Chevy and GMC Duramax Diesel Forum banner

1 - 20 of 38 Posts

·
Registered
Joined
·
51 Posts
Discussion Starter #1
So I’ve been enjoying my 05 LLY for about a week now. It’s new to me and my first diesel. It has 177k miles on a completely stock motor and man is my wallet smoking right now.

So far I have on order 4” straight pipe exhaust, 3” down pipe, knockoff s&b turbo inlet pipe (s&b wouldn’t ship to me in CA) and a CTS2 tuner.

I plan on getting a lift pump soon down the road, either FASS 150 or the Airdog 165 I think it is, just depends on if I find a deal.

Debating on the fuel pressure relief valve shim/plug but I need to look into that more. Being in CA I think that’s about all I can do and still pass smog checks (with a cat swap in of course).

I’m getting some slight knocking in the steering wheel during turning bumps which after reading sounds like it’s the intermediate steering shaft so I guess I’ll have to address that. And my dash lights sometimes randomly go off at night which I guess is a common problem of the dimmer switch housing. Gauge cluster is all newly rebuilt with Escalade upgrade so it’s not that.

Anything else I’m missing that I should look into?
 

·
Registered
Joined
·
1,136 Posts
Check your wiring harness from your FICM where it goes past the alternator. There's a sharp, metal edge on the alternator that can cut through the wire loom, causing all kinds of funky issues.

Sounds like you've got the LBZ mouthpiece taken care of. Those are 2 of the bigger, up front issues.
 

·
Registered
Joined
·
51 Posts
Discussion Starter #3
Good call. I read about that wire harness issue while researching different models but forgot about it. I’ll go check that out this morning. Is there a reroute option or just tape up the section as padding?

Thoughts on taking the resonator off and putting a plug in?
 

·
Registered
Joined
·
1,136 Posts
Just tape it up if it's been rubbing. I zip tied mine off to the side to prevent it from rubbing anymore.

You can do the resonator plug. It doesn't really have much of an effect. Supposedly, it makes the turbo whistle louder. I did mine when I did a bunch of other mods at the same time, so I didn't really have an A/B comparison. If you do, don't go the cheap, hardware store rubber plug route. It can collapse and get sucked into the turbo... bad news
 

·
Premium Member
Joined
·
3,242 Posts
Nothing wrong with LLYs. Some folks have had issues with LLY head gaskets, do a little research. The 5 speed Allison is a good trans but won't hold up if you start pushing HP, good idea to have a trans fund... I don't think the FPRV will make any performance difference unless yours is bad. Carry a few extra Weatherpack injector connectors unless your harness has been updated for the #2 and #7 issues.
 

·
Former GM Tech and parts
Joined
·
2,515 Posts
So I’ve been enjoying my 05 LLY for about a week now. It’s new to me and my first diesel. It has 177k miles on a completely stock motor and man is my wallet smoking right now.

So far I have on order 4” straight pipe exhaust, 3” down pipe, knockoff s&b turbo inlet pipe (s&b wouldn’t ship to me in CA) and a CTS2 tuner.

I plan on getting a lift pump soon down the road, either FASS 150 or the Airdog 165 I think it is, just depends on if I find a deal.

Debating on the fuel pressure relief valve shim/plug but I need to look into that more. Being in CA I think that’s about all I can do and still pass smog checks (with a cat swap in of course).

I’m getting some slight knocking in the steering wheel during turning bumps which after reading sounds like it’s the intermediate steering shaft so I guess I’ll have to address that. And my dash lights sometimes randomly go off at night which I guess is a common problem of the dimmer switch housing. Gauge cluster is all newly rebuilt with Escalade upgrade so it’s not that.

Anything else I’m missing that I should look into?
Very likely that it is the intermediate steering shaft, but also check the lower column bearing before you order parts for that. It can cause the same kind of clunking noise as the shaft. The last two trucks I've had its been the lower bearing and not the intermediate shaft.
 

·
Registered
Joined
·
51 Posts
Discussion Starter #7
Just tape it up if it's been rubbing. I zip tied mine off to the side to prevent it from rubbing anymore.

You can do the resonator plug. It doesn't really have much of an effect. Supposedly, it makes the turbo whistle louder. I did mine when I did a bunch of other mods at the same time, so I didn't really have an A/B comparison. If you do, don't go the cheap, hardware store rubber plug route. It can collapse and get sucked into the turbo... bad news
My harness was already zip tied tight to the small metal bracket there so it looks good.
I do like a good turbo whistle haha. So I ordered a knock off aluminum push in type plug. I’ll have my friend powder coat it. $8 shipped vs $30 ish with a brand name on top so why not
 

·
Registered
Joined
·
51 Posts
Discussion Starter #8
Nothing wrong with LLYs. Some folks have had issues with LLY head gaskets, do a little research. The 5 speed Allison is a good trans but won't hold up if you start pushing HP, good idea to have a trans fund... I don't think the FPRV will make any performance difference unless yours is bad. Carry a few extra Weatherpack injector connectors unless your harness has been updated for the #2 and #7 issues.
Yea I’ve read a lot on those and my friends who are “experts” warned my to only get the lbz but that would almost double my budget haha.
From what I’ve seen and read if you haven’t had head gasket issues by 100-150k miles you’re more than likely not going to (knock on wood) I’m at 177k
When I looked at the truck I made sure the truck was cold, squeezed the upper radiator hose and it pinched together no problem, wasn’t rock hard. Then checked the coolant tank and no built up pressure there. Took it for a 20 minute test drive came back and let it idle, no bubbles in the coolant tank. I’ve also checked that radiator hose two separate times at home after it sat for a couple days, same deal. So minus that blue liquid test I saw a video on it all checks to being in good shape, again knock on wood haha

How can you tell the FPRV is not functioning properly? Will it throw a code if it’s running low fuel? Does the lift pump help with this too?

