Good deal.
Martin
Martin
CK5
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'91 K5 Four Wheel Camper
This is the build for my 1991 V1500 Blazer, AKA the K5.3. It started out life being sold to the U.S. Government with a 350 TBI/700r4/241 combo. 4 years with a 5.3/700r4 Combo and now moving to an 8.1L Vortec and NV4500 5-speed.
Buzzed it to work today. Wow it's been a long time since I drove a square that far. I didn't have a prybar big enough to make an impact on the spot. Knowing what it was, I just turned the tunes up to not hear it. Borrowed a bar from one of the techs and gained about 3/16's of an inch clearance. It was quiet on the ride home tonight.
It's funny having the tallest rig in the employee lot.
Still the ride home without noise was actually odd to me, The 75 had a symphony of noises at highway speeds. Most annoying was the top bracket at the top of the windshield header on the pass side. The threads in the top were not quite up to holding on, so the bolts back out while driving. The top begins to shake at a different frequency of the header it itches on the weatherstrip like a cricket rubbing it's wings. CHIRP CHIRP CHIRP. You could tighten the bolts and they would fall out again in a hundred miles or less. I just threw an extra boxed end wrench in the console to be able to tighten it up. So driving the 91 is like night and day. Windows up the exhaust note is down to a dull muted version of what's going on outside. It's quiet enough to use the bluetooth in the radio to call out and still be heard. Couldn't do that in the 75. I'm driving it tomorrow.
It's funny having the tallest rig in the employee lot.
Still the ride home without noise was actually odd to me, The 75 had a symphony of noises at highway speeds. Most annoying was the top bracket at the top of the windshield header on the pass side. The threads in the top were not quite up to holding on, so the bolts back out while driving. The top begins to shake at a different frequency of the header it itches on the weatherstrip like a cricket rubbing it's wings. CHIRP CHIRP CHIRP. You could tighten the bolts and they would fall out again in a hundred miles or less. I just threw an extra boxed end wrench in the console to be able to tighten it up. So driving the 91 is like night and day. Windows up the exhaust note is down to a dull muted version of what's going on outside. It's quiet enough to use the bluetooth in the radio to call out and still be heard. Couldn't do that in the 75. I'm driving it tomorrow.
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Man, it would be a full time job chasing my squeaks down!
This is where Larry's prep is paying off. He's got a epic hatred of squeaks and rattles. Having a low level base model with no rear interior panels or other items to come loose makes it easy too. The heavy flooring with jute padding helps with the bedlined floor. Having the doors set right with fresh weather stripping keeps the door rattles down.
Third day driving to work. Decided to do a mileage check. Using my speedometer app to track mileage I filled up this morning on the way to work. Drove down and back and went back to the same gas station and topped back off again. 72.8 miles driven, added 6.8 gallons of fuel to the point the gas pump kicked off. Doing the math brings the reading in at 10.70 mpg. Yikes. I knew it was sucking fuel, but this isn't ideal. Tuning is top priority. It does explain the pitch black tailpipes though...
Part of that number is slightly skewed, it's probably closer to 11 mpg but I drove the first 20 miles this morning before I realized I had the shifter in third and not OD. Tunes were up, didn't notice. Really need to get the tach installed but I have a little project to finish on the tach that @mrk5 helped me with. More on that later. This truck eats up road miles well. It just has an equal thirst for fuel! Time to go play with the tuning laptop and see what I can do to lean this beast out!
Part of that number is slightly skewed, it's probably closer to 11 mpg but I drove the first 20 miles this morning before I realized I had the shifter in third and not OD. Tunes were up, didn't notice. Really need to get the tach installed but I have a little project to finish on the tach that @mrk5 helped me with. More on that later. This truck eats up road miles well. It just has an equal thirst for fuel! Time to go play with the tuning laptop and see what I can do to lean this beast out!
