97K1500Silverado
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Truck hasn't had any issues lately with cooler weather. Did you get yours figured out?
Riddle me this... hot start 'N dies, miss / cut out only in summer
- Thread starter 97K1500Silverado
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97K1500Silverado
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Good questions, this always seems to happen when I'm far away from the garage, to check these questions when on the road with a hot heat soaked engine.... Let it cool off for 10 minutes and it starts and runs just fine, can idle in traffic hot with no issues. Randomly rears its head when trying to restart when over 90 outside and engine is hot from long drive or long idle time after long drive.
1. Spark i would have to either pull a plug or get one of those lights that go in a sparkplug wire. - If no spark then its the crankshaft position sensor or something in distributer?
2. Fuel pressure would be easy check by checking for fuel spray from the Schrader valve on fuel rail? If no fuel then its the fuel pump, fuel pump relay or regulator?
3. I have one of those cheap code readers that connects to my phone. watch the rpm live data while cranking, if none then its the crankshaft position sensor?
Don't use a "light". Use this, or something similar, calibrated for HEI igntions. SEE and HEAR the ACTUAL SPARK.
www.amazon.com/dp/B003WZXAWK/?coliid=I3S98D7T1J0RLJ&colid=2VLYZKC3HBBDO&psc=1&ref_=lv_ov_lig_dp_it
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Or the coil, or the coil wire, or the ECM or the ignition switch, or the ignition fuse, or the wire harness between crank sensor and ECM.
Not an accurate test. Fuel will spray even at low pressure. Many parts stores have a loaner-tool program where you buy the tool, you return the tool and get your money back. Fuel pressure gauges are common "Loaner" tools.
Or ECM, or wire harness, or fuel pump fuse.
Depends on the sophistication of your "code reader". Worth a try.
Or the wire harness, or the ignition module, or the ECM.
Carlosm86
Newbie
any update on this? Currently dealing with this.
97K1500Silverado
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I haven’t had the issues since it’s been cooler temperatures. Only happens to my truck when it’s above 90° outside and truck is heat soaked from a long drive.
It is really unusual for a fuel-injected vehicle having the pump inside the tank, to vapor-lock.
Vapor lock is almost always seen on vehicles where the fuel pump is engine-driven; and therefore has to "suck" the fuel from the tank to the pump. The pump is heated by the engine, and lower pressure on the suction side of the pump reduces the temperature required to vaporize (boil) the fuel.
OTOH, with the pump in the tank, the pump has no engine heat to deal with, and the fuel is under pressure--9 to 90 psi depending on vehicle--which raises the boiling point just like the pressure cap on a radiator raises the boiling point of coolant.
Yeah, fuel boiling in the plumbing is "possible" but really unlikely unless it's mis-routed too close to the exhaust, or the exhaust leak is blowing directly on the fuel tubing.
evilunclegrimace
Does not always play well with others
There is not a pickup coil in the dist on a vortec engine
evilunclegrimace
Does not always play well with others
No pick up coil in the vortec dist.
97K1500Silverado
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Update:
My 97 k1500 vortec 5.7. Runs great and never misses a beat until it’s over 90 out and when you go to restart after the engine is at normal operating temp it will start, run for a second then die. Only way to keep it running is to immediately give it gas and keep rpm about 1500 or more then it will run fine until you shut it off for a few mins and go to restart.
After replacing the coil, ignition module and checking all the grounds and connections still the same issue only when it’s very hot outside.
I think I may have finally solved it! The Vortec trucks and possibly the TBI trucks as well, Have two coolant temperature sensors the one on the side of the block that is a single wire connection at the sensor is only for the temperature gauge. The two pin sensor that screws into the water neck on the intake is for the computer and this is what a scan tool will read.
When the truck wouldn’t start, and it was hot out, I had my scan tool and no codes at all even when it fired up and died. The temperature on the scan tool was reading correctly, but then I saw -40 flash for a few seconds and then it went back to reading over 200. I’m going to replace the temperature sensor that goes into the water neck. Hopefully that finally solves my hot start problem!
My 97 k1500 vortec 5.7. Runs great and never misses a beat until it’s over 90 out and when you go to restart after the engine is at normal operating temp it will start, run for a second then die. Only way to keep it running is to immediately give it gas and keep rpm about 1500 or more then it will run fine until you shut it off for a few mins and go to restart.
After replacing the coil, ignition module and checking all the grounds and connections still the same issue only when it’s very hot outside.
I think I may have finally solved it! The Vortec trucks and possibly the TBI trucks as well, Have two coolant temperature sensors the one on the side of the block that is a single wire connection at the sensor is only for the temperature gauge. The two pin sensor that screws into the water neck on the intake is for the computer and this is what a scan tool will read.
When the truck wouldn’t start, and it was hot out, I had my scan tool and no codes at all even when it fired up and died. The temperature on the scan tool was reading correctly, but then I saw -40 flash for a few seconds and then it went back to reading over 200. I’m going to replace the temperature sensor that goes into the water neck. Hopefully that finally solves my hot start problem!
Verify the wire harness and connections, too. If there's a break in the wire, the temp goes to -40. If it's intermittent...you'd get occasional spikes downward to -40.
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