tester123

If that is the final diagnosis and required repair; generally, I lean heavily towards doing it yourself but GAS is involved here. While the procedure may not be difficult, potential gas leaks can be VERY dangerous if you don't complete the repair properly to specification(s) and procedure(s). Fuel pressures are moderately high and wrong threading/loose fitting connections will Definitely leak!

So, unless you feel totally confident that you can do it, I'd strongly suggest getting it done at the dealer/shop.

tytower

All I can say there is forget the "WOWSERS" posting doom and gloom .

Firstly its going to be the temp sensor but you must get a computer readout and confirm the error codes first.

It seems to me when the engine temp part of the 4 pin sensor goes the computer astoundingly must be programmed to go to the lowest setting for temp ! Like it thinks it is in the snow country and does not know that the engine is at working temperature.

Therefore it pumps maximum fuel in for a choked start and floods the engine immediately. As the accelerator is not directly attached to the carby's butterfly any more, foot flat to the floor does not clear the excess fuel. When it does start you will smell the fuel. I have sat half an hour with tries every 5 mins before it starts again.(My fault code is only temp sender)

My remedy, that you should try first, is to rev the engine when I switch off and switch it off at the peak of revs (about 3000-3500) . This lets the left over fuel at shutdown at least get out of the engine. This has not failed me yet when I have done it properly.
that sounds like 'Bunkum' to me !
The temp sender is available from china on ebay from $3 , dealers will charge $40 and its the same stuff they put in . They are not silly . The sooner it goes the sooner they will see more of your money.

The only reason you would let them do it is its a bugger of a difficult fiddly job and thats why I have not done mine.

pr0xZen

If this is Audi dealership/services' diagnosis - then I would think they're fairly on point. Most dealerships will suggest changing "complete parts" rather than servicing/refurbing - parts is where they make good profit, and a complete new part is usually easier to change and least likely to fail during warranty period.

If the fuel lines are leaking to the point you're having big trouble starting, this will be visible (but vapourize quite rapidly), and you'll smell it.

The fuel pressure regulator housing can be a downer to replace, but the housing rarely goes. What does go is the fuel pressure regulator seals. They're not "weak points" / traditional failures, but they're rubber O-rings and thus will naturally wear with time. Good news is that they're a simple job to replace, and very affordable, OE set usually ~$10-12. Part number: 037 198 031. If you need to lube the new rings to get them on, don't use petroleum based.

You will need to depressurize the fuel lines, and always do fuel work on cold engine. A simple way is to pull the fuel pump fuse and run it 'till it dies off. Still, cover with rags, there will probably be some spillage. Pull the retainer clip, pull out the regulator, change the seals. Assembly in reverse order.

Get a roll of vacuum hose, 3.5-4mm inner diameter. The OE hoses are 3.5mm and quite flexible, so 4mm "standard" vacuum hose should be a good fit. 2 meters should be enough with spare, better to have a little extra than not enough. Cut to length and change out the cloth-braided vacuum hoses - be careful when getting hoses on/off the plastic parts, they can get brittle with age.

All in all, it shouldn't set you back more than roughly ~$20, and be an hours work at most.

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For CTS diagnostic reference;

Again - I strongly advice against the cheapo china CTSs. The CTS is a very common failure point, so its been covered hundreds of times over the forums. When the accumulated consensus is that the cheap aftermaket ones are no good, there is usually something more to that, than spending more money than neccessary. From what I've been able to gather, even VAG original manufacturing has had a hard time getting a concise production of these, with a quite siginificant volume loss through quality control discardment. The dirt-cheap china CTSs are simply of poor material and manufacturing quality and there is little or no quality control. You might get lucky, but you don't buy car parts where "luck" is a working/quality criteria.

If you still suspect the CTS to be at fault, you can warm up the engine and pull the temperature the ECM sees with VCDS/Vag-Com; Module 01 Engine, read one of the first measuring blocks. Coolant temperature should be clearly labeled, it should be somewhere roughly around the ~90'C / 195'F mark when the engine is warm.

If the engine is warm, but your readings are far off this mark, you can test the CTS operation. Pull the connector, and connect a ~275-375 ohm resistor across the ECM pins. Temp should read roughly ~80'C. 1.5-2 kohm resistor; ~30'C. If its far off this, but not at end of spectre (-40'C <-> 140'C), you're likely looking at a dodgy CTS.

If the reading is -40'C, pull the CTS plug, jump the ECM signal pins. Should jump to 140'C. If the reading is 140'C, pull the CTS plug. Should jump to -40'C. If it happens, change your CTS. If the value doesn't change when doing the procedure - you're looking at dodgy wiring (or in worst case, dodgy ECM).

(Wiring loom plug side) G62 ECM signal terminals (2 different shapes):




If you want to bench-test (in a kettle etc.) the CTS itself, you can extrapolate what pins to check from the connector images. Don't submerge it completely, just the metal part. This is roughly the resistance values you're looking for across ECM terminals :

tester123

All of this is excellent.

