warm start problems

[Dutch GT]

Ok, the mrs' rocco is at a point where most of the problems are fixed (thanks to this great forum), but the main issue at the moment is warm start problems. However, today she said the oil light flashed a couple of times whilst driving to work (9 miles, half on motorway) and that it stalled early on (within a mile still cold). She is a new driver, but think it is not her fault!?!
Mainly though, it seems to have trouble idling when started up from still being warm. If it is revved for a minute, things seem ok. It does honk of petrol which may be a clue, one of the first things I fixed was a loose leaking fuel hose to the carb (pieburg) but maybe there is still a leak? (the hose had worn thin, so I cut 10mm off and this formed a tight seal again)

Another possible clue is a relay making a crackling noise for a few seconds after a minute or two from cold. From looking on here and google, I thought it may be a carb sensor making the relay buzz (don't know what it does though?)

More info, it is VERY tappety. Will do an oil change (15W/40 best?) and filter soon to see if it helps.

Sorry if all is a bit vague, but I don't drive the car much so 2nd hand info, but all comments are very welcome. I would like to know what a carb sensor is and does? read that on google where he replaced the relay but it still buzzed and was pointed towards this - think it worked, read too much recently

The car is a 1989 GT. New fuel filter already fitted and very clean, new filler neck and tank, so don't think rust in lines is an issue, runs real well.

Cheers, Paul

[monsween]

Hi, I have this problem too mate, i'm gonna change the coil and see what happens.

Subscribed :)

[hyperdrinky]

It sounds like a lot of non-related issues to me.

If the oil light flashed on and the oil is up to the level then there can only be a few explanations. It has to either be a worn oil pump (best way to check would be a oil pressure guage) or a blockage in the oil galleries. The only other way i've been able to get the light to come on way pulling about 2-3Gs going round a long corner, which I'm assuming on a motorway wasn't the cause.

The scirocco is supposed to sound a bit like a typing pool for a short time on start up but after this it should sort itself out. If not, you could try an oil flush (people on this forum will give you different opinions on the effectiveness and dangers of oil flushes). I give mine a flush every time I change the oil and use Wynns.

As for the rough idle, I point my flabby little finger at the Pierburg, as will most people. The auto choke mechanism often develops a mind of its own (either sticking on or off, (whichever causes you the most grief) and all the fiddley vacuum control pipes have a habit of cracking, splitting or randomly leaving the car. I had the same issue with mine, that the choke was stuck on which progressed until the point where the car would idle at 3000revs until the car was piping hot and then settled out normally. I stripped down the carb (very carefully) and cleaned everything with carb cleaner but it just prolonged the inevitable, which was a replacement Weber.

[Dutch GT]

Thanks for the reply hyperdrinky.

I have questioned my mrs about the oil light as I haven't seen it come on (not driving it much at all though), and it seems that she just sees it when it has stalled and been re-started, which is normal of course. Good that she notices things though, and is still learning the joys of driving an old but cool car!

I know what you mean about the flush. Been wondering which way to go, but will definitely be doing an oil change soon, hopefully this weekend, might do a flush first.

I have also been reading up on the Pierburg and am determined to join the die-hards and keep it! I think my mrs would rather not have to pay out for a Webber if possible.
The Scirocco behaved itself yesterday, and not heard any news from today which sounds promising. The rough idling only lasts for a short while so I'm hoping it's something simple, but agree it could be the carb. Had a quick look yesterday and think there is fresh fuel leaking, but need to clean it better first to be certain it is fresh.

[bensspares]

hi.
its a carb problem.either the choke is sticking on (remove aircleaner and check butterfly valve full open or the floats arnt shutting the feul from the float chambers and its being forced into the carb through the jets.also could be the carb mounting block (cracks in the middle) spray easy start rnd the carb and if revs increase theres the problem.

anyway,bite the bullet and buy a webber,it improves performace and is realy easy to set up and tinter with.the pierburg is the carb sciroccos down fall that with the waxstat (another potential problem for high idol).

hope this helps you.
ben.

[ianaudia4]

Dutch, where are you based fella as I know an old school VW technician in Essex who is a wizz on VW carbs?

[MikeH]

If it's tappety and the oil light is flashing, it's likely that you have an oil pressure problem. It might be better to run 10w40 in it, as 15w40 is a bit thick for hydraulic tappets, but if the oil pressure is low anyway, 10w40 will make it worse.

I'd start by taking the sump off, and checking if the gauze filter on the pickup pipe is blocked up. That's the best possible scenario. If that's clear, the oil pump may be gone, or the bearings could be shot too. Any signs of bottom-end knocking under load?

[Dutch GT]

Great info thanks, I definitely need a full day looking at it now I am armed with a bit of info.

MikeH - Is the pick up pipe gauze easy to see? Never took a sump of but must just be bolts... do I need a new gasket or anything when replacing?

Benspares - I'll try the carb test, read a few things I can try and will check the pipes for splits.

Everyone - Thanks very much for info, top stuff. Might get chance on sunday if weather is good enough.