I haven’t heard of the injector connector issue. I’ll have to look into that one. Thanks
 

·
Registered
Joined
·
51 Posts
Discussion Starter #9
So I’ve been enjoying my 05 LLY for about a week now. It’s new to me and my first diesel. It has 177k miles on a completely stock motor and man is my wallet smoking right now.

So far I have on order 4” straight pipe exhaust, 3” down pipe, knockoff s&b turbo inlet pipe (s&b wouldn’t ship to me in CA) and a CTS2 tuner.

I plan on getting a lift pump soon down the road, either FASS 150 or the Airdog 165 I think it is, just depends on if I find a deal.

Debating on the fuel pressure relief valve shim/plug but I need to look into that more. Being in CA I think that’s about all I can do and still pass smog checks (with a cat swap in of course).

I’m getting some slight knocking in the steering wheel during turning bumps which after reading sounds like it’s the intermediate steering shaft so I guess I’ll have to address that. And my dash lights sometimes randomly go off at night which I guess is a common problem of the dimmer switch housing. Gauge cluster is all newly rebuilt with Escalade upgrade so it’s not that.

Anything else I’m missing that I should look into?
Very likely that it is the intermediate steering shaft, but also check the lower column bearing before you order parts for that. It can cause the same kind of clunking noise as the shaft. The last two trucks I've had its been the lower bearing and not the intermediate shaft.
How do you actually check either of these? To replace the bearing do you have to remove the shaft? I haven’t priced anything out but I could make sense to replace both at the same time if they’re together
 

·
Former GM Tech and parts
Joined
·
2,515 Posts
Disconnect the intermediate shaft from the bottom of the steering column and give the column a good shake from below. If the bearing is good, it won't have much movement to it. If its pretty solid, its a good chance the intermediate shaft if the source of the noise
 

·
Premium Member
Joined
·
3,242 Posts
......."How can you tell the FPRV is not functioning properly? Will it throw a code if it’s running low fuel? Does the lift pump help with this too?

I haven’t heard of the injector connector issue. I’ll have to look into that one. Thanks"...........

FPRV will usually cause rough or surging idle, I don't think it throws any codes. Most guys just replace it with a "race"plug, shimming seems to be iffy at best. Lift pump won't fix a weak FPRV but a LP is always a good addition due to the extra filtration..and it's easier to prime and spot fuel leaks too!! Yeah, injector 2 and 7 connectors weren't routed/supported well and the wires can break due to vibration. Had it happen one time while towing my 5th wheel, luckily I carry spare connectors. GM used to sell a kit to fix the problem.
 

·
Registered
Joined
·
51 Posts
Discussion Starter #14
Taking a quick break so thought I’d post a few pics I snapped so far. Got the turbo inlet in, that wasn’t too bad but fit was tight. I got the down pipe out and all I can say is FML those tranny dipstick bolts took forever with a 13 wrench. Get ratchet wrenches in metric!!
Just got the 500# exhaust out of there. Time to run the down pipe in loose the fit the new 4” exhaust. I will say there is not much of a difference in size so running straight pipe better be a hell of a change in itself or this exhaust was for no real gain haha
 

Attachments

·
Premium Member
Joined
·
228 Posts
Amen! Have fun....
 

·
Registered
Joined
·
51 Posts
Discussion Starter #17
Got everything mounted up and it sounds good. Turn whistle is nice and loud now. Exhaust has the jet plant sound at idle which I don’t know how I feel yet but it’s throaty when you romp on it. Going to take it to a friends house and tweak the exhaust and weld up the seems. These clamps are cheap trash.

Question now is I have the CTS2 in it and it has five total settings.

Stock
Economy
Towing
Performance
Extreme

Which one should I use for my daily driving? I only tow a few times a year in the summer with out boat. Other than what I put here it’s all stock so extreme is out plus it would probably destroy the trans. Stock and economy are out. So it’s really between tow and performance. Anyone know the differences?
 

·
Registered
Joined
·
9,949 Posts
I would run it on the stock-tow settings. Idk what the power levels are on a cts2 but you want to stay at or under 120hp to the wheels on a stock 6 speed.
 

·
Former GM Tech and parts
Joined
·
2,515 Posts
I would stay 100hp or under on the 5spd trans trucks. Sometimes they will hold 120horse tune if they have been well-cared for and have good fluid and low miles and all that. But a good rule of thumb on the 5spd trans is no more than 100hp over stock. And just remember- if you limp it, it will just get easier to happen each time from there
 
1 - 20 of 38 Posts
Top