what is this and can it cause my 1.5 del sol to run poorly and miss but only when hot? I think it's a MAP sensor. it has two vacuum lines but the replacements have only one vacuum line. the red diaphragm under the cap is bad.

 

EVAP purge control solenoid valve.

 

do I need it? does it matter if it doesn't work? THANKS

 

No definitely not. Car manufacturers anyways include random extra parts.

 

often these random extra parts are to please government pencil pushers and do nothing but complicate a simple machine. before computers we would just disconnect all this crap to make our cars run better.

 

Might be stuck open if it is causing issues when the weather is hot. Venting fuel vapor into the engine unexpectedly would make it run super rich.

 

my car runs fine cold but terrible hot so i'm hoping that this is my problem. the red diaphragm at the top of the valve was dry rotted so I used weatherstrip adhesive to glue a piece of motorcycle cv carb diaphragm over the top and I'm going to christen it FIXED. FYI: If you don't want your expensive tubes of goo drying-up on you try this: put them in a peanut container with the seal in-place and soak a rag with the correct solvent that's used in the goo then put the top on tight. I've had this same tube of weatherstrip adhesive for two years now and the end wasn't even clogged.

 

I don't think that is a diaphragm. I think it is a filter, it should be open to air on that side.

Have you done any other troubleshooting? There are a lot of other causes for your symptoms that are not that purge valve.

Valves needing adjustment is high on the list. So is a bad or failing ignitor in the distributor.

 

Your symptoms can be due to something else like Ryanthegreat1 stated.

This is some info. on the evap purge:
When fuel evaporates inside the gas tank, the excess fuel vapors are transferred to the charcoal canister. The fuel vapors are stored there until they can safely be transferred back to the engine to be burned with the normal air-fuel mixture. The way the EVAP purge valve suppose to operate is to open while driving, so the engine can suck/purge fuel vapors out of the charcoal canister and use that to be burned with the normal air-fuel mixture. However, during refueling or when the car is off, it normally is closed.

If the EVAP canister purge valve is stuck open, during refueling or high heat even more fuel vapors are allowed to enter the intake manifold. Your car can becomes flooded, making for hard starts after refueling or high heat. Pressing the accelerator pedal gets the car to start from the flooded situation.

Doesn't sound like you also have a hard start problem.

 

Agreed... i want to get this item off the list... i ordered a new intake manifold temp sensor and will try that. I'm also thinking that the timing is off maybe retarded because it idles kinda low about 450rpm. I like it but I don't know if it's normal.

yes, that makes more sense than a diaphragm. I'll remove the "fix" and put some foam there. THANKS