96 850T5 Hard restart after engine is hot in hot weather.

[misha]

Just remove it and blow through it in both directions....if it's closed...it's good.

If you can blow through it,it's bad and stuck open.

It's unpowered state is closed.

[redbeak1]

Just remove it and blow through it in both directions....if it's closed...it's good.

If you can blow through it,it's bad and stuck open.

It's unpowered state is closed.

I can not blow through in the direction of the arrow, but I can in the opposite direction. What does this tell you?

[misha]

Did you disconnected it's connector during this test?
It should be closed in both directions when disconnected.

Arrow is pointing towards intake manifold?

[redbeak1]

Yes, I removed it from the car. Arrow is pointing toward manifold when installed. I used very light compressed air. I could not get air through it in the direction of the arrow, but I was able to... going in the opposite direction. I would think that this is a one direction valve when activated.

[93ForMe]

Hi redbeak1,
I am having similar issues, and I think I may have had a break-though with it today.

My problem seemed very temperature related, but I had switched out the ECT sensor and they persisted. Today I pulled apart the female connector that the ECT plugs into and found that the sheath around the female barrel connectors had started to break down. I cut it away at the base and found a whole lot of corrosion that I cleaned out. Corrosion will increase resistance and make your car think that it is colder than it is. Cold starts, no problem. Hot starts, problem.

Here is my thread, I have a couple of links to pictures of the connector:

viewtopic.php?f=1&t=93975&start=20#p543693

[bmdubya1198]

Hi redbeak1,
I am having similar issues, and I think I may have had a break-though with it today.

My problem seemed very temperature related, but I had switched out the ECT sensor and they persisted. Today I pulled apart the female connector that the ECT plugs into and found that the sheath around the female barrel connectors had started to break down. I cut it away at the base and found a whole lot of corrosion that I cleaned out. Corrosion will increase resistance and make your car think that it is colder than it is. Cold starts, no problem. Hot starts, problem.

Here is my thread, I have a couple of links to pictures of the connector:

viewtopic.php?f=1&t=93975&start=20#p543693

That's a good point. Corrosion on this connector is very common on 850s, it's definitely worth a careful look.

[redbeak1]

Hi redbeak1,
I am having similar issues, and I think I may have had a break-though with it today.

My problem seemed very temperature related, but I had switched out the ECT sensor and they persisted. Today I pulled apart the female connector that the ECT plugs into and found that the sheath around the female barrel connectors had started to break down. I cut it away at the base and found a whole lot of corrosion that I cleaned out. Corrosion will increase resistance and make your car think that it is colder than it is. Cold starts, no problem. Hot starts, problem.

Here is my thread, I have a couple of links to pictures of the connector:

viewtopic.php?f=1&t=93975&start=20#p543693

Hi 93Forme, I read your thread a couple of times. Our problems are similar but not exact. My car has to get really hot. A run on the highway pulling a trailer in 80 degree weather and stopping for a 20 minute break would cause a hard start issue. It seems from your thread that once your car is past being warmed up, and is hot, it runs fine.
I once had a intermittent cut off of the engine problem that went on for a long time. I replaced the Fuel Injection relay(the grey one above the radiator). The problem turned out to be the defective new relay. I went nuts checking everything else. I had to wait for the engine to be completely dead before troubleshooting led me back to the same relay that was changed. The Bosch factory didn't do a good job soldering inside the relay. Once the engine was hot and I would hit a bump on the highway the engine died. I cleared the code which came up as a Throttle position sensor that was also replaced. After that the engine ran fine, but would cut out rarely until resolved.

I really hope it turns out to be the wiring in your car. After over 25 years, we can't complain that some plastics start to degrade. Otherwise these cars are tanks. I will also check that same ECT connection tomorrow.
I will keep everyone posted if I can resolve this, especially since we are going into summer!!

[redbeak1]

Just remove it and blow through it in both directions....if it's closed...it's good.

If you can blow through it,it's bad and stuck open.

It's unpowered state is closed.

Hi Misha, would you conclude that if I can blow through it in the opposite direction of the arrow, that the valve is no good? Thank you for all your help.

[misha]

Just checked mine.....closed in both directions when engine is not running.

Your's could be failing....since it's closed in just one direction.

Here you can see that a good evap valve is closed in both directions:
https://volvo850wagon.wordpress.com/tag/evap/

[redbeak1]

Just checked mine.....closed in both directions when engine is not running.

Your's could be failing....since it's closed in just one direction.

Here you can see that a good evap valve is closed in both directions:
https://volvo850wagon.wordpress.com/tag/evap/
Thank you-thank you so much!! You and everyone on this forum has helped so much. I will report back with any new findings.