recent problem!

[Jboy2]

Well, for the last 3 days my moms 1991 chevy astro has been having a weird problem. When the engine gets cool and you try to start it, it runs for 2-4 seconds then dies, and continues to do this until it heats up enough and then runs mint after. Today i removed the doghouse and check all the plugs and wires (old owner didnt ensure the plug wires were on good, so 2 wires werent firing ) cleaned the TBI and IAC, checked all the vacuum lines and cleaned the EGR (the old owner removed all the vacuum lines for it and blocked them with bolts )

So what could be causing this problem?

Thanks

[kings-x59]

No check engine light right?
My gut reaction is either not enough fuel or too much. Since it runs mint once it warms up, I'd say
it's flooding when cold. Smell any gas when this happens? You might try some fuel injector cleaner. Seafoam, works good, and many others work just as well. Your injectors may be on the way out. Try the cheap simple stuff first.
post any other symptoms you can think of. Another temperature related thing I can think of is the coolant temperature sensor, but I think that would set a code and light the SES light in the dash.

[Jboy2]

No check engine light right?
My gut reaction is either not enough fuel or too much. Since it runs mint once it warms up, I'd say
it's flooding when cold. Smell any gas when this happens? You might try some fuel injector cleaner. Seafoam, works good, and many others work just as well. Your injectors may be on the way out. Try the cheap simple stuff first.
post any other symptoms you can think of. Another temperature related thing I can think of is the coolant temperature sensor, but I think that would set a code and light the SES light in the dash.

Correct, No check engine light. and it doesnt have another other symptoms
My gut feeling it that it is fuel related, yet i dont smell fuel when the problem occurs? So then i got thinking about the CTS and i couldnt find my DMM. so i'll test it tommorow.
I'll try some injector cleaner tommorow aswell and if worst comes to worst i have another TBI downstairs that i can switch.

Thanks for the reply buddy

[Jboy2]

Well,i didnt get to check the coolant temp sensor yet
But on friday i started right up when it was sitting over night. weird
So i started it today in the morning after sitting over night and it kept stalling again.
I'm honestly confused with this problem.

[kings-x59]

check your injectors to ensure a good spray pattern. Just turn the key to the on position, the fuel pump should cycle for 2 seconds and you should see a fine mist spray from the injectors. If you see dripping gas, the poppet in the injector is stuck.
Have you checked the fuel pressure? It sounds like the pressure is bleeding off overnight.

[Jboy2]

check your injectors to ensure a good spray pattern. Just turn the key to the on position, the fuel pump should cycle for 2 seconds and you should see a fine mist spray from the injectors. If you see dripping gas, the poppet in the injector is stuck.
Have you checked the fuel pressure? It sounds like the pressure is bleeding off overnight.

Well, i know the injectors have a nice spray pattern. So thats out of the question. Plus i know the fuel pressure is good because it does start everytime, it just stalls after 2-3 seconds of running. I do however think i found the problem! My oil pressure gauge reads no pressure when it sits for a few hours/overnight. So i switched the oil pressure switch outta my project van, and wouldnt ya know, it starts and run mint after sitting for a few but i'll wait till tommorow to see if it fixed the problem. [-o<

[safariobsession]

The oil pressure switch is what i was going to suggest...

The computer overrides the switch for 4 seconds after startup (letting the system build pressure) then looks to the switch after that to keep the fuel pump running. Any loss of oil pressure and the fuel pump should turn off. Strange enough, my book doesnt show the oil pressure switch in the fuel pump circuit. Probably goes through the computer first.

Check the connector to the sensor too, just to be sure.

[Jboy2]

today i started it in the morning. It starts, runs for a few seconds then dies, then starts and runs then dies, etc. Then after a few amounts of starting/dying it will stay running for the rest of the day and run mint. i did pop off the engine coveer, and you can see before it dies the fuel cuts out. So i'll have sme more work for me ](*,) and at such a great time too (exams)

Check the connector to the sensor too, just to be sure.

Hmm, i'll have to do that

[Jboy2]

Ok, well seafoam was on sale near my place. So i seafoamed the engine about a week ago, and the idle went back to normal and you definitely feel an increase in throttle response. Today it wouldn't run at allllllll (it would start, then idle at about 200 rpms and die) So i switched the injectors and pressure regulator with a set downstairs, and wouldnt you know.....it started right away and ran mint! well i had the fuel lines disconnected i also cleaned and modded the TBI aswell as i made a new gasket since the old one was on its way to braking.

[kings-x59]

I'm fairly certain your fuel pressure is low. It'll start with as low as 6 psi. The injectors need about 12.5 psi to operate correctly. Either get a fuel pressure gage and test the pressure or have it done. If you decide to to do it yoursrelf, do not get a gage designed for high pressure fuel systems. You need a gage that will read accurately between 11 and 20 psi. My experience with pressure gages that will read the 50 to 60 psi pressures do not read accurately in the low pressure ranges.
Either your pressure regulator is toast, or you fuel pump is going out.