Strange things happening when starting.

[csun12]

Hi there, wondering if anyone can help. 

 

Car: Fabia 1.4, 16v  2004 

 

Occasionally on starting the engine it refuses start properly and initially just wont rev at all. It turns over but not even at idle speed, this problem happens every couple of weeks id say and then will be fine for a while.

 

The guy who I bought it off about a month ago said that he had sometimes experienced this problem when restarting the engine mid journey, ie after filling up, so far this has happened to me when first staring the engine. He said that he just planted his foot to the floor for a few seconds until it kicked into life, this seems to be working but obviously there is something not quite right.

 

There is an engine light on most of the time, but when borrowing a mates VAG lead and running a test there was nothing to note with the engine. 

 

Has anyone had any similar issues and come across a cause/solution? 

 

Thanks.

[sepulchrave]

This can be caused by the EGR valve being stuck open, try unplugging the EGR valve when you don't have the problem to see if that cures it, alternatively just clean the EGR valve thoroughly.

[csun12]

Thanks, will have a look at that this weekend. Any suggestions on what to use to clean up the ERG? 

[sepulchrave]

Thanks, will have a look at that this weekend. Any suggestions on what to use to clean up the ERG? 

 

Carb cleaner; the nasty potent xylene based stuff and an old toothbrush with half the head sawn off so you can get it right in there.

Edited 28 March, 2014 by sepulchrave

[csun12]

So, I cleaned up the EGR last weekend. Got all of the carbon gunk out and also sprayed carb cleaner in with the engine running, didn't seem to have a huge improvement on performance or anything like that but has been running fine all week. 

 

Then this morning the problem returned, this time however it refused to start initially then after about the 4th attempt the engine fired, but again with very low revs.

 

Anyone got any other ideas?  

[Avalon]

Get the codes read again, if the lights on it's quite unusual for it not to log an error code.

[sepulchrave]

Get the codes read again, if the lights on it's quite unusual for it not to log an error code.

 

The CEL means that a fault has been detected and logged, it would be nice to know what those codes actually are.

[exskodatech]

was it a cold morning, we used to have problems with the coolant sensors but only on Yellow fabia's - I kid you not !

 

check and clean all the earth points including the massive on the n/s/f behind the wheel cowl at the PAS pump ASSY - and the one on the gearbox

[TMB]

we used to have problems with the coolant sensors but only on Yellow fabia's - I kid you not !

 

 

What the heck?

[@Lee]

What the heck?

probably only the lemon yellow ones

[TMB]

probably only the lemon yellow ones

 

Yeah

[csun12]

Hi, thanks for the replies.

 

Get the codes read again, if the lights on it's quite unusual for it not to log an error code.

 

Ok will see if I can get hold of my mates lead again and see if anything comes up. The waning light is quite intermittent sometimes on sometimes off. 

 

was it a cold morning, 

 

Not particularly cold morning no, no colder than it had been the previous days when it started fine. 

 

Again thanks for the help, much appreciated.   

[csun12]

So, its been a while since my last post and I still have the same problem, I have since cleaned out the 'throttle body' as someone suggested that it could be the problem with it sticking and restricting air flow. To no avail. (one thing I have noted that in the process of trying to get her started after multiple attempts there is a distinctive smell of fuel, I assume that this means that there is not a fuel issue as it seems fuel is getting to the engine) 
 

I re ran the VAG test and no fault codes seem to be logged (rather peculiar). 

 

After running the car for a few more months there is a definite trend that the issue seems to only occur if the cars previous journey was very short i.e 2 minutes round the corner, or simply to move the car on the driveway. After running the engine for a short period there is a good chance that next time I come to start it it wont fire, regardless of the time-scale between trying to restart, the same occurs whether I come back to it overnight or 5 minutes later.  

 

Thanks for the help so far, but if anyone has any suggestions they would be much appreciated.  

[sepulchrave]

Have you checked the brake servo vacuum pipe for splits where it joins the unions, this is common and can give the symptoms you describe of poor cold starting, if you find any splits remove the pipe from the union, trim the split end off and heat the plastic to soften it before pushing it back on to the union.

 

Edit: You don't mention if you have replaced the ECT sensor, if not then you MUST replace it, I'm on my third sensor in five years, they are that unreliable.

Edited 13 July, 2014 by sepulchrave

[csun12]

Thanks for the reply. I will have a look at the break pipe and see what's what there. However it's not just when the engine is cold, the problem will occur even after a long journey e.g. the other day I drove for about an hour, stopped to pick something up then finished the journey a few minutes down the road, then when coming back to it about 5 minutes later she refused to start. 

 

As far as I know the Engine temp sensor has not been changed so ill also have to have a look at replacing that, although the temp dial seems to indicate no problem, it moves to about central within a few minutes and stays there. 

[sepulchrave]

As far as I know the Engine temp sensor has not been changed so ill also have to have a look at replacing that, although the temp dial seems to indicate no problem, it moves to about central within a few minutes and stays there. 

 

Unfortunately the temperature gauge is no indication as to whether the sensor is actually telling the ECU the right information, it only tells you if the engine has warmed up properly or if it's overheating, the ECU needs much more accurate information.

[Sam84]

You said its been scanned but has it been done with a genuine vcds lead? Was it done with vcds or a normal fault code scanner? Seems very odd that nothing is being recorded

[sepulchrave]

An inaccurate ECT sensor will not throw a fault, because the ECU has no reference for comparison.

[csun12]

I changed the Engine temp sensor last week and the issue seems to be solved (also the engine warning light has gone out )

Thanks for the help !