Scottfunk

Ok I have fallen on quite a bit of misfortune in the last few weeks. I have a cummins 8.3isx engine that seized a bearing and blew a hole in the side of the block. I also have a 24 valve with a spent vp44. I am trying to find a way to make one running engine out of the two. Will the 8.3 with the mechanical pump have all of the parts I need to convert the 24 valve to a p pump? And no, i won't be keeping the engine, I will be selling it to purchase a 6.7 for the Chummy. I love my quad and do not want to convert the Chummy to mechanical gauges. Is it possible?

I'm replacing my injection pump next weekend and rebuilding my fuel system to include a bottom sump and a pressure gauge (doh). I have always struggled with egt's on the Chummy. I'm looking at all of the turbo options and it's just so confusing. This is my first turbo diesel truck and I've been reading and reading and I just can't seem to wrap my mind around all the parameters. I'm happy with the power I have now and spool is good but I just can't seem to get my egt's below 800* at cruising speeds. 35's geared to 4.10. I run exactly 1860 RPM's at 70mph and I still have high egt's. I have had the injectors rebuilt and I have searched extensively for boost leaks. I have my quadzilla set on the basic tune and I drive it daily on level 4/10. My exhaust is 4" down to 5" straight with no muffler. Would a 35/40 be the best bet since I'm happy with everything else, I just need more volume up top? Or would I be better off with a 40?

Gasser? No way. I have the only 24 valve, 6 speed Allison powered Yukon in the world and I like it that way. But i am considering trading in my 24 valve for a 6.7.

I have the pcm and obd plug installed but I don't have the instrument cluster to display codes. Maybe I'll see if I can borrow a scanner.

Ok I'm really hoping I am not going to be in the market for an injection pump. Recently my truck started cutting out under moderate to heavy acceleration. Cruising at about 30% load on my quadzilla readout it seemed ok but if I got into it, it would run ok for a few seconds and slowly die down to 38%. Just before it quit running it would drop slowly until it got to about 10%. I stopped at a store and when I came out it wouldn't start. All through this the reading from the tps matched the reading on the quadzilla so I don't think it's dead pedal. After having it towed home and doing some digging I find I'm not getting fuel at the injectors. I have power at the vp plug, and I'm getting fuel from my fass pump. Another thing I noticed, whether it's relevant or not I don't know, but when I bump the starter and listen to the pump it sounds like it builds pressure and then sounds like it's not making pressure. Is it possible the fuel pressure regulator in the vp itself is not working? Please any suggestions!

OK I tried to take a screenshot on the way home but try that in rush hour traffic. Anyways, best I can tell cruising,70MPH, on flat ground my load% is 26. But oddly enough, sitting at a stop it's 12%. 7% idling in park. What gives?

I have regeared the pumpkins to 4.10. With the smaller tires I was right at 1860RPM at 70MPH and now with the 35's I'm closer to 1730 at 70. I'll probably step back down a size when I have to buy new rubber. I'm between 7-9 PSI cruising at 70MPH depending on the grade of the road. Engine load jumps between 24 and 33. The injectors were just built earlier this month and are 50 horse injectors popped at 315. Before I changed the tires I was having problems with high egt's. I was up around 840* at 70MPH. I chased down quite a few boost leaks and was able to get it down in the low 600's. There were still a couple minor leaks I knew about. After I changed to the bigger tires I was back up around 850* but after sealing up the compressor housing, intake plate, and grid heater housing I am back in the mid 600's. I will check the load numbers on the way home tonight. What is the best way to dial back the timing a little for winterized fuel? Just bump it down a couple degrees across the equalizer or in the individual timing settings? I have not played around in the Quad custom tunes much but everytime I do it seems like I make it worse.

I agree. I don't know exactly what size the holes in the banjo are but I still have the fitting at home...I'll check it when I get home from work. I definitely don't remember them being any bigger that 1/8" so basically it doesn't matter if you run a fire hose up to this fitting, if that's the point of restriction you'll never flow any more than that banjo allows. I don't believe I have excessive drag...other than the 35" mudders I put on last week, hehe. Everything in the trans is brand new and all the clutch clearances were exactly middle of the specs so I don't think that's the problem. I put the truck on jack stands and the rear wheels spin freely, as do the fronts. Stopped, and in gear, if you let your foot of the brake the truck feels like it gets moving on its own without excessive resistance. I really think this is an internal thing. I'm going to make a new boost test boot (I blew the last one up) and I'll check for leaks again. I'm new to this whole positive pressure intake situation and it's kind of blowing my mind.

