No DTCs car shuts off going 50MPH?
12-18-2006, 12:06 AM
#1
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No DTCs car shuts off going 50MPH?
Driving along at speeds over 40MPH on three occasions the car seemed to lose all power for a couple of seconds, the CAT light came on,and it felt like I had deployed a parachute like a drag racer... but no faults on VAG COM?? Any ideas?
12-18-2006, 06:04 AM
#2
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Blocked cats? Degraded over time? Do they rattle if you hit them with a hammer?
Or your fuel injection system is shutting down.
I would say either blocked air flow at the cat or the fuel is being shut down. However, I would think that the fuel being shut down would show a fault code.
I would say either blocked air flow at the cat or the fuel is being shut down. However, I would think that the fuel being shut down would show a fault code.
12-18-2006, 06:52 AM
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Could be your Crank pos. sensor. Mine was doin that but it turned out to be my ECU...
If your CAT lite is on, you have codes...id bet misfires. Check your plugs, CPs, ignition control modules (or POS as they refer to them).
12-18-2006, 12:34 PM
#4
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Do they rattle AFTER you hit them with a hammer?
Sorry, couldn't help myself. Do you notice any loss of electrical power when this happens?
Which lights come on when you first get in the car and switch the key to the run position with the engine off? Those lights should come on as soon as the engine quits running too with the key in run. If not, then you are losing electrical power to the ECU. If the power to the ECU cuts out, then you cant' record any error codes because the ECU is asleep.
If that is OK, then ...maybe intermittent fuel pump or relay (under the passenger's feet in the electrical box with the MDF cover) As luck would have it this combination relay: Fuel pump, injector power and ignition power is pretty cheap.
I don't suyppose you could let the laptop ride shotgun and have it record data (VAG Scope) while you are driving. If the scope goes dead during the flat spot, then no power to the ECU. If it stays live, then look elsewhere.
Why not start simple and check that you battery cables are clean and tight and that the grounds is getting flaky.
Good luck.
Which lights come on when you first get in the car and switch the key to the run position with the engine off? Those lights should come on as soon as the engine quits running too with the key in run. If not, then you are losing electrical power to the ECU. If the power to the ECU cuts out, then you cant' record any error codes because the ECU is asleep.
If that is OK, then ...maybe intermittent fuel pump or relay (under the passenger's feet in the electrical box with the MDF cover) As luck would have it this combination relay: Fuel pump, injector power and ignition power is pretty cheap.
I don't suyppose you could let the laptop ride shotgun and have it record data (VAG Scope) while you are driving. If the scope goes dead during the flat spot, then no power to the ECU. If it stays live, then look elsewhere.
Why not start simple and check that you battery cables are clean and tight and that the grounds is getting flaky.
Good luck.
12-18-2006, 11:54 PM
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agreed but if a earth or battery then a fault terminal 30 should show
How is the fuel filter.
If you scope the 02 that will show if it is fuel related.
odd there are no codes at all.
please keep posting re this issue
If you scope the 02 that will show if it is fuel related.
odd there are no codes at all.
please keep posting re this issue
12-21-2006, 01:29 AM
#7
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Re: Do they rattle AFTER you hit them with a hammer?
Cats have been checked out...no rattle. But interesting comment you made re the relay. Will check this out asap. Many thanks, really appreciate help.
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