1992 blazer will not restart hot.

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Schurkey

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Does the engine have spark when there's no fuel spray?

No spark, no injector pulse is typically either the pickup coil/magnet; or the ignition module--although the wire harness connecting the distributor to the ECM is also suspect.

Connect a scan tool, look for RPM when cranking when it won't start.
 

wb292

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When I thought it was a ignition problem I changed the module in the dist along with the module mounted just above the passenger side valve cover. Sunday I changed the coolant temp sensor near the thermostat. The engine turns over quickly when trying to start. Yesterday I poured a little gas down the throttle body and it started right up and ran a few seconds before dying. Along with basically no fuel coming from the injectors, I'm thinking its a fuel issue. Since it starts and runs great coming to work (70 miles) and restarts with no problems in the mornings after getting to work I'm thinking something other than the fuel pump. Could a bad O2 sensor lean the engine enough so it wouldn't start after it heat soaks from shutting down. I climb a 6% grade in 115 Arizona temps for 19 miles coming home. So I'm grasping thinking the EGT's are high and maybe the O2 sensor is bad?
 

AuroraGirl

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When I thought it was a ignition problem I changed the module in the dist along with the module mounted just above the passenger side valve cover. Sunday I changed the coolant temp sensor near the thermostat. The engine turns over quickly when trying to start. Yesterday I poured a little gas down the throttle body and it started right up and ran a few seconds before dying. Along with basically no fuel coming from the injectors, I'm thinking its a fuel issue. Since it starts and runs great coming to work (70 miles) and restarts with no problems in the mornings after getting to work I'm thinking something other than the fuel pump. Could a bad O2 sensor lean the engine enough so it wouldn't start after it heat soaks from shutting down. I climb a 6% grade in 115 Arizona temps for 19 miles coming home. So I'm grasping thinking the EGT's are high and maybe the O2 sensor is bad?
you arent the OP... but what year? Scan data?
 

alpinecrick

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When I thought it was a ignition problem I changed the module in the dist along with the module mounted just above the passenger side valve cover. Sunday I changed the coolant temp sensor near the thermostat. The engine turns over quickly when trying to start. Yesterday I poured a little gas down the throttle body and it started right up and ran a few seconds before dying. Along with basically no fuel coming from the injectors, I'm thinking its a fuel issue. Since it starts and runs great coming to work (70 miles) and restarts with no problems in the mornings after getting to work I'm thinking something other than the fuel pump. Could a bad O2 sensor lean the engine enough so it wouldn't start after it heat soaks from shutting down. I climb a 6% grade in 115 Arizona temps for 19 miles coming home. So I'm grasping thinking the EGT's are high and maybe the O2 sensor is bad?

You're not the OP and you're kinda' hijacking another member's thread, but......

I don't think the O2 sensor has the ability to shut off the truck, my Vortec will start and run with any of the O2 sensors disconnected.

If I understand correctly the truck starts, runs, and restarts when it's cool outside, but won't start once it's heat soaked?

It's a bit of a WAG, but my first guess is a cheap (poor quality) replacement fuel pump may be a culprit. Or a connection to the fuel pump.
 

351FUN

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Anyone know what the cure was? I'm having the same issue on my 91 K1500 5.7. Starts and runs great when cold or cool. When I drive it home about 70 miles with the AC on, it won't restart for at least 30 min after shutting it off. I replaced the fuel pump relay and oil pressure sensor hoping it was not getting fuel. Short trips into town and back aren't an issue. It will start easily. I drive it about 140 miles a day and it otherwise runs great. The fuel pump is a Delphi and is about 9 months old. How would the water temp sensor keep it from hot starting as mentioned in a earlier post? I replaced it with a new one when I rebuilt the engine 2 years ago.
This was the cure

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The blazer has just been sitting this whole time and its either getting sold or getting a new engine altogether since its not the daily anymore and we do need a camping rig.
 

351FUN

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You're not the OP and you're kinda' hijacking another member's thread, but......

I don't think the O2 sensor has the ability to shut off the truck, my Vortec will start and run with any of the O2 sensors disconnected.

If I understand correctly the truck starts, runs, and restarts when it's cool outside, but won't start once it's heat soaked?

It's a bit of a WAG, but my first guess is a cheap (poor quality) replacement fuel pump may be a culprit. Or a connection to the fuel pump.

That's how mine is acting, if I read it right theirs just wont start at all.
 

df2x4

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Question for the people with trucks having this problem, have you tried turning the key to run and then back off a few times before attempting to start the engine? Point being to prime the fuel system really well before attempting to start. It appears to be a decent temporary workaround to a "hot fuel module" failure, which some of these trucks apparently have. More info in these threads...

https://www.gmt400.com/threads/possible-replacement-for-hot-fuel-module.54679/

https://www.gmt400.com/threads/seeking-88-98-hot-fuel-module-fuel-pump-driver-answers.57613/
 
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