Mackpro

We just sold this RW and its heading to Florida to get on a ship and head to South America. I dont know much about the older Macks all I get to work on now is MP series engines. Truck over all is in good shape. I had offered $2500 for it but we sold it for $5000. I was want one for a restore job and this would have made a great one. People overseas are buying our used trucks left and right and shipping them to who knows where.

Since you already have a 427HP, to go to 454HP if you have a VMAC2 fuel pump engine (which I think you do) or 460HP if you have a ETECH engine. Just the download is all you should need, the 427 and the 454/460 use the same injectors and turbo in most cases. I dont know what the download will cost, I have seen some that were free from Mack but you never know. Best thing to do is go to your local Mack dealer and fill out a Horsepower Change Request Form and the dealer will fax it to Mack and in a day or so Mack will fax the dealer back with the parts that need to be replaced (if any) and the cost of the download (if any). If you tell the dealer" upgrade me" the dealer signs the request form and refaxes back to mack where they turn on the download(in a day or 2) The dealer should do this paper work for free or at least we do this for free for the customer because if customer wants the HP we can at least get an hour labor for the download plus parts/labor that need changing. Most of the time Mack will want you to upgrade/replace the clutch to a larger tourque rating unit. We have never done this and have never had any problems. On ETECH engines 350 or 400 HP upgrading to 427 or 460 HP Mack will want you to change the cam keyway to an offset keyway to retard the timing,(unless you have an ETECH CCRS or ASET engine) you must do this or it will run hot in the summer, trust me ,we tried it. Hope this helps. P.S. ETECH 427's already have the offset camkey. Around 2001 the CCRS engine and in 2004 the ASET engine came out, these were easy to upgrade due to the engines all being the same regardless of HP (except for turbo and injectors and download) these engines all had straight cam keys and big balancers so the turbo and injectors and download were the only difference between a 250HP and a 460HP engine. On the MP motors all parts/engines are the same regardless of HP only the download is different.

Around 1991 in CH trucks the VMAC1 computer controlled engines came out but you could still get manual pump engines in RD,DM,Rb and MR style trucks up till around 1997. As far as bumping HP up with computer downloads, it can be done but depending on year model and how many HP you want to go up sometimes requires turbo, injectors, bigger balancer,pistons, and offset cam keyway. When we do HP upgrades we fill out a HP Conversion form and fax it to mack and they fax back what is parts to change. Say on a 1999 CH you wanted to go from 350 to 400 all required is a bigger balancer and a computer download, but to go to a 460HP you need turbo, injectors, offset cam keyway, bigger balancer and download. Really depends on year and how high in HP you want to go. These guys bring their 350 hp trucks in and think we can just walk out to their truck and plug our laptop in and crank up the HP, well it dont work that way. With EPA looking over Macks shoulder its getting harder to get the HOT downloads that we used to get, we are in a fight right now between Mack and a customer because of low power and with 4 dyno results to prove it .

Go to a mack dealer and have them look up the correct part#. Many of the switches look the same but open or close at different pressures. We have seen this on CH style trucks where the tech or parts guys guess and the wrong switch gets put on causes weird problems. Gotta a model # (MR688S) and last 6 of VIN and I can look up the part#

We had lots, I mean lots of 1999 models ETECH engines that had pistons rings that were to hard and were eating up the liners and we did alot of cheape overhauls where we reused the steel pistons and heads and just replaced the liners and rings, rod and main bearings and this solved our blow-by problems. There is a Mack service bullitin about this, mainly about the new rings, I can get you the bullitin # when I get to work. On the other hand I had a Mack engine engineer tell me not to worry about blow-by only if engine uses more than 1 gal oil every 1200 miles. We have a 99 CL with a 490XT that fogs out a steady of white stream of blow-by all the way to the ground but dosent use any oil and its been like that for 3 years and the truck is used every day( over 500000 miles on it). If the engine dosent have a coolant filter on it , it could be liners leaking coolant into the oil pan. Around 99/00 the coolant conditioner filter became an option and some engines didnt come with them, well 5-6 years down the road after the owner didnt keep the coolant DCA levels in check, the block ledge would get eaten out under the liners and coolant would get into the oil pan and steam would come out of the blow-by tube. We also have seen turbo shaft seals leak and turbo boost pressure would get into the center section/oil side of turbo and the turbo boost pressure would go down the tubo oil return hose into the oil pan where then the pressure would be forced out the blow-by tube making it look like bad blow-by, although this mainly happens while going down the road or engine idled up high. Hope this helps. Good luck.

