Had my 1994 E7 V-Mack runaway on me yesterday.

[Joey Mack]

I just went back to PAI,,  I did have an account to look up parts..  The breakdowns are great..  Thats true..  but what I dont have is a shopping cart to put my parts in so I can buy them..   I should have been clearer, I guess...  I dont have buying power...   jojo

[theakerstwo]

Our mack dealer sells PAI parts.They sold me some E6 engine parts last week.I have used alot of PAI parts for cat.

[jzack]

Well, Mack says it was the fuel pump, no big surprise. Sending it out to get rebuilt now. The oil looked good, no metal. Valvetrain also looked good, other than a couple of frost plugs leaking. The mechanic said he will put the rebuilt pump on and see how it runs. He did start it briefly already and said there wasn't any bad noises. Thinking about putting it on their dyno to see if it can put power down without any issues after the new pump install and go from there.

Picked up the T880 today. Kind of surreal going from a 28-year-old truck to a 28-day old truck LOL!! I can already tell my Mack has a better ride. The KW ought to really go though with a 510HP/1,850TQ and 12 speed auto. Amazing they can get that from a 12.9L.

[fjh]

11 hours ago, jzack said:

Well, Mack says it was the fuel pump, no big surprise. Sending it out to get rebuilt now. The oil looked good, no metal. Valvetrain also looked good, other than a couple of frost plugs leaking. The mechanic said he will put the rebuilt pump on and see how it runs. He did start it briefly already and said there wasn't any bad noises. Thinking about putting it on their dyno to see if it can put power down without any issues after the new pump install and go from there.

Picked up the T880 today. Kind of surreal going from a 28-year-old truck to a 28-day old truck LOL!! I can already tell my Mack has a better ride. The KW ought to really go though with a 510HP/1,850TQ and 12 speed auto. Amazing they can get that from a 12.9L.

Decent hope it all works out for ya ! Just keep an ear on it for a popping sound in the future as stated earlier! Over speed can crack a lifter and it will run fine for a bit! Hopefully It has newer style lifters and it will be Good!  I am Rooting for ya! 

[jzack]

Thanks fjh. I'll make sure and ask the mechanic about the lifters. I'm curious now.

[Joey Mack]

do you feel like they should drop all 13 bearing caps and check for wear?  I would,  hell get a set of bearings from PAI and roll them in just because..  jojo

[fjh]

10 hours ago, jzack said:

Thanks fjh. I'll make sure and ask the mechanic about the lifters. I'm curious now.

When it runs again we will all know! Good luck with the KW too hopefully it stays away from the shop for a bit ! and you guys bought lots of warranty on emissions stuff! The down fall of MOST ALL equipment these days is cheap wire / cheap sensors The tech would be ok for the most part if it weren't for those two things  they can put people in space but they can't build a reasonable sensor or good wire with a few more strands in it for a truck these days! They need to Go All the way here and go fiber optic ! Better yet wireless! then they could hire All Computer nerds to work on stuff!

[67RModel]

I was just wondering since it was determined to be diesel fueling alone that caused the runaway can the engine overspeed on diesel fuel alone? Can the pump/injector lines supply enough fuel to kill the engine by themselves? Typically a runaway is from an unrestrained lube oil supply in addition to diesel fuel. Just wondering how much more the pump and injectors/lines can give beyond wide open throttle. I don't know just asking.....

[fjh]

27 minutes ago, 67RModel said:

I was just wondering since it was determined to be diesel fueling alone that caused the runaway can the engine overspeed on diesel fuel alone? Can the pump/injector lines supply enough fuel to kill the engine by themselves? 

Yes an engine can self destruct in any kind of run away event diesel or otherwise! once there is no governed speed all bets are off!

[dogg rescue]

A buddy of mine had a '97 e7 454 run away from him, it was the fuel pump. A week after getting it fixed he broke a rod bolt. Keep your fingers crossed. 

[Joey Mack]

like I said... drop the 13 caps, one at a time,  inspect each and put it back up to hold the crank..  get a new bearing set, and yes,,,  new rod bolt's, which I didnt mention,,  and tidy up the bottom end..  small $$ for some security...  at least you will know how the crank journals look, and if in the case something else starts 'a' knockin..  the backbone is good..  You will be able to inspect the cam and lifters while you are underneath.  take the oil pump out of the way,  you can also take the oil pump apart to inspect the impellers and the housing for major scratches on the bottom plate, and on the inside and the brass thrust washer, if equipped...  on the upper housing,  and pump shaft 'play'  should be zero, the gear as well, which I'm sure survived..   put youre eyes on the parts,,,  so you can see what you have... jojo

[Joey Mack]

another thing,,  when removing the butress bolts, the one behind the air compressor can be removed by  taking the bottom plate of the compressor if it a bendix tu-flo.  wabco leaves room to get the bolt out,  and i forget if midlands have a lower cover.. I think they do..  point is, no need to pull the compressor unless you want to..  I just cut a new gasket out of a sheet and put it back on with Mack RTV when im done with the mains..  

