MSD Propane injected LB7 hits the road

[Mark Rinker]

Finally completed the install of the MSD propane kit, 22 gallon tank, lines, gauges, etc.

First drive was impressive. The extra power is linear and smooth, no significant increase in engine rattle or EGTs. It seems to come on a bit early and creates a noticable 'surge' of power when accelerating from a stop, but nothing abrupt. If not for that, you wouldn't know you were burning LPG.

Ratio of diesel to propane consumed over the first 775 towing miles was 2.4:1, which seems a bit on the high side for economy. (My driver likes the extra power, and we might see a temporary reduction in economy until that wears off a bit. The first tankful also included some hard passes by yours truly with trailer and skidsteer in tow. Very impressive when you can leave the lights with normal traffic and keep up the pace with 10K in tow.)

Combined fuel consumption was 11.9 mpg with 47 gallons of #2 and 19 gallons of LPG burned. Lower than anticipated as this unit averages 13's doing the same type of work on #2. More power has its cost - fuel.

We are collecting a couple of weeks worth of towing data with bone stock out-of-the-box settings before making any modifications to the user settings, or doing any other performance enhancing mods like exhaust or boost. I am anticipating an increase to the boost pressure threshold to keep propane from flowing unless we are accelerating, towing heavy, or running hills. Right now, I believe that propane is flowing if we are moving with a trailer on. That seems unecessary and defeats the purpose I am looking for.

Once we find that sweet spot, we'll experiment with more boost to burn the additional fuel on tap.

Digital gauges are nice, but different to read when compared to old school needle gauges. Recall features are nice, I am seeing max of 20lbs boost and have yet to see EGTs over 800 even with my foot in it.

[More Power]

Great Job! :D Keep us posted on longterm fuel economy and driveability...

Jim

[87max]

It's great to get hard numbers on these trials not just the I like this answers. Thank you!

[Mark Rinker]

I just sent this message to MSD support. I am still on vacation, and trying to describe what my driver is experiencing back home.

JK, you predicted a 'strange limp' that I might encounter on the 2001 after installing propane. The only difference between LPG fill 1 and fill 2 is the size of load that was being towed. Should we go to GM and get the latest update to the ECM? Do codes need to be cleared before normal operation can resume?

Truck continues to run fine and tows normally on diesel only.

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We are on second tank of LPG after new installation on 2001 Duramax. Always towing as this is a commercial hotshot truck/trailer. First tank operated (awesome!) normally, although LP filler didn't think tank was purging properly at first. After second fill, driver loads an unusually heavy trailer (16K lbs) and after a few minutes of towing, the engine runs rough under load and then appears to go into what is likely a 'limp mode'. The red MIL comes on, and stays lit until MSD system is powered off. Truck resumes normal operation after a full shutdown and restart, but now has 'Service Engine Soon' dash indicator set. Same scenario repeats with both loaded and unloaded trailering - usually after a few minutes and after noticable jerking when under fuel demand (hills). Driver brought this to my attention and discontinued attempts at use. Question: Could this be the result of an improperly filled/purged tank? Does a limp code need to be cleared completely before normal operation will resume?

[Mark Rinker]

(Hello from the LiveWire Internet Cafe on the sunny island of Maui, Hawaii. Yours truly is getting ready to pack up and head home. The girls need more shopping time...Dad has opted for iced coffee and an hour of internet time...only $12.... :)

Getting lots of good data back via email from the first 2,500 miles of use. Have developed an Excel spreadsheet to keep a running total of diesel and propane consumption, prices per gallon, and the combined cost per mile of burning both fuels. Over time, a solid average combined fuel cost per mile and an optimal ratio of diesel to propane should emerge.

Optimization will have to do with both settings and tunings (user controlled parameters like boost and RPM thresholds) as well as operator knowledge of when to engage the system, and knowing when to leave it off.

I am carefully watching data on the days where we are towing heavy - as these are the days when diesel fuel costs are the highest, and MORE POWER is needed. So far, it appears that the combined fuel cost per mile on those days is significantly lower compared to when we were burning #2 alone. One early data point after heavy towing was a combined fuel cost of only 18 cents per gallon. Burning #2 alone under the same circumstances would cost around 23 cents per mile. Only pennies per mile, but the pennies add up fast in this business! So far, it appears that running propane over diesel while running around unloaded simply burns more fuel, raising the average combined fuel cost per mile. Not suprising, actually. Unused power = wasted fuel = wasted money.

I am thinking a simple (and expected) business rule will emerge: "Only run the system when the trailer is loaded." Its tempting to start fiddling with the settings and trying to optimize things!!! I think a few weeks of 'out-of-the-box' data first should yield some valuable baseline knowledge.

More info soon, and a link to my spreadsheet for any of you curious enough to stare at the raw data... :) Its enough to make your eyes go blurry. Can't wait until it all boils down to a few hard and fast business rules that can be applied to SAVE MONEY while making MORE POWER!!!

[conway]

Welcome to the neighborhood.

[Kennedy]

The odd isses that haunt some 2001 trucks are not going to be fixed in any OE 2001 programming updates. It's best IMHO to load a 2002 OS which is something we've done for quite some time with great success. We used to have to swap the ECM (from a 2002) as the Tech 2 will hose a 2001 ECM if you try this, but now with EFI Live we can overwrite it no problem.

[Mark Rinker]

Conway - just arrived home. What a wonderful place you call home. Hope to visit again soon - won't wait another 43 years this time.

JK - I'll get the codes from this last episode and see if it was a tranny slip or phantom boost codes you refer to. Will likely need your assistance in dialing this thing in. The dyno would help get some numbers to back up the mileage stats.

[Mark Rinker]

Picked up a used Predator for cheap mostly for reading and resetting codes until everything is sorted out.

JK you were right, boost codes were causing the de-fueling incidents that we encountered when towing heavy loads, or simply driving it too hard (75mph uphill loaded...). There were no faults related to TCM, until later in the day...read on...

Today I unhooked the trailer and experimented with modest to maximum amounts of propane over modest to maximum Predator tunes. After many fast passes on country roads, I limped it with a full fuel full propane full throttle acceleration from 50mph to 90mph. TCM fault. I assume the torque converter slipped. Cleared the codes with the Predator, but the SES light stayed lit. JK?

A huge perma-smile is now etched on my gearhead face...and I want more, but will go back to the modest settings tomorrow and try to get some MILEAGE out of this thing, rather than black smoke... :)