Starts good, gets worse, gets better again

[tall pete]

83 mk1 gti

Something keeps my engine idling well for 5 minutes after starting(Auxillary air valve?) then it drops off to a real awful idle speed until the engine warms up when it gets good again. Is the warm up regulator supposed to do something to stop this?  

Never did it in the summer. Oh the joys of winter.

peter

[mk1]

Could be that the heater in the warm up regulator is faulty or not getting a live feed or earth. This will make the engine run rich during warm up as the warm up regulator takes a lot longer to come up to the hot engine setting as it has to rely on conducted heat from the block to heat it. Check that you have 12v and a earth at the connection to the reg, also check the resistance across the two pins on the reg. If it is open circuit, it's toast. Cant remember the resistance specs, some clever member on here will help out .
Steve.

[tall pete]

Thanks, I will check. Be great if it just needed a clean, yeh right.

Gonna sound dumb, but is there a trick to getting the square plastic connector thing off? I don't want to snap it. Theres a similar connection on something else that someone has smashed trying to get off.  

Peter

[richandhazel]

Can you see a piece of wire running along one edge of the connector? If you can, push that in towards the plastic of the connector and at the same time pull the connector off.

[mk1]

Or on other type, with a small flat bladed screwdriver unhook the open ends of the clip so they are away from the connector. Pull the plug off and refit the clip.
Steve.

[richandhazel]

Or on other type, with a small flat bladed screwdriver unhook the open ends of the clip so they are away from the connector. Pull the plug off and refit the clip.
Steve.

Thinking about it I think yours is more likely to be the type Steve has just mentioned as I think the one I'm on about was introduced on the mk2's

[tall pete]

Warm up regulator, continued.....

Managed to get clip off, gentle wiggling and patience.

here are the results of tests.
Checked Voltage with engine running, around 12V which is OK.
Checked resistance, just under 20ohms, haynes says ok.

So this morning conducted Experiment A.

unplugged regulator, drove in to work and...

exactly the same, 5 mins of good idling, then crappy period whilst engine warms. Then after a good blast down bypass, idles fine.

So now, I don't know what to do. Whats keeping the idle good for 5 minutes and why does it turn off before the engine is warm?

And having looked on some K jet websites I don't understand the reason for powering the regulator. It should shut off from engine heat anyway so why the electrical resistance heating?

Are warm up regs expensive, They look it!

Don't fancy messing about with pressurised fuel in the street much anyway.

Thanks for the help.

Pete
Brighton.

[tall pete]

Anyone?

Help?

Peter

[mk1]

The heater is there so the warm up reg dosn't have to rely on engine block temp to bring the enrichment off, blocks take a lot longer to come up to running temp than the inside of the head. (try leaving the plug off to see if it is worse-better)

If the warm up reg is ok, check for air leaks around the inlet side. Check the injector "o" rings, if they are leaking in air the over rich mixture when cold will stand the leak. When the engine is hot, the mixture may have been adjusted to compensate for the weak mixture. During the transition fron cold to hot running, the enrichment is coming off and the engine is not hot enough to stand the weak mixture. V hard to diagnose these probs remotely, best to see whats happening with a gas analiser. Good luck, and keep on it .
Steve.

[tall pete]

Just thought I'd finish this one off.

Problem solved by visit to the Bosch approved garage.

With all their dials and gauges they pinpointed the aux air valve. Good clean and bobs your uncle.

Also found that ( amongst other things ) the car only starts on 3 cylinders so looks like some new injectors are needed sometime.

Peter.