Engine Dies While Downshifting

[Coconut]

The suspicion about a problem with SAI system would appear to be a possibility.

The purpose of the SAI System ( Secondary Air Injection System ) is to reduce harmful emissions from the exhaust.

This is done by introducing "Secondary Air" via Reed valves into the exhaust circuit
under controlled conditions at certain engine speeds, determined by the ECU,
which helps promote secondary combustion of the exhaust gases
within the exhaust ports and headers.

This secondary air is admitted under the control of the SAI Solenoid valve, attached to the Airbox.

The following is purely my own guess at what might be happening :

If one or more of the hoses from the SAI Solenoid valve to the Reed valves were detached or split,
I would expect / suspect that the mixture in the exhaust system / at the O2 sensor, would be Leaner, not richer.

However if the SAI Solenoid had failed and remained closed, so that no "Secondary air" was admitted
to the exhaust system, then I would expect the mixture in the Exhaust to be constantly Richer,
and when the O2 sensor detected this. it could trigger adjustments to try and compensate,
which, theoretically could result in the problems you are experiencing.

The SAI Solenoid valve DOES have 2 DTC's ( Fault codes ) associated with it :
P0413 - Secondary air injection system short circuit to ground or open circuit, and
P0414 - Secondary air injection system short circuit to vBatt,
but of course the Valve could have failed / seized without generating any DTC's.

I would ask the mechanics to test the SAI Valve 

Cheers 

[digital]

I want to add to Coconut comment that when there is a fault from the SAI solenoid or its sleeve, the motor usually changes from a normal, usual sound to a throaty sound.

[nesnfred5]

So appreciate all the help…will report back when I hear more…Happy Thanksgiving!

[STJIM]

Originally Posted by nesnfred5

Heard from the shop today...SNIP ....  They said the fuel trim levels were high on all the cylinders.  SNIP .....

A Google seach says high trim levels ( widening of the fuel injector pulses ) means the ECM is compensating for a LEAN mixture.
This can be caused by low fuel pressure ( fuel pump and/or clogged fuel filter )  or a vacuum leak.

I'm thinking now the SAI not working properly shouldn't cause high trim levels.

Did the dealer check the fuel pressure yet ?  When was the last time the fuel filter was replaced ?  My guess is low fuel pressure could be causing the stalling when the throttle is closed.

Also, does anyone ( Digital !! ) know if the Trophy has a fuel pump filter sock at the input side of the fuel pump ?  My Conours does and it was pretty clogged up after only 20K miles.

Take a guess at which filter sock is the new and old sock in the below picture.

[digital]

Those are the filters on the fuel pump.

[STJIM]

Digital :

What has been your experience as far as the sock filter clogging up ?

How often do you think it should be replaced ?

To tell you the truth, I don't recall what mine looked like at the 20K mile check.  I did have the fuel pump / filter assembly removed because I wanted to verufy that the previous owner replaced the cylindrical fuel filter as his service log said.  Based on the date code on the filter, it must have been.  So I'm sure I checked the sock filter and it looked OK,  not like the one on my Concours looked at about the same number of miles although on the '08 Concours it had been installed for about 11 years  vs. only about 6 years for the Trophy.

I'm planning on replacing both the sock filter and cylindrical filter at the next 20K service along with the other maintenance requirements.

BTW, some BMW models use the exact same fuel filter as the Trophy and it may cost a little less too.  It's a Mahle KL-145 filter.  Just checked :  $20 on EBay w/shipping - even cheaper than the BMW dealer.

And I just checked Hermy's - the cost of a sock filter is $251 !!!  Unbelievable !!   I'm sure you could match an auto sock filter up with the right size input at your local auto parts store.  They usually have a nice assortment to chose from.

[digital]

My experience is that I have about 212,000 kilometers and I have only replaced the fuel filter, I have not replaced the sock because I did not see that it was necessary. It was completely clean.

But of course, I have to say that the dirty effect of the gasoline filters is very relative, since it will depend on the state of the oil refineries and surely on the country.

That is why I cannot advise when it is necessary to replace the fuel filter and the sock. Now, for what a fuel filter is worth and when the second valve adjustment is done, since the fuel tank has to be disassembled, it may be good to check those filters. So we can be talking about 80,000 kilometers.

I have to prepare for a new valve adjustment, with which I will replace the timing chain, timing chain tensioner, spark plugs, air filter and it will be time to replace the fuel filter and the sock.

[STJIM]

I read an engineering article a few years back that said there have been big improvement in gasoline fuel filters and the new filters should last 100K miles.  Hard to beleive.

The Honda St1300 has a large fuel filter like on our Trophy and it isn't a maintenance item and the Yamaha FJR doesn't even have a large fuel filter.  A lot of cars today don't either which amzes me - just a sock filter.