1994 Chevy Blazer Vapor Lock, I think?

94FULLSIZEBLAZER

MEMBER
1994 CHEVROLET BLAZER
V8
4WD
AUTOMATIC
113,000 MILES

When it gets above 90F outside my engine shuts off? It is worse the hotter it gets and with the air conditioning on. Usually shuts off when I let off the gas pedal. Sometimes it happens with my foot on the gas. When this happens all the electrical is normal, but the engine is stalled. In this situation I pull off to the side of the road and wait five minutes and the engine starts up like nothing is wrong? If I only wait one minute to start the engine, it tries to start but not quit. The fuel filter was replaced a year ago. The fuel pump and injector on the throttle body is original (16 years old.) The hotter it is outside, the longer I have to wait on the side of the road to restart the engine. There seems to be no electrical problems. I have had this same problem with carborated engines, but this Blazer has a TBI (throttle body injection) system that is supposed to stop vapor lock.

6 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Hi 94fullsizeblazer, Welcome to 2carpros and TY for the donation.

Check and monitor the fuel pressure if its within specs if okay shut it down, keep the gauge connected and monitor the residual pressure if it drops real quick could be a leaking injector/s, fuel pressure regulator or the fuel pump check valve.

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Saturday, July 17th, 2010 AT 6:09 PM

KHLOW2008

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Hi 94fullsizeblazer,

Thank you for the donation.

What is the idling speed when the weather is hot?
Should not be a problem with vapor lock if the vehicle is running.

When problem occurs, check the fuel pressure if it could not be started. After restarting, does the problem occur again?

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Saturday, July 17th, 2010 AT 6:10 PM

94FULLSIZEBLAZER

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I'm not sure how to answer this? This Full Size Blazer does not have a tachometer. The idle speed sounds the same when it is hot or cold outside. Of course, when the engine stalls out on hot days there is no idle speed. Once I wait five minutes after the engine is dead to restart it, it idles just fine. Like nothing happened. Everytime this problem happens, when I get the car restarted again I drive home immediately. That only takes ten minutes usually (small town.) So it has never happened a second time. Having the air conditioner on seems to causes the engine to stall out when it is only 90F. With the a/c off it has to be in the high 90's to stall the engine. It sounds like a fuel pump problem. The problem is it is very difficult to connect a fuel pressure guage to my full line. There is no fuel rail with a valve to screw on a fuel pressure guage. I'm told I have to remove the fuel filter and screw in the fuel pressure guage. Difficult situation. I think the fuel is boiling in the fuel line just before it reaches the throttle body, causing the engine stall even if my foot is on the gas pedal. Are there other things I should check other than fuel pressure?

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Sunday, July 18th, 2010 AT 5:09 PM

RASMATAZ

MECHANIC
75,992 POSTS

The scantool will tell you the engine RPM, you need to check the fuel pressure and get back with the readings so that we can continue to help you out

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Sunday, July 18th, 2010 AT 5:13 PM

94FULLSIZEBLAZER

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3 POSTS

My reply was for the questions KHLow2008 asked me. However, you are right. I will find out what the fuel pressure from the fuel pump is. It may be a week before I get back with an answer on the fuel pressure.

Thank you.