Community Forums

TimLoon · 05-14-2022, 03:04 PM

Noticed this at end of last year and again when I took the MH for new tires this morning.
If I come to a rolling stop or coming out of a turn, I feel like the engine/transmission is lugging. Not sure how else to describe it.
Once I am rolling along all is fine. On highway, going up hills it moves right along, no hesitation. No CEL's.
Unit has 24K miles and wires were replaced at around 14K miles. Tranny fluid done 2X with transynd.
Any thoughts?

wolfe10 · 05-14-2022, 03:14 PM

Exactly what is the engine RPM when you feel it is lugging?

Any transmission DIAGNOSTIC CODES?

Notayurt · 05-14-2022, 03:24 PM

Tim,
Once again you have hit on a topic that will elicit multiple viewpoints about "lugging" and concern/not a concern about this engine behavior. Old school guys ( I am one) always were told that lugging was on the par of original sin and you don't deserve to own a car/van/truck if you let this happen.

But, reported cases of engine damage attributed to "lugging" didn't ever really pan out. There was usually another issue with the motor or its lack of maintenance that seemed to be contributing.

Fast forward to new oil technology, new metallurgy, new electronic ignition timing, variable valve timing, etc, and most all new engines tolerate lugging EVEN better that the older gems in our teenage cars.

I would not worry about occasional lugging with colder oil when pressing the motor for uphill or large load efforts. Take it easy and wait to get up to temp, use quality engine oil and enjoy your RV for years. AT 24,000 miles so far, you probably have 200,000 more miles with proper maintenance before your motor is ready for major work!

Be good, and maybe I'll see you down the road.
Regards,
Chris

MrMark52 · 05-14-2022, 03:30 PM

Watch your fuel trims. Record them if possible (hopefully you OBDII scanner will record. Mine will - it’s a FoxWell 301).

Double check your fuel rail on top of the engine, over #7 cylinder - see if there is a fuel pressure regulator on the fuel rail. Chevy quit using them somewhere around 03/04 but just to be sure. There is a vacuum line that comes off the back of the regulator that goes to straight to a port on the intake manifold. Pop that line off and see if you get a squirt of gas, or can smell gas. Mine was bad and I got a squirt.

Check your MAF - especially if you don’t have the OEM air filter. Or if an air filter has been used that had any kind of oil applied to help it catch dirt particles. If not oiled properly, the oil will get on and fowl the MAF. Our coach had the OEM filter on her (we got with about 38k on her) - with the help of Jon at Brazel’s, and his assessment of the data from my FoxWell, I had to replace the MAF, even after an attempted cleaning. I pulled an OEM filter out, but I have no idea what any previous owner of our coach might have done.

FWIW - I had already replaced the plugs with 101’s, and Ultra plug wires, both from Brazel’, prior to digging deeper into why my fuel trims appeared wonky. That was when I found the fuel pressure regulator issue and dumping of raw fuel into the intake manifold. Fuel trims still weren’t any better, cleaned the MAF. Fuel trims still wonky (LTFT’s in the 18-20 region) - sent to Jon, told him what I had done, he said replace the MAF, I did - the coach became happy, happy.

But - I never experienced sluggish pull out as you mention. But all of what I mention above could just as easily contribute to it.

The only other thing that I can think is it seems there was/is a knock sensor issue and possibly a timing sensor issue on the 8.1’s. You might want to do a search on issues as well just to become enlightened of how they their failure presents to the user.

TimLoon · 05-14-2022, 05:07 PM

Have had a scangage installed for quite a few years.
Don't' have it set for fuel trims but will try to program before taking it back in for tire issue next week. What readings should I see on the MAP settings?
Will watch the RPM's for condition but I would say around 2,000.
Clean MAP yearly and air filter changed every 2 years with minimal mileage.

00 Buckshot · 05-14-2022, 07:56 PM

Sounds to me like it might be the torque converter is not unlocking as it should and causes a lurching feeling while stopping.

Just my thoughts.

1972VWbus · 05-14-2022, 09:40 PM

What transmission?