Sometimes I see folks come here to get 2nd and 3rd opinions about an issue they may have (and, there is nothing wrong with that).

Is the OP capable of performing repair(s) himself? If not, pages worth of discussion (by the way, very good) may not help much and could cause even more confusion (depending on a person's knowledge in these matters). Just something to consider.

tytower

Personally I come here looking to find if someone else knows how to fix a problem. If they have had a similar experience to what I have now and they have fixed it then that can put me wise to what I can expect to have to do.

If someone who does not know what they are doing comes here they go away armed with knowledge and can use that in their battle to get a fair deal from the dealers. Let me tell you from experience , they certainly need that.

tester123

No doubt! I think it's great that people can use the knowledge from here/elsewhere and utilize it for benefit. No issues and definitely not trying to obstruct here.

This is a frequent topic since I've been here. This thread in particular felt like we are going everywhere while the OP was either may be not wishing or capable of performing the repair by himself or what he is doing about this.
Just wanted to see another success I guess. We still don't know if he addressed the issue as he never posted back (did I miss?).

triechane

Same problem here. It won't start I have to wait. It's trying to start but no then when it finally starts car stinks while driving like gas. Found code P3081 not sure what's that. And my CEL has been on for awhile. Help!

pr0xZen

Code is for engine temperature too low. See my post above, regarding the point where the ecm sees -40 degrees (Celsius), and how to test that. 98% likely either a broken CTS, or a broken plug wire.

kelisko

I drive a 1997 manual and I don't know if what happens to me sometimes is what is being described here but it sounds like it. I don't see it like a major issue though. To me, it's the car trying to adapt to your driving style.

This is what I noticed. When I drive the car at higher RPMs before turning off the engine, it starts fine. But when I drive it at very low RPMs before turning off the engine, it does not start as well as in the first case.

My solution: If you did drive the car at very low RPMs (saves gas), before turning off the engine, push the gas pedal to have the engine run at higher RPMs for a 2-3 seconds. Could do the trick.

Then again, I'm no expert. I'm just giving my opinion based on my experience with my baby.

tytower

!0 minute job as it turns out
Got around after 12 mths to doing this .
Ordered parts from China Ordered 3 just in case I have to do it again . Under $2 AUS each
Green Engine Coolant Temp Sensor Water Temp Switch FOR VW Golf Passat Audi | eBay

Opened the radiator overflow to release pressure and then tightened it up again
Took the black air boot off -loosened the plastic plate with 3 bolts and a lot of stuff attached and undid the small plastic 3/16ths pipe going down drivers side in AUS. Moved plastic plate to the side a little and was then able to get both hands down behind motor .
Tied a bit of wire through plastic locking clip just in case I dropped it , put a little pressure with a screwdriver down on top of the sensor and eased the plastic clip out toward steering wheel. Freed the sensor with wires still attached. O ring stayed in and is well greased so I left it there (rubber grease or glycerine only)

Then the fun started as the silly german clips are all different throughout the car and you have to try work out how to get them off. Looking at the new sensor it has an outward facing wedge and the clip that locks it in slides down the side of the wires plug and over the lip. I did not see an easy way to remove that clip because it is locked under the wedge. broke the top then the sides trying so just broke the clip out eventually . The plugs still good with sealing boots etc in good condition.

Put some copper impregnated marine grease on the plug so it went inside the 4 pin holes then cleaned the outside thoroughly. Don't leave grease on the outside .
Put it back on the new sensor and pushed it all back into its housing . Held it down with a screwdriver again as I put the old clip back in. Left the wire on it just in case.

Reconnected the plastic pipe , rebolted the plate and slipped the rubber air boot back with a little rubber grease on the lips to make it easy.
Started her up and used Vag-Com to confirm reading temp OK now . Starting beautifully , no leaks, no fluid loss anywhere on the whole job.

Done !

Now the Dealer quoted me about $260 , 40 for sensor and I'll lay odds they use the same source as I did. Then the con , " Oh which sensor is it , front or back ?" "Eh there's only one isn't there ? "No there are 2 ,we will need the exact error code to get the right part"-2 days getting the laptop working again
I would lay odds again that when I came to pick it up they would have found some other major problem to fix and up the bill and they would have charged for fresh radiator fluid .

Right! . So thats why I did it myself and anybody can do it . Just follow my steps exactly.
Look with a torch at the top of the sensor plug and you will see how many wires are coming out of it .If 4 then you will be here because of the starting problems .Two of the contacts drive a temp gauge on the dashboard and the other two feed a temp to the engine computer . So you will only get here if the engine computer side is not reading properly .

My car was getting -49C no matter what the real engine temp was and obviously was fully choking up the fuel injectors to start in such cold extreme so the motor just flooded .

Cheers