JoeH

Someone else might chime in, with a computer you should be able to individually shut down one EUP at a time to find which injector nozzle/eup might be faulty. I've never had a need to hook one up to a computer but the book says you can. See if your local non Mack Dealer shop can accommodate you on doing that. One truck I just looked at for potential buy had a miss when I cold started it, but once the truck warmed up I shut it off/restarted and the miss went away.

Looking at a 1999 rd688s with an etech motor turned up to 475 hp at the rear wheels. (Heavy hauler triaxle tractor) and an 18 speed. It has the exhaust side computer. Is this vmac III? What concerns should I have about the computer being mounted under the turbo? Truck is in great shape, only 300+k miles. I don't need 475 rwhp, but I sure as hell won't let the dealer touch that eecu if I buy it. Thanks! Joe

They would stop me from being able to do 50% of my work lol. Half the day I'm driving, other half I'm mixing and wheelbarrowing/raking concrete. When I'm not doing that I'm welding or an a roof. Boots every day, sun up to sun down.

Just looked at it again, yours appears to be bolted together, ours are crimped together.

My dad's 1980 DM uses one of those valves. Not sure if our R and RD trucks have them too, I assume they do. It's on the firewall under the hood, near the steering column. It prevents the air from going to driver seat and other cab features until truck hits 60 psi. They're cheap, he has had some fail after a year or so I believe. Keep a couple on hand, I think he had one blow apart where it is "crimped" together. I believe it's probably an emergence feature to protect air brake system from auxiliary system leaks. Starting your truck after sitting for a month is a luxury, stopping on a downgrade with an air leak is a necessity.

Update on the sputtering? Did fuel filters fix it? Our 1995 did a sputtering miss kind of thing this last year, new fuel filters cleared it up. Came back a week later, another set of filters, been running like a champ since. It had acted like one or two injectors would momentarily stop working then clear up. Sounded almost like the Jake brake operating, but I pulled the wires off the heads and it'd still do it. Seemed strange, normally a clogged fuel filter results in feeling like the engine hits the governor at a noticably lower rpm. All our trucks are mechanical. A 1976 endt676 (just retired due to frame rust) and a 1979 endt676 (285 hp maxidyne) stock governed at 2100 rpm, pulls strong from 1200 rpm all the way up. Pyrometer says to downshift at 1125 degrees. Mack got away with such a broad power band by putting out a lot of oil pressure at low rpm to help lubricate a crank making so much power at low engine speeds. Our 1979 makes 90+psi on the oil at low rpm. Our Maxidynes have oil spray nozzles that spray the underside of the pistons to keep them cool, no idea what newer engines (read as anything newer than that 1979) have. We have never had the oil pan off our 1995 mechanical 350 hp mack in the 10 years we have owned it. We've had one valve cover off once. =D. It's no Maxidyne, but it's proved itself to be reliable, if a little weak. It's a diesel, it's governed where it's supposed to be. Load it up, run it hard and see how it wants to work. Don't grind gears, don't overspeed the engine going down hill, don't throw your back out on the potholes. You've been driving mechanical engines your whole career, some of them just had computers in them too. About the only hurt you can do to it us run it out of oil or coolant.

Just read most of this post last night. First thought: "It's a party bus, duh..." The wealth of collective knowledge here is astounding.

Sometimes the head gasket blows across the fire ring straight to the water jacket, without crossing any oil galleries. On combustion, it'll force air through the head gasket to the water jacket, putting air (and pressure) into the coolant. I'd look into that sooner rather than later. If the head gasket gets bad enough, coolant will seep into that piston when it's shut off and you'll break your crankshaft trying to start it. Get someone to do a compression test to make sure your head gasket is still good... Truck will work well until you're stuck on the road somewhere... 😓 Do you mean injector EUP or cup? Not sure what an injector cup is, not very familiar with the newer models.

Are you overfilling it? When the engine is cold, it gets filled to the cold line. It expands when it heats up, so if you put too much in when it's cold it'll push it out the over fill tube. Blown head gasket can put air into the water jacket and cause this too... Thought I'd start with the easy stuff though.

Anyone notice the guy working on the crank is wearing flip flops?

Probably won't be able to look into it for a few weeks, I sub out for an oil delivery company in the winters, and we're starting a major overhaul on one of our concrete mixers. Jake brake is more of a toy than a necessity here. No mountain driving in our neck of the woods. But it has it so it should work!

My 1995 e7 350 is all mechanical. It does click when it's set to both heads. Rarely works on both heads, just on one. And it's pretty weak. So that's an intermittent power issue feeding the relay then?

My 95 does the same thing, I hear solenoids clicking in the glovebox when it does it. I'd like to know what's going on too.

Did you forget to attach a smaller wire to the battery/starter solenoid? Or break a wire? Our older Mack's use the starter solenoid to steal power for all the accessories and the key. No idea how Molvo does it now.

