Car wont start when cold (sort of?)

[JohnnyLeitrim]

Hi,

First some history:

My girlfriend bought a 98 Bravo 1.4 SX from her brother, and it worked away merrily for about a year. Then it started cutting out when the engine got hot. After months of reading the Haynes manual, we finally tracked the problem down to the TDC sensor. Went to the wreckers yard, they only had half a sensor. So my mate soldered the two parts together, bit of heat shrink, and the car was back on the road (100 miles trouble free!)

Current problem:

After a journey of about 40 miles, I park the car and leave it for about 1 or 2 hours. Come back to the car; will not start. The engine is turning over fine, and I can hear the fuel pump kicking in.
Strangely, if I leave the car for maybe 5 / 6 hours, it normally starts first time.

My Questions:

*) How can I determine if the HT leads are working, and there is spark in the engine when this problem occurs?

*) Do you think it's likely to be some type of fuel line problem since the car was left basically untouched for 5 months.

As always, any help is GREATLY appreciated

 

[Tom]

Take it for a diag. Most likely its the same fault but a diag will hopefully show exactly whats broken.

 

[Allan Wall]

re

as above is the easiest way,

you could take the plugs out leave them plugges into ht leads and turn key, you shoudl see them all spark! just done hold them when you do it!

 

[JohnnyLeitrim]

The problem I have is that the nearest Fiat dealer is 40 miles away, and the local garages can't read the fault codes off the ECU for some reason (even though they said they bought the Fiat software).

I was thinking of pulling out one of the spark plugs and seeing what happened (while disconnecting the other 3, of course )

 

[Allan Wall]

re

just pull them all out and lie them down so not touchign anythgin on engine, and crank it over! you will see them all spark in firing order if they are working

 

[Ash]

check the lamba sensor, temp sensor, and oil pressure sensor. there is also a fuel cutoff switch under the drivers seat that you can tru pressing (its in the passenger footwell on newer models.) also is the code light going off a few seconds after putting the key in?

 

[JohnnyLeitrim]

Ash,

Yes, the code light goes off (just before the injector light).

I tried pushing the cut off switch (just under the passenger seat on my model) but no joy there.

The first time this happened I though it was clogged fuel lines, but the last time I just left the car overnight and it started first time (without being moved), so I guess it's not that...

 

[JohnnyLeitrim]

Checking Spark: Haynes Manual

Reading the Haynes manual last night, it says that the "outdated" practice of holding the HT leads slightly away from the spark plugs to check them is a bad idea (bad for ECU, bad for YOU etc.), timing lights should be used instead. Fair enough.

It then says that if all looks okay, then the problem must be with the spark plugs, and they should be checked. it doesn't describe how they should be checked though.

How would you normally check this? I don't want to just replace the spark plugs and find I still have the same problem. (On a side note, I have a horrible feeling that the plugs will be really difficult to take out of this car).

 

[Anonymous]

bad starting

although the plugs may show a spark out of the cylinder when under pressure a spark may be non-existant. usually the leads. only sure way though is a diagnostic check

 

[Allan Wall]

re

i dont mean holding the lead away from the plug, i mean take the spark plug right out and leave it on the lead!

it may not be the same as in the head but it gives you a clear yes or no to whether its sparking

maybe its just cos i'm a farmers son and like to look at things as simply as possible before havign to plug a computer into it.


even though i work in IT now!

 

[JohnnyLeitrim]

Thanks Allan.

I see that the post says to keep the spark plugs away from the engine if test firing them outside. Where's the best plate to put them then, since my HT leads aren't too long and I'm not even sure where else I could put them!

 

[Allan Wall]

re

well i led them on the engine, but make suyre the bit that sparks at teh end isn't touchign anythgin!

allan

 

[Ash]

as said earlier they may not be sparking under pressuer so testing them outside of the engine would be pointless remember that under compression the spark plug is exposed to over 250psi!!! i would try changing the coil pack first

 

[Allan Wall]

re

surely if he cant get to a diagnostics machine it proves that teh leads and spark plugs stil work, and he will see if one is ssooted up or anything?