Since my search online for mefi4 bin files is coming up empty, I decided to get in gear and figure this out. Going through the tuning laptop I was able to find some other bin files to look over. Little backstory to catch up some. This system (mefi4 controller and harness) was originally installed on Larry's K10 when the 8.1 was first installed. Larry was breaking some ground here as at the time nobody had used that controller with an 8.1 so no bin files existed. It got him running and ran it for a little while, but it lacked refinement. Biggest issue was the fact he is running a manual trans and a drive by cable throttle. The idle would freak out, flare and hunt when the clutch was depressed. Pretty soon he decided to go with a new custom harness and a stock GM pcm to run it and have more capability. Most of you that have followed him know that was the way to go. So when Larry was starting out with the mefi4 system he did a lot of data logging, send it off and the tuner would look at what he had, make changes and send a new bin file back. I must have found close to 20 or more bin files on the laptop. Problem was most of them had been altered to manage the fuel needs for the engine that is almost 3 liters bigger than what I got.
In my digging I did find a basic un-altered LS1 file on the laptop. Went out and uploaded it to the pcm and it fired right up. First thing I noticed is the annoying deadspot in the throttle off idle was gone. It was like driving a carburated engine with a worn out accelerator pump. It would pull through it, but it was obnoxious. Now that is gone. I decided to take it for a run and invited the wife to take a ride in it for the first time. First thing she said as we were pulling out of our neighborhood was that this one is a lot nicer than the old one. She was impressed with the night and day difference from the two. I noticed the driveability down low improved. Put about 20 miles on in and barely saw the fuel gauge move. The only thing I noticed is the idle speed fluctuates a couple of hundred rpm when the trans is in park after the throttle is snapped. It calms down when I put it in gear and then back to park. Should be easier to tune out than trying to alter the fuel curve down so far. It's a good starting point.
In my digging I did find a basic un-altered LS1 file on the laptop. Went out and uploaded it to the pcm and it fired right up. First thing I noticed is the annoying deadspot in the throttle off idle was gone. It was like driving a carburated engine with a worn out accelerator pump. It would pull through it, but it was obnoxious. Now that is gone. I decided to take it for a run and invited the wife to take a ride in it for the first time. First thing she said as we were pulling out of our neighborhood was that this one is a lot nicer than the old one. She was impressed with the night and day difference from the two. I noticed the driveability down low improved. Put about 20 miles on in and barely saw the fuel gauge move. The only thing I noticed is the idle speed fluctuates a couple of hundred rpm when the trans is in park after the throttle is snapped. It calms down when I put it in gear and then back to park. Should be easier to tune out than trying to alter the fuel curve down so far. It's a good starting point.
Sounds like you're off to the races! 
That would explain the fuel mileage!!
like to see what kind of change is made there.
Me too. I've got to go get a cheap inverter so I can keep the vintage laptop running while I drive. This way I can log data. I thought a freebie might work, but the one I put in there is dead. I'll get some data this week. By the laptop, but the proof will be at the pump.
I will say this, even at 10.7 mpg I'm better than where the 350 q-jet was on it's best day. I think 8 mpg was the best I could pull out of it. I know the 5.3 has more left on the table.
I'll be watching this, I'm wondering how good the mileage could get. Everyone says 20mpg
I know people have claimed 20's out of diesels, but not sure a gasser would do it... That being said my wife driving the 05 ram hemi gets about 12-13 in town, so that or better I'd consider a success.
Lies.
I had an 05 Ram and when driving between Dallas and Houston I would regularly get 18+ but when I drove it around town it would drop to the 13 or so you were talking about. High MPG's are only really going to pay back on longer driving at a sustained higher rate of speed rather than anything stop and go but I am sure you realize that. It is what it is though, While I did pick my 85 and LS stuff to convert over and be my daily driver I never expect it to get the mpg's my frontier gets but then again I never expect my frontier to have as much total badassery as my 85 K5 (at least not once I get it up to normal DD duties, lol).
I'm completely realistic this truck is not going to get 20 mpg. Maybe downhill with a tailwind, but most of the time I'm climbing up in elevation. I'd say I would be happy with 15 mpg. That might be a tad optimistic, but if my rpm at 60 is any indication it's optimal for good mileage. It's pulling 1700 rpm in 4th (tcc clutch off right now) at 60 mph. Not bad with 4.10 gears.
Today's fun started with replacing the dead invertor so I can run the laptop on the fly. I know it's not the best, but a 400 watt unit from harbor freight is only 25 bucks so I grabbed one. I got it wired up inside the console and got the laptop fired up.
I decided a cruise was due so I headed west to Beulah from my house with the laptop recording. It was an awesome late summer afternoon to run in. Warm down at home, but clouds were building where I was headed, plus I'm climbing up in elevation on the way. Beautiful country out here.