If I recall this banjo had a 5/16" line going into it. Those two puny little holes don't hold a candle to a 3/8" swept elbow. In any event I'm getting too much fuel. What would you suggest? My turbo is not the he351 so would I be gaining by doing the 35/40 hybrid or would it be better to pick up a 351? I'm planning on going VGT at some point this year so I don't want to sink too much into it but would like to increase my efficiency some in the meantime.

So I'm still working through this. My egt's are still higher than I'd like and I've done everything I can think of. This weekend I replaced the intake plate gasket and RTV'd the hell out of it, as well as the compressor cover on my hx35. While I was putting the fuel system back together I got to thinking about the fuel inlet. Since I was doing a conversion I had the opportunity to build the whole fuel system from scratch. I replaced the banjo fitting going into the injection pump with a 3/8" elbow. The reason I'm mentioning this is I'm wondering if I'm producing more fuel at any given throttle than the hx35 can keep up with. Any chance a 35/40 hybrid would help keep up with the fuel I'm supplying to the engine?

No the back end of the housing. I like your idea of some rtv there but getting that snap ring back in there sucks.

What's the easiest way to get that stupid ring back in there. I think rtv is a great idea but the last time I had it apart it took nearly an hour just to get the ring back in. Finally had to ask my wife for help...that wasn't embarrassing.

Nope. I buy that one though because the seats aren't "lapped in" like a high performance set of valves would be. Now that I have a better understanding of how much pressure these things make it makes sense to me. If the orifice sizes are measured in thousandths of an inch then a ten thousandth of an inch variance from the manufacturing process could have a measurable effect. The tech that rebuilt them said he recently rebuilt his own injectors and went from 20mpg to 14. Believe me I'll be watching cuz crap mileage was what sent me on this journey anyways. As far as boost leaks I did make a plug for the turbo inlet and test it. I'm surprised I was able to make any boost at all! Leaks everywhere! This is my first experience with turbos and diesels and such so it was a bit of a learning curve but I think I'm gaining on it. Wish everything didn't have to rattle itself loose though, lol. Even the dang half moon hold downs that keep the turbo cartridge attached to the exhaust housing were coming loose. I really don't know how this thing even ran. If nothing else I have really enjoyed learning more about these amazing engines and I'm finally getting to where I've rebuilt everything in the truck twice and am finally happy with it. On to the interior... Ya know, I've heard it both ways. But here's my take...the compressor wheel doesn't even press fit onto the shaft, nor does it have any splines on it. It simply slides on and is held in place by the reverse threaded nut there. In my opinion if the engineers had thought it was that critical to maintain the alignment they would've put some sort of positive retention in there. Just my $.02. Also, I like that it has an odd number of vanes and I believe that helps. If you ever spend a bunch of time just staring at the rims of the cars around you almost all of them have 5 spokes to the wheels. I think this is done to minimize out of balance issues but I could be wrong. Again, all totally just my opinions but I believe the facts speak for themselves.

I think I'll try a 3.3k resistor and see how that works. I think mid 120's *F is where I get the smoothest performance. My only question is this: does the ECM not think there's something odd about an IAT in the 120's when the coolant temp is less than 32*?

Well I got the new compressor wheel in today. Didn't see any drastic changes in EGT or Load% but there was some improvement. The guy at the shop where I got my injectors rebuilt said to expect to burn through a little extra fuel in the first 10,000 miles so I guess I'll just have to be patient. The improvement in power was DEFINITELY noticeable though. YEEHAAAAA!!! Ignore the tooling marks around the outside of the wheel that was just me trying to get the wheel off without pulling the whole cartridge. I use a diaper rash paste to check the alignment when I set up ring and pinions, it's basically fish oil with a zinc additive. Would this be a safe substance to use to wipe a little around the tip of my fuel tubes to check the seat in the injectors? I just recently read the specs on torque for the fuel line/fuel tube retaining nut and I grossly overtightened them. I don't have any specific reason to want to check but I'm a bit of a worry wart and even more of a perfectionist.

Speedy recovery brother!

Although somewhat indelicately said, I would mostly agree with this. There are basically three types of knowledge: the type of knowledge gained through personal experience, the type of knowledge gained through research, and knowledge gained from third parties. You could talk until you're blue in the face and you would never convince me that Craftsman tools are not the best mechanic's tools out there...personal experience. My truck has a Cummins engine but an Allison transmission...research. Not saying I'm right or wrong with either of those but I have a personal connection to the information and so I trust it. The trouble with third party information is that you have no personal connection to the information, so you can only validate or invalidate it through one of the other methods. There really just is no way to know without trying. That being said, I rarely rule anything out because of the label on it until I've personally evaluated it. I have a Harbor Freight MIG welder out in the garage next to my Everlast TIG welder. I only expect to get 3 years out of my Harbor Freight welder that I paid $200 bucks for, while I might hope for 10-15 years out of my $1000 Everlast. Does that make the Harbor Freight welder a bad value? For me, no. I forked over my money knowing that eventually I'd have to replace it. There's nothing wrong with buying an inexpensive turbo off of eBay as long as you go into it knowing it MAY not last as long as others. It may or it may not, but either way when it bites the bucket you'll know if it was the right choice for you and have the personal experience with it to know whether you'll make the same choice in the future.

