16V Engine quiz :)

[Deefadog]

Ok to find the last problem on my golf i thought i would have a quiz -

Question - As far as warm up is concerned, what stops working once the engine is at Normal Temp?


Reason being from cold to normal temp every time i stop, the revs dip below 960rpm they go as low as 550rpm, once warm it is absoutely fine

so it's either something that is working at warm up or something like the ISV only starts to work correctly once it has warmed up!

The prize for the first person who get's it right will have a few beers and a knackered part LOL

[tobz.]

Sounds like the warm up regulator isn't doing its job.
Now where do I claim my free beer??

[Deefadog]

Hi tobz, i thought this also, either that or the iSV, there is no vacume leaks and the car is set up properly!

How can i check the warm up?

[tobz.]

Possibly the ISV although the symtoms are quite often hunting or revving high etc.
The warm up regulator is a difficult thing to check for correct operation. It's found on the right-hand side of the block with a couple of fuel lines and an electrical connector. You can remove the connector and measure the resistance of the bi-metallic strip (should be in the order of 20ish ohms), you can also measure the supply voltage is present when starting from cold. However to check the thing is really working you have to 'break' the fuel system and put a pressure gauge in the line. The pressure should be low during warm-up and rise once the engine is hot, I forget the exact figures but it's something like 3 & 5bar.

[Deefadog]

Cheers! First thing i'll do is disconnect it! If i everthing remainds the same then that should be the cause! I can run the car with this dissconnected yes?

[tobz.]

Yep it's fine to run the car without it, effectively it's just like starting a carburettored car without the choke. If there is no difference then the regulator could well be the problem, another symptom of a faulty regulator would be gutless hesitant running during the warm-up period.

[Deefadog]

I don't get the gutless hesitant running during the warm-up period! and thinking anout it the revs do rise for about a minute or too when i first turn her over so the reg must be working, but i'll disconnect anyway just to make sure

It's like the ISV is asleep and it take it about 10 seconds to bring the revs up

Aloso when the revs drop to around 550rpm and i just blip the accelerator pedal, the revs rest to normal around 950rpm, go again and stop and they rest at 550rp etc etc untill she is warm! very strange

[Gambit]

disconnecting it will make no difference. the electrical connector simply heats the little spring within the warmup regulator. if the little heater aint working then the spring is just heated via engine block heat

if it aint working then the mixture is all messed up on cold starts, so will splutter etc and wont idle to well on its own for about the first 30s or so.

sounds more like your ISV is sticking, once its warmed up then it moves more freely.

[Deefadog]

As you can see that was my first thought! I have cleaned it out, maybe another clean is in order!

Anyone got a spare i could borrow to test, i'll pay all postage etc

Gambit - Also I have not forgot about the rear wiper relay. i'll get that posted back to you next week!

Cheers

[Gambit]

just leave the ISV overnight in Petrol or cellulose thinners. it needs to be cleaned out with something that will not leave a residue after it dries

also give the throttle body switch a clean, its this which sends the signal to the ISV control unit to tell the ISV to operate

id forgotten about the relay lol did u fix the wiper?