Glensts

Those are off of a Mack CHU 613 Rawhide.  Mine is a 2013 with these mirrors

The 686 meant it was a 300hp(I thought) 688 meant 350hp.  Someone can sure prove me wrong though.

I have a 97 e-7 427 drop in Mack crate motor with the high volume lower psi oil pump.  We noticed no difference in the Jake from the original engine.  It still sucks.  They aren't good jakes in those years.  We also

have the factory butterfly valve in the exhaust pipe which will double the performance of the jake, so its just poor instead of sucky.

If you get all 6 banks working you probably still won't be happy but its better than nothing

Heater fan will always run, tried that, so now I'm leaning more to that we could be losing prime.  Will try and find the stuff to try the pressure and sight glass idea.

7 hours ago, Mack Technician said:

Put a pressure gauge and sight glass on the line into pump and get the actual rolling pressure reading. See if it really is a quirk. You have electronic V-Mac pump or mechanical? 

V-Mac

My first thought was we were losing prime but have come to realize that we aren't.  As soon as you turn that key off and try again it'll fire right up or try one more time guaranteed.  You could crank it for 30 seconds and it'll never fire, you could do this 4 times and it'll never fire.  Turn key off and back on and crank a second and poof its running. 

Have owned this truck for over 20 years so know it inside out.  Have had trouble starting it lately, crank it for 30 seconds and it won't go, crank again and it won't go. Turn key off and pump up injector pump and it'll fire up instantly. Just seemed strange.

Have now figured it out that if it doesn't start within the first 5 seconds of cranking, turn key right to off, try again and it'll fire right up.  Next time it might fire right up too.

So its almost like the fuel isn't getting turned on.

Its a 95 Mack with the E7 350.   Only thing I'm thinking is that its the computer or may be the voltage isn't right somewhere.  So it never leaves us stranded but the first time in the morning it may not start right away until you try a couple times and turn off the key all the way each time.

Any ideas???

TIA

On 3/27/2019 at 6:21 PM, JoeH said:

I had a slight miss on my 95 e7-350 last year, 2nd set of fuel filters cleared it up. Almost sounded like the Jake brake was engaging at higher (15-1600) RPMs.  Pulling the Jake wires off the heads eliminated that possibility. First set of fuel filters made it good for a day or two, second set made it go away, hasn't happened since. 18,600+ hours, 250,000 miles, original engine, never rebuilt that we know of.

  Only ever get 26 psi boost out of it, would love to know how you guys get 30+ psi! This dog is no maxidyne, we thought there was something wrong with the engine because it just didn't pull like we thought a Mack 350 should. But we had only ever driven endt676 maxidyne 2 sticks prior, and this truck makes the same boost they made. We just had to get used to a totally different power band.

95 e7-350, also only 26 lbs of boost. Pulls good tho. Our 427's get over 30lbs. 23000hrs on the 350. Only time I've ever remember a flutter issue the the throttle threw a code and had to replace the foot pedal

If you tap the dash to the right and below the speedometer, thats where the buzzer is.  Quite often ours quit but start once you tap where the buzzer is situated

On truck 2 we had the issue and it was cracked head port which would allow intake air from turbo to pressurize coolant system.  coolant never leaked back tho when it was stopped.  Heads got checked for cracks was how they found it after we did so much other stuff

Had the peanuts in the power divider giving us grief and clunking.  If we engaged the power divider it wouldn't do it anymore.   46000 mack rears airride

I think my 95 and 97s are terrible.  Have the butterfly in the exhaust too which helps as the Jake isn't much help

I did my 95 Mack, it had eaton rears and Mack front axle.    I was able to get the rears from a truck parts shop but the Mack front I had to get from Mack.  I couldn't find any at a wrecker.   Prices weren't that bad but I'm not sure what the

rear mack ones will cost.   In fact I can't remember what I paid for any of them now.   The bearings took some figuring out and a good old parts man came too my rescue as numbers changed a bit.

I jumped to 24.5 from 22.5 as well and now all my trucks and trailers have the same tire size which is what I wanted.

We've had issues with vibration at 55 mph and king pins and bushings are wore.  Sometimes we can change front tires side to side and it goes away.   

A drop in 427 from Mack cost me $12000 canadian.  This was quite a few years ago. With labor and extras it was pushing $18000.   Maybe cheaper in the States but it'll be up there.

on the 97's the relay and fuse panel is under the dash in front of the passenger seat.   Not sure if the 2003's are still there or not

The clicking is probably the relay, I have had to replace the motor pump assemblies before.  Easy job on my 1997 Ch's so should be the same as yours.  You could always put a test light on the wiring when you unhook from the motor and get someone to push the button.   The pump is attached to the washer fluid reservoir.

I have a 1995 ch with the electronic 350 and a 9 speed and I think it is great.  Purchased it when it was about 5 years old.  First thing we did was pull the injectors and pump.  The injectors were wore and this really spruced it up. The engine now has 22000 hours and 1,400,000 km.

I added a turbo boost gauge as well and maximum pressure for it is about 26 lbs in the cold weather.

I have 2 other ch's with 427's and one with a 454.

We drag raced the 350 and the 427 each hauling tandem loads of grain in the field and they stay side by side until you get to the last couple gears so I see no reason why it should feel doggy.

Also I've never seen my pyro over 900 degrees ever on the 350

Hoping this helps you a bit

Glen

My Electronic 95 350 makes 20 lbs boost. My 97 427's make 28-33 lbs of boost.

I thought 20 was low too but it is the specs of Mack and it pulls great. Service manager gave me the specs as we thought we had issues as well.

Gauges arent all they are cracked up to be either, I'd check gauge and see what specs are before trying anything else.

This is different style. Was there more than one?

http://m.ebay.ca/itm/221246183438?nav=WATCHING_ACTIVE

Hope this works as I'm not to familiar with mobile app

Well he only lives a couple hours from me. Would love to see it

Had that happen on a 300+ years ago, Put a new dipstick in and never got the peice out until we pulled the pan a couple years later to do a bearing roll

I had an 84 2 valve and an 87 4 valve, both 350's. I always thought the 4 valve pulled harder.

When the peanuts were wore on my 46000 diff's they would snap and jump like missing a cog under heavy load. You could feel it all the way through the stick shift. If I engaged the power divider switch this went away. I always wondered if it was caused by front and rear axle tires being new or wore out and not all the same tread depth

Took a pic for you of my spare one,

it is swiveled on both ends, so if you have same part number then that might help you