I was using this for the air filter, mounted directly on the turbo inlet. That cute little chrome button in the middle got tired of being there one day and tried to escape through the turbo. Needless to say I'm running a different style filter now. I'm sure some small particles made their way to the engine but I'm guessing most of it is hung up in the intercooler.

I believe it was 315. They said they should settle into the middle of the range once the seats wear in. I don't have an exhaust brake yet, but I would like one. A 4" outlet would be nice too! Maybe a 35/40 with a billet wheel? hmmm...

On second thought I think I'll just replace the wheel for now and upgrade to a VGT in the future. Think that'll make me happier for top end and spool up. Thanks

OK I've had my injectors rebuilt and matched and chased down multiple boost leaks. My load/egt numbers are still pretty high and I haven't seen a marked improvement in fuel economy. I observed a couple weeks ago when I started on this quest that my compressor wheel had sustained some damage. I think SOME damage may have been a serious understatement. Judging by the pictures, would this be a possible source for my problem? I noticed recently that even under FULL acceleration I couldn't get 30psi. Assuming that at least most of my leaks are gone, should this be my next focus? That being said what would be the best way to fix this? I can get a replacement wheel on Amazon for $40, a whole new hx40 with t3/t4 adapter on eBay for $220, or an hx40 wheel/housing combo for abot $180. I know there would be some adaptations with the second two and maybe some turbo lag which I could probably adjust for slightly with the Quadzilla. I'm happy with the power I have now but do plan on using her for a towing rig in the future and it feels like the bigger turbo should help with EGT's, but if that's not going to be significant then I'll stick to stock. Keep in mind I have a Cummins/Allison combo in a '96 GMC so adaptation is the name of my game. Thoughts?

All the talk about boost got me thinking...when WAS the last time I heard the wastegate open? Since I couldn't remember I made a pass through downtown Boise on my way home last night and did a couple 5-35 MPH full throttle blasts and sure enough no wastegate. I threw together a test boot and slapped it on and sure enough leaks everywhere. Must just be settling in from normal heat cycles. Anyways I tightened down all the clamps on the intake and it sounds much better, EGT's are down a bit but I still hear a bit of a wheezing sound from under the hood so I guess the search is not yet over. Don't tell my wife I could have saved $400 on new injectors if I would've thought to test for boost leaks BEFORE getting the injectors rebuilt. Shoot they needed it anyhow...

Man I had no idea. If you need a meal or anything else I can do to help let me know.

What's the best way to find a leak in the intake? I can't build boost sitting in my driveway and I can't put my head under the hood while I'm driving...Rebuilt injectors helped some, and I'm hoping once the seats get worn in it will get a little better, but it's not good enough yet. I saw 1380* today getting on the freeway (aggressively yes, but still). My intake exists of sections of 3" aluminum tube joined with silicon rubber 90* connectors (rated to 90 psi). Also, maybe I should have looked into this earlier but a previous air filter I used, which was installed directly on the turbo inlet, had a little metal button on the tip of it that held the filter together (see pic, my description doesn't do justice). It's not totally obvious from the picture but this little button has an outside rim that makes the button EXACTLY the same size as the turbo inlet. So...one day I was driving down the road and hear this weird grinding sound. I pulled over to the side of the road, opened the hood, and listened for the sound but of course it went away. I got back on the road again and the sound came back so I headed home immediately. Upon removing the air filter I found the button in the turbo inlet and it had worn off the turbo wheel around the outside of the inlet hole. Considerably. Could this possibly be the source of my problem? I immediately replaced the filter and the power felt like it came back but honestly the filter could have been THAT bad. They get real dirty riding right behind the alternator. I bought a TIG welder and I'm practicing up so that hopefully some day soon I can build the whole intake system out of stainless including a cold air that's routed away from the filth of the engine. Anyways, worn turbo wheel affect fuel consumption and EGT's yes or no?

OK @Mopar1973Man I need help. My #6 injector won't go back together. It feels like its in all the way, the keeper feels right when you bolt it down, but the tube won't seat in the side of the injector. There is evidence on the tube and the nozzle that the tube is riding low in the seat but I can't find anything wrong. I used a flathead screwdriver to make sure the old copper washer isn't stuck down there and it's not. Of course it's number 6 so I can't look down the injector bore. Check out the pictures...