gti 8v now running well but...

[rutter123]

after fitting a new coil, repairing part of the injector loom, and a replacement fuel pressure regulator, we now have life and running quite well, just a few small issues.

seems to run a bit hot even at idle showing 90 deg c (according to the gauge), with the cooling fan running 50% of the time, water is full, no leaks.

can only get a good idle @1050rpm, a little high? even with the idle adjuster backed off, worn throttle body??

how many turns should the air/mixture screw be set at?

on the air intake hose to the throttle body there are 2 pipe fittings for breathers, of which one is open ended, other is almost closed with just a small hole, which one does the breather connect to?

where is the water temp sender located?

cant get a good idle from cold start, drops to 500rpm and stalls?

your thoughts, many thanx

[sdelasal]

Can you post some pictures of your engine bay - is there a flap type air meter for example. You need to make sure you have no vacuum leaks - with engine idling, spray some of the easy start around the breathers that you mention try & identify if you have any leaks. Depending on the system there can be an idle adjuster on the air meter - via which you adjust the amount of air by-passing the meter. If this is screwed right in it suggests there is air leaking into the intake manifold. Other system also have adjustments on throttle stop positions - which adjustment do you mean?

Stall: Water temperature sensor is an obvious one - I think they are usually around the thermostat. There will also be an idle airflow control valve that allows in more air on a cold engine - this may be broken - a good clean can help if it is gummed up. It will be plumbed in as a by-pass around the throttle body. Again, depending on the system there may be an air temperature sensor / compensator in the air meter - if this has gone it can mess up cold start.

The haynes would be useful to you - for example on idle speed check it describes 6 different fuel injection systems, Bosch LE3, motronic ml4.1, motronic m1.3 (with & without cat), motronic MP3.1 and Magneti Marelli!
Steve

[Jaba]

Cold start : Check the cold start device. This device bleeds a little air from the air inlet hose into the inlet manifold at cold start time. This may be stuck closed or partially closed which will give you both a bad idling when hot and richen the mixture when cold too much.

Overheating : Check the thermostat, is the rad cold at the bottom ?

Sensor : Its at the rear almost underneath the water housing at the LH end of the cylinder head.

[Tim Leech]

Idle at 1000rpm should be the norm, my 1.9TZI stays always the same whether cold or hot.

Well done on getting her going though!

[rutter123]

cheers all, will run some checks, been a bit of a battle and a long slow process, ended up stripping a lot of the loom back to find some very botched repair job ( which caused dead short on the injector loom) which has now been soldered properly and insulated thus so..in the process dropped the coil and broke the connector block clean off, managed to get another one locally for £18, also found the fpr was leaking back fuel into the vacuum pipe, sourced a known good one on the bay, hoping to get it in for its MOT next week after getting it up on the ramps for a full inspection, should go thru ok as its only done 88 miles and one journey since its last test.

[Way2go]

Idle at 1000rpm should be the norm, my 1.9TZI stays always the same whether cold or hot.

Bit fast isn't it? My GTi idles smoothly at a tad under 900rpm.

[rutter123]

result, most of these issues have now been solved, thanx jaba as i found a split in the cold start air intake pipe which was hidden under the t/stat housing, replaced with a length of new, nice cold idle @ 1100rpm settling down to 950rpm once warm.

[Tim Leech]

Idle at 1000rpm should be the norm, my 1.9TZI stays always the same whether cold or hot.

Bit fast isn't it? My GTi idles smoothly at a tad under 900rpm.

Erm, always been like that, sits level and purrs, so ive left it alone.