'87 fuel tank collapsed today
10-03-2013, 07:32 AM
#46
Rennlist Member
WAG: Saab 4 cylinder isn't going to draw as much gas as a Porsche V8 so this variant is built for lighter duty? The fuel pressure is roughly the same though, so that's probably wrong.
10-03-2013, 08:30 AM
#47
Pro
Thread Starter
These valves don't actually meter fuel, but fuel vapors stored in the canister. The Porsche version could be more stout inside to handle a higher level of manifold vacuum though...
10-03-2013, 08:34 AM
#48
Rennlist Member
Right. I was thinking there could be higher demand across all aspects of the system given the larger size of the engine, double the number of injectors, etc.
10-15-2013, 06:03 PM
#50
Pro
Thread Starter
Well, the problem continued. I filled up the tank for the first time since replacing the purge valve, and after a spirited drive I noticed the top of the tank collapsing again. The tank was nearly full, so the bottom of the tank had not distorted yet.
I found the PET diagram of the system, and disconnected the hose from the tank neck to the expansion tank in the right rear wheelwell (so the tank would be vented until I could fix it).
I removed the expansion tank and found I could blow compressed air through it freely. I then blew air through the rubber line from the expansion tank through the inversion valve to where it meets the metal line to go to the charcoal canister. It was free flowing and the inversion valve worked properly.
I then removed the right front wheel and liner, and disconnected the vent line that goes from the canister all the way to the back bumper of the car. I found that I could NOT blow air through this line...completely obstructed. I then disconnected this line under the car where a 3" rubber section joins the two metal hard lines (about halfway back), and found that I could blow air from the hose at the canister to that break, but I could NOT blow air from that break to the outlet at the rear bumper.
I used a coat hanger to dislodge a blockage of dirt (mud wasps?) in the first 90 degree bend of the vent line at the back bumper. I could then blow freely either direction, put it all back together, and could blow air from the bumper outlet all the way to the charcoal canister.
I found the PET diagram of the system, and disconnected the hose from the tank neck to the expansion tank in the right rear wheelwell (so the tank would be vented until I could fix it).
I removed the expansion tank and found I could blow compressed air through it freely. I then blew air through the rubber line from the expansion tank through the inversion valve to where it meets the metal line to go to the charcoal canister. It was free flowing and the inversion valve worked properly.
I then removed the right front wheel and liner, and disconnected the vent line that goes from the canister all the way to the back bumper of the car. I found that I could NOT blow air through this line...completely obstructed. I then disconnected this line under the car where a 3" rubber section joins the two metal hard lines (about halfway back), and found that I could blow air from the hose at the canister to that break, but I could NOT blow air from that break to the outlet at the rear bumper.
I used a coat hanger to dislodge a blockage of dirt (mud wasps?) in the first 90 degree bend of the vent line at the back bumper. I could then blow freely either direction, put it all back together, and could blow air from the bumper outlet all the way to the charcoal canister.
10-15-2013, 07:02 PM
#51
Team Owner
thanks for updating this post and testing and finding a solution /remedy,
FWIW when the car was new there was a rubber collar fitted over the tube by the rear bumper and then a screen in the end,
this to keep out mud daubers
FWIW when the car was new there was a rubber collar fitted over the tube by the rear bumper and then a screen in the end,
this to keep out mud daubers
10-15-2013, 08:02 PM
#52
Pro
Thread Starter
I am planning to get a couple of those vent tube end caps/screens...mine was completely gone, and my brother's '88 has his hanging by a dry rotted thread...they are not expensive.
10-15-2013, 08:48 PM
#53
Three Wheelin'
Cool find on the purge valve/solenoid being essentially interchangeable! That's great. I myself nearly fell over when i saw the list price of a new one. Not surprising though since many Saabs (Euro cars in general) use Bosch EFI systems with all the same Bosch components as one another.
10-15-2013, 09:37 PM
#54
Pro
Thread Starter
Cool find on the purge valve/solenoid being essentially interchangeable! That's great. I myself nearly fell over when i saw the list price of a new one. Not surprising though since many Saabs (Euro cars in general) use Bosch EFI systems with all the same Bosch components as one another.
10-15-2013, 10:01 PM
#55
Nordschleife Master
