My del sol wont start when warm, it seems to ba a fuel pressure problem. If i open up the gas tank and let the pressure out it starts right up otherwise i must wait 5min.... what could be the problem??

 

Is the CEL on?

When the engine won't start:
-do you hear the fuel pump prime for 2 seconds when the key is turned to ON(II)?
-have you checked for spark?

 

no light
has spark
the pump primes
and it turns on fine when its cold...

 

It sounds like a bad main relay, but if this were the case the pump would not prime when the engine won't start. Are you sure the pump primes when you have the no-start problem?

 

yea i hear it right before it starts cranking....
if it was the relay then i guess the car wouldnt start even when cold...?

 

Main relays are notorious for causing no-starts specifically when the weather or engine is hot.

What you need to do when the engine won't start is:

1) Turn the key to ON(II), and then carefully listen for whether the pump actually primes.

2) Check for spark and note what color the spark is. It should be bright white.

 

My dad and i checked both the spark and listened for the pump.... but how do i check the relay?

 

I saw main relay or even possibly a bad starter...

 

Again, any tests you do are meaningless unless they are done when the engine won't start. What color was spark? Did you check for battery voltage at the fuel injector connectors?

 

the starter wire was a bit loose but i tightened it and still the same...

 

and in the morning i will check for voltage at the injectors.... can it be the pressure regulator? cuz when i open the gas cap i can start it right up...

 

Is this a cranking problem or a no-start problem?

 

cranks fine and starts but rpms quickly go down and it dies...

 

its a 50/50 sometimes wont start and sometimes starts and dies... but leave alone for 5min. and no problems...

 

From what you have said, the engine starts fine when cold in the morning. Therefore, avoid doing any tests until the engine won't start.

 

yea ill run it till it wont turn on again... what else can i check/test?

 

You also might want to measure the fuel pressure.

 

i nkow i need the gauge but where do i measure?

 

The fuel pressure is measured at the fuel filter.

 

From the things you have said, I have to agree, it really sounds like an intermittently failing main relay. Take it out, pop its cover off, and re-solder the solder points on the circuit board inside (not hard, the circuits are very simple and large).

 

ok ill do both tests tomorrow..... anything else i should know??

 

and ill check the main relay solder points too..

 

Checking them won't help. You can't visibly see the weak connection... it is underneath the bubble of solder on each solder joint. Just take your soldering iron to each solder point and melt the solder on the solder point to re-solder the connection.

 

ok ill do that then... and why you think the problem goes away when i open the gas cap??

 

You can test the main relay, but the problem is intermittent, complicating the results. Click here to learn about how to resolder the joints.