2002 Workhorse W22 with 8.1L Vortec and Ally 1000 drivetrain 53K miles

[penman39]

Took Alice out for our first trip of 2020. The engine seemed to struggle and run rougher when in a higher gear with large throttle open and speed steady or decreasing right before a downshift. After downshifting and getting the RPM's up everything was normal. No CEL light came on and no other visual indicators lit up.

I have a OBD data reader but I haven't hooked it up yet. I called a local performance shop to describe my problem and they suggested new plugs and wires before even bringing it over for a diagnostic interview. 

Have any 8.1L Vortec owners noticed a problem similar to mine and if so what did you do to solve the issue??

 

[Isaac-1]

The 8.1L in some coaches is prone to burning plug wires, due to poor airflow over the top of the engine.  I ended up buying the Magnum Extreme plug wires sold by Ultra RV Products / Brazels after burning through 2 sets of $130 Taylor Extreme plug wires.  Also you really should monitor LF1 and LF2 on an 8.1L engine constantly as out of range long term fuel trims will not set a check engine light on the 8.1L even though they should, and left unchecked can lead to engine failure. I used a Scangauge II to monitor it on my coach, anything above +/- 10 and I go looking for the cause, cleaning MAF is a good first step here.

 

[Arch Hoagland]

If you are on the original plugs and wires...replace them.

Clean the MAF.

Have the hoses and belt been replaced?

 

[penman39]

If you are on the original plugs and wires...replace them.

Clean the MAF.

Have the hoses and belt been replaced?

All the parts are original to me, the third owner, since I bought it in 2015. I will have a closer look at the service records to see. The hoses and belts don't look 18yrs old. A second mention of the MAF means it is getting a bath. I will have to make sure to take my OBD reader with me next trip. I do know it can look at fuel trims.

 

[Henry J Fate]

Almost 3 years ago I purchased 2001 brave workhorse 8.1. Ran like crap. Plugs and wires was all it needed. The engine at the time had 20k on it. The wires had been some rodents lunch. The plugs did not look that bad but they are cheap. I also changed out the air filter. The air intake is up front in the engine grille. Looks like the end of a saxophone where the air is sent downward to the filter box then back up to the engine. That air passage was also part of the rodent society. Pulled the old filter and had to vacuum out the acorns and what have you. I would suggest to do plugs, wires, oil, air filter. That may solve things and at least should be done anyway.

 

[Isaac-1]

On the spark plugs when you install new ones regap them from the original .060 to about .045, see https://www.irv2.com/forums/f22/8-1l-spark-plugs-41-101s-gapped-045-a-208465.html  also I suggest using the tapping method to regap iridium spark plugs as a spark plug bending tool can break the delicate Iridium tip.  See https://www.youtube.com/watch?v=2D7FZfrVgAQ  Any solid surface will work for tapping, I have used a wood block and an adjustable wrench as surfaces to tap on in the past.  Part of the issue is that they start out at .060 originally and after 30,000 miles or so that erodes out to .070-.075 which is too much gap, check the gap on the old plugs when you pull them out.

 

[penman39]

Thanks Guys for the good info! I like the .045 gap idea. Have you run into any issues getting the plugs out? I am assuming that mine are original.

 

[Isaac-1]

No issues, the 8.L Vortec is an iron head engine

 

[Gary RV_Wizard]

Plugs are worth checking, but 53k miles does not indicate an automatic plug change in a modern gas engine unless it hasn't been running properly for awhile. With the ECM maintaining an optimal (aka stoichiometric) air/fuel ratio, the plugs can easily go 100k miles with almost no burning or pitting. However, a few thousand miles with a poor air/fuel mixture will do the opposite, burning or carbon-ing plugs quickly. A bad sensor  (O2, MAF, etc) can cause things to get messed up. Likewise a faulty injector.

If new plugs produces a marked improvement, I'd start looking for an underlying cause.  I'd also compare the plugs and note whether one cylinder is worse than others. That's one clue for a bad injector or bad wire vs a more general problem that affects all cylinders.

 

[Heli_av8tor]

Plugs are supposed to last 100k these days, right?

Here's mine with around 55k. I was getting a miss when under high load and terrible gas mileage.

Gary's likely right in that there must be an underlying cause to have such nasty plugs so quickly.

