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

Post by **misha** » 06 Jun 2020, 03:01

Fuel pressure is ok,like i said.
Time to check ect wiring.
That check valve shouldn't be a problem...but i can't say that for sure.
Is vacuum line(hose)between purge valve and intake ok?

redbeak1 · Post by **redbeak1** » 06 Jun 2020, 08:26

bmdubya1198 wrote: 05 Jun 2020, 22:58 Try blowing through the check valve to test it. They do occasionally fail, I've had them fail before.

Should it be open in the direction of the manifold and closed toward the canister? This really is a heat soak problem of some kind.

redbeak1 · Post by **redbeak1** » 06 Jun 2020, 08:42

misha wrote: 06 Jun 2020, 03:01 Fuel pressure is ok,like i said.
Time to check ect wiring.
That check valve shouldn't be a problem...but i can't say that for sure.
Is vacuum line(hose)between purge valve and intake ok?

Brand new hoses all around. This is the third summer I'm having this issue. So when it first happened the radiator, thermostat and ECT were brand new and only 2 years old. But I will check again. If fuel vapor occurs, (vapor lock) would a fuel pressure test show at the time the engine is hot and not starting well, a low number? Really a crazy issue, since the car runs great after it starts or when it's cold outside.It starts, sounds like a misfire and stalls. It seems like as it gets more cooler fuel pumped into the rail, it starts and runs great.

Post by **bmdubya1198** » 06 Jun 2020, 11:04

You should be able to blow through towards the manifold. The arrow points that direction.

Post by **misha** » 06 Jun 2020, 11:47

I'm talking about ECT wiring....it's connector from the wiring loom side...it gets corroded and sends wrong resistance to ecu.
When wiring have corrosion...the heat makes things worse.As heat goes up...then resistance of bad wire also goes up.

Post by **misha** » 06 Jun 2020, 11:50

bmdubya1198 wrote: 06 Jun 2020, 11:04 You should be able to blow through towards the manifold. The arrow points that direction.

Yes...it's one way valve.

redbeak1 · Post by **redbeak1** » 06 Jun 2020, 19:44

bmdubya1198 wrote: 06 Jun 2020, 11:04 You should be able to blow through towards the manifold. The arrow points that direction.

I can blow through easily in both directions!!!! It seems to be defective, but I'm not sure how this would affect hot start since it's downstream of the new purge valve that is now operating correctly??
Thank you for all the help.

Post by **bmdubya1198** » 06 Jun 2020, 20:12

redbeak1 wrote: 06 Jun 2020, 19:44 I can blow through easily in both directions!!!! It seems to be defective, but I'm not sure how this would affect hot start since it's downstream of the new purge valve that is now operating correctly??
Thank you for all the help.

Definitely replace that check valve. Not sure it would cause this problem, but you definitely don't want to be sending boost to the purge valve.

redbeak1 · Post by **redbeak1** » 06 Jun 2020, 20:20

misha wrote: 06 Jun 2020, 11:47 I'm talking about ECT wiring....it's connector from the wiring loom side...it gets corroded and sends wrong resistance to ecu.
When wiring have corrosion...the heat makes things worse.As heat goes up...then resistance of bad wire also goes up.

Yes, i did read your other threads about this. Certainly on my to do list. But I'm wondering how sensitive a electrical issue could be with an issue that is so time critical for it to show symptoms.If I stop and try to start within 5-10 minutes, there is no problem. If I wait around 30 - 45 minutes, misfire and rough idle for a couple of minutes and then back to normal. If I wait over an hour...no problem. Very strange.

redbeak1 · Post by **redbeak1** » 06 Jun 2020, 20:31

bmdubya1198 wrote: 06 Jun 2020, 20:12
redbeak1 wrote: 06 Jun 2020, 19:44 I can blow through easily in both directions!!!! It seems to be defective, but I'm not sure how this would affect hot start since it's downstream of the new purge valve that is now operating correctly??
Thank you for all the help.
Definitely replace that check valve. Not sure it would cause this problem, but you definitely don't want to be sending boost to the purge valve.

I just checked where I can buy this check valve. FCP and Euro parts say that it won't fit my 96 Volvo 850 T5 The part # is 00194031 also 95T 64 is also written on it.Do you have any suggestions where I can buy this valve?