Cold Starting Problem

[scbond 15 1 Cars]

Probably all sick of seeing threads like this but I'm starting to feel a bit stuck on the issue. I searched quite a bit but couldn't find anything specific or a complete solution.

 

Over the past few days to a week the engine, when started from cold, will start fine but then the revs drop and it nearly cuts out. It has stalled once during this issue but usually it recovers immediately and just appears to be a rough start. The time it did stall I had to feather the throttle to keep it going for a minute.

 

I'm aware this is a common issue and so attempted to test the SAD by squeezing the inlet to it. When I did this there appeared to be no difference at all other then a faint, high-pitched sound. Sounded almost like an electronic warning but my thought would be an air leak maybe? Shouldn't the idle have become rough when I squeezed the SAD inlet i it were working correctly?

 

A bit more information...I got the car during the warmish weather earlier this month and it started fine, just seems to be rough after a cool night or when it's been cool and raining. Apparently the vacuum advance was replaced not long before I bought it and I think the AFM was either checked/repaired...certainly doesn't look new though so I'd guess it was just checked.

 

Starting to get a bit stumped as surely if the SAD was faulty it would always start rough like this?

 

Appreciate any input.

[hoodygoodwood 70 3 Cars]

Does sound like the SAD , the small aperture should be open when the engine is cold . It will gradually close over several minutes as the engine warms up .It is fed 12v from the loom which powers an element inside which moves the disc .Yours sounds like it is shut all the time as when you pinch the hose soon after starting the revs should drop .Could be jammed shut with crud or blocked . Looks like you will have to remove it and its 2 hoses and give them a clean then inspect them . Once the SAD is off the car you can connect it to a 12v battery with some wire and the tiny triangle shaped hole should move round and block the airflow .

The noise you got when you pinched the hose does seem to indicate that there is air moving through it though .

Will be a good opportunity to check all your oil vapour hoses for cracks/splits and dodgy connections .Check you are getting voltage to the loom connector when the ignition is on .

If its all connected ok and closing correctly the problem could be elsewhere .Water temp sensor starting to play up ?

[scbond 15 1 Cars]

Ok, cheers. Will take another look shortly.

[Alan77 78 1 Cars]

I'd replace the coolant temp sensor as well. (sensor with blue connector, round by the SAD)

A cheap fix that can make a huge difference.

[scbond 15 1 Cars]

I'd replace the coolant temp sensor as well. (sensor with blue connector, round by the SAD)

A cheap fix that can make a huge difference.

 

Not 100% sure but I think this was replaced late last year by a previous owner.

[scbond 15 1 Cars]

Bit of a development...sadly not a good one! Just went to start the car. It fired up and the revs dropped and it stalled. Tried again but with the foot on the throttle a bit and it fired up but felt a bit lumpy and then died. Tried again after a small wait and nothing...it turns over but won't start, even if I have my foot on the throttle to catch it.

 

Is this common? Could it be the battery on it's way out? Was running fine when I got it and then over the course of 2.5 weeks it's gotten worse at starting.

Edited March 27, 2014 by scbond

[scbond 15 1 Cars]

Disregard the last post. When the issue first started I noticed that the cone filter was hanging off so removed it along with the AFM. When I put it all back on the AFM had slipped back out without me noticing. Made sure it was all really tight and everything appears to run perfectly. Also tried the SAD again by squeezing the pipe and the revs dropped slightly so that's working fine.

 

Any changes for the worse and I'll report back.

 

Thanks for the help!

[scbond 15 1 Cars]

Ok, this didn't take long...just dropped in revs after starting just as before. SAD appears to be working so not too sure what's up.

 

Did just notice that the radiator fans are coming on full whack, even on short journeys, and they stay on for a few mins after switching off and leaving the car.

[scbond 15 1 Cars]

Ok, bit of an update to this. Hopefully someone can help as I'm stumped

 

I just replaced the ECU coolant temperature sender but the car still struggles to start from cold.

 

Whilst I was in the bay I noticed the following wires which have been spliced in at some point in the past. They weren't connected to anything but hopefully someone can identify the original wire so I can figure out what was put across it as these two red wires both appear to be on it.

 

 

 

The spliced wire is the cream coloured one next to my index finger on the left.

 

As said previously, the SAD appears to work normally and I believe that was investigated before. The vac advance is supposedly new and it does look like it is. Just replaced the sensor and there's no change...does the ECU take time to learn from the new sensor?

 

There appears to be an oil leak. It drips from the back edge of the sump and across the full length of it and I'm assuming that the gasket needs replacing. I do also have a heater matrix leak but coolant is being kept topped up.

 

Gauges...oil pressure is normal (sits around half-way and moves slightly with revs), coolant and oil temperatures stay low (they move initially and sit just below the first marker...is this normal?). No warning lights or anything like that...everything appears normal.

 

Now not sure what else it could be causing it. I guess the engine sounds rough as I add throttle to start it but this is for around a second when I can then let off the throttle and it'll stay running. Idles at around 1,500 while warming up. If I set off after a few mins of warming and the revs have dropped to around 1,150 then when I come to a stop at lights or whatever the revs will be a little rough, fluctuating between around 600 and 1,100. After a short while of driving, when the engine is fully warm, it stops hunting and settles at around 1,000 to 1,100.

 

Really hope someone can help!

Edited April 5, 2014 by scbond

[Pugn'Awesome 0]

I had a similar problem to this (and still have the problem of almost not starting when cold). I've replaced a few hoses with cracks, and also played around with the idle screw, however I'm told this is not a good idea until you figure out what exactly the problem is. This solved my erratic idling problem however it still struggles most mornings. I'm pretty sure that brown connector bit is lingering around the back of my engine block not connected to anything, so I'm not sure what it's purpose is but I'd surely like to know

[George 205 gti 1.9 dkz 0]

Anyone solve the problem , I have the same thing , fans are working 5 minutes . Difficult cold start / no start . When warm it’s ok