zak20vt

As per the title, when hot or cold, the Q7 will sometimes not start straight away. The engine will crank strongly but will not fire. After the 3rd or 4th attempts of 7 seconds of cranking, it will start.

General starting seems to take around 4 or 5 seconds of cranking before it will fire.

Vag Com / VCDS doesn't show any error codes.

I have had the fuel filter changed and this hasn't affected the starting issue.

Any ideas?

Thanks.

Jusforfun

I generally wait for the preheat light to go off but even if I forget and crank it only takes about 3 seconds to fire up. Once warm it is almost instant.
I have not read a solution but two or three owners have made this same complaint. I think all in the UK.

If you generally do not lock your car just hit unlock button before you get in anyway. The Q7 has a priming pump that is actuated by unlock.

Franklin Andrada

morning long cranking and sometime no start and theres a white smoke , when its start ill leave it idle for 10 minutes turn off then try to restart it will start cleanly but sometime it will take a long cranking 7 sec. to fire up or no start at all , but when it starts then try to drive the vehicle it run no problem it run fine also theres no error code , i have replace the battery , fuel filter , fuel pressure sensor , fuel pressure valve , high pressure pump , fuel retention valve , 6 injectors , egr , coolant temp sens. crankshaft sens. cam shaft sens. maf sens. i also tested the cylinder compression and it was fine , all above replace still the same symptoms scan it with vag no fault code , almost everything is replace , ive been doing this for 2 weeks , the ECM was also updated thru svm still desame , grrrrrrrr now i will try a new ECM for this will see what happen

TMQ206

I think the plugs need a second or two to warm, and there's a little indicator on the dash that goes out when they are warmed. Also, diesel engines don't always warm well if left to idle as they are rather efficient, so one needs to drive a bit to warm the engine. Do you live somewhere cold or leave the vehicle out at night? It is December. I recall some other comments/posts in this forum about slow TDI starts even in warm weather.

zak20vt

Have you tried connecting a battery pack/jump starter to the charging posts under the bonnet and seeing of this improves the starting?

Franklin Andrada

i havent try yet replacing the ECU , its hard to remove the connector socket from the ECU ,cos theres a 4 bolt security enclosing the socket connectors , ive already tried putting a jumpstart at the engine bay jumpstart post with already a new battery replaced still no good , but starter is good it cranks speed is 320 rpm ive measured it with vas in measuring block , no air fuel in fuel lines no leaks , glow plugs are good also , when i try to start ignition on wait for glow plug to turn off and then start just cranking too long , im from phillipines its tropical climate the car has only 19198 km

maximq7

Haven't run into this problem on my 2010 Q7 TDI - but will keep my ears open if I hear anything.

reljay

Hi all. Please help. I have exactly the same problem as above. Bought a 2007 Q7 about 2months ago. Noticed the starting problem almost immediately. It's gotten worse since and one day it did not start at all. I got the AA out. The guy tried to jump the car but no luck. He mentioned the fuel going in for starting seemed low. They towed the car to the garage. The battery was charged overnight and the car started in the morning but still with a lot of cranking. For up to 8 seconds. They replaced the fuel filter and it go slightly better. I still have the problem now. Most mornings I get 5 to 7 seconds of cranking and sometimes 2 to 3 attempts . The white smoke thing happens every now and again. I am confused and don't know what to do. I don't want to be exploited by the garages. Has anyone overcome this problem and how. Thanks in advance

zak20vt

Reljay,

Have you had your injectors tested for leaks?

The Audi dealer changed both fuel pumps and various other parts and the problem was the same. I then asked them to check the fuel injectors again (they told me these had already been tested but I did not believe them) and they found 2 with internal leaks.

The 2 injectors were replaced and the problem resolved.

Edd W

I do the same, on cold mornings I just press the start button without the brake pedal, then after about 2 seconds I press the brakes and start button again. This way it starts instantly rather than after about 3 seconds of cranking.

This is with a V8 tdi by the way.

One thing I noticed, the V8 cranks over a lot faster than the same engine did in the A8 I had before. I just put it down to Audi using a larger starter motor on the Q, weight saving being less important than on the A8 where everything is biased that way.