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Does the Check engine light come on when this happens?? If not then and you have a mack 18 sp trans There is a switch on the range cyl ( Or should be)( if not the wires will be there) that can cause the ECU To think the engine is in low it will cut the power in half if the wires re rubbed together or broken they could be causing you greif! Just another place to look Had this happen!

Yup pricey Parts Are getting scarce And can be anything from a bad injector to a rod bearing to a dropped valve seat! All expensive with the exception of an injector You get the parts and send it up to Canada here I'd Love to work on it for ya! LOVE V8's

Most everyone else (paccar ,freightliner and the like ) have been using this setup for quite some time volvo/mack is just catching up! Just like they will likley be changing the fuel system to common rail at some point! they were leading edge at one point they have fallen behind somewhat !

FAULT COD >E IDENTIFICATION TABLE - VMACIII - 1998 & NEWER 1-1 Engine Oil Pressure Sensor 1-2 Barometric Pressure Sensor 1-3 Fuel Temperature Sensor 1-4 Ambient Air Temp Sensor 1-6 Starter Input 1-7 Engine Coolant Level 1-8 (ASET CEGR) Estimated % Fan Speed 1-10 Aux. Cooling Relay Output 2-1 Engine Coolant Temp Sensor 2-2 (ASET IEGR) Boost Air Pressure Sensor 2-2 (ASET CEGR) Boost Air Pressure 2-3 Intake Air Temp Sensor 2-4 Trans Oil Temp Sensor 2-5 Front Drive Axle Oil Temp Sensor 2-6 Rear Drive Axle Oil Temp Sensor 2-7 Engine Oil Temp Sensor 2-8 (ASET CEGR) Combustion Air Temperature 2-9 (ASET CEGR) Combustion Air Temp Sensor 3-1 Exhaust Temperature Sensor 3-2 Engine Speed Sensor 3-3 Redundant Engine Speed 3-4 Engine Position Sensor 3-5 Engine Brake Output #1 3-6 Engine Brake Output #2 3-8 Trans Splitter Position 3-10 (ASET CEGR) Engine Brake Output #3 4-1 Vehicle Speed Sensor (VSS) 4-2 Fan Clutch Output 4-3 Auxiliary Output #1 4-4 Auxiliary Output #2 4-5 (ASET IEGR) Wastegate Output 4-5 (ASET CEGR) VTG Position Sensor 4-6 Tachometer Output 4-7 Speedometer Output 4-8 Customer Defined Statement 4-9 (ASET CEGR) EGR Valve Mechanism 5-1 Throttle Position Sensor 5-2 Throttle Position Sensor Reference Voltage 5-3 Engine Shutdown Lamp/Alarm 5-5 Electronic Malfunction Lamp 5-6 Spare Relay #3 5-7 Engine Oil Level 5-8 (ASET CEGR) EGR Temperature 5-9 (ASET CEGR) EGR Mass Flow 6-1 Fuel Level 6-2 (ASET CEGR) Turbocharger Speed 6-3 J1708/J1587 Link 6-4 J1939 Link 6-5 All Communication Lost - Engine Shutdown 6-6 Fuel Control Module 6-7 Power Relay 6-8 J1939 Link 6-9 Other ECU Affecting Operation 7-1 Service Brake Switch 7-2 Parking Brake Switch 7-3 Speed Control SET Switch 7-4 Speed Control RESUME Switch 7-5 Battery / Alternator Voltage 7-6 Switched Voltage 7-7 Exhaust Temp Reference 7-9 VTG Actuator 8-1 Electronic Unit Pump #1 8-2 Electronic Unit Pump #2 8-3 Electronic Unit Pump #3 8-4 Electronic Unit Pump #4 8-5 Electronic Unit Pump #5 8-6 Electronic Unit Pump #6 8-9 Solenoid Boost Voltage 9-1 Transport Protocol 9-2 Power Reset Without Key Switch 9-3 (ASET CEGR) Aftercooler Outlet Temperature 9-5 (ASET CEGR) Compressor Discharge Temp 9-8 (ASET CEGR) Auxiliary Output Device #1 9-9 (ASET CEGR) Auxiliary Output Device #2 9-10 (ASET CEGR) Auxiliary Output Device #3 10-1 (ASET CEGR) Internal Sensor Voltage 10-2 (ASET CEGR) 5 Bolt Supply 10-3 (ASET CEGR) Sensor Supply Voltage #1 10-4 (ASET CEGR) Sensor Supply Voltage #2 10-5 (ASET CEGR) Fuel Filter Differential Pressure 10-6 (ASET CEGR) Fuel Delivery Pressure 10-7 (ASET CEGR) Odometer Save Area Failure 10-8 (ASET CEGR) GPS Position Data Not Received 10-9 (ASET CEGR) Watchdog Timer Reset

