SLEDGE

Hello everyone, I bought a 99 qclb 5 speed dually from a friend a few months ago.... It now has 210k on it and everything on it was replaced within the last 15k miles (lift pump, injection pump ect). The problem I'm having is the truck runs awesome when empty. But when hooked to my toyhauler (12,800lb empty) I have a miss under load from 1500-2300 rpm. It's enough to make the truck buck... It's most noticable when in 5th slightly accelerating. I can grab 4th at full throttle and I don't notice it. Fuel pressure never drops below 8 psi @ wot and acts the same with the comp on or off. The injectors are still stock so I was just wondering if it could be an injector problem or pump. I really dont want to buy another VP... Oh and no codes are thrown either. Thanks in advance for any input

lovinCTD59

First off completely disconnect the edge, and try running without. My truck acted up BAD when my edge went south. I didnt have enough power to pull 3rd gear abover 1400 rpms.

SLEDGE

I will try that tomorrow, didnt even think to remove it completely, figured turning it off would bypass it.... Thanks for the input I will post up either way tomorrow.

RVTraveling

I wish someone could solve this issue. My 99 does EXACTLY the same thing. I have changed the VP,injectors, crank sensor, and removed the 50HP chip...STILL does it. I'm about to give up on it.

SLEDGE

Pulled the edge as suggested with no change... I am also wondering if it could be the APPS. Mine went out right after I bought the truck... Started acting up about a month later. Maybe I got a bad one?

Mike Holmen

Might be the injectors. Have you put in new injectors recently? I had a few sets of poor grade injectors that caused hot irregular idling issues. I would also check to see if you are having the head adjuster nuts tight at the head. The head cross tubes orings are a know issue. Earlier VP trucks might need to have them upgraded, to the newer style cross tubes. Good luck.

SLEDGE

Thanks for the input, I was kinda hoping for an excuse to get new injectors. I reset and recalibrated the apps and I dont think that was the problem but when I got back I was lucky enough to find a blown head gasket. So, Im gonna throw in some studs while I'm at it... Thanks for the help guys I will post up after the truck is back on the road.... Happy Thanksgiving too

Mike Holmen

Post some pictures of the blown head gasket once you get it out. I've done a few over the years.

You going to performance injectors or buy stockers? SDX offers decent performance value. I've pretty much run everyone's injectors. F1's are about the best, then come Weston's 7 holer stickers. I have a few sets going into a few 12V builds I have on the go.

SLEDGE

Will do, I hope to get some time to pull the head this weekend. As for injectors, I was looking at the Dragonflys but looks like injectors will have to wait a bit. Tis the season to spend money on presents for everyone else. Maybe I'll get some this spring.

SLEDGE

well, I pulled the head today and gotta say it went a lot smoother then I thought it would. The gasket was leaking at the normal front and rear corners and luckily that was it. I did have a hell of a time with one of the injector tubes though. It was corroded and frozen in the head. So, I'm gonna get the head surfaced and checked for cracks, get new tubes, studs and have the injectors tested. And while I'm at it, my timing cover is leaking and I may just do that too since Im halfway there anyway and since the cam has to come out, I might as well throw a Hamilton in there. My long term plan for the truck is a dedicated tow rig with planned upgrades such as bigger turbo (62/65 or 62/71 not sure which yet), dragon flys, cam and studs so I figure I'll get these outta the way so when I can afford the turbo I will be set. I want to do injectors now but not sure if I can swing it financially... Being winter AND holiday season and all... Sorry about the long post fellas.

Hey Mike H, I tried to post some pics but it said invalid file. I'll have to dig out the camera tomorrow and try that instead of my phone.

Mike Holmen

How much bigger sticks you going with? I would figure out a way to bump up your fuel pressure to mid teens. 8 psi is getting pretty low.

My choice would be to run twins. That stock turbo over a S475 (cheap around $600 new). A hybrid 35/40 turbo works well and they are cheap.

I'm building a tweaked 6.7L engine for my 02, this spring. At some point I'm going to put some big twins on it. I use this truck for work, so it should be interesting. Hoping to run around 1000rwhp on fuel.

SLEDGE

I have heard good things about the Dragonflys by II, 100Hp rating so that should be about perfect for me.

Twins? Oh crap my wife would love that.....lol. I really considered them at one point but decided just stay with a good single. If I had the money to buy the right setup I'd be all over it but I just dont have the time or knowledge to build my own and tune it properly..

And a 1000hp work truck??? Good lord man!! Cant wait to see that. It's going to be awesome.

Mike Holmen

Been a slow process of collecting parts for the fresh engine. It shouldn't be to hard to reach those kinda of numbers these days. Funny thing been building a ton of 4.5 to 07 CR engine these days. Almost no time to work on the old truck. I'm running a set of 110's ddp's in my truck with no programmer or fueling box. The truck actually runs pretty decently for almost stock. The truck has been over 500rwhp for most of its life, must have run a dozen or so twins set-ups on the truck.

SLEDGE

Good deal, keep us posted on the progress... The machine shop called me today, looks like the valve seats are cracked. He's gonna pull the valves to see how bad they are and shoot me a price. Sould I even bother having them fixed or just find another head?

Mike Holmen

Very common 24VP issue, good luck find another head without cracks. Lots of choices, to bad nothing cheap. I would buy new. Down the road spray water/methanol, it seems to slow down the cracking process. Probably search the internet and a cheap skate fresh head.

Another option is to find a 12V engine and just sell the 24VP engine. Tons of 24VP run around with cracked heads.

For my 6.7L project, I'm running the hamilton head and going with larger valves. Intake plenum is going to be removed. I also plan on running R&R rods, and a mains gridle. I just got my 13mm p7100 done up. Schieds sells a CR P7100 gearbox housing. It should look like any other 12V once I'm done, nothing special. Might even throw a old banged up 215HP 12V valve cover shield on the engine, just for laughs.