What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

2004 Silverado Crew Cab Solid Axle Swap (LLY with ZF 6 speed)

Overview Gallery Discussion
I actually had someone wait by my truck at Lowe's the other day because he wanted to talk to me about it. He had just ordered the kit from WFO to do his own truck.

It's crazy because of all the rigs I've owned, this one is the most incognito, everyone just thinks it's another brodozer. The S-10 gets way more attention because it's so crazy looking, even though the Silverado is a way more bad-ass build IMO.
 
Today we replaced the bent tie rod. I actually found a place that makes a heavy duty replacement (PMF suspension), it's 1.75" .250" wall DOM. To give it a bit more strength I got a 1.25" aluminum rod and sanded it down a bit until we could slide it inside the tie rod.

I didn't notice it at the time, but it's obvious that I bent the tie rod pretty bad, but the ram mount hit the diff cover and straightened it back out quite a bit.

IMG_20210227_144117568.jpg


Here's the new one all finished up, I went ahead and tacked the jam nuts in place so the ram wouldn't break the tie rod loose.

IMG_20210227_182404740.jpg
 
There is another issue I've run into and I'm wondering if any of you guys have any ideas. While I was on my way to Sunflower Mine, there are a few decent hill climbs. I wasn't really paying attention to my gages because I didn't have a trailer and it's winter, typically I'm only limited by water temps on these hills when pulling a trailer and never really have to worry about EGTs.

I just happened to glance over at my Edge CTS monitor to check the water temps and saw my EGTs well over 1600F, I had just been cruising up the hill with the cruise control on so I tapped the brakes and let the EGTs come down. Obviously I didn't melt a piston, I didn't hear anything wrong or feel any drop in power, everything seemed completely normal.

I dropped my tuner down to 1 (+25 hp, it was on 2 which is +50) and I watched the monitor like a hawk after that letting off the throttle , and I've taken the truck out one more time (pulling a trailer with the S-10 on it) and the EGTs just climb like crazy, I was seeing 1400 at 15lbs of boost and 1/4 throttle. I can easily spike the temps well over 1400F, I have my tuner on the lowest level (+25hp in theory).

I did some research and found that apparently the Edge probes are crap, so I ordered a replacement US made one with the right pigtail (https://www.amazon.com/gp/product/B07BHYH3PW/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1) and installed that today. I took it for a quick test drive and I can shoot EGTs past 1400 in 3rd (ZF 6 speed with a granny, so it's more like 2nd in a normal car). Any amount of throttle pushes the EGTs past 1000F.

The truck really isn't dumping black smoke, in fact as the RPMs come up and the EGTs climb the exhaust clears up.

If it was a bad injector I feel like I would have melted a piston already, if it was accurate, I also feel like I would have melted a piston or 8 when they hit 1600F sustained. I have a stand alone Autometer gauge that will be here on Monday, but I wanted to see if any of you guys had an idea.

This whole thing did inspire me to finally do all the other engine upgrades I wanted to do, so I'll be posting that here soon. I've got a Mishimoto radiator and intercooler on the way as well as ARP studs, new head gaskets, new intercooler piping, down pipe (thanks Jack!) and I plan on getting my injectors rebuilt and the turbo rebuilt with the wicked wheel while I'm at it.

Let me know what you think. I'm really hoping I didn't trash my engine. It still drives fine, isn't dumping smoke or fuel out the exhaust, power delivery seems normal, sounds normal, but the EGTs are scaring me.
 
I’ve had my egts sitting on the 2000* peg long enough to raise the water temps to near 230* and not melted a piston. How are the boost levels? Seem to climb normal and have the same max? Egt’s getting that hot that quick sounds like a boost leak to me.
 
I haven't pushed the boost to see if it goes up to the same max because I let off way before that. I'll look closer tomorrow, but when I had a bad boost leak before, it was rolling coal like a mofo, exhaust goes clean as the RPMs and EGTs rise, but I've been hyper focused on EGTs and not paying that much attention to boost.
 
That’s a good indicator but a little boost leak can cause EGT issues. A leaking injector could to but I thought the LLY’s had fixed that issue. Retarded timing is another thing but you should have thrown a code. Yank the edge off and see what it does. Intercooler not blocked?
 
