2009 Kw K108 Cm 871 Sid 251

[Rocco K108]

Hello everyone and thanks for letting me post here. I have a 2009 Kenworth K108, Australian, with a CM 871 @550 , 1.4 mil km and 27500 hrs. There is a working Roadrelay 4 fitted. I bought this truck September last year privately, with a lot of work done recently with invoices. The truck sometimes it's hard to start. It can be staying one week with isolated batteries and start after half revolution or take 10 times before starting.. lifting pump running, batteries decently new.. I fitted new lifting pump and gasket firstly, nothing changed. Then I noticed the starter motor sometimes being very weak even after long hours driving, so I replaced it. But no difference. I replaced the shut off solenoid, no difference. Still no check engine light coming out and didn't know how to read the Roadrelay 4. In the while I start learning about the Roadrelay 4. I actually started looking into the Roadrelay 4 when it came out " Sid 251 active with a number increasing every time the error comes out. Sometimes it let me delete the error and it stay clear sometimes it won't delete. I redone the major earths, at the beginning seems very better but after the third day it started to get worst and worst. I Isolated the battery and it started and got better. Last week I turned right a bit quickly into an intersection and the engine light came out, fan on, derate , pull aside, wait a minute, turn it off, it struggles to shut, it shuts, Isolated the batteries, try again, perfect. The day before this, after 2 days nearly of running continuously, it struggles to shut, like the solenoid is playing funny.. at the end it makes to shut the motor. Try to crank, and the starter motor was very weak.. so I Isolated the batteries, turned on again, went to sleep with the bunk cooler on, in the morning started well. Then in the evening shut while turning right, then again after 5 hours driving. Then the next day I bypass the battery isolator. Since then it's always started, the sid 251 came out a couple of times, but the crank strength it seems to be more consistent and stronger. Earlier, I checked with the multimeter and alternator is in the high 13volts at idle, same as the gauge on the dash, same as the voltmeter on the inverter. The voltage reading on the road relay 4 it's around the 11.5/12.5 now with the battery isolator bypassed and before was in the low 11 v. Any help would be highly appreciated.
Thanks in advance

Rocco [/size]