Jump to content


  • Content Count

  • Joined

  • Last visited

Community Reputation

106 Excellent

About turckster

  • Rank
    BMT Veteran VIP

Profile Information

  • Gender
    Not Telling
  • Location
    Lubbock, TX

Recent Profile Visitors

2,733 profile views
  1. When replacing injector(s) you should program their calibration codes and perform a learned data reset. That way the engine ecu relearns idle characteristics and so forth to adjust for a smooth idle. Or, let the engine idle for a while with all accessories turned off so it can re-adjust/learn accordingly.
  2. When you torque the inj. hold downs to 15 ft/lb, 180 deg, back off to 7-8 ft/lb, torque to 18 ft/lb and torque turn to 90 deg that averages 45-50 ft/lb. Therefore there is no way when backing off a bolt that you are going to get 60 ft/lbs. Several years ago there was a recall that require retorque/check of MP8 injector hold downs and the torque spec was 45 ft/lbs. It may be that is the problem, not tight enough. But, what do I know, I'm not an engineer, just a dude that fixes their mess ups.
  3. Use to replace injector cups once a year and some more often on the same trucks it seemed until the most recent install tool came out (88800513). But, I think its also very important that the injector bore, tip bore and conical seat area is clean and pit free (seat area). Proper torquing technique is very important as well. I've seen some techs in our shop zip right through injector replacements only to see them come right back several months later.
  4. If you have air bubbles in your return fuel you will have to determine where it is coming from. Most likely it is injector/cup issue. If there is no air in return fuel and is not hard to start then you have a problem elsewhere. You can reuse injectors but it depends on the injector to cup wear pattern. On the conical tip of the injector if it has a uniform thin wear pattern around it and there are no signs of soot/carbon above it you can reuse that injector. If that wear pattern is thick and thin or there are signs of soot/carbon above it then it is not reusable. Any time an injector is removed the cup gets replace , can not be reused.
  5. The cruise and dash light circuits are not related. The cruise will stop working because of- bad /mis-adjusted clutch switch, service brake switch or that circuit activated, Fuse, short/open in circuit.
  6. There are 2 different fuse blocks (that I know of), I only have a picture of one, hope it is correct.
  7. There are 2 types of electronic viscous fan clutches, the Borg-Warner and the Behr type fan clutch. The Borg-Warner is huge and probably what is on the engine. As stated above, unplugging the B/W fan clutch should engage it within 30 seconds according to service info (usually happens immediately). If the engine is equipped with the Borg-Warner fan clutch and it does not engage then it must be replaced and updated to the smaller Behr type fan clutch and kit. It also needs to have the EECU software updated.
  8. I never said it was a bad transmission, I just don't care for it and I don't think it would be a good trans choice for the OP"s question. BTW, I doubt I'm alone on how I feel about the Allison trans.
  9. Personally, I would go for the Mdrive. The least expensive rout would be a manual trans but with it comes routine service(clutch adjustment). The Mdrive requires none of that but, as pointed out above, is expensive come clutch time. I'm not a fan of the allison trans. A few oil field companies tried to run some in their fleets locally and they were just a pure pain in the tush. Plus, any automatic trans robs horsepower.
  10. The Ishift/Mdrive have a diaphragm clutch which is non adjustable. Volvo and Mack are pushing to have customers spec the AMT transmissions and I think they have been a pretty good trans. Most drivers that I talk to really like them.
  11. The speedo sensor has an ohm value, the circuit does not have voltage other than what the sensor itself creates when the truck moves. Depending on type of sensor, the ohms should be approx 100-200 ohms, typically around 150-170 ohms measured either from the sensor itself or from the VECU.
  12. I'd check the bellhousing to make sure the mount flange still has some taper--hasn't been run loose. Also looks like it may need an input shaft by the looks of the throw-out bearing area. If the bellhousing is in bad shape then the only good thing its good for is parts.
  13. Some coolant reservoirs have a burn hole in the pressure cap/overflow side that can cause coolant loss. Pushing coolant can also be caused from a bad air compressor head, leaking egr cooler, bad injector cup and cracked head.
  14. After idling for about 5-10 min check in each fuel tank where the fuel returns inside the tank. If there is bubbles in one or both tanks then the cause is most likely injector cups. To make sure, check the small plastic cap at the fuel filter base (next to the primer pump) is not wet from fuel leaking around it. If so, the problem is the cap---leaking o-ring sucking air into system. You can get a replacement cap from Mack. If ok make sure 7th injector air purge "t" check valve isn't leaking air back to fuel system. Remove the fuel line from the "t" fitting, turn key on and there should be no air coming out "t" fitting. Some '07 emission engines had the air purge line, some didn't . If both above items look ok then most likely you have injector cup issues.
  15. Never seen that particular situation. Is 10% the highest duty cycle the 7th injector gets or does it get higher? Is aftertreatment fuel psi low across the board? I've had to replace the shut off valve because of low fuel psi.
  • Create New...