Cranks won't start

Tiny
AUDLEY
  • MEMBER
  • 2002 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 240,000 MILES
2002 tahoe 5.3, 48 psi fuel pump pressure, spark at plug wire, installed crank positioning sensor won't start, cranks a little faster and sounds as though it wants to start, but won't. Battery is up and there is plenty of fuel. I don't want to start putting any more sensors on at random. Audley
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Tuesday, February 1st, 2011 AT 3:19 AM

58 Replies

Tiny
ERNEST CLARK
  • EXPERT
If the crank sensor was bad and toy replaced it the sensor will need to be programmed to the car a shop can do this for about $130.00.

You're computer needs to see both a crank speed reading and cam position reading for it to tell the coils to fire a spark to the plug.

Since you've checked spark and fuel pressure, use an automotive stethoscope to listen for your injectors firing. You'll hear a distinct clicking sound. If your injectors are firing, the valve timing may be off (bad timing chain). You can verify this by doing a compression test.

If your timing chain has slipped, just replacing the timing chain wouldn't be economically sound, as that would be like putting a band aid on a gunshot wound. The rest of the motor will be just as worn as the timing chain. However, I do not recommend rebuilding this motor unless you want to keep this truck for 10 more years. There are too many low-mile used engines for dirt cheap.

It isn't your ignition switch. If that were the case, you wouldn't be getting spark at the plugs. Your ignition timing is controlled by the computer. If that's out of wack, your computer would be bad. Sometimes an intermittent fault with your sensors will fail to set a code. Depending on which sensor is faulty, the computer will have to determine it has been faulty for a certain amount of drive cycles or time. If the sensor acts good, the computer will shut off the light by itself.

If a scan doesn't produce anything, you'll need to continue your diagnoses on the systems components the computer can't always read. These would be the mechanical components of the engine.
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Tuesday, February 1st, 2011 AT 11:59 AM
Tiny
AUDLEY
  • MEMBER
Good call on the reprogramming apparently you will have spark with the new crankshaft sensor but it will be at the wrong time so the engine will not start. All fixed thanks for the advice. I love this site.
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Tuesday, February 1st, 2011 AT 7:11 PM
Tiny
ERNEST CLARK
  • EXPERT
Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help

Cheers
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Tuesday, February 15th, 2011 AT 2:51 AM
Tiny
TAHOE037
  • MEMBER
  • 2002 CHEVROLET TAHOE
  • 144,000 MILES
I tried multiple times and it did the same thing each time. I am thinking its the starter or spark plugs because it wouldn't ignite but would turn over the first time.
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)
Tiny
PROMECHANIC
  • EXPERT
The first thing to check is your battery cable connections. Make sure they are clean and tight. The next thing to do is have your battery load tested. You can also check it yourself by getting a voltmeter reading when it is just sitting there and another when you are trying to start it.
If you want more help then let me know what voltage the battery has. You can get a cheap voltmeter at walmart or any auto parts store.
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)
Tiny
TAHOE037
  • MEMBER
Well I had it to a shop maybe 3 weeks ago, they did a battery inspection and said it was fine. Ill try that tomorrow but if thats not the case whats should be my next course of action?
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)
Tiny
PROMECHANIC
  • EXPERT
The next thing I would suspect (After making SURE that the battery is good. Be sure it is "load tested") is the starter. You can try to knock on it with a hammer to see if it breaks free. You can also see if it is getting battery voltage when you try to start it.
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)
Tiny
LAURA PASILLAS
  • MEMBER
  • 2002 CHEVROLET TAHOE
  • 0.5L
  • V8
  • 4WD
  • AUTOMATIC
  • 190,000 MILES
Replased ignition now car won't start wonts to but bogs outnan dies had a locksmith repace it for me it wonts to start oh security light is on until I turn it over I replased fule pump but wasn't problem when I turn it over it caches byt don't bogs out befor it does catch an dies
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)
Tiny
HMAC300
  • EXPERT
Try resetting security sytem see pic
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)
Tiny
STRANDED IN TX
  • MEMBER
  • 2002 CHEVROLET TAHOE
Computer problem
2002 Chevy Tahoe 6 cyl Two Wheel Drive Automatic

