forum.audiv8.com Foren English Audi V8 Forum Trouble starting 3,6l (PT)

Hi.. I've just bought two Audi V8's with P 3,6l engines.
My problem is that none of them will start.
The "best" one, is turning on starter, but will not fire, andt the gasoline pump is not running. BUT if I force the pump-relay to work, the gas-pump runs, but still the engine will not fire...
Any good ideas?

Is it so that the gas-pump should start for a sec or two when turning the ignintion ON? And if so, what must be working for the pump to start?
Tried changing gas-pump-relay, "no-func", checked all of the park plugs, ok. Seems like there is no ignition...

Read out some errors, G4 and G28, but could these also come because of the engine not starting?

Any suggestion / idea will be helpfull...

Does the Cars have a Conlog Alarmsystem?

As far as I know the car doesn't have a alarm system at all, du what should I look for then, IF tha car should have one?

If the Conlogsytem has a Problem the Engine wil not start.
If the Car has a Conlog,
there is a Plug with a red LED in Centerconsole above the Radio.

Hi,

readout the ECU fault codes (instructions on the internet - no computer needed). I bet it's whether the ignition point sensor and/or the engine speed sensor. Always change both, it costs you a 200.- EU, but then you're on the save side.

Best regards

Bastian

Hi. I've read out the error-codes, they say
00514 - Ignition Point Sensor (G4)
03-00 - No Signal
00513 - Engine Speed Sensor (G28)
03-00 - No Signal
So may be You are right about the ignition Point Sensor, but will not the fuel-pump engage at all because of that?
And another funny thing, all of this worked when the car was put away.?

Hi,

the sensors tend to fail immediately - and their behavior is dependending on the temperature. The warmer it becomes, the more troubles you have. Try to "ice" down the sensors to below 0°C and they will probably work. The V8 only needs the ignition point sensor for starting the engine (to know the upper dead center of C1), the rest is done by the engine speed sensor. So it may start properly, you drive an hour, stop the car and can't restart it until next morning

Regarding the pump: The relais for the fuel pump is not activated by the Motronic before both sensors deliver (valid) signals. It is a very common wrong diagnose that the fuel pump is broken; in fact the sensors are.

Change 'em - both of them in one go.

Best regards

Bastian

PS.: Just for fun: You don't accidentely have a friend driving a Porsche and who spent some monthes in Aalborg, Denmark two years ago?

Thank You for information, You don't actually know where to buy them both at cheapes price?

About Denmark 2 years ago, I've just bougth the two cars, so that I don't know... :-)

Hi,

have a look at http://www.autoteile-legan.de

or just write an email to: info@autoteile-legan.de

Including shipping it's probably not way cheaper than when you buy the parts at your local dealer. In your situation I would buy two new sensors (ignition point and speed are absolutely identical - buy the cheaper one twice!) and replace them in one of both cars.

Then you take both old speed sensors and trash the ignition point sensors and put them in the other car - et voila, you most probably saved 200 bucks (for now - sooner or later the old ones will also fail).

Don't be confused: When the engine is _not_ running, the speed sensor will _always_ be stored in the fault memory. The correct way to read out is to ignite, start, stop starting and to not turn the key back. When you read out the codes then, you see if the speed sensor is really broken or not.

Bastian

Hi. Do not have an alarm-system on either of the cars I found out...

Then it would bee what Bastian wrote.

Thanks a lot. Haven't had the time to check this out, but is there any good On-line instructions to chnge the G4 / G28?
Br

Espen B

Mmm,

I'm not aware of any English ones. Try that one out:

http://www.audiv8.com/german/faq/faq_show.php?id=201

Bastian

Thank a lot, no problem with understanding this
Now I'll get to wrok...

while cranking the engine over, does the tach needle bounce? If yes, the reference sensor (black) is good. you may have a bad engine speed sensor(gray) both sensors are the same, just different color. Best way to check them, is to put an ohm meter on them. Should read 1k ohms. Allan