We have had only one major engine problem here with the M series engine and it was a broken injector rocker arm on an MP-8. Mack is aware of the problem and is having new stronger rocker arms made as we speak. There will be a recall on all MP-8 injector rocker arms. It did make a small gouge on the camshaft, but being an overhead cam it was super easy to change out the cam. Only the MP-8 had the bad rockerarms, the MP-7 are ok.

I didnt know they were bringing back the Rawhide edition but one showed up at the shop today so I had to take some pics. It is close to show truck standards with all the chrome. MP- 485 hp' It was is in-transit from the bed company headed to I dont know where. Only had a blown brake light fuse so it wasnt here long.

these are only on the etech engines and some Asets engines 1999-2005

Heres a pic of a good/new pin. The floating part should be around .008 past the the threaded body. If its flush or up inside the body its really bad. If one is bad change them all. On the new style ones the floating part is silver.

If it has a jacobs engine brake, we see this all the time. The floating jake pin in the valve yoke is worn out. Mack has come out with a new improved floating pin that we use. part #421GC41CM These pins wear down and then the yoke starts to wobble and then breaks off the valve yoke pin in the head. Most of the time we can drill and slide hammer the pin out of the head. Good luck.

Does it have a manifold (turbo boost) pressure guage in the dash. If it does it should read 21-27 psi under a hard pull. If it doesnt have a guage you can get a low pressure air guage 0-50 psi and run a 1/4 inch plastic air line from the intake manifold up into the cab and hook it to the guage and run it down the road. We do this all the time to check boost pressure. The intake manifold is on the driver side of engine and has a 1/8 inch pipe plug in it, install your fitting/hose there. Does it black smoke under a load? Check air filter also. Fuel pressure is also key with an ETECH engine.

It is made into the printed circuit board behind the speedo and tach. We just sold one this morning because the low air buzzer quit working, I thought they said it cost around 300$. If it were mine I'd try to solder one on.

We have seen this complaint many times and have also talked to the factory engineering several times. At one time they did have a download for this "rough idle" as they call it but I was thinking it was for 1999/2000 models and the 427 seems to have it worse than any of the other HP's. We have seen it where the whole truck shakes but as soon as you idle it up it goes away. We have never been able to get one to quit doing it. We did put a 100psi fuel valve on one and it helped but other than that no luck here.

This is true, dont reflash the eecu, Mack has a voluntary recall on alot of trucks in the 1999-2000, they offer you a free oil change if you come and let the dealer reflash/reprogram the eecu. More EPA bulls**t

I never really looked up the specs of the 460XT till now, but this morning I was checking out the 1999/2000 Mack tune up specs manual and the reugular 460 and the 460XT have the same HP "487" but the XT has 1760 ft. lb of torque and the regular 460 has just 1660 ft. lbs of torque. Make sure your turbo boost is between 27-35 psi under a load, with closer to 35 the better and fuel pressure going into the block around 100 psi, Mack has a 100 psi fuel valve, we put them in all the time. A good injector shop can add a little flow to your injectors, we use United Fuel and Turbo in Birmingham Alabama.Keep your air filter changed, watch your pryometer and make sure the hole in your hood is lined up with your air filter housing so your not sucking in hot engine bay air.

HP is at the flywheel on Macks. On the dyno Mack had the" 80/20" rule. You should get 80% at the wheels, lose 20% through the drive train. Last week we had a 2006 CV with a 460 and it only put out 322HP at the wheels which was very low, should have been around 365. Turned out to be weak injectors. We have a couple of 460XT's CL's around here and the guys love'em.

