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Egr Venturi tube!

Agree ! The turbo needs to spool to create heat for the regen if the EGR valve is held open whether being told to by the computer or by the turbo being stuck it cant do it! If the DP sensor Or The Ports are clogged under the sensor the egr valve will gradually l be commanded open by the ECU as it thinks there is not enough egr flow !this creates more soot yada yada Its a vicious Circle! this seems to be one of the most common causes of face plugging pf the dpf From what we see at our shop!

Agreed 100 percent! Forgot is a big one for me these days!😡

I Second and third that ! If the truck is running wait till the parts are in your hands and are accounted for ! Specially Worse These days the parts chain is so messed up by the pandemic shit going on! LIsten GOOD!

The other option you may have! is to back the gland nut out and stuff It with a leather shoe lace around the tap shaft and re install the nut just something to try if its leaking around the tap shaft! DO IT When the tank is low!

Could be ! Any truck chassis ! including a Mack mack used that style bumper on several models

just Create and an account under a a bogus name joe blo repairs or something like that I did that just so I can cross reference parts when the parts guys can find stuff I go look for my self! you can order I'm sure

Yes old cam and new lifters is fine ! If the Cam looks usable it probably is! The problem you have there is Your working with an unknown ! And We are working with what you are telling us! In turn we are offering up the best advice according to our experiences! An over speed would constitute anything much over governed RPM !Back in the day this would happen a fare amount specially on a V8 Because these engines were so quiet! It would sneak up on ya on a down hill with the engine brake on! It Would be easy to look down at the tach and say Holy Crap!!!!! 2500 RPM 😡 Unless you got a good ear and tuned in to your unit Its sure to happen ! Very easy to do! Answer to the question Safe max RPM is Governed RPM! the engine can probably tolerate 2600 How ever Do you want to go there??

Yup joe I didn't want to create an argument about it the opportunity arose to correct the statement here so I took it! 😇 The hundred psi statment was not an un truth just old news that had been revised!😌

The pressure started out At 100 psi when the eteck first came out They lowered it as they had trouble with the EUP orings were hard to seal As I said earlier long as the fuel pressure stays between 60 and 80 full load it will run and pull fine ! The key here is the fuel pressure should stay above 60 when under load! When you stomp on the pedal in a no load condition the pressure should Go Up Not Down! The numbers you posted are good numbers! Very reasonable from what I have witnessed over the years! just sayin

So just something to think on Here ! If indeed this engine had an over speed go on! These old style lifters didn't take kindly to being over speed conditions! The work face is brazed on and would shatter or crack! Personally Knowing what I have seen over the years here ! If indeed this engine got over sped and you are doing all this work , its worth the extra 500 or 1000 bucks to pull the cam and buy A SET of lifters from PAI and replace em! We just done a Cam here Sept 20th 2021 on a 88 RB . Mack parts was twice the price PAI did'nt have the cam at that point So we was stuck with the Volvo Criminalized pricing for the Cam but PAI had the new style lifters for a third less! and in this instance the lifters are the weak point! and if the truck has the old style lifters It may be a safe bet to change em! In my opinion Not worth taking a chance if your going this far! Just Sayin!

Build a plate to install under the egr valve ! How ever after several miles /KMs the egr code will come up due to lack of egr flow! On the older engines this didn't effect performance ! I am not sure on the later models if a derate will occur ! the one I did was an 03 - 04 the guy put 1.5 plus Kms on it with out issue!

Check the compressor inlet tube connections at the intake and compressor end!

Good to know thanx for posting your fix!

The fuel pumps on the a feable on these the shaft seal can give out and they can wear to the point they wont pump !

Sorry didn't read the whole post my bad ! no metal in the pan! So I have seen the pump drive fail on these its a fiber coupling ,is it possible for you to remove the top rear cover of the fuel pump 6 -1/4 inch bolts and see if the pump is turning! althou this has nothing to do with compression its somthing to check! But if it wouldn't fire on ether its likley a compression issue as you are saying! In my opinion your heading in the right direction checking the valve set and push rods! If you got bent rods the engine has likley seen an over speed event!

Bro (Take the advice) posted ! Not trying to be an ass here! But were trying to help! you need check the fuel pressure you need to have at min 60 psi prefer a little more how ever.........! Just sayin! Also remove the elbow at the primary fuel filter from the tank and check for debris in it I have seen rags fuel conditioner lid inserts and rocks stuck in this elbow! several times! just some more things to look for! This will likely show up on the fuel pressure check as low pressure when you stomp on the throttle the pressure will drop off if there is a restriction or a loose gear , where normally it would increase some!

Quick check of the pan plug should tell the tale on this if there are pieces on the plug there you likly have a cam failed or the engine has been over speed and bent some valves ! Just a place to start! also you can pull the valve covers and check to see if the push rods are straight!

also pull the drain plugs on the diffs and check em for pieces !

(Rephrase) There were several software updates that were released to TRY and correct all kinds of issues and several for low power!

I would still check fuel pressure as stated above! Also if its a mack 18 speed disconnect the torque limit switch on the shift cyl at the back of the trans! and see if this helps!

Highly doubt it!

I agree it sounds like the synchronizer this a weak point on the Auto a fairly common Failure specially I its left with the second speed programing in reverse ! This is a theory however ! But it Seems to knock the sycro cone loose from the hub due to its design it seems to happen more frequently on those with the two speed reverse program left enabled!

This Mp7 year was the only one that kept the spinner oil filter of old! Then 2008 they chucked that idea too made it totally pure bread Volvo trash Swedish Vallhunds instead of a bulldog on the hood! Joe I"m A 18 Sp fuller believer ! Even thou I have got a bit of work out of the Mack trans over the years durability wise fuller is as good as any Mack trans and as I have said before cheaper to repair !Mack has innovations that work nice like the multi speed reverse that is nice to the dump application thou! That Is not offered by fuller !the expense issue still remains!

If you measured where Joe said to measure there you WANT to See 24 or better for a 470 hp engine Just sayin! You can MAYBE get away with less on a lower HP engine but not highly recommended ! And 002 thou definitely wont cut it! .002 between liners is OK under the same head As long as the lowest is 24 or better! ALSO note ! Have you pulled the injectors? Were there any with carbon on the bottom of the bore where they seal ? We have ran across them where the injector COULD NOT be removed from the head even with a porta power they were so clogged with carbon! And there are instances where the compression can get by the injector sleeve ! Seen it happen. Just sayin