No, I did not take the valve and associated tubing completely off to inspect it at that level... hit the bolts with PB blaster for a few days before attempting removal?

I tried to loosen the 2 bolts securing the SAI valve and they are frozen. didn't wanna risk snapping them so I just opted to check as far inside the valve as I could get my finger and rag to clean it.

this will be a TO-DO in early Jan. btw, thx for replying....any help is appreciated.

 

Pb will def help, but quite honestly i never had problems unbolting those. The nipple part has a square wrench flat so you can jam a small adjustable wrench against exhaust manifold and undo the stainless tubing nuts without risk of twisting the piping. Inside the nipples there is hex bore, which may make it look larger than the actual air passage.

 

took the vacuum line off from the vacuum reservoir thru to the SAI solenoid to inspect the lines and connections. all are in like new shape...no tears/rips or holes. the only thing that would
be in any way questionable would be the connection to the vacuum reservoir which in the rovers north site shows an elbow on both connections to the vacuum reservoir. The prior owner
put a straight rubber tube over the end of the hard line to the vacuum end of the canister. not sure if that is affecting things. I probably should source one of the elbows and replace that
so it's more stock. wondering if that rubber line is collapsing internally when under vacuum.

btw, the truck threw a P1412 and P1415 when I fired it up this morning. So, next item to more thoroughly test will be the SAI solenoid to make sure it's closing off when not energized and
allowing vacuum when energized.

 

The vacuum reservoir should hold vacuum for at least a couple of days, so if you pull the elbow off the canister (straight tube in your case) few hours after last drive it should suck up air (loud hissing noise). I'm also pretty sure the stock tubing is glued together, so prob buying whole line set from ebay is a safer way to go.

 

correct on the elbow. those suckers won't come off the hard lines (easily anyway)... when I pulled the lines off the vacuum reservoir there was a hissing sound
released...so it's holding vacuum. some anyway. next test will be to get a length of rubber hose from the vacuum nipple on the intake to each SAI valve and see
if they open and emit exhaust. this should rule them out as being good/bad. I presume I disconnect the rubber air supply into the valve before doing this....
I bought a set of 4 elbows from Dorman. for vacuum purposes.

 

So it sounds like the lines are fine. Probably preaching to the choir here, but any after market rubber pieces like this will start cracking and falling apart in about a year, if not sooner, especially in the engine bay...

 

I put a new (pierburg) SAI solenoid valve on...new elbow (dorman) on the hard line going from the intake to the vacuum canister. still getting P1412 and P1415....grrrrrr

so either there is a break somewhere in the line from the intake to the vacuum canister or from the back end of the canister to the SAI solenoid valve. Note that I did a
blow thru test on the line from the intake to the vacuum canister and the line is not obstructed and if I suck on it holding my finger on the end going into the vacuum
canister is appears to be holding a good vacuum. if it was broken, I would expect that would not work. I do hear/feel the SAI pump coming on and the exhaust
is noticeably louder in the cabin for the 90 seconds that it runs.

what would be the next diag step here?

 

Maybe take the lines off. Plug them on one end.immers in a tub of water and give it some air from compressor. See of you get any air bubbles.

 

this is getting quite frustrating....the SAI pump is not running long enough. I think that is what's going on. The valves stay open for at least 90 seconds. I just put a new relay
in from atlantic british so it's not the relay. next test is to jumper the SAI pump and see if it will run and produce good air output to the valves. I'll take the rubber hoses connecting
to each SAI valve and verify.

 

Even 90 seconds seems short. Mine is going for at lest 4-5 min.