Mack E7 question

[Jeff D.]

buddy barry has the blue mack which is a E7and the thing is acting up. driving it at highway speed, all it does is act as if sme one is turning the key on and off.

Tell Buddy Barry I said "welcome too my world".

I hope they can find the reason and fix it for him.

I may have jumped the gun with the code info for Serve, I dunno.
I was just searching through my Mack stuff and my 2003 Mack CX613 doesn't say E7 anywhere on it, or in its paperwork. Rather it says "E-tech". I dunno if that's a completely different animal than the E7 or not.

If so, Sorry for the mis-information Serve, and others.

(although the problems seem to have a very similair nature, either way)

[Serv]

Serv, I've not messed with the sensors at all yet. My truck has idled like it does from day one. At just over 200k miles I lost 3 lobes off the cam from cam followers seizing. They pulled the engine down (front geartrain included), and replaced everything bad. I hope they would've cleaned the metal from the sensors at that time but Might be something for me to check. That'de be great!! I wish I had an expert to work on mine. I've not stepped foot in my local Mack shop in better than two years since all my troubles. I have to travel 180miles south to another Mack dealership now for any work my regular independant shop can't do. They (my indep.) are not "Up" on all things Mack, but do their best for me.

I went and took some pics of the ground the dealership added on mine to see if it is connected to the same part. It connected inside to the back of the instument cluster, came through firewall (first pic black wire right of box), and goes up along the inside of the overflow tanks to the connection I'm pointing at.

I also took a pic of another common Mack fix. The AC switch. The little push button one burns out. I replaced mine with a toggle switch. It's hard to wire in being it's against a board, but better than continuously replacing the stock switch.

Sorry for the late response and thanks for pics. You are actually pointing to the box that I am referring to in your second pic.

The Mack guy down here says when that fails internally, all kinds of random electronic issues can happen.

As for the wiped lobes at 200k, how did they get away with not doing a rebuild after all that metal was sent through your engine?

[Serv]

We have had turbo prlblems, oil leaks, electrical, and whatever else. The one tractor is always down it seems and the warrenty takes care of it. Two other new one is having computor problems. We have 3rd axles on all of them and pull side dumps and belly dumps with them, also lowboys. Next tractor will be different with 550 or 600 Cat. Our old 2000 Macks have really done well but these new ones are a head ache Serv. Ken

Thanks for the info.

come join us over @ http://WWW.BIGMACKTRUCKS.COM



They are some knowable folks there & we will be glad to have yall




bulldog

I joined about a week ago under the same username I use here.

[Serv]

Tell Buddy Barry I said "welcome too my world".

I hope they can find the reason and fix it for him.

I may have jumped the gun with the code info for Serve, I dunno.
I was just searching through my Mack stuff and my 2003 Mack CX613 doesn't say E7 anywhere on it, or in its paperwork. Rather it says "E-tech". I dunno if that's a completely different animal than the E7 or not.

If so, Sorry for the mis-information Serve, and others.

(although the problems seem to have a very similair nature, either way)

You didn't mislead me. The only thing is that my intermittent CEL problem was taken care of the other day when I worked on the truck all night.

Using the cruise control method of pulling codes only reads active codes (constant CEL) so I didn't get anything other than a code 73 which is "speed control set switch" according to your list. So it has to be working and will be a valuable tool when or if we get the dreaded CEL light again.



Back to the intermittent idle problem we have, my driver showed me that when he turns the cruise control on at idle, just one click of the CC made the bumpy idle issue go away without even really raising the idle. I hope I'm making myself clear here. I called my mack guy and told him that and he said he can take care of that by electronically bumping my idle up just a hair. I'll report back if this fixes my problem. So far, I seem to have most of these little thing almost under control.

[Jeff D.]

As for the wiped lobes at 200k, how did they get away with not doing a rebuild after all that metal was sent through your engine?

It was a pretty extensive repair job, but it wouldn't qualify as a complete rebuild. I was told anything worn due to the failure would be replaced.

I called my mack guy and told him that and he said he can take care of that by electronically bumping my idle up just a hair. I'll report back if this fixes my problem. So far, I seem to have most of these little thing almost under control.

Yup yup. I can tell you how to do that yourself, if you'de want to try. It involves turning the cruise's main switch (the left/power) off and on three times very quickly(within a couple seconds). Idle will then fall to 500rpm. Here's the tricky part, raise the rpm to where you'de like your idle to be, with your footfeed, and then hit "set". This will be your new idle speed. The hard part is finding that RPM without going past it. You know how touchy that pedal can be.Maybe you Mack guy has a way to find that "sweet" rpm by using the switches instead of the footfeed?

I can copy the exact procedure from my book for you, if you want to give it a try?

I did try and calm my idle down using this technique, but had to raise or lower the rpm too much to find a calm spot. It may work great for you though.

[King of Obsolete]

thansk, will be right back.


thansk

[Jeff D.]

