Help - E7 Renault Engine misfire and losing...

[MR688S]

Throttle response.  I just got this MR688S out of the Postal delivery yard this morning and it limped out missing on one or two cylinders.  I took it for a test drive on a back road about a mile and it got progressively worse and now just idles with very little throttle response.  Trans was good.  Air cleaner clean.  Now, looking at clogged fuel filter/s on the drivers side of the engine.  The unit also has a DAVCO clear external filter - I don’t know what it does beyond being the first filter, then fuel goes over to the engine filters.

Any thoughts?

Thanks! 

[41chevy]

Water separator.

[MR688S]

41 Chey -  thanks for the reply. I put myself through Mack school that day and that filter water separator was a complete locked up mess the bottom of the unit was black we cleaned it all out with brake cleaner and got it I got a new filter in truck started right up it’s been running great ever since it’s got a little air leak in the in the Davco fuel filter separator it drops down about an inch every man every two hours so we’re gonna work on that and see where the leak is it’s not a not an external leaks but other than that the trucks running great now 

[Miami Cossack]

I see fuel filters and separators that look like they have been on the truck ten years. People overlook this stuff a lot. Coolant filters too. They want to replace them when they rust out and overheat. The quality of drivers these days is pathetic. They do zero inspections or have no mechanical aptitude or caring. They just want a paycheck for holding onto the steering wheel while they gab on the phone. 

[MR688S]

Miami Cossack - Thanks for the reply.  I rebuild wrecks and work on engines all the time.  OJT Mack school was cool.  I learned that the Postal guys don't do much maint beyond oil, filters, belts, etc... the truck was never cleaned, caked with dirt and grease on the suspension, engine, etc...  I'm not for pressure washing engines, but some degreaser and a bit of water from the garden hose goes a long way.  I'm steam pressure washing the undercarriage and detailing the engine this weekend.  I spent time on the Davco Filter/Separator and found some gunk in the ball check valve that was letting the reservoir drain around the filter.  She's staying full now. 

This unit is governed at 60 mph/1700 rpm with the Allison Automatic 6 speed. (I'd tell you the model number, but it's so covered with dusty oil gunk, that I've decided to clean it before I start looking for the label and all those details.  It's probably an HT4060, but we'll see when we see.  It's definitely electronically controlled.

Anybody ever shut off the governor on one of these units?  I understand the E7 doesn't like to go over 1800 rpm, but I'd like to get in that neighborhood for a 63mph cruise at least.              I predict it's an ECU re-program.  If you've done one, please let me know.

The only other large item to deal with is driveline vibration.  This truck has 458,000 miles and it appears that the U-joints may never have been changed, and possibly not greased very much.  The truck has a large auto greasing system, but the grease reservoir is basically empty.  Looks like it takes about 2 liters of grease.  I'm sure the carrier bearing is not a happy camper either.

The vibration comes under torque, usually uphill in high gear when I put a bit more power to her.   I'm going to just start swapping the u-joints and carrier bearing and checking the driveshaft yoke positions, then look at pinion bearing adjustment and transmission yoke play, etc...  somewhere in there things are pretty loose.  I lost a driveshaft due to u-joint death in my old 58 Chevy Suburban when I was dumb and in college and this vibration sounds the same,  just tandem axle bigger.

If there are any common Mack MR688 problems related to any of this stuff, everyone, please feel free to jump in with your suggestions.

Thanks to everyone for reading and responding to this project!

 

 

 

[MR688S]

Oh yeah, I forgot to mention that all the diagrams online for the Mack E-7 engine show and say that the two filters under the left/USA driver's side of the engine are Fuel Filters.  They even give a fuel filter part number for them.  I reality, they're OIL FILTERS on that tandem manifold.  Looks like all the fuel is filtered through the DAVCO Unit and that's it.

If anyone knows of other placements of secondary fuel flters on the E-7 Renault engine, please let me know.   I haven't been looking real hard after removing the two oil filters and getting them back on the engine and getting the DAVCO unit working properly with a new filter and cleaning.  It will be nice to know that I've hit every filter that's in that system and there are no other variables.

Thanks!

[Miami Cossack]

To turn the gov off you're probably going to have to go into the ECM. I get a lot of fleet stuff that is governed, especially buses and I find that if the ECM is sent to the stealership to be flashed and you DON'T specify the governed speed, it will come back with no speed governed every time. The driver loves it. I mostly do Cummins, Mercedes Cat and Detroit. Mack is likely the same as everything is electronic now.