Front of the dump body had a pressure point sitting on the top flange, the rubber pad on the dump body is a little thicker there for some dumb reason. Not operator error, body builder error.... no engine codes, drives and shifts great. Good truck apart for this crack... rebuilt engine... my dad and I have a reputation for taking "junk" and getting decades out of them. Just gotta do our due diligence before making decisions.

Can anyone tell me if a 2004 Mack Granite double frame triaxle splays out around the engine and transmission like the older R models? PG Adams can make new frames, but they can't splay the frame out. They can only do straight rails and depending on dimensions, a "drop belly". Granite we're looking at buying is 45 minutes away, and about 8 inches behind the cab the left inner and outer rails have a 4-10 inch horizontal crack at the top bend of the sidewall.

I asked Andy and Rich at Associated Truck Parts in Warminster, PA about swapping to bud hubs earlier this year. They told me just get them inner and outer wheel bearing numbers and theyll look up which hub it gets. Made it sound like it was easy as cake. All our trucks are spoke hubs. One man brake jobs are a nightmare. Buds you don't have to pull the hub, brake drum goes on the wheel studs. We only run a 15-20 mile radius from our shop, (concrete delivery company) so we never have to do a roadside tire swap, and we plan brake jobs when we're both around to slide the hub off on the car jack. I used our harbor freight trans jack last time, it worked surprisingly well. Could be an alternative to swapping hubs.

Correct on tip turbine, that's exactly how our 79 r686 is. "Charge air cooler" (intercooler) is mounted on side of the engine, excess turbo air blows through a bypass line through the tip turbine(fan), which pulls air through that second intake to cool the turbo air before it goes in for combustion. Tip turbine air just vents into the engine compartment as soon as it goes through charge air cooler.

It is a gusset section that basically acts as a third inner frame rail at the trunion cross member. On this truck there are no sideways torque arms, just the ones from each rear to the trunion cross member. The eagle serves to hold the trunion and the frame square, I assume before they started using sideways torque arms. It won't let me upload photos to show you. This 55k suspension is massive. Inner and outer frame rails are 3/8th inch thick each, our 95 RD688 triaxle has a 5/16th outer frame and a 1/4 inch inner frame and different spacing on the rails. There's almost a 1/4 inch less frame rail thickness on our '95 with 44k Camelback than our '80 with 55k camelback. Back to my original question, is converting from air ride to camelback a dumb idea? Should I just look for a different truck?

Good to know, it's a 12/2003 build date I think. I'll be careful measuring, may have to pick up a cutoff from similar year.

www.ebay.com/itm/MACK-V-MAC-III-V-MAC-II-Shop-Manuals-Service-Manuals-OEM-Lot-of-4-/182209849582?redirect=mobile Something along these lines. Not sure if your truck is vmac ii or iii

Get the engine mechanical and software books from Mack. They're not expensive, and they have a ton of useful info. The etech motors can be diagnosed with blink codes through the dash, mechanical book tells you how, and the code book tells you how to troubleshoot every code.

Check & clean any sensors on the egr system? According to my books on the earlier aset engines, the computer would only put the truck in limp mode to prevent catastrophic damage to the engine. But that's limp mode, not total shutdown. Check for bad power or grounds to the engine, including battery terminals. I had a 99 dodge Cummins auto that would slip in and out of overdrive due to voltage fluctuations caused by a barely loose battery connection. If you can wiggle the battery cable at all its too loose. Could also check your battery cells to make sure you aren't losing a battery. Computers rely on sensors operating in a very specific voltage range.

We're going to compare those measurements when we go to test drive it. My assumption is that outer to outer all trucks should be the same. Inner I can see fluctuating due to rail thicknesses and quantity. We'll have to make new eagles for the camelback, rust has perforated the left one.

Dad and I are getting ready to go test drive an air ride 2004 cv713 dump truck with 44k air ride. Air ride is a no go for us because it'll be converted to a volumetric concrete truck, top heavy and it'll get some off-road use, don't want to get stuck! We just retired a 1980 DM with 58k rears on 55k camelback. Any reason not to buy the truck and use our camelback to do a suspension swap? Are 55k springs too much shock for the cv713 double frame? The DM has a double frame but the frame under the cab to the lift axle is noticeably deeper than over the rears. I'd hold out for a granite with camelback, but there's nothing else (in this century) in our price range. Salesman sold my dad his first Mack (79 R686ST, still runs most days) in 1986, so we're getting a good price on the granite. Easy enough to get a cutoff with 44k camelback, but if I can use what I already have I'll save $2k. Any other cautions to look for would be great! It has a 427 horse computer engine, I'll check for codes. (I bought the etech books a few years ago, they're priceless. They cover the etech ai and ac engines) and a maxitorque transmission, not sure how many gears. Are the modern maxitorques as bullet proof as our 2 sticks powered by Maxidyne 283s are? Also how easy would the air ride sell here? Rears and all. Located in Bucks County PA. Thanks! Joe