It cranks has spark but wont start?

Tiny
FLEAGLE0202
  • MEMBER
  • 2001 VOLKSWAGEN BEETLE
  • 160,000 MILES
I was driving stopped at a light the car shut down, it cranks has spark but wont start. I was told by a backyard mechanic it has to go back to the dealer to unlock the computer, I also took the battery terminals off for a while then reconnected but no luck. Is it true just the dealer has to reset or jnlock something? Before I spend on a computer etc?
Friday, October 4th, 2013 AT 4:24 PM

14 Replies

Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
Do you have fuel pressure? And do you have injection pulse? Check these and run a scan as well you first need to know what has failed before considering your next step.
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Friday, October 4th, 2013 AT 4:26 PM
Tiny
EXOVCDS
  • MECHANIC
  • 1,883 POSTS
If you have spark, then you are missing fuel.... fuel pump relay or fuel pump.

Could also be a broken timing belt.

Backyard mechanics give the industry a bad name. If he can't fix it, find someone who can here:

http://autorepair.iatn.net/

Thomas
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Friday, October 4th, 2013 AT 4:51 PM
Tiny
MADMIKE1735
  • MECHANIC
  • 951 POSTS
What size engine is this? And when the car shut off, did it shut off instantly like you turned the key off, or did it kind of stumble a bit, like it ran out of fuel? Any little details can go a long way is helping you diagnose this. Was there any noise in the engine before it shut off?
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Friday, October 4th, 2013 AT 5:01 PM
Tiny
FLEAGLE0202
  • MEMBER
  • 12 POSTS
Yes, it shut off as if you turned the key. I have fuel pressure and spark i'm going to check if the timing belt isn't broken also checking key chip.
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Friday, October 4th, 2013 AT 5:06 PM
Tiny
MADMIKE1735
  • MECHANIC
  • 951 POSTS
For it to act as if you turned the key off, then its electrical. Somehow your losing spark, and thats causing the instant shutoff. Is your check engine light on? Also, after it "dies" will the car start immediately, or does it seem like its a longer than usual crank before it starts?
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Friday, October 4th, 2013 AT 5:15 PM
Tiny
FLEAGLE0202
  • MEMBER
  • 12 POSTS
Timing belt is fine I have no spark sprayed starting fluid into intake nothing it just cranks. I guess it's the main computer or it could be the security system shutting down the system? Guess time for the dealer
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Friday, October 4th, 2013 AT 7:24 PM
Tiny
EXOVCDS
  • MECHANIC
  • 1,883 POSTS
Security system does not cut spark right away.

Security / Immobilizer will allow the engine to run for 2 seconds and then shuts off the engine. If your engine does not even run for 2 seconds, then it is
not a security / immobilizer issue.

Crankshaft position sensor / engine speed sensor, is the main input to the ECM... without a crank signal, the engine will not run.

Here's a video on how to replace the crank sensor: (2.0L Jetta, same location on a Beetle).

http://www.youtube.com/watch?v=UK0oDLrSo4c

Scanning for trouble codes would still be the first step.

Thomas

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Friday, October 4th, 2013 AT 8:14 PM
Tiny
FLEAGLE0202
  • MEMBER
  • 12 POSTS
Well took it to the dealer the computer is bad they can only replace it with a used one for $890.00 I will get one out of a junk yard for $100 but they said I have to get the computer reprogrammed which they say is another $300 is that true they need to be reprogrammed?
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Saturday, October 5th, 2013 AT 2:04 PM
Tiny
EXOVCDS
  • MECHANIC
  • 1,883 POSTS
It needs to be matched to the other modules, so yes. Software coding needs to be done.
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Sunday, October 6th, 2013 AT 9:40 AM
Tiny
FLEAGLE0202
  • MEMBER
  • 12 POSTS
Just to help you guys that think you know everything about cars. The problem was the car shut down at a traffic light, the car cranked, no spark or gas. The main computer blew out. Put a new computer in matched the key to the computer and off it's fine. I just can't believe the wild goose chase you guys put people through.

I will never put any trust in you guys again your all parts changers.
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Monday, October 14th, 2013 AT 7:08 PM
Tiny
MADMIKE1735
  • MECHANIC
  • 951 POSTS
We can only do so much with your responses. Parts changers? Really? Most of are are Master Technicians. We do alot more than change parts.
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Tuesday, October 15th, 2013 AT 3:28 PM
Tiny
EXOVCDS
  • MECHANIC
  • 1,883 POSTS
Nobody here told you to change any parts. You yourself said that you have spark! We gave you suggestions based on the
info you provided.

Oh wait you did, but the dealer was too expensive!

My next honest reply was "yes, the computer needs to be re-programed / matched" (again, I was correct).

Thomas
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Tuesday, October 15th, 2013 AT 6:39 PM
Tiny
MADMIKE1735
  • MECHANIC
  • 951 POSTS
Exovcds great diag. If this guy cant thankyou for the help, his problem. I'm glad to see another tech step up and come up with an diag. We didnt have much to go on here. Keep up the good work!
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Friday, October 18th, 2013 AT 6:52 PM
Tiny
BACKWOODSFREAK
  • MEMBER
  • 1 POST
Don't let this guy get you down. You guys help. A lot. Could only imagine the last time this guy diagnosed a precisely timed electronically controlled explosion machine from thousands of miles away with only the info deciphered from the monkey squeaks provided.
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Saturday, October 3rd, 2020 AT 9:30 PM

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