ataDude
Mod Maniac
... while I was doing maintenance on my early model 2008 SM... #1704.
A disclaimer: I am not a trained engineer or mechanic and everything below are just my personal opinions and observations but... I did stay at a Holiday Inn last night.
Like some folks here, I found a number of things I didn't like... thus all of the new plastic wiring looms protecting fuel, radiator and vacuum lines at the top. I understand that the 2009s forward may already have some of this protection.
Two things I really didn't like:
1. High-voltage / Fuel Line. The front cylinder's high-voltage spark plug wire (#2 in pic) was crossed and resting on the primary, high-pressure fuel line (#1 in pic) from the fuel tank (though the fuel filter). I re-routed the plug wire to behind the fuel line and added two more layers of wiring loom for protection (the pic is "after").
This, in all probability, is not a huge issue as the high-voltage wire insulation would need to (a) fail and (b) fire to a ground. A "perfect storm" issue might arise if (i) the wire's insulation failed and (ii) moisture was present which could present a ground.
2. Emissions Canister Vent Hose. As some of you have already noticed, the emissions canister vent hose is a short, U-shaped hose that could emit excess downward directly onto the rear cylinder's exhaust header pipe. The open end of the vent is about 2" forward, and 8" higher, than the exhaust with nothing in between.
I believe that the purpose of the vent hose is to allow atmospheric pressure into the canister so that the "purge valve" can suck (using engine vacuum) any excess fumes from the canister into the fuel injection throttle bodies.
However, this vent appears to be the only portion of the fuel system open to the outside world.
In my opinion, a couple of things might cause a problem with the vent location:
a. First, if repeated fuel tank "over-fillings" cause the charcoal in the canister to become saturated with liquid gas, that liquid after expansion from heat could be forced from the canister through the vent hose.
b. Second, (i) if the fuel tank is really full (over filled), and (ii) if the tank is heated either by engine heat, climate or both, and (iii) if the engine is turned off while the fuel is expanding from the heat, there is virtually no other place (that I am aware of) to which the expanded fuel (under pressure) can exit other than through the vent hose... directly downward onto the exhaust header. (Close your eyes and picture a long ride... the engine is hot... you fuel up (over fill) and then take a break; or picture a long ride... you fuel up (over fill) and return immediately home to park it).
Bear in mind that while the engine is running, and the purge valve is functioning correctly, any excess would probably be sucked right into the throttle bodies. That, in theory, could cause a momentary "rich" running condition which could be noticeable from a performance perspective.
Short of a complete "canisterectomy" noted on other threads, I opted to just replace the short vent hose with a longer one (5/16" ID) to exit in the center in front of the rear tire. I have dual-side exhausts so there is no "safe" place away from the muffler heat other than in the center... don't rag on me.
I left the canister, purge valve and other related plumbing intact as I have had no issues (gas smell or performance) before, or after, the software update.
Both of these suppositions assume (uh, oh) that there is no one-way valve in the canister vent circuit -or- or that there may be a one-way valve in the vent circuit but it is malfunctioning. We will not know for sure until someone with a spare canister cuts it apart as it would have to be inside.
That's my $0.02 and I'm sticking with it.
In the pic below, the upper "spotlight" is the open end of the canister vent hose. The lower "spotlight" is the rear cylinder exhaust header. #1 notes the fuel line to the throttle bodies and #2 is the front cylinder's high-voltage spark plug wire.
.
.
A disclaimer: I am not a trained engineer or mechanic and everything below are just my personal opinions and observations but... I did stay at a Holiday Inn last night.
Like some folks here, I found a number of things I didn't like... thus all of the new plastic wiring looms protecting fuel, radiator and vacuum lines at the top. I understand that the 2009s forward may already have some of this protection.
Two things I really didn't like:
1. High-voltage / Fuel Line. The front cylinder's high-voltage spark plug wire (#2 in pic) was crossed and resting on the primary, high-pressure fuel line (#1 in pic) from the fuel tank (though the fuel filter). I re-routed the plug wire to behind the fuel line and added two more layers of wiring loom for protection (the pic is "after").
This, in all probability, is not a huge issue as the high-voltage wire insulation would need to (a) fail and (b) fire to a ground. A "perfect storm" issue might arise if (i) the wire's insulation failed and (ii) moisture was present which could present a ground.
2. Emissions Canister Vent Hose. As some of you have already noticed, the emissions canister vent hose is a short, U-shaped hose that could emit excess downward directly onto the rear cylinder's exhaust header pipe. The open end of the vent is about 2" forward, and 8" higher, than the exhaust with nothing in between.
I believe that the purpose of the vent hose is to allow atmospheric pressure into the canister so that the "purge valve" can suck (using engine vacuum) any excess fumes from the canister into the fuel injection throttle bodies.
However, this vent appears to be the only portion of the fuel system open to the outside world.
In my opinion, a couple of things might cause a problem with the vent location:
a. First, if repeated fuel tank "over-fillings" cause the charcoal in the canister to become saturated with liquid gas, that liquid after expansion from heat could be forced from the canister through the vent hose.
b. Second, (i) if the fuel tank is really full (over filled), and (ii) if the tank is heated either by engine heat, climate or both, and (iii) if the engine is turned off while the fuel is expanding from the heat, there is virtually no other place (that I am aware of) to which the expanded fuel (under pressure) can exit other than through the vent hose... directly downward onto the exhaust header. (Close your eyes and picture a long ride... the engine is hot... you fuel up (over fill) and then take a break; or picture a long ride... you fuel up (over fill) and return immediately home to park it).
Bear in mind that while the engine is running, and the purge valve is functioning correctly, any excess would probably be sucked right into the throttle bodies. That, in theory, could cause a momentary "rich" running condition which could be noticeable from a performance perspective.
Short of a complete "canisterectomy" noted on other threads, I opted to just replace the short vent hose with a longer one (5/16" ID) to exit in the center in front of the rear tire. I have dual-side exhausts so there is no "safe" place away from the muffler heat other than in the center... don't rag on me.
I left the canister, purge valve and other related plumbing intact as I have had no issues (gas smell or performance) before, or after, the software update.
Both of these suppositions assume (uh, oh) that there is no one-way valve in the canister vent circuit -or- or that there may be a one-way valve in the vent circuit but it is malfunctioning. We will not know for sure until someone with a spare canister cuts it apart as it would have to be inside.
That's my $0.02 and I'm sticking with it.
In the pic below, the upper "spotlight" is the open end of the canister vent hose. The lower "spotlight" is the rear cylinder exhaust header. #1 notes the fuel line to the throttle bodies and #2 is the front cylinder's high-voltage spark plug wire.
.
.
Last edited:
opcorn:Shop rag story??
