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86' 740 EVAP System Questions

waynegarbo said:
Ok thanks I'll check it out.
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Ok EVO I took the air box out. Yeah my thermostat sits in a molded cylinder in the air box. Yes, when you push on the thermo it opens the flap. The thermo spring cylinders a probe attached to the flap. That spring, I'm not able to remove, hence, remove the thermo.
So I shimmed a piece of rubber hose between the pivot and the housing in the open position and spread some glue over the top of it to keep it propped open.
 
ZVOLV said:
You want it stuck closed so it doesn't stay remain stuck open and suck hot air all the time.
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ZVOLV-I thought the flap works the way I propped it open. I propped it open to allow vent air in from the larger port facing the radiator?
 
PCH said:
When there is an open in the EVAP system you will usually smell gas either inside the car, under the hood or in the garage (if you park in one). Simply having no pressure escaping the tank when you remove the cap is not an indication that something is wrong.

Back when I was doing pressure tests on EVAP very often the STANT adapter used with the pressure machine had bad fit on many Volvos (mainly 240's) which made it difficult to pass functional test. IIRC we were allowed to actually skip doing the pressure test because Volvo filler neck was not working well with Stant adapters. I don't know if they use revised adapter now or what.
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I did fail the evap test with a gross evap leak reading. I do not smell gas anywhere. I have checked all the lines and fittings. Previous to the fail, I changed my sending unit seal but I do not smell gas around the sending unit. I have done a hand vac test on the gas line(s) to and from the rollover. Vac held. When I did a vac test THROUGH the rollover I get no vac.
I did a smoke test from the canister, and from the rollover. I also blew cigar smoke directly
into the filler. I do not see any leak. But then again it's not professional and the car is on jack stands.
 
ZVOLV said:
Make sure you have the preheat hose and that the thermostat in the airbox isn't stuck open.

How fresh is the cat?

Make sure the ignition timing is correct.

For the evap test they pinch off the line going into the charcoal canister from the tank and apply pressurized nitrogen into the fuel neck and check if it holds with the machine.
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Have you ever know a gross evap leak because of the rollover
 
Your smoke test would reveal that. What kinda smoke machine are you using?

Evap leak on these cars shouldn't be too hard to track down with a good machine and the car in the air.
 
ZVOLV said:
Your smoke test would reveal that. What kinda smoke machine are you using?

Evap leak on these cars shouldn't be too hard to track down with a good machine and the car in the air.
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I'm using the paint can, with incense, and a air compressor with a air flow regulator, with the psi around 2-5.
 
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