If anyone is going to try that Mack idle adjustment I mentioned I should also mention a few things first.

1)There must not be active fault codes present (no "CEL" on)

2)This won't work on an automatic equipped truck. You can get the idle to drop with the 3 quick off-on switches of the cruise power, but it won't set to the new RPM, and will go back to it's preprogrammed RPM once the cruise power switch is turned off.

3)The clutch pedal must be pressed atleast once after the new RPM is set. Otherwise it'll revert back to the previously set RPM.

Mack also recommends an idle RPM between 500-750.

FWIW, I found my truck idled smoothly at the 500rpm level, but engagement torque is marginal. I didn't want to be stalling it all the time, and 750 seemed too high to me.

[Serv]

Thanks for the idle adjustment procedure. I think it helped me further narrow down this erratic idle.

I tried it and found that no matter what I set the idle to with the above procedure, my idle was still intermittent. And on the same hand, no matter what I set the idle to with cruise control at idle (whether it be 500 or 1000 rpm and anywhere in between), the intermittent prob would not be there, period. So I'm thinking is has something to do with the sender on the throttle pedal.

Does this make sense to anyone here?

[Jeff D.]

I tried it and found that no matter what I set the idle to with the above procedure........

........ So I'm thinking is has something to do with the sender on the throttle pedal.

Does this make sense to anyone here?

Serv, I don't understand the workings of the engines electronics well enough to guess if it is related to the throttle pedal sender, but.................

Here's what I've noticed with mine:
It'll idle "jumpy" at it's current idle rpm of 600 when ever it's not cold (above 150degree's, and no engine load)

It's "jumpiness" is a quick 50-75 bump in RPM at about a once per second frequency.

Any slight load on the engine, whether that's just the AC pump or even the air compressor while building air, is enough to smooth out the idle so it's perfect.

If I increase idle to 700rpm the jumpiness sound more like a slight miss, and at 800rpm it's perfectly smooth.

Mine is the same whether on cruise, or not.

I've been told by other Mack Drivers(not professional mechanics) who've had this idle issue too, that the fix is testing & replacing of faulty injectors, fine adjustment of the rack, and computer reprogramming. No mentions of sensor or sending unit's although that doesn't mean it's not in your case.

[King of Obsolete]

don't ask, will be right back again, LOL

thansk
KoO
Published Author

[Serv]

Serv, I don't understand the workings of the engines electronics well enough to guess if it is related to the throttle pedal sender, but.................

Here's what I've noticed with mine:
It'll idle "jumpy" at it's current idle rpm of 600 when ever it's not cold (above 150degree's, and no engine load)

It's "jumpiness" is a quick 50-75 bump in RPM at about a once per second frequency.

Any slight load on the engine, whether that's just the AC pump or even the air compressor while building air, is enough to smooth out the idle so it's perfect.

If I increase idle to 700rpm the jumpiness sound more like a slight miss, and at 800rpm it's perfectly smooth.

Mine is the same whether on cruise, or not.

I've been told by other Mack Drivers(not professional mechanics) who've had this idle issue too, that the fix is testing & replacing of faulty injectors, fine adjustment of the rack, and computer reprogramming. No mentions of sensor or sending unit's although that doesn't mean it's not in your case.

That sounds strikingly similar to what mine is doing. Have you tried setting the idle at ~600 then the cruise control at anything above that whether it be 625 to 700? Mine clears up no matter what RPM while idling on CC. I'm going to try putting a load on mine today while normal idling to see if it does the same as yours.

I'm guessing that your idle prob is unrelated to your engine/power cutoff problem.

[Jeff D.]

I'm guessing that your idle prob is unrelated to your engine/power cutoff problem.

I'm guessing they are not related. I think possibly the problem with the guages and the occasional engine stalling might be related, although they never happen at the same time. The speed at which they'll quit and start working is similair though. And they only happen very occassionally, maybe once a month on average. That's why I don't get too worked up about the problems, and as for my idle issue, that doesn't seem to have any negative effects other than sounding weird, but I sound weird sometimes too so............

don't ask, will be right back again, LOL

Okie Dokie, we're still waiting here patiently...........well CB's getting alittle antsie, but........

[Serv]

Just to update, my intermittent idle problem completely went away after my local KW/Mack dealer did a top end adjustment of the valves and injectors. Or at least that's what they said they did. It cost me $450.00 but it's getting a little better fuel mileage and idles smoother than it has since I've owned it. I'm finally starting to like this truck now.

[Dozerboy2]

anybody here know the torque for 350 E7 main, rod bearings, and head bolts?

[Iron Horse]

Do the trucks have an idle step up to increase the idle when the AC is on ? If so it may be a faulty AC sensor . Mack really blew it with these engines , they are garbage . They will do a cam and lifters every 500,000 kilometres and then they will do a crank . The only good one is one that is fitted with a series 60 .