[bensspares]

dutch gt,
before you go into the sump,check the connector on the oil pressure sender,clean the terminal and check the connector fits snugly.

replace the pressure sender before you do anything.

my advise is to buy a oil pressure gague and physicly watch the oil pressure.when cold the pressure will be high and decrease when engine is warm.

what's the milage.oil pumps should last atleast 175,000 miles.if its a high milage engine low oil pressure at idol is acceptable.pressure drop at speed is significant of a blocked pickup(normaly bits of old gasket from previous work,or bits of plastic from a deteriorated plastic dip stick holder).

ben

[Dutch GT]

The milage is low to be fair, just gone past 100K, all documents back it up. I forgot to say that there is no knocking from bottom end that I have noticed. I need to drive the car myself on a longish journey to get a gauge of how things are, with a few warm starts for good measure.

I'll try oil and a new filter first to see if the ticking gets any quieter. As for the pressure/pump, I'm not too great with tech sides of engines so wouldn't know how to fit an oil pressure gauge, and also wonder if the mrs will want a newer car at some point, so don't want to spend too much just yet. I do want to learn though, might even look at the tappets and see if I can adjust them, but don't yet know what a shim kit is exactly or how to tackle it without making it worse, ha !

I will look at the sender though, I can handle that ! And check the easy stuff on the carb to see if there is a leak or knackered diaphragm.

Oh yeah, I'm in Stockport if anyone knows of carb specialists this way or Manchester!

[bensspares]

what car/engine is this ?????

if its a genuine 100k ish engine like it sounds,its almost certianly the choke sticking on re the carb,the carb mounting is also a candidate.

re oil pressure, a guage from a factor ie halfords is aprox £20.fitting will be removing the sender from the head and fitting an adaptor that houses the original sender and an aditional peice for the guage then running the cable or pipe through the bulk head via the gromet that the speedo cable runs through and mounting the guage with in the car,i fitted them onto the trim that covers the pedals.

my money is on the oil pressure sender or the connector.unless the oil pressure dropped when at speed its almost certianly one of these.

if when driving the pressure light comes on and stays on then pull over,shut the engine down,wait a few mins and restart.the light should go out until next time.this will be because the blockage is being held in place by the suction of the pump and when engine stops the pressure nolonger holds the blockage in place.

i hope the information iv given is of help and it should allow you to determine exactly what the fault is.
ben.

[Dutch GT]

Ben, your info is very much appreciated, very helpful for a numpty like me!!
The car is a 1989 GT 1.8 and I suspect you may be right about the sender, as I have asked the mrs, and she says the light hasn't come on for the last 2 or 3 days. I am also wondering if it is only when the car has stalled or idling bad, but cannot be sure as I am not in the car so often. It's 2nd hand info as stated before.

I will focus on the carb first and a quick oil change. hopefully there won't be a thunder storm like right now... chucking it down !

I'll let you know how it goes. Thanks again for all the info and ideas.

[bensspares]

no worries,

changing the oil and filter wont shut the tappets up so not a remidy to you problem.overcast here in leicester b.t.w.

the engine should be engine code ex.it should have hydrolic tappets,(the cam shaft will be of 4 bearing type rather than 5 if its bucket and shim.so no adjustment is possible to the tappets.

noisy tappets isnt uncomon on your type of milage especialy if it does lots of short start stop journeys.they will easily cover 5000 from the first time you hear 1 ticking and will normally shut up after 10-15 miles.

the last set i bought was from midland vw,they were very helpfull and purchaced a set of 8 for alittle over £60 delivered.dont forget to buy a rocker cover gasket if your replacing the tappets & for gods sake (being polite) follow the haynes bible re camshaft removal as failure to follow the correct removal proceedure can and does result in snapping of a cam bearing cap which will open a new lot of issues.
dont be put off its easy realy just giving you the benefits of my experience.

ben

[fonzooorooo]

You mentioned a crackling noise... There are 2 electric heaters - one on the carb itself, the other in the inlet manifold. A lot of people on here unplug them both unless they've got problems with carb icing. I found the little one on the carb on mine was faulty, so that it'd spark against the body of the carb... not ideal! After that, the relay which controls them was clicking in and out.... It clearly didn't like it much. If it's a relay related crackling, that's a nice simple one to change.

People have so much trouble with pierburg carbs... (I reckon they simply weren't designed for the life span we expect from them... ) It's a Weber for an easy (if not necessarily cheap) life!

[Dutch GT]

Ok, had a look this afternoon and decided it has beaten me and will take it to a garage, as I don't want to make things worse!
I managed to find out that the relay that is crackling is in position 2, so Fonzooorooo, I think you may be correct that a heater/sensor is to blame.
I think also that the pulldown unit may be knackered. I did a test where you blow on the lower port that lifts the choke half way (which it did). Then cover the upper port with a finger and blow again. It should open fully, but mine didn't. Also, there is no air escaping from the upper port when finger removed and blowing on lower port (there should be).

A few quick questions for now though:

1. Should there be a gasket between the air-box cover and the carb? Don't think there should be, just checking as I could see fuel here.
2. What hose is this (below) and is it still available? It split when I moved the airbox out of the way (that's why I don't want to carry on messing!) and is cracking along the bend too.
3. Can I drive the car to a garage with this split or will it end in tears?



There is another perished hose under the carb that I don't want to mess with and I am sure it is leaking fuel from here or somewhere else.
So can anyone recommend a garage in Stockport who knows carbs?

Thanks for everyones help. As for the oil light, I have driven the car and it never comes on, think it is the mrs when she stalls it.