TimLoon · 05-15-2022, 04:10 AM

Allison 1000

MrMark52 · 05-15-2022, 05:44 AM

Quote:

Originally Posted by TimLoon

Have had a scangage installed for quite a few years.
Don't' have it set for fuel trims but will try to program before taking it back in for tire issue next week. What readings should I see on the MAP settings?
Will watch the RPM's for condition but I would say around 2,000.
Clean MAP yearly and air filter changed every 2 years with minimal mileage.

I bought a Scangauge but didn’t like it - it won’t record live data, and for a lot of troubleshooting you need a stream of data. The FoxWell, and I assume other brands, will.
I ended up selling my programmed ScanGauge.

There are pages and pages as well as videos on YouTube about what all the OBD scanner data points tell you, and they are all inter-reactive.

Again, Jon at Brazel’s was a major help in my efforts to get our coach operating within factory limits once again (assuming it ran within limits at any point in its life prior to our purchase and my investigation).
Our coach didn’t run bad - I just wasn’t happy with its gas mileage and wanted to make certain everything was running as it should. Thank goodness I did because the fuel pressure regulator issue could have been disastrous had I not caught it.
And in the end after Jon gave a thumbs up to the data, we still only get about 6 mpg with an 18k# coach tossing a 4400# Jeep Wrangler.

wolfe10 · 05-15-2022, 06:08 AM

No first hand experience with the Allison 1000. But on the larger series, it is easy to check for diagnostic codes.

Have you done that? Because "feels like it is lugging" but at 2,000 RPM sound like it could be a transmission issue.

Quote:

Originally Posted by wolfe10

Exactly what is the engine RPM when you feel it is lugging?

Any transmission DIAGNOSTIC CODES?

LETMGROW · 05-15-2022, 07:20 AM

Agreeing with what has been said above I would suggest you have someone put a diagnostic scan tool on your coach which is capable of reading live data. Take the coach for a road test and monitor what the transmission is doing, what gear it's in and what the torque converter is doing.
It sounds to me like the transmission is not shifting down properly as you are slowing down or the converter is staying in "lock up"mode. Either of these problems may be a simple as a faulty control solenoid in the transmission which once diagnosed is a relatively easy job to perform a replacement.
Some shops such as AAMCO will do a free diagnostic check and most are capable of doing the repair.

TimLoon · 05-15-2022, 06:50 PM

Will need to find someone willing to scan. My scanners only do ABS and OBII

MrMark52 · 05-15-2022, 07:09 PM

Quote:

Originally Posted by TimLoon

Will need to find someone willing to scan. My scanners only do ABS and OBII

FoxWell 301 or 602 (I have the 301) - they will do what you want. Amazon. Economical. Good quality.

Only thing you can’t get that the ScanGauge will give - transmission fluid temperature. But there are other devices you can use to give you that (in fact due to the sensitivity of both engine coolant and transmission fluid temps - I’ve been trying to find a 2 channel temperature alarm).

And FWIW - I’ve yet to find anything that will give you ABS codes for a Workhorse chassis except the GM TechII.

Sorry for the TMI.

CamJam1 · 05-15-2022, 07:26 PM

Quote:

Originally Posted by Notayurt

Tim,
Once again you have hit on a topic that will elicit multiple viewpoints about "lugging" and concern/not a concern about this engine behavior. Old school guys ( I am one) always were told that lugging was on the par of original sin and you don't deserve to own a car/van/truck if you let this happen.

But, reported cases of engine damage attributed to "lugging" didn't ever really pan out. There was usually another issue with the motor or its lack of maintenance that seemed to be contributing.

Fast forward to new oil technology, new metallurgy, new electronic ignition timing, variable valve timing, etc, and most all new engines tolerate lugging EVEN better that the older gems in our teenage cars.

I would not worry about occasional lugging with colder oil when pressing the motor for uphill or large load efforts. Take it easy and wait to get up to temp, use quality engine oil and enjoy your RV for years. AT 24,000 miles so far, you probably have 200,000 more miles with proper maintenance before your motor is ready for major work!

Be good, and maybe I'll see you down the road.
Regards,
Chris

That was manual transmissions. Not sure how you "lug" a vehicle with an automatic transmission in the way we normally think of it.

I had a Jeep Grand Cherokee once that would feel like the parking brake was on when accelerating. It was a recently rebuilt Jasper transmission, and they ended up replacing it for me under warranty.