Erratic idle on 16V

Nick · Post by **Nick** » Mon Aug 11, 2003 7:57 pm

Hi all,

Problem:-

1999 Mk4 1.4 16V Polo - engine idle speed is erratic on deceleration, and is most noticable when de-clutching to change down for a round-a-bout etc. When clutch is depressed, instead of revs dropping nicely to normal idle speed, engine will only drop to about 1500rpm, then "wave" about for a bit, then eventually drop to normal idle speed and then settle. Almost feels like the "choke" is still out, and the engine still pulls, when trying to slow down.

My car is still covered by the VW Approved Used warranty, and has been back twice now, to try and cure the fault - once for a water temperature sensor, and also for an engine ECU change. Neither have worked.

Should i keep taking the car back? - although it seems even VW are stuck on this one! or try and work it out myself.

Any thoughts or ideas appreciated,

Nick

polo2k · Post by **polo2k** » Mon Aug 11, 2003 8:10 pm

i was gunna suggest the water temp sensor but since its been done and i assume they checked all the wireing try cleaning the throttle body abd make sure all the admission is clean

Nick · Post by **Nick** » Mon Aug 11, 2003 8:22 pm

Wow - fast response!

Ok - i'd heard about the throttle body before - any chance of a rough location, and the best way of cleaning it?

Nick.

jakethesnake · Post by **jakethesnake** » Mon Aug 11, 2003 11:01 pm

Hello mate

Still no luck with this prob then ?!

Remove the lid of the air filter housing then take out the filter, you can see the throttle body on the RH side.
Not sure what to clean it with though.

Are you taking your car on Saturday ?.

Speedlaw · Post by **Speedlaw** » Tue Aug 12, 2003 12:07 pm

Brake cleaner? or Carb cleaner perhaps?

I'm sure Ash knows....

delipolo16v · Post by **delipolo16v** » Tue Aug 12, 2003 12:23 pm

1.Spray some carb cleaner in there
2.Read the riot act to the dealership and make them fix it, if they don't/can't fix it tell them you want another car (they make enough money as it is don't accept substandard service your money was not substandard when you paid!!)

polo2k · Post by **polo2k** » Tue Aug 12, 2003 12:41 pm

yeah open the throttle so the plate moves to let air into the engine and clean out all the goop with brake cleaner, carb cleaner or rubbing alcohol, make sure you get it all clean and shiny

and make sure nothing falls into the inlet manifold as if it does it wilol say hello to mr valve then mr piston and then you say hello to your bank manager to buy a new engine

Nick · Post by **Nick** » Tue Aug 12, 2003 3:02 pm

delipolo16v - problem is that i didnt buy the car from the dealer; the previous owner had the warranty when he bought the car.

Ash - thanks for the advice; i'll give it a go and see what happens.

JTS - you have PM,

Nick.

delipolo16v · Post by **delipolo16v** » Wed Aug 13, 2003 12:02 pm

But it's still coverded by the used warranty right?

Nick · Post by **Nick** » Wed Aug 13, 2003 8:51 pm

Yep - just getting fed up of keep going back now.

If the fix requires money, then i will defo have them do it. But if it's the simple fix as above (hopefully it is) then i will do it myself.

Nick.

jakethesnake · Post by **jakethesnake** » Wed Aug 13, 2003 9:25 pm

Due to the nature of the problem I can't believe the service department hasn't cleaned the throttle body as a matter of cause !. The TB oiling up is a known problem.

Try giving it a clean yourself and then take it back to them if no joy.

Nick · Post by **Nick** » Wed Aug 27, 2003 7:43 pm

Back to the dealers tomorrow -

Third time lucky, maybe?

Nick.

jakethesnake · Post by **jakethesnake** » Wed Aug 27, 2003 9:03 pm

Hope it gets sorted this time then

Nick · Post by **Nick** » Sat Aug 30, 2003 7:59 pm

Picked car up today, after two days at the local dealers, and they've basically done bugger all!!

Car returned with "no fault found" and showing no faults on the ECU

I have been told that the fault has been registered with VW, and when they find similar cases, and a fix, then they will contact me!!

Sounds like s**t, to me, untill the warranty runs out

Snotty email to VW time, i think,

Nick.

Speedlaw · Post by **Speedlaw** » Sat Aug 30, 2003 10:47 pm

That blows.

Perhaps an independent specialist knows something?