1997 1.4 16v idle problems tried everything! HELP!

[calumcc]

Hi,

New to the forum but have been reading for a while.

I own a 1997 Polo 1.4 16v.

The timing belt recently snapped bending all 16 valves. Any normal person would of replaced the engine but not me lol. Any way £700 worth of parts alone later (which i will go into another time but basically had new everythings so the engine is practically new) I have an idling problem. The problem is that the when the car starts the engine idles at 2500 rpm for a minute or so from cold and then settles to idling between 2000 and 2500 rpm, rising and falling continually. I replaced the throttle body which i was told is most likely to be the problem by many sources including my mate whos a VW mechanic. Sourcing a 16v throttle body was extremely hard and found one in the country. Anyway fitted this and problem still there. Carried out more checks and discovered there was an air leak somewhere around the throttle body, below it to be specific as when I sprayed brake cleaner around where the throttle body meets the manifold the engine struggles to the point it almost cuts out, indicating that it is sucking in the break cleaner and therefore air where it shouldnt be. Although i would of thought this could cause the engine to idle higher, i cant understand why it would idle eratically as it is doing. Anyway turns out the throttle body gasket was missing (which is wasnt before the engine rebuild) so i ordered one from VW and waited a week for the part to be shipped from Germany. I assumed this was the cause of the air leak. It wasn't. The idle problem was still there and when carrying out the brake cleaner test again i got the same results. Has anyone else experienced this problem? Could the leak be caused by the gaskets or maybe from the manifold or something else?

Please Please Please if any one can help i would be forever greatful. Any suggestions welcome, I have spent too much time and money on this car to give up now.

Thanks!!

(and sorry for the massive post lol)

[bstardchild]

You still have an air leak

- inlet manifold gaskets

- Injector O rings

Whatever it is there is unmetered air being drawn into the engine and that will cause elivates idle rpm and the hunting is the ECU which knows it's not right trying to correct it but it is way outside the parameters for adjustment

[calumcc]

Hi,

Thanks for your reply, i knew there was still an air leak just didnt know where!

Is the O-ring the rubber ring under the metal gasket of the throttle body? If so this doesn't appear to be damaged.

Where would i find the inlet manifold gaskets to check?

Again thanks alot for your help its appreciated

[dragon_green]

Hi,
Where would i find the inlet manifold gaskets to check?

on either end of the inlet manifold

[calumcc]

oh yeh lol thanks

[Jackdcruz]

If you have changed the throttle body, the new one needs to be programed. I had the same problem with my polo a while back, the auto electrician programed the new one and all was well.

Hope its helped

[calumcc]

I was told the throttle body had to be basic set, but i think this isn't the issue and im sure its been done. I think the problems an air leak as when i spray break cleaner where the throttle body meets the manifold the engine slows and struggles as if the air is being replaced by the brake cleaner and so not combusting. I have just been told the inlet manifold gaskets were replaced when the engine was rebuilt and the rubber ring gasket under the throttle body is ok to. I think the air leak is somewhere around under the throttle body as this is where i am spraying brake cleaner when the engine struggles, but i am not too clued up on mechanics and so dont really know where the problem could even be coming from.

Thanks for everyones input so far

[sylvester]

Was it a new complete head? It's better to list new parts fitted, makes life easier to help