Hi guys I’m having a problem when I turn my truck on after if being warmed up.

[94singlecab350]

So I’m having this issue that when my truck is warmed up i will turn it off and if I leave it off for more than 30 min I will try to turn it back on and it will like want to stall out,they will be a loud hissing sound as well.i have to rev it for about 30 secs for it to stop wanting to stall.but if I let it cool down it will start up no issues.idk what the problem can be can anyone help.it runs prefect beside it doing that.

 

[SAR K2500 Burb]

Could be several things associated with "hissing" and hot starting issues.

Things that can hiss: coolant and fuel systems.

Hot starting issues are mostly vapor lock and fueling, but ignition can also be a culprit with overheated ICM and coil situations.

If you have to clear it out, I would suspect things like a bad FPR (my $1 guess), bad injector, or the hissing could be an unrelated coolant leak.

Details of the truck would be nice, to include existing fault codes, and borrowing a fuel pressure tester for free next time you pass a parts store. Takes less than 5 minutes to get that information.

Does your oil smell like fuel, does the coolant look clean and green?

 

[Peaches93Z71]

I had this EXACT problem with my 1993 k1500 tbi 350. It was the coolant temp sensor on top of the intake manifold (not the one on the side of the head, it just controlls the temp guage). After the truck is warmed up under circumstances where it would normally try to stall if started, unplug the sensor and start it. It should run. It'll run a little rough because it'll probably go into open loop, but it will verify the issue. Also, if it leaves you stranded like it did me, unplugging it will get you home. ACDelco GM Original Equipment 213-928 Multi-Purpose Temperature Sensor is the one I used and it works perfect.

 

[Schurkey]

So I’m having this issue that when my truck is warmed up i will turn it off and if I leave it off for more than 30 min I will try to turn it back on and it will like want to stall out,they will be a loud hissing sound as well.i have to rev it for about 30 secs for it to stop wanting to stall.but if I let it cool down it will start up no issues.idk what the problem can be can anyone help.it runs prefect beside it doing that.

WHAT VEHICLE? WHAT ENGINE?

 

[94singlecab350]

I forgot to mention it’s a 1994 Silverado c1500 5.7.i have done spark plugs coolant temp sensor erg valve fuel filter and more basic stuff.when it’s at operating temp it works fine.the trucks runs fine,just the issue is that when I try to start it warm (after it being off for more than 30 mins.she will stutter and want to die unless I give it gas.if i start it after I turned it off for less than 25 it will run fine but more that 30-2 hours it does that.my apologies I know this doesn’t make sense lol but it’s a weird issue

 

[GoToGuy]

Just like ordering parts, start with, Year, Make, Model, Eng any else that applies. Coolant temp sensor gauge = left head . Coolant temp sensor in intake manifold = ECM data input.
You start a vehicle, not turn on. You turn on lights, radio, etc ..Be specific, we're all blind. Terminology is important for the best answers.

 

[docstoy]

The hissing noise your hearing may be your IAC being stuck or extremely slow if as you say revving it, it will finally correct itself . So it could be loose terminal connection or a terminal that's not latched in connector causing poor continuity to IAC which could make it slow in operation . Just a SWAG . Hope this helps

 

[Erin]

Just like ordering parts, start with, Year, Make, Model, Eng any else that applies. Coolant temp sensor gauge = left head . Coolant temp sensor in intake manifold = ECM data input.
You start a vehicle, not turn on. You turn on lights, radio, etc ..Be specific, we're all blind. Terminology is important for the best answers.

Looks like his handle has basic truck info.

 

[MeatPlow]

The hissing noise your hearing may be your IAC being stuck or extremely slow if as you say revving it, it will finally correct itself . So it could be loose terminal connection or a terminal that's not latched in connector causing poor continuity to IAC which could make it slow in operation . Just a SWAG . Hope this helps

Exactly what I was thinking; a vacuum leak, stuck open pcv valve, or a dirty IAC will creep to idle eventually but slowing up that much sounds like it’s packed in.
I’d remove it, clean the bore and pintle, and rehome it. Also verify the engine/body/chassis grounds, PCV valve operation, and replace the TBI to intake gasket (OE was notoriously weak and would ulcerate if the air filter got too restricted at WOT).
Are you able to monitor loop status change, validate the coolant temp sensor range of operation, and have you reset the ECM?

 

[Schurkey]

Looks like his handle has basic truck info.

As it turns out, yes.

But there's no knowing in advance if he's asking about that truck, or some other truck he owns.

Vehicle description ideally is the first thing mentioned in the body of the first post of his thread. Preferably not in the title, or in the signature, or as a user-name. Then there's no ambiguity about what we're dealing with.