2002 Chev Tahoe 5.3 liter. Had low fuel, I filled it up at the gas pump. Car will not start. It sounds like it wants to, but lacks fuel. Replaced fuel pump and fuel filter, checked all wiring and connects, fuses and sensors. Help!
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)
Tiny
RHALL77
  • MEMBER
What is your fuel pressure. Are you getting good spark. How is your injector pulse.
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)
Tiny
JM807
  • MEMBER
  • 2002 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 112,000 MILES
Engine Mechanical problem
2002 Chevy Tahoe V8 Four Wheel Drive Automatic 112000 miles

I bought this truck in the summer time and it ran perfect. Here we are in the middle of winter and i'm limited as to how much I get to drive it. The problem is anytime air temp drops around 32 degrees or lower, it wont start. You can hold the key over for about 10 sec. And it will start but, suddenly die and wont stay running. I've had it in the shop when running but of course it triggered no codes. The told me it had a tiny intake leak but not enough to affect it in this way. Do you have any idea of sensors, or anything that can be causing this problem? I really like the truck and cant wait to get back behind the wheel, but need pointed in the right direction.
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi:
Have you checked for trouble codes? Also, the intake can have this type of effect.
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)
Tiny
JM807
  • MEMBER
When it was in the shop they ran a diagnostic on it but it wasnt that cold then, so the truck started and ran fine, not triggering any codes. Its frustrating because its like the vehicle knows exactly what temps. It doesnt want to start at. At 33, 34, or warmer it starts. At 31 or 32 has trouble but after a few tries it'll start, 30 or below your waistin your time. After crankin and crankin it'll fire and die suddenly. Keep in mind any other temp. Or time it drives perfect, with no signs of trouble.
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
Hi:
Believe it or not, today's cars do know the temp. My best suggestion is to wait for colder temps, 30 or below and take it to the dealer the day before it gets that cold. Have them check it first thing in the AM when you are confident the problem will occurr.

I realize it's a pain, but that is the best you can do.

Let me know what they find. I would really like to know what they find.

Joe
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)
Tiny
AUDLEY
  • MEMBER
  • 2002 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 240,000 MILES
2002 tahoe 5.3, 48 lbs fuel pump pressure, spark at plug wire, won't start, cranks a little faster and sounds as though it wants to start, but won't. Battery is up and there is plenty of fuel. I don't want to start putting sensors on at random. Audley
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)
Tiny
RASMATAZ
  • MEMBER
**Cranks but no start condition:

Get a helper disconnect a sparkplug wire or 2 and ground it to the engine at least 3/16 away from ground -have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, Do you hear the fuel pump come On when you turn key on? If not check fuel pump fuse and fuel pump relay if so, check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs, coil's resistances, distributor pick-up coil, ignition control module, cam and crank sensors and computer Note: If it doesn't apply disregard it.
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)
Tiny
MOTORACER215
  • MEMBER
  • 2002 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 10,000 MILES
Electrical problem
2002 Chevy Tahoe V8 Four Wheel Drive Automatic 10000 miles

My wife and I just inherited a 2002 Tahoe from her parents, however whenever you go below half tank of gas the truck wont start. If you add a few gallons to it, then it will start. Even though there is plenty of gas in the vehicle, for some odd reason it thinks that is empty. Is this a fuel pump? Thanks
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)
Tiny
BLACKOP555
  • EXPERT
Sounds to me that the pump is getting bad causing it not to be able to create enough suction to suck up the gas.
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)
Tiny
GEORCHMB
  • MEMBER
  • 2002 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 120,000 MILES
Engine problem
2002 Chevy Tahoe V8 Four Wheel Drive Automatic 120000 miles

The truck will not start up until I try several times when it is cold. It seems worse the colder it is. The engine will turn over but not start. Thanks very much
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Tuesday, March 6th, 2018 AT 5:10 PM (Merged)

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