Yes, I did hook up a vacuum gun to the FPR and simulated it and it resolved the issue. The unfortunate thing is it wasn't the FPR that was the issue. Even if the pump isn't the issue which I suspect it is it is good maintenance to change it at 185k. The car actually does have a full tank of premium at the moment and its not good enough to go drive around and burn up the fuel, I will be getting a fuel line quick disconnect and just putting it in a jerry can. If the pump doesn't solve my issue I can only assume it will be the DIC which is the last thing I want to try, it is brand new and does have a warranty on it though.Dropping the tank is not difficult. First time on a fuel pump I cut the hole, but the second time I dropped the tank. Overall, took about the same time. The variable I suppose is whether there's a full tank of gas - I knew I needed to replace the pump before it died, so I ran the car until the light came on, then another 5-10 miles and when I dropped the tank there just wasn't much in there. The third time the tank was pretty full, so I disconnected the fuel line at the rail, slipped a hose over the end, and ran the pump off a 12v battery for a while to get most of the fuel out. As you get to the last 5 gallons or so, I think it's advisable to run the pump in 5 minute bursts to prevent it overheating. Obviously you don't care if the pump dies, but I've seen failing pumps shred themselves and create aluminum shavings. You don't want those floating around or ruining your new filter.
There are two straps that hold the tank against the body. Soak them in penetrating oil for a good long time before you tackle them. Even in California the strap threads get corroded and penetrant will help the nuts come off. Back east, it can be a bear. Be aware you only need to loosen the nuts maybe 1/2", then you can slip the straps off the brackets. Disconnect all the electrical under the back seat. Disconnect the filler pipe. Lower the tank slowly so you can disconnect the evap system. IIRC you need a fuel quick disconnect tool to do that. I'd recommend removing the banjo on the input side of the fuel filter to eliminate the risk of damaging that nylon hose. TBH, there is nothing special or weird or complicated here - it's like any other gas tank. If you go slowly, you can deal with bits as they come at you.
All that said, 35psi of fuel pressure is low but not criminally low. Did you try running the pump with the engine off, and using a vacuum/pump on the FPR to simulate engine vacuum/boost and see how fuel pressure responded?
My main fear is making the cut up top just to have road debris flying up under the seat and soiling the interior, I'm not sure if that is a rational fear or not but if there is a way to seal it back up when I'm done I'm not against it, it's just a nice car and I don't necessarily want it be cutting it apart.If your tank is full, I would go with the hole cut. Also, you avoid dealing with pushing around some very old hoses and clamps. Let sleeping dogs lie. MHO. The hole cut is easy to do, just a good set of offset Wiss shears. It you have a compressor, there's also the nibbler option or the air shears. Just be careful with the wires under there. But, pick your poison.
Either way you need to loosen the tank straps to get some flexibility to move the lines gently on top. Oddly, I've found the nuts always come loose easily despite my advance fears. Adding to what jvan said, there's a 10 or 11mm hex on the tank strap stud. Put a wrench on there to keep the stud from twisting when you loosen the nut(s). I usually pick up a set of 8mm nylock nuts to replace them once I'm in there so that it will be easier the next time... when I have to do the brake cable. Just pull one strap off at at time after the pump job is done and drop it down where it's easy to work on and pull the nut off completely with a deep socket.
Not pushing you either way, but... No way that will happen. The fuel tank is in there so tight that you can go drive on the rainiest day possible and the top of the tank is still dry. There is a simple, unsealed plastic cap over the hole Saab left for access to the fuel pump wires - always broken now because it's paper thin plastic. Connections are not waterproofed to the pump. Clearly Saab wasn't worried about the issue you raised.My main fear is making the cut up top just to have road debris flying up under the seat and soiling the interior, I'm not sure if that is a rational fear or not but if there is a way to seal it back up when I'm done I'm not against it, it's just a nice car and I don't necessarily want it be cutting it apart.
My little plastic piece has managed to survive 18 years somehow, I've also put sound deadening in the entire car so id have to get through that as well. I'm just about to go test fuel pressure again and single out the pump as the issue I hope.Not pushing you either way, but... No way that will happen. The fuel tank is in there so tight that you can go drive on the rainiest day possible and the top of the tank is still dry. There is a simple, unsealed plastic cap over the hole Saab left for access to the fuel pump wires - always broken now because it's paper thin plastic. Connections are not waterproofed to the pump. Clearly Saab wasn't worried about the issue you raised.
BUT, the way I did it was using Jake's method... start at the stock hole and cut on three sides. Leave one side like a hinge. Bend the metal up, make your repairs, bend it back down. Some guys will fiberglass the new cuts, some duct tape it, etc. I was thinking that before I do my latest car I'd get a bolt on panel from a 9-5 and install that after cutting. You could also make your own out of simple sheet metal.
It's a 3 bar regulator, and brand new. I understand it should decrease with vacuum and increase with boost. I guess I'm just confused how it runs like crap with the vacuum line hooked up but when pulling atmosphere it runs happy and healthy?The point of the FPR is to keep fuel pressure at X bar (whatever the regulator is rated at) above manifold pressure. At atmosphere (vacuum line disconnected) that should be 3 bar, but it will go up or down depending on whether there is pressure (boost) or vacuum (idle) in the manifold.
I guess all I can think it could be now is an air leak although I've tested multiple times with different substances and no result, I already installed a brand new MAF, Injectors pulse fine. I'll get back to diagnosing tomorrow before work.That generally describes a mixture problem. With the vacuum connected, pressure and thus volume is reduced. With it disconnected, using atmosphere as reference instead of manifold, pressure and volume is increased. That suggests it's not getting enough fuel... which is consistent with what you've experienced on the road. That could happen from too little fuel (bad MAF, clogged injectors, etc.) or from too much air (air leak).
I guess I'm not suggesting this is your problem, but a possible explanation for what you're seeing.
I'll be doing some in depth investigation tomorrow to see what the cause its, the chain was tight I didn't think that the tensioner was over extended but I can only assume it was. As of now I'm going to take a step back and take a breather, regroup and come back to it tomorrow.Definitely off a tooth, and that would cause the problems you're describing.
The wear pattern is interesting - there "top" of the chain rides on a pair of plastic guides, but I wouldn't expect them to be able to do that sort of damage unless they're clobbered too. It's possible you have a problem with the tensioner and/or guides and the chain is flopping around in there, maybe damaging the guides or maybe jumping a tooth.
Unfortunately it's hard to see down in the head, but I would be shining a bright light down there to see if you can get a sense of the guide health.
Failing that, you could always remove the tensioner, then remove the cam sprockets, and then you should have a decent view of the guides. Be sure you remove the tensioner correctly - hex bolt on top BEFORE you remove the main body - so you can check tensioner extension and infer chain wear. I suppose you'll be doing this anyway to reset the chain, so no extra work.
Not my intension to fear-monger, but there are examples of people accidentally breaking the top off a chain guide when reinstalling the head, so be sure you check the guides as thoroughly as possible. Not only will a damaged guide cause problems with the chain, but then you end up with pieces of plastic in the engine.