The Craftmans Shop > PowerSports
Reducing Fuel Consumption of an 30 Year Old 8 Cylinder Pickup Truck
BillTodd:
This reminded me of my brother's approach to complex electronics ....
Faced with a 3.0l Merc with dead injection and a tight filming schedule ( the Bond film 'Octopussy' I think ) . To get the recalcitrant merc to roll a few hundred yards down a railway line, he simply sawed off the injector and welded on a carb :-)
https://randomrailways.wordpress.com/2021/01/01/bond-on-rails/
vtsteam:
--- Quote from: AdeV on January 23, 2025, 04:33:10 AM ---Seems like a brave choice to me, mucking around with the OEM stuff.... Were you never tempted to do something like replace it all with a Megasquirt? EFI (if you've not already got it on the truck) would also be good for fuel economy, not to mention cold starting etc.
I know what you mean about '96. We were still just getting over the shock of seeing WIndows 95 for the first time... Most of us were still using i486 powered computers (the Pentium was out, but sooo expensive, but also sooo fast), computer memory was measured in megabytes not gigabytes, and a 1GB hard drive was considered cavernous!
--- End quote ---
Thanks Ade, :beer: I actually don't feel brave re. the OEM stuff -- I don't know much about the megaSquirt, but just looked it up and it seems much more involved and costly -- I'm on a water budget, not even up to good beer standards :lol:. Looks like you need $600 to play megasquirt, and that doesn't include options like various temp and crank position sensors, etc. Also you may need a wideband O2 sensor -- mucho additional dinero.
The OEM PCM I will be swapping in is called an 0411 by Chevy folks -- and specifically I will be using one tuned for a 2001-2002 Chevy Express Van, which had options for the same 5.0L Chevy Vortec engine I have in the '96. So basically the tune is already set up except for a few parameters, which are documented. I'm not breaking new ground here. The PCM, pre-programmed for the swap cost $150, and probably would have worked by simply repinning the connectors. No need for the cable I'm making.
But I'm a cautious experimenter, and if there are problems I don't know about, and I want to return to my old black box PCM, the cable would allow a simple swap back by plugging the old one back in.
A possible issue, for instance, might be passing inspection with a swapped PCM, in my state. The new PCM contains the VIN of the vehicle. It presently has the VIN of a 2001 Express Van. I can change that with editing software to match the Silverado's actual VIN -- but how will that affect the other engine parameters the PCM uses? The VIN encodes many vehicle and engine options. Does the PCM look at the VIN and decide what engine and options are onboard and how to operate?
I don't know. That's just one issue I can come up with among many I can think of, and I don't seem to get knowledgeable answers when I ask others about their experiences. For one thing, every state has different rules for inspection. So one person's answer may not work for me. Some states don't care about a PCM swap. Others insist that the VIN of the PCM match the vehicle VIN.
Anyway, I think a cable will be worth it for me to just experiment with what I have and get real answers to my questions.
Oh yes Win95 -- I forgot about that! Yes Win98 was so advanced! Actually, I was originally a TRS80 guy to start with, and then a Amiga fan, before eventually getting a genuine IBM PC. I was kind of disappointed at how conservative the PC was when I first got it. My old LNW-80 (home-built 5.3 Mhz TRS-80 upgraded clone) ran circles around the PC, but I did like the open spec and swappable boards in the IBM. Which of course led to IBMs downfall in the PC market. I sure wish Amiga had survived, it was to me the best combination of forward thinking at the time. Oh well.... :beer:
vtsteam:
--- Quote from: BillTodd on January 23, 2025, 09:29:03 AM ---This reminded me of my brothers approach to complex electronics ....
Faced with a 3.0l Merc with dead injection and a tight filming schedule ( the Bond film 'Octopussy' I think ) . To get the recalcitrant merc to roll a few hundred yards down a railway line, he simply sawed off the injector and welded on a carb :-)
--- End quote ---
Thanks Bill :beer: I love that! :thumbup: :clap:
vtsteam:
I should add a few things about this project, since the PCM swap is actually just a part of what I have planned. I'm also hoping to address the Silverado's wind resistance, to try to improve fuel economy. To relate to you, my cousins across the pond, let's just say it presently has the aerodynamics of Winchester cathedral.
I've come to realize just how this affects the truck at various speeds by installing an inexpensive bluetooth monitor dongle in my truck's OBDII port, and using a program on my cell phone to record several parameters while driving. Very interesting stuff. My truck gets better gas mileage, for instance, at 35-45 mph, than it does at 50-55 mph. Obviously, wind resistance is a big factor here.
BTW in case anyone is interested, the dongle I use is a Vgate iCar Pro Bluetooth, which cost me about $30.
I run the Torque Pro App on my phone and tablet (about $5). This is an amazing, to me, combination. I can configure any on-screen gauges to monitor a selection of maybe a hundred different engine and vehicle parameters, in real time, and even create logs.
Here's a graphed example of a log I created for some specific engine parameters I wanted to record for a test drive which included idling, in town driving, highway driving, and country road (curvy, hilly, low traffic, few stops) driving. I'm attaching a screenshot example (sorry, too wide for forum inline placement).
vtsteam:
Here is a great little series of DIY experiments with a pickup truck aimed at reducing air resistance:
https://www.amateuraerodynamics.com/2022/04/optimizing-aerodynamics-of-truck-part-1.html
And this is a PC board I've been working on to mount the connectors. I managed to get a mask onto it after many trials and much tribulation using printer transfer methods.
I haven't etched it yet. I finally hit on a transfer method that works for me. That took a week of experimenting. Some here may recall a similar problem I had back when I wanted to make an etched brass plaque for my electronic leadscrew project. I never did get a good enough mask then. I might revisit that now that I have a system that works.
re. pc boards for this cable....I would have liked to have just spliced wires between the old PCM to the new PCM connectors point to point, in order to make up a conversion cable. Unfortunately, the salvaged PCM connectors are right angle PC mount, and that would not work for a cable. So I drew up two short narrow PC boards that bring out the pins. I can then solder wires in the proper direction as a cable. These narrow boards mimic the orientation and spacing of the two back-to-back PC boards that I removed the connectors from. This orientation and spacing will help mate the connectors easily to the vehicle's bundled and wrapped connector harness. That's the hope, anyway.
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