Engine/Transmission (1994 - 1998) dissapointing results

[DuallyDean]

I guess it's my turn to inquire of the great Oracle of knowlege known as the TDR membership why my recent BOMBing mods haven't panned out as I expected.

I'm dealing with my '94 Dually with 4:10 gears, 5 speed, #4 cam plate in the 160hp pump, 215 hp Bosch injectors and a 16cm turbo housing. The Cat is gutted, muffler went AWOL and the air filter was upgraded to an AFE Mega Cannon. For much of 180K miles, the truck was stock with the exception of the air filter, exhaust and a #6 cam plate. In that form, it dynoed 249Hp/615lbs-ft. Over the winter storage season I added the 215's, 16cm housing and #4 cam plate. On the test drive my boost level would peak at only about 19-20 psi, and EGT never broke 1000 degrees. Before that, 35psi and (when towing) 1300 degrees plus were possible. Smoke is about the same as before, but turbo lag is up a bit (expected with the larger housing). It certainly does not feel like it has any more power than before, possibly less. I have not had the opportunity to dyno the truck in this form yet.



Any suggestions on what to check for? A compression check was done while swapping injectors, cylinders 1-5 were at 450-460 psi, #6 was only 420. Valve lash was also checked while doing the mods. I am still running stock timing. I have not towed yet this year, possibly this weekend will be the first opportunity. I would have expected that standing on the throttle in 4th gear from about 30mph would have given the engine a big enough load to drive boost and EGT levels above 20lbs / 1000 degrees. Sorry about the length of the post, but I'm stumped. Any insight would be much appreciated!

 

[Lsfarm]

Plate location?

Hello Dean, did you install the #4 plate all the way forward? and slide the AFC housing all the way forward as well? Did you make sure you hooked up the boost line to the AFC housing again?? Not doing any of the above will result in less fuel than before.



Timing makes a big difference too, get it bumped up to 16. 5* and make sure the other items above are right, you should make more power than before.



The 160 pump really likes the 3 GSK governors spring kit. It may be what you are lacking to get the most out of your setup.



Have you taken care of the KDP?? if not forget the bombs untill the Pin is safe. !!



Hope this helps, Greg l The Noise Nazi.

 

[ChillyDog]

I would also check to make sure the governor lever is hitting the plate where it should. There are instructions on Piers website on how to check this. I would also highly recommend getting the timing checked/bumped up.





Bill

 

[DuallyDean]

Greg & Bill--

The boost to AFC line is hooked up, but no, I didn't slide the plate or AFC all the way forward. The plate was installed in the same spot the #6 ran, and the AFC remains about in stock position. I figured mounting positions being equal, the #4 plate should fuel more than the #6. The injectors should have increased fuel flow also. I will open it back up and push the plate full forward once I tow this weekend and verify that EGT's aren't a factor. They were getting that way with the #6 (albiet with a 12cm housing), which is why I held it back on the initial install. When repositioning the plate, I will double check the governor lever. As for the AFC, I will sacrifice some off-idle "snap" if I can tame down the smoke output. Washing the trailer constantly is a drag...

I was advised that the 3000K gov spring kit can be a real bear to get right with the #4 plate, which is why I haven't done that yet, and was told to try it without one first.

The plan called for pump timing to be bumped to 16. 5 degrees, but not all the tools to do it have been aquired yet. It is, however, on the "to do" list. I was under the impression that pump timing advance was primarily to help control EGT's--am I mistaken?

 

[Deezul1]

For sure check the lever adjustment. When my 4K GSK went in the truck was way less powerful than stock right after the install. After the lever adjustment (Thanks to Cord + Jim) it went right on the dyno and did 405hp.

 

[Jeff H]

Were having a truck meet in Elk River MN on may 8th.

See events forum. Josh Peters posted it.

Theres a few around that can probably get ya hot roddin again.

 

[Lsfarm]

3GSK

I've yet to have a problem with a 3GSK install with any plate. The difference in with a 3GSK is huge, I wouldn't own a 12v without it.



The GSK keeps the fueling going for more than an additional 400 rpm, this is significant. The stock springs start defueling around 22-2400 depending on your pump. This is where your engine will want to get going and make some power with the 16 housing, and then it gets it's fuel cut off!



The timing makes a lot of power, if the fuel is injected earlier, then it has a lot more time to burn in the cylinder and the cylinder and piston convert that heat and expanding air/fuel into energy. If the fuel comes in late, then it can't convert the heat into energy, instead the heat and still expanding gasses go out the exhaust hotter than if fully burnt. So timing helps to reduce EGT's and increase power. If advanced a lot, the timing will start to decrease the low end power some, but it adds a lot to upper rpm power.



Hope this makes sense. Greg L

 

[Howard Durand]

I'll add my praise for the 3KGSK. It seemed to make a dramatic change in performance in my truck.

Possibly it just made it possible for the previous upgrades to reach their potential.



You may have a boost leak somewhere in the intake air system.

Check the torque on the intake manifold cover bolts and all of the hose clamps.

 

[DuallyDean]

I get the feeling I'd better get my butt in gear and get the GSK...



Jeff--I'll try to get up to Elk River on the 8th, but time is a precious commodity for the next month or so. I would like to check out fellow BOMBer's rides.



