jzack

Well this was an awful experience. Been driving this truck for 28 years with no major issues. Over 1.3 million miles, 45,000 hours all original engine, even down to the turbo. I left with my second run for the day and the accelerator started acting funny. When I would let up to grab the next gear the RPMs would immediately drop too fast for me to grab the next gear, then they would come back. Like the accelerator lost signal momentarily. Did this twice, then the electronic malfunction light came on and the engine de-rated. Great I thought. So I started moving to the shoulder, pushed in the clutch to grab a lower gear and, BAM the engine immediately went WOT!!! Of course I panicked for a second, turned the key off, no response from the engine. I got it pulled over, remembered reading about runaway engines and what to do, so I grabbed my jacket and stuffed it in the air cleaner intake. That slowed it down to what sounded like a safe RPM but she kept going! White smoke pouring out the exhaust. Now what? Next, I grabbed a wrench and started to crack loose the fuel line to the filter tree. Two or three turns and it finally shut down. Whew!! Not sure how long it ran like that but probably a good 2-3 minutes at least. So disappointing, I'm sure anything in or attached to the engine will be suspect for failure now. An old mechanic at Mack suspects something gave way in the injection pump. We'll see I guess. They are a week out on service work. Three weeks to re-build the pump maybe. The worst part is, short of a full overhaul, not sure I can trust this engine again. Am I right? Before this, she was still running strong with no issues or symptoms whatsoever. On a side note, my Old Man, who I love but enjoys Monday morning quarterbacking, said I should have jammed it in gear and side stepped the clutch? Not sure the drivetrain would have enjoyed that experience though.....

Interesting, maybe I'll try that when I finally get to the end of my rope on this.

I've got a 1994 CH with the E7350. Back in December I replaced #4,5,6 injector lines. They were leaking at the head. Now 4 months later all three have failed with small hairline cracks behind the nipple at the injector. Mack has been warrantying the lines but I'm really growing tired of replacing them every few months. Yes, I make sure all the line clamps are good and tight. The lines stay dry for weeks, maybe months and then bam, they start dripping on the manifold. My original lines were 0.25" OD, the new OEM ones from Mack are 0.23 OD I noticed. I let Mack know about this.... Do I have any other options here?

Follow up question- How many ft/lbs do you torque the "outer" nut to on the budd style wheels? I've seen sources say 600ft/lbs for outer, 450ft/lbs for the inners. But most people seem to say 450ft/lbs for both. I'm asking because i've been having problems with my lugs coming loose.

Try adding a centrifugal filter system. All Macks have had these for years and they work great.I think Amsoil makes an aftermarket system you can add to almost any motor.

The Jake in my Mack has always worked great. I also use 2 gallons of Lucas at every oil change.

No, I'm complaining that the last 10+ years of R&D have been too focused on decreasing emissions instead of increasing MPG.

I agree, too much focus on cleaner emissions and not enough on improving MPG. A truck that gets good fuel mileage will, by definition, emit less pollutants AND save the operator $$$$$. I mean c'mon, 20 year old technology is still capable of getting the same if not better than a brand new truck. THATS CRAP!

Check your codes. My truck did the exact same thing and it was throwing a code for the Econovance solenoid (sits in front of the fuel pump). Threw in a new solenoid and problem solved.

The 427 and 454 are both 10.0 BTDC. The only difference between the two is the data file in the V-mac program. I probably have 250,000mi on my Blixxton in my 94 E-7 350 now and I still just love it. My guess is the Blixxton keeps the timing advanced throughout the RPM range because I notice a definite lumpy idle when I have the switch set to 30%. Idles like I have a hot cam in it, kinda cool! While I haven't had your particular issue, I have heard that re-pinning the connector has cured similar issues as yours. I have also heard of wires shorting out on the firewall behind the washer fluid reservoir causing erratic running quality.

I agree. You can't blame Volvo for tougher EPA regulations or the more competitive global market either. Both of which played a part IMO. Mack's management probably could have done better.

I love my 94 CH w/E-7. Has 992,000mi and still running with the original motor, including the turbo and injectors. Still gets 6-7 MPG too. The motors built today would have a real hard time matching that kind of reliability/longevity. Where's the progress?

