- Jul 22, 2015
- 2,724
So I finally fire up the Sierra with its new 340lph fuel pump & u-joints, so I can get it out of the garage, and another vehicle in. 3 in the stable again, and something needs repair on all three. Can't win... LOL 
1st thing I noted was that the engine still took an extended crank to start -- in fact, it doesn't start on the first crank sequence. It does fire right away on the 2nd. Funny thing, because before this all started, the engine would fire immediately. It even fired immediately when I did the first start with the new cam (I did prime it 3x with the key before cranking it).
Might be a tuning issue, as I recall this starting ('not starting'?
) right after I started changing things in HPT (but I thought at the time that it was the fuel pump check valve failing, not the tune).
I had put most of the fuel I drained back into the tank, along with another 5 gallons. When it started, it immediately turned on the low fuel lamp, along with showing me the DIC message. The gage was pretty much on the 'E', which I thought was a bit strange, given that I'd put 5+ gallons into the tank. But I shut it down, and got the other two Reprisemobiles out of the driveway, so I could take the Sierra for a drink of liquid hydrocarbons.
About 5 min later, I started the Sierra again (this is when I found out for sure that the truck would no longer fire immediately, as it used to). Made a mental note that the fuel pressure regulator (external, on the intake) might be the next thing to look at; the TBSS intake will get a C5 Vette FPR when I put it on, so if nothing else, it'll prompt me to put it on sooner, rather than later.
Now the Sierra's gage showed nearly a quarter of a tank, and the DTE updated to just under 60 miles (from 26 or so when I first started it.) Feeling better, I headed off to the nearest gas station of the ones I frequent, and put about 10gal in (tank is 26gal, so with the 5 already in, I should be at about 1/2 tank. Also noted that my venting / pump shutoff issue had returned (but maybe that's because the tank was so empty... fingers crossed).
Climbed back in, started the truck (after 2 cranks, so I definitely still have the problem there), and... I'm still registering under 1/4 tank on the gage. WTF? By this time, I've got the range / DTE on the display; it's agreeing with the gage. But it's sloooowly climbing. About 10min later, the gage and DIC are reporting about where I think they ought to be. Let it idle a few minutes before shutting down. Immediately restarted, and DTE showed an immediate increase of 5 more miles DTE (which never happens, if the truck is parked level). Within a minute, it had gone back down to where it was when I shut it off a minute prior. Parked on the street, and put the Envoy in the garage.
5 min later, I start the truck again (another 2 cranks), and the gage / DTE were right were they were, so I don't think they're going to creep up any more until I put more fuel in. Fire up the laptop, and google my issue... apparently, I need to look at the sending unit (isn't that part of the pump?), or perhaps the float sticking. The new pump came with a new float assembly, and I didn't have any trouble attaching it, and it moved freely afterward.
I do still have the old float, so I could swap that out, once I put the truck back in the garage... it's in line behind the other two, now.
So... now I'm looking at tracking down a new issue with my fueling system. But it'll have to wait, as the Envoy has the more urgent issue with losing coolant, and I need to do some work on the Accord, as well (but I won't detail those things in this thread, at least).
And, finally, as I suspected... my new u-joints didn't do a thing for the thumping noise in the rear, so I'm back to the beginning on that one, too. When I was under the truck, it seemed (?) like there was more axial play with the driveshaft than there was when I first put that new axle in. Can't remember, exactly. If I'm right, then I'm looking at another pinion bearing (at least the rear isn't howling on coast decel, like the original axle did when I first got the truck). But I'll have to take it in and let an axle specialist take a look. If it *is* the pinion bearing, I'm going to have a long, hard decision to make about whether to keep the Dana 60 in it, or replace it with an AAM "Corporate 14-bolt" (which is what normally comes on the HD trucks). I'd lose the Quadrasteer, if I did that, but I'm pretty sure I'd gain reliability with it, vs. putting more into the Dana. I'd also gain a full-float axle, vs. the semi-float that this Dana has (it has C-clip retainers in the carrier).
I'd also have to replace the driveshaft, the pinion yoke, and the rear wheel hubs, so it would be a fairly expensive proposition to swap axles. The funny thing is, it's usually the electronics that go on these... mine are fine; I just seem to have bad luck with the Dana 60 diffs (which are supposed to be a 'tougher' axle than the AAMs... go figure)
Oh, well... too bad the Sierra isn't green instead of blue... then I could name it "Money Pit" LMAO 💸💸💸
In a way, I'm almost glad to be working on the Envoy... it'll take my mind off the Sierra, at least for a little while. And I'd just bought a "little something" for the Sierra, too. More on this, later (I still have to install it, so we'll be looking at roughly, what -- 2024 or so? LOL
(Hey, mods... where'd the 'Preview' button go, for new posts?)