I just called and put insurance back on the truck, I have some skid-loader work to do for a friend tomorrow, so I should have a better feel for what it's doing under load by tommorow night. I'm gonna check the governor arm and slide the cam plate and AFC all the way forward right now (and try to figure out why #6 high pressure line is leaking at the injector). So much for making it an early night...

 

[Bhale]

My 3K GSK went right the first time with my #4 plate. Just take your time, follow the directions and you'll be OK.



BTW, 6" dial calipers are a real help with the 3K install.



Brian

 

[JoshPeters]

With boost that low... . did you install the boost elbow that came with the 6 and/or 4 plate? With a 6plate, Boost elbow that came with the kit, 215's and a 180 pump I made 304hp.



Josh

 

[DuallyDean]

I'm pretty confident that I don't have any loose clamps, boots or the like in the intake system. I've been over the works 3 times. now, if there is some fluke like a cracked intercooler, I'm not sure how I could check that without total disassembly and a pressure test. I'm not jumping to that conclusion yet.



There is no boost elbow anymore, because I just swapped to the 16cm housing as I said at the begining of the post. I do recall that boost seemed a bit low last fall before I put it away for the winter, but I was half suspecting the wastgate on the still stock 12cm wastegated housing. I knew I was going to the bigger turbo housing, so I didn't give it much more thought.



I just slid the #4 plate fully forward and checked the governor lever for contact (it contacts just at the top of the "nose" on the plate, just where it should). I then slid the AFC housing all the way forward and buttoned everything up.



The thing that keeps getting me is that my EGT's aren't going thru the roof. If it is getting the fuel it is supposed to, and boost is low, shouldn't I have very high EGT's and sustained smoke under load? Since the EGT's still don't go above 1100 (100 more than before moving the plate full forward) and boost still doesn't break 20 psi, I suspect it just isn't getting the fuel it is supposed to. The fuel filter has less than 4000 miles on it, and I haven't done anything to the tank or supply lines to stir up any crud, but I guess that is the next thing on my list.



After a second attempt at tightening it, I still have some wetness around the #6 injector that I think is coming from the high pressure supply line. I don't know why I can't get a complete seal. The next step is complete removal of that line and inspection. I doubt this "seepage" is causing the magnitude of my problems, nevertheless, it is making a mess of the passenger side of the block.



I checked AFC operation by ramping up from 0 - 30 psi of compressed air and everything seemed to move freely. I am curious if it could be blocking fuel delivery though. Anybody know of a quick way to bypass it to test the theory? I'm also considering a quick spin without the cam plate in at all, just to evaluate the difference. I don't want to run without the plate permanently, however. I even want to verify the accuracy of the boost gage, just to rule out THAT possibility. It's all going to take time, and right now it's tough to come across any, so it might take a couple of days to run through all this stuff.



I'm still looking for ideas, so continue to feel free to share your thoughts!



Josh-- you are at the HP window I was shooting for, I hope I can get up to the get together on May 8th.



Brian--when the time comes, I don't think it will be hard to come up with the calipers (I'm a machinist), but will it be o. k. if mine is digital? ;-) Thanks for the heads up though, cause I usually don't bring it home from work.



BTW--anybody know the spec for compression on a Cummins? Stupid Haynes manual goes into great detail about how to test it, but doesn't give the specification for it (at least I couldn't find it).

 

[Deezul1]

I just remembered a power loss problem I had on my 96 and it was a faulty overflow valve. If yours can be taken apart (some of the early ones couldnt) stretch the spring to measure . 550 and see if the power comes back.

 

[DuallyDean]

Deezul--the overflow valve has crossed my mind. You're right, I'd better check. My gut says for some reason it is a fueling problem, and boost will improve when EGT's can get up to 1250-1300 or so.



Thanks for reminding me (the check list is starting to get long!)

 

[mikel]

If you have low boost and no EGT issues then you are not getting fuel.



What is your fuel pressure?



When was the fuel filter chanced last?



Mike

 

[Howard Durand]

The overflow valve in my 94 was one that can't be taken apart. Yours may be too.

I got one of the new style from Piers when I ordered my 215's.



BTW, do a search for "boost leaks" on this forum and you will find several good ways to pressurize the system.

 

[JoshPeters]

I had found a cracked intercooler on my truck. I could still hit 30psi of boost with my 14cm housing. I also was suffering from low power... etc. Pull your fuel filter off... and dump it into a clear container. Since the truck has sat... . Critters may have moved in. If you have black, graphite like crap that comes out of the filter, let me know. Torque Diesel has the biocide to kill the critters. I had a bad bad dose of them. My truck had less power than stock when they got me!



Josh

 

[DuallyDean]

Josh--

I'll check the filter tomorrow. The truck sits every winter from about November 1st to almost Memorial Day for the last 4 years. I've never had critters in the fuel before, but stranger things have happened... BTW--where on the intercooler did you develop a crack?



Howard--I'll do the search tomorrow and try some troubleshooting. I'm too tired tonight to wait on my slow dial-up internet connection.

 

[Joseph Donnelly]

I'd check the overflow valve and lift pump. Also fuel filter. The injector leak could be the line (clean the end of the line with about 320 grit and be sure no grit gets into the line or injector). Also could be an internal leak in the injector leading outside. If you overtightened (beyond 44 ft lb) the injector nut, you may have damaged the injector body.