Maybe I'm a glass half full guy, but I think Volvo really does know and respect Mack to a certain extent. I mean here we are some 12 years into this and Mack is still here. A guy can still spec a "Mack" truck that has a Mack hood, cab, interior, transmission, axles, and an engine tuned and programmed by Mack engineers. These aren't just re-badged Volvos as some would say. No one in this global economy can go it alone anymore and this marriage has gone better than many others. In fact, if Volvo owning Mack "is a crime" than what GM did to Saab should be considered man-slaughter! Remember the "Trollblazer"? Simply a re-badged Trailblazer for the SUV shopping Saab faithful. No wonder Saab is dead! Could Mack have been better without Volvo? Who knows? Maybe, but it could also have been worse than it is now, a lot worse.

Had this problem also with the Holset compressor on my 94 CH. Went through 3 compressors before switching to a Bendix and the problem seems fixed 3 months into it. The Holsets all passed oil almost immediately. BTW, the Holset comp. were Mack grey, while the Bendix is blue/green.

Sorry to hear you don't like the 444's. I really think they are the best drive tire for the money, but I don't go off road either. You may find they'll last longer than the Michelins though based on my experience. About the caps, like everyone else here said, they can be a great value, just be sure to use your own casings.

Found out recently that the service bulletin with update kit has been discontinued for the Holset compressor. Not sure why. As stated above, I'm currently on my THIRD Holset now in 7 months and this one seems to be passing oil from the moment I left the dealer!! Thinking about asking Holset to refund the cost of their compressor and labor to remove it so I can replace it with a Bendix unit.

David, could you find the part# for that filter kit? I'm on my THIRD Holset now in less than 6 months and am at the end of my rope trying to figure this out. Mack has tested everything Holset has told them to check (including the coolant lines) and can't find the problem. Does this kit reduce the boost pressure to the head of the compressor? I heard Holsets can't handle more than 30PSI or they will burn out. This could be my problem. Just searched through Macks Technical Service Bulletins since '94 and didn't find anything about this kit using 'holset' and 'compressor' as my search words........ Thanks, Jeff

America losing its manufacturing base is mostly myth. America still builds more things by GDP than Germany, Japan, and yes even China. Many of the job losses people hear about in manufacturing are do to automation and other efficiencies of a post-industrial economy. Our industial base is still the envy of the world, thats why all the major global players have to come here to compete in the global economy that AMERICA MADE.

I also do mostly stop and go local work. I deliver steel with a flatbed or conestoga trailer loaded with up to 6 or 7 stops per run, so I'm not grossing 80k all the time. I do have some decent idle time though as I usally let the truck run during stops. We've had several E-7 350s with 9-speeds, both mechanical and electronic, and I don't recall any of them dipping below 6mpg all that often. If I had to guess, I'd say your 442 rears probably hurt your mileage more than anything, especially if you do alot of freeway running at 65mph.. Keeping the rpms down is the key, 1,500 - 1,600rpm seems to be the sweet spot for mpg for the E-7 in my experience. I'm not so sure about the electronic E-7 making power quicker than the mechanical. In my experience the V-macs all had a bad dead spot from 1,200-1,400rpm, where as the mechanicals pulled hard right away. Probably something to do with the electronic puff limiter because adding the blixxton would make the dead spot go away.

94 CH600 E-7 350 V-mac I w/ Blixxton upgrade Fuller 9-speed 3.86 Mack rears 67 mph@ 1,600rpm 6.0 - 6.5 mpg winter 6.5 - 7.0 mpg summer

I highly doubt you need a new pump. You said yourself the truck runs fine until it goes into de-rate mode. I would almost bet it needs a new Econovance solenoid. We have had two mid-nineties CH's this past year have the EXACT same symptoms as your truck, same code 35 (timing actuator), and both were fixed by replacing the Econovance. It is that box at the front/top of the pump with the round solenoid and two wires sticking out the side of it.

Code 35 on my 94 ch600 was the econovance solenoid. Took it to Mack that night and was back to work the very next day. Yeah it cost $1,000 but it saves me ALOT of headaches by just bringing it to the dealer and having a guy work on it who knows these trucks inside and out. Mine has 970,000mi and 32,000hrs and is still a very reliable truck.

You mean the GTO Judge, right?

Is the Shutdown light and buzzer coming on? If so (seems you already know this) only oil pressure, coolant temp and coolant level would cause that as far as I know......

You can do a self-diagnostic without a scan tool if that is what you need. Just turn the Speed Control switch to OFF, then press and hold the SET/DECEL switch until the fault lamp goes off. The blink codes will follow with a two digit code, each digit seperated by one second delay. Let me know what you find, I have the blink-code guide.