[JoeH]

I'm in Joey's court on this one.  Dropping the oil pan costs a gasket and shows any broken bits that find their way to the oil. You're already changing the oil, you're just spending a few more bucks for an oil pan gasket and the mechanics time checking the crank.  You'll have eyes on the cam lobes from underneath too to see any gouging and scratching.  I'd do this before wasting money on rebuilding a fuel pump.  Would be a shame to drop 3-5k rebuilding the pump to find out you've eaten a camshaft too.

[fjh]

11 hours ago, JoeH said:

I'm in Joey's court on this one.  Dropping the oil pan costs a gasket and shows any broken bits that find their way to the oil. You're already changing the oil, you're just spending a few more bucks for an oil pan gasket and the mechanics time checking the crank.  You'll have eyes on the cam lobes from underneath too to see any gouging and scratching.  I'd do this before wasting money on rebuilding a fuel pump.  Would be a shame to drop 3-5k rebuilding the pump to find out you've eaten a camshaft too.

With This said! You can hardly see the lifters one can be cracked and the cam may not show any sign of damage yet The failure could come a day to weeks from next startup! OR it my not its a crap shoot! In terms of years this engine sounds like its  is well into the era the new style were in production and he my have a good outcome here!

[jzack]

Ok, I'll ask about dropping the pan to inspect the cam. The mechanic working on it has been working on Macks for 29 years and really knows his stuff so I trust his opinion.

Even though this engine has 1.3M miles it wasn't showing any signs of being on its last legs. I've maintained it since new with regular filter/fluid changes, did the overhead every 300k or so. In fact, the overhead was just done in Dec. along with new injectors.

[fjh]

4 hours ago, jzack said:

Ok, I'll ask about dropping the pan to inspect the cam. The mechanic working on it has been working on Macks for 29 years and really knows his stuff so I trust his opinion.

Even though this engine has 1.3M miles it wasn't showing any signs of being on its last legs. I've maintained it since new with regular filter/fluid changes, did the overhead every 300k or so. In fact, the overhead was just done in Dec. along with new injectors.

Sounds good,Sounds like your in good hands! keep us up to date! Were  Rootin for ya!

Edited August 7, 2022 by fjh

[jzack]

Well, I'm back at work! All that was done was the re-built pump and replaced all the frost plugs on top the head. Mack said everything else looked good. Fingers crossed I guess. The truck seems to sound and run exactly as it did before except a little stronger. The only issue I have had so far is a leaking input seal on top the steering box. Hopefully it just needs a new seal. Maybe the over-run caused higher pressure in the system blowing past the seal?

I'm also hoping my issues with cracking injector lines could be solved. There is much less vibration on the lines now with the new pump. I've had to replace lines 4-6 several times the last six months.

Oh, and after driving the 2023 KW T880 for a week, I wouldn't trade my 94 Mack even up. Seriously, trucks have not come as far as you would think in the past 28 years. The ride in that KW was horrible.

[Joey Mack]

if you replace the input seal on the steering box, when you get the old seal out, look to see if there is a grove in the input shaft.  If so, a new seal wont last long..   Glad to see you back in the CH.....  jojo

[theakerstwo]

A easy way to get the seal out is remove the retainer snap/ring holding the seal down and then remove the return line from the box to the reserve then cap the port that is in the box.Crank the engine and most of the time it will blow the seal out before the engine starts.You will have to wash your engine when its done.

[mrsmackpaul]

If a groove is worn put a speedie sleeve on the shaft, I think in the States people frown upon using these but they are very common in Australia 

Also I find the using a blue neoprene seal for a hydraulic ram works in these situations were the shaft speed is reallly slow and they last a lot longer on worn shafts than a normal sleeve 

Hydraulic places frown upon this but I have had 100% success rate with these 

 

 

Paul 

[jzack]

Thanks for all the tips on the input seal, I'll make sure to look for a groove in the shaft.

I might try a novel way to pry out the seal I saw on a video the other day. The guy carefully drilled a small pilot hole in the top of the seal. He then screwed in a tall screw enough to grab the seal. Then grabbed the top of the screw with a pliers and used the top of the input shaft for leverage to pop it right out. No mess, easy peasy. If that fails, I can try the messy way!

[Joey Mack]

yep,  1/8"drill bit, centered between the seal lip, and the seal housing,  it will leak some oil, no biggie...  jojo