• Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!

Mack MR688S Low power in high gears

sschmied1965

sschmied1965

New Member
Joined
Aug 22, 2017
Messages
4
Location
Illinois
Occupation
Mechanic
I have a 1998 Mack MR688S .I have just recently began a problem of no power in high gears .When going from a dead start go all through lower gears no problem goes up to 2000rpm in higher gears as you go hard to get to 1500rpm and no power .I have replaced fuel ,air filters checked turbo spinning free no restrictions .it is getting worse the beginning was that of a stutter in high gear like you took foot of accelerator pedal for a second and it would come right back and it may do it 2 to 3 times then go away .now to add I have no codes at all.the check engine light comes on at start like usual and goes out after engine start and you step on the pedal in drive way full rev 2100 rpm .any help would be great .thank you
 
walkerv

walkerv

Senior Member
Joined
Jan 21, 2016
Messages
1,125
Location
wingate nc
sschmied1965 said:
I have a 1998 Mack MR688S .I have just recently began a problem of no power in high gears .When going from a dead start go all through lower gears no problem goes up to 2000rpm in higher gears as you go hard to get to 1500rpm and no power .I have replaced fuel ,air filters checked turbo spinning free no restrictions .it is getting worse the beginning was that of a stutter in high gear like you took foot of accelerator pedal for a second and it would come right back and it may do it 2 to 3 times then go away .now to add I have no codes at all.the check engine light comes on at start like usual and goes out after engine start and you step on the pedal in drive way full rev 2100 rpm .any help would be great .thank you
Click to expand...
E tech engine? If so check your fuel pressure with a guage before you o throwing money at it. The fuel transfer pumps have a tendency for the plastic gear to get loose on the shaft.
 
You must log in or register to reply here.
Top