dustydogg
04-06-2020, 16:57
Long time 6.5 owner here. I just picked up the fourth one I've owned about a month ago. After a bad experience with my third I swore away the 6.5 and went on to newer 6.0 gassers and they never let me down. but I had an itch that just had to be scratched. So I ended up picking up a 97 K3500 dump with 80k on it that easily ran better than my other three. I was on cloud 9. I trailered it home and started driving it 2 days later and noticed a very slight hesitation pretty much only at cruising highway speeds (when feathering the throttle) it was barely noticeable but annoying. I went and got a new fuel filter which was already my plan. I replaced along with changed the oil to synthetic and checked the air filter (looked new). When bleeding the fuel from the FFM it sprayed right up and hit the bottom of the hood. Didn't change a thing with the stumble. The PMD was relocated by the previous own and looked pretty recent. He had it loose in front of the driver side battery, heat sink in a box in the cab. So I relocated it to the front bumper on the heat sink. No change. Checked fuel lines, didn't see any leaks (has 2 tanks and 2 lift pumps, nothing looked bad). Tried the test of opening bleeder on fuel filter with it running and didn't skip a beet. So now I'm thinking maybe the cat is clogged up so I hacked it off right before it and put an intake on her so she could breathe a bit better. Here's where it gets weird. It pronounced the hesitation. I was now noticing it at lower speeds through acceleration but if I put the throttle down and built up some boost it would take right off without a hitch. I noticed it seemed only to happen between 15-2500 rpms on acceleration and still at cruising speeds. When this happens the tach doesn't jump around at all like it feels. I checked the gm8 and shes tight, so as a quick solution I ran to the store and got a boost guage, a spring, washers, and all thread and made a turbo master. I turned her up to 10 pounds and boy did she love it. Except didn't change the stumble, just hid it a bit on acceleration because it got into higher psi faster so less time stumbling, cruising speeds were the same if not worse though. So my plan the entire time has been to build this one the way I always wanted but couldn't afford in my early 20's. So I've got a bunch of stuff being shipped as I'm typing but this hesitation has got me erked. List of items I have coming, hx35, intercooler, 3" intake plenum, 3" downpipe along with crossover, 4" pipe and muffler, egt guage, no 9 resistor (not part of the plan but the pmd has no resistor) delco balancer, pulley, and seal, a few delco fuel and oil filters, delco glow plugs and that's it so far. I was going to get a new pair of ep158's but the lift pumps seem strong, initially planned on injectors because its about a year from 100k and I'd already be working next to them a lot but it doesn't smoke a bit and when she run boy I tell you she runs. So I figured I'd wait on those. I was going to purchase SS's tune (along with a lot more) but called and emailed before my order just to present my problem for some insight and got no response (2 weeks ago) so now I may be going with heaths tune but I don't really want to buy anything more before I figure this out because I've played that game with a 6.5 before, running out of money trying to chase a problem. I've had pmd's go and injector pumps and neither were like this. Also I have checked grounds, replaced both batteries with a new matching pair on day one as well as made an oil catch can for the cdr.
2006 2500HD 6.0, 125k reg cab long box, 4.10's, g80, 4x4 on floor (only reliable truck I have)
1997 K3500 dump, 6.5, 80k, DRW, 4x4 reg cab, with lots of goodies on the way
1998 C3500, vortec 350, 105k, DRW, flatbed dump, reg cab
2000 K3500 (sold for pennies) , 6.5, 100k, 4x4, crew cab long box, srw, junk moneypit
2000 GMC K3500 (gave to brother), 6.5 then vortec 350, 95k, 4x4, reg cab, srw, flatbed fred
1997 K2500 (drove wrecked to junk yard) 6.5, 4x4, 277k, srw, reg cab long box, dp, 5" back, intake, turbomaster at 15 psi, tuned, wrecked. (the one that started this dumb addiction)
2006 GTO 6 speed, (hit 2 too many deer)
2006 2500HD 6.0, 125k reg cab long box, 4.10's, g80, 4x4 on floor (only reliable truck I have)
1997 K3500 dump, 6.5, 80k, DRW, 4x4 reg cab, with lots of goodies on the way
1998 C3500, vortec 350, 105k, DRW, flatbed dump, reg cab
2000 K3500 (sold for pennies) , 6.5, 100k, 4x4, crew cab long box, srw, junk moneypit
2000 GMC K3500 (gave to brother), 6.5 then vortec 350, 95k, 4x4, reg cab, srw, flatbed fred
1997 K2500 (drove wrecked to junk yard) 6.5, 4x4, 277k, srw, reg cab long box, dp, 5" back, intake, turbomaster at 15 psi, tuned, wrecked. (the one that started this dumb addiction)
2006 GTO 6 speed, (hit 2 too many deer)