1st thing I noted was that the engine still took an extended crank to start -- in fact, it doesn't start on the first crank sequence. It does fire right away on the 2nd. Funny thing, because before this all started, the engine would fire immediately. It even fired immediately when I did the first start with the new cam (I did prime it 3x with the key before cranking it).
Might be a tuning issue, as I recall this starting ('not starting'?
) right after I started changing things in HPT (but I thought at the time that it was the fuel pump check valve failing, not the tune).I had put most of the fuel I drained back into the tank, along with another 5 gallons. When it started, it immediately turned on the low fuel lamp, along with showing me the DIC message. The gage was pretty much on the 'E', which I thought was a bit strange, given that I'd put 5+ gallons into the tank. But I shut it down, and got the other two Reprisemobiles out of the driveway, so I could take the Sierra for a drink of liquid hydrocarbons.
About 5 min later, I started the Sierra again (this is when I found out for sure that the truck would no longer fire immediately, as it used to). Made a mental note that the fuel pressure regulator (external, on the intake) might be the next thing to look at; the TBSS intake will get a C5 Vette FPR when I put it on, so if nothing else, it'll prompt me to put it on sooner, rather than later.
Now the Sierra's gage showed nearly a quarter of a tank, and the DTE updated to just under 60 miles (from 26 or so when I first started it.) Feeling better, I headed off to the nearest gas station of the ones I frequent, and put about 10gal in (tank is 26gal, so with the 5 already in, I should be at about 1/2 tank. Also noted that my venting / pump shutoff issue had returned (but maybe that's because the tank was so empty... fingers crossed).
Climbed back in, started the truck (after 2 cranks, so I definitely still have the problem there), and... I'm still registering under 1/4 tank on the gage. WTF? By this time, I've got the range / DTE on the display; it's agreeing with the gage. But it's sloooowly climbing. About 10min later, the gage and DIC are reporting about where I think they ought to be. Let it idle a few minutes before shutting down. Immediately restarted, and DTE showed an immediate increase of 5 more miles DTE (which never happens, if the truck is parked level). Within a minute, it had gone back down to where it was when I shut it off a minute prior. Parked on the street, and put the Envoy in the garage.
5 min later, I start the truck again (another 2 cranks), and the gage / DTE were right were they were, so I don't think they're going to creep up any more until I put more fuel in. Fire up the laptop, and google my issue... apparently, I need to look at the sending unit (isn't that part of the pump?), or perhaps the float sticking. The new pump came with a new float assembly, and I didn't have any trouble attaching it, and it moved freely afterward.
I do still have the old float, so I could swap that out, once I put the truck back in the garage... it's in line behind the other two, now.
So... now I'm looking at tracking down a new issue with my fueling system. But it'll have to wait, as the Envoy has the more urgent issue with losing coolant, and I need to do some work on the Accord, as well (but I won't detail those things in this thread, at least).
And, finally, as I suspected... my new u-joints didn't do a thing for the thumping noise in the rear, so I'm back to the beginning on that one, too. When I was under the truck, it seemed (?) like there was more axial play with the driveshaft than there was when I first put that new axle in. Can't remember, exactly. If I'm right, then I'm looking at another pinion bearing (at least the rear isn't howling on coast decel, like the original axle did when I first got the truck). But I'll have to take it in and let an axle specialist take a look. If it *is* the pinion bearing, I'm going to have a long, hard decision to make about whether to keep the Dana 60 in it, or replace it with an AAM "Corporate 14-bolt" (which is what normally comes on the HD trucks). I'd lose the Quadrasteer, if I did that, but I'm pretty sure I'd gain reliability with it, vs. putting more into the Dana. I'd also gain a full-float axle, vs. the semi-float that this Dana has (it has C-clip retainers in the carrier).
I'd also have to replace the driveshaft, the pinion yoke, and the rear wheel hubs, so it would be a fairly expensive proposition to swap axles. The funny thing is, it's usually the electronics that go on these... mine are fine; I just seem to have bad luck with the Dana 60 diffs (which are supposed to be a 'tougher' axle than the AAMs... go figure)
Oh, well... too bad the Sierra isn't green instead of blue... then I could name it "Money Pit" LMAO 💸💸💸
In a way, I'm almost glad to be working on the Envoy... it'll take my mind off the Sierra, at least for a little while. And I'd just bought a "little something" for the Sierra, too. More on this, later (I still have to install it, so we'll be looking at roughly, what -- 2024 or so? LOL
(Hey, mods... where'd the 'Preview' button go, for new posts?)
