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7.4 gm hard hot starts

7.4 vortec is hard to start when hot but starts when cold

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Posted on Jan 02, 2017

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SOURCE: 98 Escort Hard starting when hot

sounds like a dodgy mis reading of a sensor caused by electrical resistance which is turning choke on and flooding engine.know the fault but without car in front of me its difficult to diagnose,could be auto choke sensor which is on right hand side of cylinder head ,but not is probally dealer have you tried spark plug gaps ??25th although this would cause problems with cold starting not hot starting but its worth a look

Posted on Nov 28, 2008

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SOURCE: hard to start chevy 350 vortec

You will need to do a fuel pump pressure leak-down test, the pump must not loose more than 5 PSI overnight, u will need a cheap fuel pressure test guage, the test port is on the fuel supply rail to the injectors on the intake manifold, it looks like a tire valve but metal with a plastic cap on it, u may be able to borrow this guage from Kragen, Autozone or a parts store like them, if not they are very cheap, less than $20 US. Run the engine with the test guage hooked up, turn off the engine and then check it in an hour or so, if it drops more than 5 PSI then u will need to replace the fuel pump in the gas tank. One note make sure the connection for the guage is tight with no leakage or the test is invalid

Posted on Jan 16, 2009

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SOURCE: 454 ci gm turns over hard backfires timing ok acts flooded

Check fuel pressure, and regulator. A leaking regulator gives a warm engine more fuel [ it does not like it] a cold motor does. same as a flooded motor. Good luck

Posted on Mar 24, 2009

  • 33 Answers

SOURCE: hard to start hot or cold runs good when it starts

I think it may be time to change the spark plugs and wires.

Posted on May 18, 2009

  • 1 Answer

SOURCE: Hard to start when engine gets hot

could quite possibly be a bad starter on your 4.3 .... i have had trucks and cars where .when the engine gets hot the exaust manifold puts heat on the starter making it harder to operate.... when the truck cools it will start no???

Posted on Aug 05, 2009

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My Blazer cranks over and over...killed the battery : morning the second time I tried cranking it over it made a poof sound and started but with a lot of chugging. Can anybody help please?

Lynda, If it is the 4.3 V6, they are prone to getting moisture in distributor which causes the symptoms you are talking about including the poof. You can have scanned to see if trouble codes are stored, you may get multiple misfire.
If continues doing this have cap and rotor replaced and if wires and plugs are old do them to. Check the attached links,instruction and guides, Good luck
"I hope this helped you out, if so let me know by pressing the helpful button. Check out some of my other posts if you need more tips and info."

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Apr 01, 2016 | 2001 Chevrolet Blazer

1 Answer

Why does my astro with vortec engine start hard when hot, and surges along wit misfire, but runs good after starting/

if flooding, (and this causes MISFIRING)
there is an injector leaking
no year stated,
not scanned ? , why not scan it.? got p03xx codes.?

you replaced expensive parts before spark plugs. really?
do a full tune up, ?

Mar 25, 2015 | Cars & Trucks

1 Answer

Why is my 2002 siverado with a 5.3 vortec start hard when warm and fine when cold?

My guess is you have an engine temp sensor not operating properly. The cold start is OK but there is something not telling the ecu when hot. There are multiple sensors and you may need specialist help to test them. There is a dedicated fuel management system on vortecs but I think that's on later models.

Nov 03, 2014 | Cars & Trucks

1 Answer

Fuel pressure regulator

Throttle plate may need cleaned and check your plugs.

Jun 15, 2014 | 1998 Chevrolet K1500

1 Answer

1999 gmc suburban 5.7 vortec hard starting only when cold

The original "poppet" style fuel injectors used in these engines were notorious for causing hard starting/misfire issues on a cold engine. GM has since redesigned the injector "spider" that works much better than the original. Not saying that's what's wrong with your engine, but it is common on them. :)

Sep 16, 2013 | Cars & Trucks

1 Answer

93 S-10 blazer, vortec v 6 cpi, when cold it is very hard to start, you have to shoot ether and it will start right up, new fuel pump and filter and fuel pump relay, once it starts it will start right back...

Issue with PCs Valve Check for vacum lost cracking rubber connection Pre-Heater and Primer System Mal-Functional Check also for Idle sensor Relay for bad connection....good luck

Sep 28, 2010 | 1993 Chevrolet S-10 Blazer

1 Answer

Hard to start when engine gets hot . 4.3 vortec,auto 2wd.

could quite possibly be a bad starter on your 4.3 .... i have had trucks and cars where .when the engine gets hot the exaust manifold puts heat on the starter making it harder to operate.... when the truck cools it will start no???

Jun 24, 2009 | 1994 Chevrolet S-10

2 Answers

My 1999 GMC Jimmy won't start without jumping it from another vehicle. This is when I do a cold start. The Battery is New! It will start without jumping once it is warmed up..

When the engine is cold, it takes a lot of current to crank the engine over and this pulls the voltage down that is available to the fuel pump. The GM vortec injectors have poppet valves that are pressure activated. If they do not get full pressure, they just don't open even if the injector solenoid valves are being fired. The combination of reduced voltage at the pump and dirty injectors or possibly a pump that is getting weak will prevent the engine from starting
Gm released a bulletin describing a special injector cleaner for this problem, it goes in the gas tank. The idea was to clean the poppet valves so that they opened a little more easily. You could ask your dealer about this, or just try dumping a couple bottles of generic injector cleaner in with a fill up. If this doesn't help, you may have to replace the fuel pump.

Apr 14, 2009 | GMC Jimmy Cars & Trucks

3 Answers

1998 Chevy tahoe Hard to start when cold

replace your MAP sensor(manifold absolute pressure) the map sensor is the computer for your fuel pressure regulator telling how much pressure. Unless your tahoe runs like **** going up hill than it inevitably your fuel pump

Feb 17, 2009 | 1999 Chevrolet C/K 2500

2 Answers

My 2001 chevy diesel truck is very hard to start below 35 degrees

check the glow plugs usually nd external check would indicate power to the plug but in your case i would suggest you to pull atleast a couple of plugs and makes sure that they are getting hot you will find that the plugs are not working replace the glow plugs and the engine will have no problem in starting adn if you live in a cold region make sure that our electric corde is plugged in all night since the diesels need to be warm to operate necause they strictly work on heat from the engine and they do not have spark plugs to ignite the fuel.

Nov 19, 2008 | 2001 Chevrolet Silverado 2500HD

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