I agree, we had a simple dash and switches and now with the "volvo dash" everthing is super complicated, even the new wiring diagrams are hard to read. The VCADS program is a pain to use, before VCADS we could run out to a truck and check mafunction codes with the pro-link or laptop in a couple minutes. Now with VCADS we have to bring the truck in to the shop because the battery in the laptop will run down before we get the codes read. I like the engine and frames and most everything about the new trucks but wiring and electronics are volvo and are to complicated for what it needs to be. If volvo came to rewire your house it would take 2 extra tons of copper wire to do it their way, they cant make a simple light circuit without running it through 2 relays, a computer module and then working it of a ground.

In 2004 the ASET engine came out for EPA reasons and after that first year Mack found out that there wasnt enough room for the bigger radiator and aftercooler needed for the ASET's water cooled EGR system, all that extra heat put a strain on the fan belts on the 2004's( ask anyone who had one) under hood temps were so hot they would melt the windshield bottle on the fire wall. Going to the "N" frame standardized the frame parts for the MACK/volvo assembly line. 2004 CX is 34" wide at the front and CXN are 42 and a half if my measurements are correct.

I was doing a recall on an MP8 the other day and had the rocker arm shaft off [ about 150 pounds] and its built like a tank. I was dreading working on it, but now its not that bad at all. Its just that its so different than the E-6,E-7, ETECH and ASET which really have changed very little in the past 30 years. Its like working on lawn mowers all your life then one day you start working on corvetts, kinds scary at first.

Our biggest DPF problem here lately had been drivers hitting the "delay regen " toggle switch and forgetting to hit the regen button later, and they just keep driving till the DPF gets plugged and derates the motor till we have to go get it with a wrecker. I working on one as I type here. The salesmen sell these trucks and dont tell the owners or drivers about the DPF switch and how to use it and it makes it look bad on Mack when they get towed in all the time. The instructions i get from Mack are vauge in how the DPF switch works, I wish they would make it eaiser to understand for thr drivers.

After doing several small recalls on 3 CXU's during the last week , I decided to run one down the road for a test drive. The truck has a M-P 8 415C , 3.73 gears, 10 sp fuller and 22.5 fullsize tires. I could not believe the power, it pulled to 2200rpm in every gear and pulled hard. On a very short on-ramp on to the interstate I hit 70mph from a dead stop from the stop light to the interstate. I have drove the MP-8 485 hp before and this 415 hp was almost equal in power. Of course this is with no trailer or load. It reminded me of the V-8 when driving, it felt like kicking down in passing gear on a car. I know alot of people on here dont like Volvo and us using the volvo motor in the Macks but we finally got a motor with a 100 cid more than we ever had since the V-8 days. The MP8's are holding up great, the only problems are with the damn DPF filters that we have to run on them, (thanks EPA) We have yet to have a low power complaint on any M series engine(except for DPF derates) and we have quite a few running around here. Any one else out there drove any M series engines?

I will agree, as we have had no crossmember failures or any other frame problems with the "N" frame like we did with the regular CX/CH. I replaced alot of crossmembers behind the cab and under the 5th wheel on the CX/CH when they were used to pull tankers and when used offroad/farm use.

In 2005 you could get the "N" stlye frames, we called them "volvo frames" they are wider at the front and allowes for a better radiator/aftercooler setup plus they are alot easyer to work on versus the 2004 cx/ch with the ASET AC engine. The "P" style means it has the deeper cab behind the driver seat, new style "volvo" dash and MP-7 engine only. The "U" style means same as "P" but MP-7 or MP-8 engine but has DPF exhaust filter. And after working on 3 different MP-8 engines (DPF issues) in the last 4 days I say stick with 2003 or older CX/ CH's and 2006 or older CV/CT's if you do your own services/manintence.

My scanner isnt workin so i took a couple of pics of the fuse panel diagram, hope it helps, this is for a 1988-1992 ch mechanical fuel pump truck. If you can read some of it let me know.

I found the truck using our Mack warranty system, its a R688st, put inservice on 8/6/87, must have been a fleet truck as there was 20 made exactly the same one serial number apart, it has a E-6 300hp 4-valve head engine, trans is a fuller XF12609AX. it has rockwell rearends with 4.44 gears. The vin# is 1M2N188Y6HA018998. Hope this helps.