All,
Time to close this one out I think - I hope that hasn't tempted fate
Coming to the end of 2,000 miles around the UK, lots of warm / hot starts thrown in for good measure - no problems at fuel stops - all looking good and back to pre-problem starting when hot, ie: first turn of the key
.
So, what did we find / repair to solve / cure the problem - in short, NOTHING
What trouble shooting /routine maintenance did we undertake in our quest for a solution ....
In short, over the space over several weeks / journeys ......
We hooked up pressure relief valves and some pressure gauges in the line between the HEUI pump and the engine oil gallery (injection actuation port) for external / third party monitoring (and confirmation of the operation of the IAP sensor) - this was made much easier by the fitment of a 'T' on the outlet of the after market IFS filter body
We observed that output from the HEUI pump was satisfactory / adequate for starting at ALL engine temperatures - so perhaps I didn't need the new HEUI pump that Finnings / CAT over here advised would cure the problem
We noticed that output pressure would decline / drop on the engine side as soon as the motor was turned off when the engine was hot - and not return to a sufficient pressure to allow the ECM / injectors to 'fire' when trying to restart
Hoping it was nothing more serious,
we 'bit the bullet", covered all the cream carpets in the bedroom, and pulled / replaced ALL the injector O-rings - as suggested by CAT / others on this forum
No oil compression O-rings were broken BUT ALL were showing their age (16 years) and had significant witness marks where the O-ring was positioned at the 'gap' in the back up ring
It was interesting to find that only 2 of the 12 injector clamp bolts required 'cracking' - the remainder were only finger tight, if that, and wound out easily
At approaching 35,000 miles - we also adjusted the valve lash / valve clearances - and found that only 2 out of the 12 clearances were anything like 'correct' - the remainder had at best oil drag clearance, many not even that
Having re-assembled everything, the engine started (cold) as expected - fast idle to normal operating temperature, then .....
engine started first turn when hot
Several hot starts later - connected to CAT ET - it was time to rebuild the bedroom and put the coach back in running order
So, 2,000 miles later, the engine hot starting is still performing as it was 'pre-problem' ....
No, that is not true .....
the engine now sounds far 'sweeter', wants to accelerate quicker, cruise faster, appears to have "more power" -
around the UK on the motorway / freeway network the coach is happier now @ circa 65 mph - doesn't drop gears when climbing gentle inclines but 'knuckles down' increases boost pressure and "pulls like a train" ..... and over a couple of fuel 'fill ups' appears to be doing about another 0.8 mpg
What would I do differently next time ....
I wouldn't blindly believe the Finnings tech guys, (and save myself the cost of a HEUI pump
)
I would hook up external pressures gauges to determine exactly where in the system the pressure is being lost,
I would pull / replace the injector O-rings as a matters of course - and given the witness marks on those replaced will schedule routine replacement in a few years
My own copy of CAT ET has been a god-send and paid for itself many times over as well as helping with correct toque settings etc
Apologies for the long post - hopefully it might help somebody else's trouble shooting somewhere down the road
Finally thanks to all who contributed / made suggestions along the way, "we got there in the end"
Safe travels
Ian S.
Exeter UK - although travelling around Scotland at the minute
2005 CC Allure 430 #31231
CAT C9 - 400 bhp # 9DG02935
Linear Mode