 

[Isaac-1]

Mine looked a little better than that when I changed them at 74,000 miles

 

[PJ Stough]

Plugs are supposed to last 100k these days, right?

Here's mine with around 55k. I was getting a miss when under high load and terrible gas mileage.

Gary's likely right in that there must be an underlying cause to have such nasty plugs so quickly.

Here is a link that shows different issues with plugs.

https://dannysengineportal.com/spark-plug-how-do-i-read-my-spark-plug-condition-what-they-tell-you/

 

[penman39]

Plugs are supposed to last 100k these days, right?

Here's mine with around 55k. I was getting a miss when under high load and terrible gas mileage.

Gary's likely right in that there must be an underlying cause to have such nasty plugs so quickly.

So Tom, did you find anything else wrong? Dirty MAF or a bad plug wire/coil pack or was it just new spark plugs that made everything better?  :-\

 

[Heli_av8tor]

I wasn?t patient enough to try fixes one by one to know if there was a single major cause. Here?s what all I did:

Plugs
Wires
O2 sensors
Replace leaking donut between exhaust manifold and exhaust pipe
Air filter
Cleaned MAF
Ran Lucas and Techron gas additives

Mileage increased 20% or a little more. Barely 5 mpg to almost 6-1/2.

 

[penman39]

Replace leaking donut between exhaust manifold and exhaust pipe

Could you feel exhaust gas leaking or did you hear it making a chugging like sound? Mine makes a little chugging sound at idle or lower load but I couldn't feel any exhaust gasses leaking at the joints. Last mileage check I was getting 6.7 to 6.8 MPG.

 

[garyb1st]

The 8.1L in some coaches is prone to burning plug wires, due to poor airflow over the top of the engine.  I ended up buying the Magnum Extreme plug wires sold by Ultra RV Products / Brazels after burning through 2 sets of $130 Taylor Extreme plug wires.  Also you really should monitor LF1 and LF2 on an 8.1L engine constantly as out of range long term fuel trims will not set a check engine light on the 8.1L even though they should, and left unchecked can lead to engine failure. I used a Scangauge II to monitor it on my coach, anything above +/- 10 and I go looking for the cause, cleaning MAF is a good first step here.

Our motorhome also has the UltraPower package by Brazels.  It's been on for almost 30,000 miles.  Looking at the prior owners history, they had an engine miss but it turned out to be a loose plug wire.  IIRC, the wires in ours are Taylor.  So far at just under 50,000 miles, our performs very well.  But I really have nothing to compare it to other than our previous early edition 275HP Ford V10 which got the job done but very slowly. 

Mileage is generally about 6 to 7 and the only thing I've done in the 3 years we've owned it is have the MAF sensors cleaned.  It has always started at the turn of the key and if there's any miss, it's so minimal I don't feel it. 

I don't know what LF1 and LF2 are and don't know how to check them.  How do I do this?

We have a Torque plug-in gauge that we use to monitor engine temps since our dash gauges don't always read correctly.  Can this be used to check the LF1 and LF2 numbers or do we need to invest in a scan gauge? 

 

[penman39]

Gary,

I am not familiar with that unit you mention. An OBD code reader that has live data capability should be able to read fuel trims and O2 sensor data. Do a little research on code readers and you should be able to find one that suits you needs for less that $100. 

 

[Isaac-1]

I don't know if Torque supports LF1 and LF2 reading, I use a Scangauge II mounted to my dash board, which can simultaneously display 4 its, I usually have it display LF1, LF2, Transmission temperature (only available for certain models), and battery voltage.  Here is a link to a thread I started on another forum a few years ago about this issue which has some comments from Brazels in it https://www.irv2.com/forums/f22/8-1l-vortec-fuel-trim-352528.html

 

[garyb1st]

Thanks for the Linc Issac.  I'm a member of IRV2 as well. 

Penman, the Torque OBD reader is a blue tooth plug in and I suspect connects to the same port as a scan gauge or some other reader.  It doesn't have a screen so the only way to read the info is with a connection to a cell phone or computer.  We only use it to monitor engine temps since the gauge on the dash go nuts from time to time. 

 

[Heli_av8tor]

I could feel and hear the leaking donut.

I'm a bit longer (and likely heavier) which isn't going to help mileage. I can live with what I'm getting now compared to before.