Yup Now we got more room to put more junk on the frame for the next round of emissions standards. Great!!!

Glen I was lead to believe That The dynatard Cam would still work on a jaked engine (I could be wrong on this ) How ever the jake model you quoted sounds correct But I beleive the turbo should be to be changed for the jaked engine At least I know there were two gauges to set em 85 thou and 80 thou for diffrent turbos! Had to set by turbo number.

A Maxidyne engine will hold on right down to 800 rpms Its not the best thing for em but they generate good power even below 1000 rpm! It is real amazing! Huge power band As for the R never seen one sorry! Might be as stated Restricted upper rpm duno!

Make sure the throttle lever has no wear at the throttle shaft If the lever internal springs are worn it will cause the idle to be erratic . if the lever is good then the governor is worn and heeds to be removed and repaired! OR just live with it!

how's the fuel pressure ? if it has unit pumps it needs 70 psi to run decent, if it has vmac 2 it needs 15 psi min to run right low fuel pressure fuel transfer pump failing or sum bad fuel lines coming to and from the pump also fuel drainback valve issue

The fixed shift rail can break and also cause this !u need to lift the lid off and look! also a loose lock bolt on the air shift could be an issue

possibly Injector Cups

25- 30 psi

Codes ????

Or Loose wheel bearings

I'm a bolt and pry bar guy as well the kent tool only comes out when it got a stuck one!

Its possible the boost pop off valve has stuck open ! its the brass fitting hose and 1 inch steel pipe that lead back to the exhast pipe from the inlet and egr mixer tube!

HELLO???? This is a Mack forum bleeding the air from the cable is a little tough! that assist is constant feed . ARE you driving a volvo or a mack?On A volvo hydralic Clutch you sumtimes have to stand the slave cyl upon its end to bleed em!

Yup keep an eye on both ends the coolant and the trans I just ran across the beginings of one of these the other day! Fortuantly didnt wreck the trans yet! we ussually get em after the damage is done!

injection lines yada yada you need a donor engine to do this it would be too pricy otherwise

Make sure you observe the width of the roller on the pump you take off if its a wide roller your OK if the roller is a narrow roller you can cause your self problems Compare the pump your putting in to the pump your taking off! Wide on narrow is ok narrow to wide is a problem.

These were notorious for loose valve seats and worn valve guides! listen carfully after the engine is warmed up, when shuting it down you may hear a pop pop coming from the head area!That is tipicly a valve seat.

You need to preasure test the Whole intake system for leaks ! I have seen intake gaskets blow a chunk out! cap off the hose at the turbo side of the charge air and put regulated shop air into the hole where the puff limiter reversing relay WAS and crank it to about 30 psi you will likly find a cracked cooler or intake gasket blown out! OR At idle run propane or ether around all of the intake system if ya hear and increase in RPM you have found your leak pay real close attention to the ends of the charge air core they tend to crack!

If you have steel rims check for a cracked inner wheel! (Usually) power divider problems are an fairly evenliy spaced clunk along time in between usually caused by missed matched tires.

Thanx for clearing that up Staxx I Kinda wondered about the bearing issue ,they we only did half a dozen trucks here and heard no more about it, as time went on the issue kind of faded!