[MR688S]

1 hour ago, Miami Cossack said:

To turn the gov off you're probably going to have to go into the ECM. I get a lot of fleet stuff that is governed, especially buses and I find that if the ECM is sent to the stealership to be flashed and you DON'T specify the governed speed, it will come back with no speed governed every time. The driver loves it. I mostly do Cummins, Mercedes Cat and Detroit. Mack is likely the same as everything is electronic now.

Thanks MC.  I'll see what the local Volvo/Mack people say about that and the price.  I run mostly Cummins ISX15's in Internatiional Prostars and I'm happy with them as long as we keep the EGR/DPF Systems clean.  These Macks are for a local haul contract that's fairly casual, so, they're not going to be running all the time and we can do maint. on them easily.

[MR688S]

1 hour ago, Miami Cossack said:

To turn the gov off you're probably going to have to go into the ECM. I get a lot of fleet stuff that is governed, especially buses and I find that if the ECM is sent to the stealership to be flashed and you DON'T specify the governed speed, it will come back with no speed governed every time. The driver loves it. I mostly do Cummins, Mercedes Cat and Detroit. Mack is likely the same as everything is electronic now.

Also, MC you mention Mercedes - as in Freightliner Cascadias with the "DD" 15???  It appears that once Mercedes was given Detroit Diesel, they just canned the Series 60 and put up the Mercedes engine and called it a DD whatever.  I see lots of plastic and aluminum parts on those engines and they scare me.  I saw a video of the top end aluminum cam/rocker holder blocks having their hold down bolts just strip out of the aluminum blocks with helicoils gone bad that are supposed to hold them in place.  Why would they put aluminum on such an important part of the engine.  When the bolts go, the engine becomes pretty useless.  I would have a hard time trusting the repair on those blocks after that.  Have you experienced this?  Let me know what you think.  All the Best!

[Miami Cossack]

A lot of that was emissions, they couldn't meet the emissions as it got stricter. I was told that they still make the series 60 for export. The Detroits are a fortune when they break something and the old days of fixing them quickly is over. That valve train girdle thing has to be replaced as one big expensive assembly if anything breaks and it's a fortune. Everything is machined fit and has to be replaced together like the European car engines. You can't just take parts out of one engine and bolt them into another and run it. A lot of this is like with car assembly, these decisions are driven by union honchos to make assembly easier. Also, it has to be compatible with robotic processes which may not be an improvement from a quality standpoint, merely it facilitates a step in the assembly and nothing else whatsoever. They weren't really concerned about what you or I would be going through as that engine aged. I would rather have a man or 18 liter Klimov, even an Cat 3406B. I feel for anyone trying to make a buck with these new trucks. Stick with Cummins/Insite and do your maintenance.

Edited September 4, 2020 by Miami Cossack

[MR688S]

On 9/4/2020 at 1:08 PM, Miami Cossack said:

A lot of that was emissions, they couldn't meet the emissions as it got stricter. I was told that they still make the series 60 for export. The Detroits are a fortune when they break something and the old days of fixing them quickly is over. That valve train girdle thing has to be replaced as one big expensive assembly if anything breaks and it's a fortune. Everything is machined fit and has to be replaced together like the European car engines. You can't just take parts out of one engine and bolt them into another and run it. A lot of this is like with car assembly, these decisions are driven by union honchos to make assembly easier. Also, it has to be compatible with robotic processes which may not be an improvement from a quality standpoint, merely it facilitates a step in the assembly and nothing else whatsoever. They weren't really concerned about what you or I would be going through as that engine aged. I would rather have a man or 18 liter Klimov, even an Cat 3406B. I feel for anyone trying to make a buck with these new trucks. Stick with Cummins/Insite and do your maintenance.

MC - Thanks for the info.  I'll stay with Red Engines on my OTR Tractors.  Meanwhile, I'm playing with two Mack MR688S COE tandem axle 80K Tractors with the Renault E-7 E-Tech Engine - 2006, 2007, just before the M-7 came out, well, a "special" US Postal Service Contract run of the COE's.  At least they have DAVCO FuelFilter/Water Separators - easy to drain, swap filters, fill and GO!  I'm still looking for E-Tech E-7 Manuals to show how to flash the ECU to get the governor turned up or off.  All the Best!

[james j neiweem]

Was the E-7 engine a Renault? I thought it was a 673 stroked.

[Mark T]

That Davco filter isn't supposed to be full. That's how they show they're in need of replacement .

The higher up you see the fuel, the dirtier the filter is and needs to be changed.