SOURCE: RPM Oscillating
have you had the vehicle speed control reprogrammed if not that could be your problem
SOURCE: Intermittent boost pressure
a bad pop off valve. Or boost controller. Sadly with 100K on the speedo things are far from mint.
SOURCE: 99 dodge cummins. Have a code of P0237 turbo boost sensor low v.
The Volvo S80 did not come with a cummins engine
SOURCE: 97 legacy no boost
The second turbo simply follows the first when the system activates it by bringing it in parallel with the first. The first turbo is only designed for a 1200cc motor so it can not deliver enough compressed air at revs for a bigger motor so they arrange to bring in a second turbo of the same size when the first one runs out of puff.
The first turbo is a semi-mechanical device. The ecm raises the boost level at which it operates but it should be producing some boost regardless.
So concentrate on the first turbo.
Isolate it from the ecm control system
(There is a misleading tip on youtube involving pulling hoses but it is misguided, the comment is ignorant, and I do not recommend it)
Instead, as per the manual, on the first turbo remove the system pressure lines from exhaust and wastegate. Loop a short piece of vacuum hose from the primary turbo output to its own wastegate.
Blank off the system hoses you disconnected. Fit a boost gauge, drive it and observe the boost gauge readings (manifold pressure). If the primary turbo is OK this will make it operate at a lower boost level (5-7psi ?) than the system control (10-17psi) but it will be a purely mechanical operation which will isolate where the fault is.
If there is no boost and the pressure stays zero down then the turbo is not working. Check for the wastegate being stuck or maladjusted. If that is working then you bave a faulty turbo for whatever reason. Maybe there is a loose bolt stuck in it from the engine rebuild?
If the turbo is working OK then it points to an electrical issue with the the boost control solenoid which is inside the wing near the vacuum tank beside the battery compartment. The control voltage from the ecm usually pulses it on/off at a fast rate to give a measured control and it may be stuck. Maybe it is the ecm or maybe the valve. But before you go dig it out, first check the pressure lines such as 10 and 23 are connected or not reversed at their connectors where they go through the wing (just behind the battery)
Good luck
19 views
Usually answered in minutes!
×