Totally spoiled this area is 20 minutes from my driveway.
What a difference a few miles and 1500 feet up in elevation does for the environment. It's dry and cooked off the foothills, but up here it's green and lush between the evergreens and hayfields in the Beulah valley. Sorry I got a little pic happy at this point, figured I would share here.
I stopped one recording and started another to gather some lower speed data as I tooled around the Pueblo Mountain park above Beulah.
Yes, dirt on the tires...Keep in mind this is just a picnic type road, no 4wd needed. Just a scenic spot in the trees to get out of the heat for a little while.
Sitting at about 6700ft of altitude here. At this point in the 75 I would have felt a noticeable loss of power from the almost 2000 ft of gain from home. The 5.3 never skipped a beat. It showed no loss by stabbing the throttle when needed.
Poser shot. Had to do it.
Then it started to dump rain. No wonder it is green up here! It was so bad I had to shut down the computer on the passenger seat and roll up the window to keep it from getting rained on. Lightening was starting to hit around and I started to make my way back down again. Out running the storm I thought it was pretty cool to look out and see Pike's Peak in the distance with the storm clouds overshadowing it.
All in all, it was a good drive. Need to put fuel in it as I went 50 miles round trip on this run. I'll run it to work to get a better gauge. The main issue I've noticed with this tune is an idle flare. First I noticed it idling in park if I throttle it, the idle goes from rock steady at 800 to fluctuating up to 1100 and back down again. If I throw it in gear and back into park it calms down again. I did notice it doing the same thing while putting around the mountain park at low speed. Watching data I can see the injector pulse width go from 1.5ish to 0 and back up again right in time with the idle movement. Like it's cutting off the injectors and turning them all back on again. Weird. Not sure what to do to dial it out.
Today's fun started with replacing the dead invertor so I can run the laptop on the fly. I know it's not the best, but a 400 watt unit from harbor freight is only 25 bucks so I grabbed one. I got it wired up inside the console and got the laptop fired up.
I decided a cruise was due so I headed west to Beulah from my house with the laptop recording. It was an awesome late summer afternoon to run in. Warm down at home, but clouds were building where I was headed, plus I'm climbing up in elevation on the way. Beautiful country out here.
Totally spoiled this area is 20 minutes from my driveway.
What a difference a few miles and 1500 feet up in elevation does for the environment. It's dry and cooked off the foothills, but up here it's green and lush between the evergreens and hayfields in the Beulah valley. Sorry I got a little pic happy at this point, figured I would share here.
I stopped one recording and started another to gather some lower speed data as I tooled around the Pueblo Mountain park above Beulah.
Yes, dirt on the tires...Keep in mind this is just a picnic type road, no 4wd needed. Just a scenic spot in the trees to get out of the heat for a little while.
Sitting at about 6700ft of altitude here. At this point in the 75 I would have felt a noticeable loss of power from the almost 2000 ft of gain from home. The 5.3 never skipped a beat. It showed no loss by stabbing the throttle when needed.
Poser shot. Had to do it.
Then it started to dump rain. No wonder it is green up here! It was so bad I had to shut down the computer on the passenger seat and roll up the window to keep it from getting rained on. Lightening was starting to hit around and I started to make my way back down again. Out running the storm I thought it was pretty cool to look out and see Pike's Peak in the distance with the storm clouds overshadowing it.
All in all, it was a good drive. Need to put fuel in it as I went 50 miles round trip on this run. I'll run it to work to get a better gauge. The main issue I've noticed with this tune is an idle flare. First I noticed it idling in park if I throttle it, the idle goes from rock steady at 800 to fluctuating up to 1100 and back down again. If I throw it in gear and back into park it calms down again. I did notice it doing the same thing while putting around the mountain park at low speed. Watching data I can see the injector pulse width go from 1.5ish to 0 and back up again right in time with the idle movement. Like it's cutting off the injectors and turning them all back on again. Weird. Not sure what to do to dial it out.
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Love the road trip pictures. 
Sounds like you're getting closer on the tuning end of things.
Sounds like you're getting closer on the tuning end of things.
Sounds like a good drive! With the pulsewidth shutting off, almost sounds like the throttle position may be 0'ing out. Many of the pcm's will shutoff the injectors when 0 throttle while moving...
