Car Won't Start..

[rich_w 0]

(i've removed my orginal text and posted this on his behalf)

 

I have a 56k miles xu9ja engine that has just had the head removed for replacement of stem seals (MOT failure)

 

The head was removed and all new gaskets and seals replaced.

 

I am an engineer by trade and consider myself mildly e3xperinced atr this kind of work. After all its just chunks of metal and bolts with a bit of rubber in the middle to stop stuff leaking !!!I

 

I have come to put the engine back together to which I believe I have done as a reverse of taking apart. Head torqued up correctly, timing checked, triple checked and verified (cheers rich!)

 

The car refuses to fire or even give any hint of firing. As stated before the timing ( as per Haynes ) is correct ...the marks on the timing belt match up to the marks on the cam pulley and crank.

 

There is spark available (have had 4 plugs on the rocker cover sparking as expected)

There is fuel available (smell and see fine mist when turning over without spark plugs in)

 

A pressure test was conducted and was shown to be a little low (circa 10.5 bar)

 

Will this have an effect on the ability to run ( I personally think not as turbo engines run lower compression than this).

 

I am at a loss as to why I am not even getting a pop, bang or chuff ?!

No wiring has been messed with... just unplugged and reconnected

Edited April 14, 2006 by rich_w

[Guest BrainFluid]

Lack of air?

Edited April 14, 2006 by BrainFluid

[easypug 0]

My first thought would be igniton amp, or billy basic are all the leads on in the right order ?

[Anthony 1,003]

If the basics are correct and you've got fuel, spark, compression, and one assumes air (you are breathing after all), then it has to be one of them in the wrong quantity or at the wrong time.

 

Check that you put the dizzy back on in the same place/position as before, as if it's wildly out then the engine won't start as the ignition timing will be out by a country mile. As above, make sure the ignition leads are on in the correct order (remembering that you can put the dizzy cap on back to front and throw it out by 180 degrees!)

 

If that's all OK, then check the wiring to the AFM and ECU temp sensor is correct - the ECU temp sensor in particular, as if this is disconnected or the wiring/connector is damaged then the engine won't start as it's cronically overfuelling and floods.

 

A simple test to see if it's overfuelling is to try starting the engine, disconnect the injector wiring, and try starting it again - usually if it's flooded thanks to overfuelling then it'll start and run for a second.

 

Most other issues I'd expect the engine to atleast attempt to start.

[Guest BrainFluid]

and one assumes air (you are breathing after all)

 

you know what I mean.

 

Nate.

[jackherer 543]

and one assumes air (you are breathing after all),

 

I've seen a reversed air flow meter keep an Mi from starting despite good spark+fuel because it was choking it of air!

[vee6 0]

Thanks for replies people

The dizzy was taken off in a complete unit (including spark plug tray with plugs attached. The dizzy was marked up so that when replaced it could go back to the exact position it was removed from.

 

The AFM was removed in one unit with filter attached so that went back the same way but thanks jackherer it did get me thinking for a second !!

 

I am intrigued about the ecu sensor. The two 2-pin plugs that go round the back of the engine . 1 blue & 1 black. I didnt make a note of these plugs but have gone with convention on this . Blue plug to blue connector (blue to blue and blue because its water ?? or have the french thrown a curve ball ??)

 

Is there a test to prove the ECU air temp ?

 

I'll disconnect the injector wiring and post results

 

Does anyone think that 10bar is too low for it to run ??

 

Thanks again for the hints .. keep em coming !!!!

[pugrallye 0]

to be honest, even if any sensors were faulty, like cololant temp, it would still start, or try to start, since you have fuel and spark, is it 'coughing' when you turn it over or just spinning? are plugs gapped correctly? possible that the spark is not present when plugs are screwed into head

Edited April 15, 2006 by pugrallye

[vee6 0]

to be honest, even if any sensors were faulty, like cololant temp, it would still start, or try to start, since you have fuel and spark, is it 'coughing' when you turn it over or just spinning? are plugs gapped correctly? possible that the spark is not present when plugs are screwed into head

 

 

There was plenty of spark when i had the plugs on the rocker cover all sparkling away in turn and the plugs are the same ones that were removed prior to all this nonsense so i can safely say that the gaps are ok ( plugs are relatively new too ).. .. as for turning it over with everything in its place, its as if all HT leads were disconnected and no fuel present (there is .. god knows i have checked enough times !! ). and not single sign of life .. no cough ,splutter ,pop, bang or chuff!

 

Thinking back i recall always having a heavy smell of fuel and when an engine is flooded (badly ) the symptoms as i think about it are as i am experiencing so i'll put it all back together and take Anthony's advice and turn it over without the injectors plugged in and see if we make some progress that way.

 

again thanks for your tips .. anything to keep the grey matter from stalling is useful this end !!

Edited April 15, 2006 by vee6

[pugrallye 0]

no i mean coughing as if there is compression, engine rocking etc or is it turning over like there is nothing there? always good start to unplug injectors as anthony said to make sure its clear, would firstly check your coolant temp sender for ecu is plugged in though, as that would be a prime cause of overfuelling.... when your spinning it over trying to start it are plugs wet if you take them out straight after???

