also have a 2004 motorhome with the 8.1 and Allison.

I put about 45,000 on the truck and have 60,000 on the motorhome and haven't run into your problem so far.

I've burned everything in the motorhome while going around the country, including 85 octane which was all I could get in the midwest.

It will be interesting to see how your new plugs hold up. Keep us posted.

Thanks for your feed-back. It's good to know someone hasn't had this issue and has enjoyed many trouble free miles. Maybe it was a one time occurrence for me. This is the valuable kind of assistance from a forum like this.


All times are GMT -6. The time now is 08:55 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.