I just did a quick check on all my intercooler couplers and they look fine, I'll pull everything out tomorrow and inspect it more thoroughly.

If I pull the edge off, then I don't have an EGT gauge (until Monday) so that wouldn't really tell me anything.
 
No, just the 25hp setting. Because I have a manual and the 25hp is based on the Allison it's more like 50-75hp over stock manual.
 
Last edited:
Everyone that has responded seems to think boost leak, so today I went ahead and pulled both intercooler pipes and checked them and the boots/couplers. I couldn't find anything wrong there, but I went ahead and installed the hot side pipe I had bought.

IMG_20210228_103210732.jpg


A friend of mine has a boost leak tester, so we're going to go borrow that and see if we find anything. I did notice while I was wrestling with the couplers that the bottom of the radiator/intercooler stack can move front to back by about 1/2 inch so it is possible that I've worn a hole in the intercooler. I have replacements for both of those ordered already so if that's the problem I'll be able to fix it soon.
 
We put it all back together and tested with the boost leak checker. I couldn't hear anything leaking by the intercooler, it seemed like all the pressure was going through the engine or leaking out around the turbo intake elbow (just a v-band clamp). We got it a bit over 15psi, so we should have been able to hear that leaking.

Test drive after putting it back together and cleaning the air filter shows the same behaviour. 2nd (3rd if you count granny) gear 3/4 throttle, boost climbs like normal, it gest to about 20psi before I let off due to EGT hitting 1400+. Exhaust is clear at idle, smoky as boost is coming up, then clears up around 15psi of boost and is clear until I let off.

Next test will be with the Autometer EGT gage, that should arrive today.
 
Also, someone else mentioned that maybe the VVT vanes are stuck, I could see that causing this if they're stuck in a closed position. That was brought up late last night so I'll have to look at it after work today.
 
If the turbo vanes were stuck it would either have low power on the bottom end or on the top end depending on how they were stuck. If it's not smoking like a mofo at that egt I'd guess your sensor or gauge is reading off.
 
I'm guessing the vanes are stuck closed causing the turbo to spool quickly (like normal) but then causing a massive exhaust restriction and high EGTs. I have engine braking programmed in on settings 1 and 2 so it shuts the vanes down on downhill sections. When this issue first started I was going through the mountains, so it would have been moving from full closed on descents to full open on climbs.

I don't know if it's down on power at the top end because I'm letting off due to EGTs.

I've already replaced the EGT probe and I have an Autometer getting delivered today so I'll be testing that out later. I just need to figure out how to check to see if the vanes are stuck. I have a readout on my monitor for it, but I don't know if that's actual vane position or just what the computer is telling it to do.
 
I don't know on a duramax but on a 6.0L powerstroke when the vanes are stuck if you get on it and then let off real quick it makes like a chuffing noise out the intake due to the vanes basically choking off the exhaust flow.
 
I've got the new EGT gauge in hand now so I'll install that and do a test drive after work and actually watch the VVT position on my monitor.

I'm not familiar with the noise you're describing, but the 6.0 and the DMAX use the same turbo basically. I'll see if it sounds weird to me this afternoon as well. It's always made a "woooooooooooooo" sound on shifts (manual) especially since I got it tuned.
 
If you did have an issue with the vane positioning system it should have set codes to that extent. P0045, P0046 or P2563 are the main ones. A P0299 would be a possibility to set for an underboost situation as well. Even a '04 would be fairly sensitive to setting any one of those codes if it was having issues.

We've seen our share of stuck vanes from carbon build up or a stuck solenoid control valve. Normally they set the assorted codes still.
 
Interesting, I'm really just grasping at straws because I have no idea why I'm getting high EGTs. I'll know today whether the EGTs are real or not and whether the VVT vanes are moving.
 
r3dd0g said:
Interesting, I'm really just grasping at straws because I have no idea why I'm getting high EGTs. I'll know today whether the EGTs are real or not and whether the VVT vanes are moving.
Click to expand...
GM's diagnostics don't look at egt's at all so I'm not much help there.
 
You must log in or register to reply here.

Latest Posts

Top Bottom