Edited April 15, 2006 by pugrallye

[jackherer 543]

Does anyone think that 10bar is too low for it to run ??

 

10 bar is ~150psi which isnt going to stop it running.

 

there is a fairly common mistake that can be made with these engines, if you fitted a new inlet manifold gasket its possible you were supplied the wrong type and its now blocking the injector spray so thats worth a check.

[vee6 0]

no i mean coughing as if there is compression, engine rocking etc or is it turning over like there is nothing there?

 

Ahh i c ,

we compression tested and each cylinder was roughly 10 bar which we discovered is about 2 bar off 'normal' but my battery was runnig out of puff and engine was turning slower (Used Rich W's 309 as a benchmark.. circa 12 bar with a fully charged battery and whizzy starter).

 

I have absolutly no idea if the measured 10 bar will effect the ability to run. My initial thoughts are not because turbo'd engines run lower compression too and when turbo car is idling the turbo is not creating positive pressure so the engine is idling on its standard low compression anyway.

 

 

10 bar is ~150psi which isnt going to stop it running.

 

there is a fairly common mistake that can be made with these engines, if you fitted a new inlet manifold gasket its possible you were supplied the wrong type and its now blocking the injector spray so thats worth a check.

 

Checked that too .. both manifold gaskets supplied were identical ! and we removed the manifold to see that the injectors were not fouled in any way

[pugrallye 0]

no car would still start with that sort of compression is it 10 bar across the whole four? it is a bit low, though.

Edited April 15, 2006 by pugrallye

[Anthony 1,003]

to be honest, even if any sensors were faulty, like cololant temp, it would still start, or try to start, since you have fuel and spark

In the case of the ECU temp sensor that's not always true which is why I explicitly mentioned it.

 

I've fixed a car for someone on here before that wasn't starting, and it turned out to be a bad connection on the ECU temp sensor causing all the problems - the engine would flood itself as soon as you cranked it over, and only gave the slightest hint of catching (that you'd not really notice unless you were listening for it) before just endlessly whirring on the starter with no life at all. Admittedly that was on a Motronic management based car, but I believe the same applies to Jetronic as well.

 

A faulty ECU temp sensor will usually appear to start and run perfectly though as the ECU still "sees" a reading from it, just gives poor MPG as it always runs in cold start enrichment mode.

[pugrallye 0]

we on about the ecu coolant temp sensor anthony? remebered how intolerant they were on these engines, lol, yeah they would negate a wiring prob most definately, as would be running in open circuit

Edited April 15, 2006 by pugrallye

[vee6 0]

am i right in saying that the 2 plugs at the back of the engine are blue plug to blue socket (Water temp)? Black plug black socket (ECU air temp ??)

 

It'd be just my luck and typically french that they are the other way round .. but have tried it that the other way too with same result ! but maybe it was flooded by then.

 

Is there any quick way of testing the ECU temp sensor ?? any sort of clicking or it is a voltage output type thing that needs to be measured at the ecu end?

Edited April 15, 2006 by vee6

[pugrallye 0]

as anthony was saying, if sensor was faulty it should still more than likely run, even if like a bag of poo, prob best place to start IF it is flooding is the actual wiring harness for connection/ integrity, blue socket on blue sensor is normally correct

Edited April 15, 2006 by pugrallye

[vee6 0]

A simple test to see if it's overfuelling is to try starting the engine, disconnect the injector wiring, and try starting it again - usually if it's flooded thanks to overfuelling then it'll start and run for a second.

 

BINGO !!! You have earned a Silver Star award

Followed instructions and into life she went if only for a second or 2

 

A Gold Star Award ( Beer Token !!) is available to the successful applicant who cures this problem!

I had a 309 a few tears back that did exactly the same thing just a lot worse .. the injectors were basically open under 3 bar fuel pressure !! so much fuel was pushed into the cylinder that it filled up and escaped through the opened valves at the top and drained into the sump .. i never got to the bottom of that problem because it caught fire .. so had to have an MI instead !!

 

Are we looking at ECU air temp wiring problem ??

or a duff ECU ?

Edited April 15, 2006 by vee6

[vee6 0]

Problem solved !!

 

Big Thanks to Anthony & Rich W !!

 

Water sensor plug on back of engine had (blue plug had one pin pushed back !)

 

Sorted that and off she went yippee

 

Just shows that these forums have a great pool of experience and have prooved to be very useful indeed !

Edited April 15, 2006 by vee6

[rich_w 0]

Tim posted some huge pics (and removed them) showing what he thought was the water temp plug - it was the SAD plug.

[Anthony 1,003]

Water sensor plug on back of engine had (blue plug had one pin pushed back !)

Yup, that's the ECU temp sensor that I was talking about, and as said, if there's a bad connection it overfuels so much that it won't start. Glad you got it sorted

[steve@cornwall 100]

Problem solved !!

 

Big Thanks to Anthony & Rich W !!

 

Water sensor plug on back of engine had (blue plug had one pin pushed back !)

 

Sorted that and off she went yippee

 

Just shows that these forums have a great pool of experience and have prooved to be very useful indeed !

 

had EXACTLY same problem following an engine change last year, before I found this forum, took four weeks to find it!! (by checking voltage at ecu compared to running gti) shows the value of this site.