OutlawDrifter
Long Roof K2500 Driver
And it never will, that's one of the few downsides to the swap. Plenty of positives however!
My '89 Cheyenne DD LS swap
- Thread starter Leeztruk
- Start date
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And it never will, that's one of the few downsides to the swap. Plenty of positives however!
Road test: Not your father's SBC!! The little fella has nice manners but will accelerate nicely when asked. The trans shifts well. Not bad for a pair that's sat for the better part of 12 or more years. Without trying to count the chickens before they hatch, this is gonna be a pleasure to drive. On an aside, I may take the cluster back out and replace it with a unit without the tach. This one's not working. I've boosted the signal with a 12v source and pull up resistor, but no movement. Just a minor inconvenience
OutlawDrifter
Long Roof K2500 Driver
May require some more tuning to the ECU to make the tach work properly.
Yeah, I'm thinking that too. Gonna put a few miles on the truck, and maybe see someone with a dyno to fine-tune the PCM, and at that time have them take a looksee at what's happening with the tach signal. While just a nicety, it'd be nice to see my cruising rpms. I know the 4.8L will definitely spin higher than what this tach will read, but then again, this is just a driver (wink wink, nudge nudge). Even 76 yr. olds can get stupid with the gas pedal occasionally.
Well, played with the tach today. After much searching on the interweb, ("You need a 10k/5k/4.7k/1k ohm resistor, yada-yada-yada), I decided to put a variable resistor in the circuit to see what, if any, resistance is actually needed. Started the truck, and with the pot set to 0 ohms, slowly increased the resistance until the tach turned on. Turns out 5k ohms and above, turns the tach on. So now, my 'Burb gauge cluster is a full, working unit! As a side note, this little 4.8L has put a great big smile on my face. What a pleasure to drive. Even with a stock convertor and 3:08 gears, it has more than enough power for all that I need
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Took the truck for its' first highway run. NICE acceleration!! BUT... MIL turned on. Got it home, pulled out the Solus and scanned for codes. Had two, P0327, P0332. Both are knock sensor codes. But they're new, as well as their harness. So, unplugged the harness to read resistance. Both ohm'd out at 99.7K ohms (should be 93k to 107K). Reconnected the harness, and went to the PCM. Same reading there. Guess a diet of 87 Octane is not what the engine wants. Gonna try a bottle of Octane Booster in this tank (almost full) and see what happens. After that, it's gonna be 91.
If/when I can get to a dyno, I'll have them check the timing. When I had the PCM initially set up, I told them I'd like the PCM set for 87 Octane. However, being that they are associated with Texas Speed and Performance, and that was my cam of choice, they may have programmed the PCM to what they like to see. Who knows? Anyways, I'm VERY happy with this swap
If/when I can get to a dyno, I'll have them check the timing. When I had the PCM initially set up, I told them I'd like the PCM set for 87 Octane. However, being that they are associated with Texas Speed and Performance, and that was my cam of choice, they may have programmed the PCM to what they like to see. Who knows? Anyways, I'm VERY happy with this swap
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Gonna explain some fixes before I put this posting to bed. When I put in the new cam, I also changed the oil pump. Here is where I made 3 vital mistakes. 1; I put the correct o-ring into the oil pump cavity before installing the pick-up tube. When trying to put the tube into the pump, it wouldn't fit. So, I used the smaller o-ring. The tube fit, and I secured the tube to the engine. 2: I didn't pay attention to the tube, in that it has a retention groove for the o-ring. 3; I discounted the low oil pressure reading on the gauge as just a faulty instrument.
Early in this posting I had mentioned that I had 2 DTC codes relating to the knock sensors. Thinking it was an octane rating too low for the PCM timing, I added a bottle of octane booster to see if that was the cause of the DTC'S. Road tested to duplicate the problem. When I got off the highway, there was a very discernable tapping. A lifter had collapsed or failed all together, and the MIL re-illuminated. Hmmm...
Lifted the engine off its' mounts, pulled the oilpan, undid the 2 8mm nuts that hold the pick-up tube to the windage tray, undid the 6mm screw that secures the tube to the pump, and the tube literally fell out of the pump. So did the o-ring I put in the pump cavity. All along, the pump was sucking air, the gauge was correct with the low pressure reading, and the knock sensors were just doing their job telling me that, indeed, there was noise they were hearing (lifters pumping down). At this point, I noticed the o-ring groove in the tube, put on the correct o-ring in the groove, then fit the tube back into the pump with a little effort, put the pan back on, reattached the engine to its' mounts, and fired it up. WOW! Instant oil pressure ( almost 60psi). Took the truck back to where the codes would set, only this time NO DTC'S, and the engine seems so much stronger!
I guess we're never too old to realize our mistakes, and make the needed fixes. Live and learn. Anyways, that's my story and I'm sticking with it! I'm glad I made the change. The truck is so much more pleasurable to drive
Early in this posting I had mentioned that I had 2 DTC codes relating to the knock sensors. Thinking it was an octane rating too low for the PCM timing, I added a bottle of octane booster to see if that was the cause of the DTC'S. Road tested to duplicate the problem. When I got off the highway, there was a very discernable tapping. A lifter had collapsed or failed all together, and the MIL re-illuminated. Hmmm...
Lifted the engine off its' mounts, pulled the oilpan, undid the 2 8mm nuts that hold the pick-up tube to the windage tray, undid the 6mm screw that secures the tube to the pump, and the tube literally fell out of the pump. So did the o-ring I put in the pump cavity. All along, the pump was sucking air, the gauge was correct with the low pressure reading, and the knock sensors were just doing their job telling me that, indeed, there was noise they were hearing (lifters pumping down). At this point, I noticed the o-ring groove in the tube, put on the correct o-ring in the groove, then fit the tube back into the pump with a little effort, put the pan back on, reattached the engine to its' mounts, and fired it up. WOW! Instant oil pressure ( almost 60psi). Took the truck back to where the codes would set, only this time NO DTC'S, and the engine seems so much stronger!
I guess we're never too old to realize our mistakes, and make the needed fixes. Live and learn. Anyways, that's my story and I'm sticking with it! I'm glad I made the change. The truck is so much more pleasurable to drive
Very common with high mileage or when you mess with it for any reason.
Drunkcanuk
I'm Awesome
Ya....the old "don't broke what don't need fixing"
Good catch, and hopefully no lasting damage.
Good on ya for letting us know about your "learning opportunity"
Good catch, and hopefully no lasting damage.
Good on ya for letting us know about your "learning opportunity"
Another "learning" update. Having thought that the knock sensor issue was taken care of, it wasn't! Taking the advice of many that have had a similar concern, I decided to just replace them with real GM sensors. I had used a Dorman sensor kit when I put the engine together ( sensors and harness). So, upon pulling off the plenum, I attempted to remove said sensors. When trying to unscrew them from the block, the top hex portion just spun inside of the sensor body. Tried to tap the bodies out with a small chisel and hammer, but because they sit so deeply in the valley cover, I couldn't get a good bite. Ended up just breaking the bodies off of the threaded studs, which created another problem, as the studs left nothing to grab onto. Ended up having to drill the stud centers and use an easy-out to remove the studs. With that completed, I purchase some real GM sensors and harness. Put it all back together, and after several hundred miles of varied driving, all is well!! The little 4.8L has proven to be a very nice motor, exceeding all of my expectations. Definitely has more everything than the 305 it replaces. While not a "fire breather" like a 5.3 or 6.0, it takes care of all of my simple needs. Even sounds good too. I'm really enjoying driving my truck
