Engine cutting out

[thatnutter]

My felicia 1.3 mpi stalls for no apparent reason. It only does it when I'm on a fast road and I brake for a roundabout or the traffic slows down suddenly. As I get to the roundabout / traffic and am nearly at a standstill with the clutch in the engine will cut out. It always starts again first time and never does it when I'm traveling at slower speeds. The car is R reg and has done very nearly 100,000 miles.

I have been told by the mechanic that just did the service and MOT that it is probably the ignition coil. It has the type that is fitted over the spark plugs. I am inclined to believe him and it does look like an easy job that I can do myself with my fairly limited abilities. However he says he doesn't know Skoda's very well so wouldn't like to say thats what it was for certain. I was wondering if anyone could confirm what he says or suggest something else.

Thanks, Rhys

[TeflonTom]

more likely to be throttle body related

[harryhill]

Crankshaft sensor?

[richardsfavorit]

Try cleaning the throttle body to start with, then move on to more difficult and expensive items

[poorly_felicia]

map sensor? it could very well be air pressure related to me. If you are engine-braking (i really hate it when people do that) and it stalls then it could be a faulty MAP sensor sending incorrect data to ECU, which in turn incorrectly adjusts the fuel ratio.

I would not think throttle body as it is only a resistance strip which would cause problems during any engine speeds and loads.

[TeflonTom]

I would not think throttle body as it is only a resistance strip which would cause problems during any engine speeds and loads.

not so.. the stepper motor sometimes gets out of alignment which allows the throttle plate to close too far, hence the stalling, but you are right in what you say, it could well also be a problem associatied with the map sensor, or it could even be a vacuum leak

[poorly_felicia]

not so.. the stepper motor sometimes gets out of alignment which allows the throttle plate to close too far, hence the stalling, but you are right in what you say, it could well also be a problem associatied with the map sensor, or it could even be a vacuum leak

thanks for the knowledge! ill remember that.

[thatnutter]

Thanks for the ideas so far guys. I've been down and had a look this morning and was going to take the throttle body off and have a look and clean it but I couldn't cos I don't have any star shaped screwdriver bits. I opened the throttle plate up and had a peer down inside and it looks fairly clean in there.

With everything back assembled and the engine running I held the throttle open by hand while I was stood looking at the engine. At tick over it runs mostly fine if occasionally a bit irregularly and at moderate revs it seems to run fine but at high revs the whole engine block would jerk every now and again in an irregular fashion. I'm guessing it shouldn't do this! Ive never revved the engine with the bonnet up before. Would this indicate that there is an interruption in the firing of cylinders? To me that reinforces the ignition coil idea but I'm no expert.

Approx how much do coils cost? I've been trying to ring White Dove all morning to get an idea how much various bits and pieces might cost me but I can't get through. I managed to break the window winder handle off which isn't good in this weather!

[TeflonTom]

it would be handy if we knew which engine you have?? pics??

i would try replacing the spark plugs before changing the coil/coilpack

[thatnutter]

it would be handy if we knew which engine you have?? pics??

i would try replacing the spark plugs before changing the coil/coilpack

Its a 1.3 mpi. I said in my first post )

The spark plugs were changed last week during the service and it hasn't made any difference.

Thanks, Rhys

[TeflonTom]

yeah i got that... is it a 135M or a 136M??

some have a convertional distributor and cap, and the others use a wasted spark coilpack

[thatnutter]

yeah i got that... is it a 135M or a 136M??

some have a convertional distributor and cap, and the others use a wasted spark coilpack

I don't believe there is a distributor. It has a Simos 2P coil unit (according to my Haynes manual) that fits over the spark plugs.

[thatnutter]

Where would it say if it is 135m or 136m?

[TeflonTom]

doesn't matter... yours has wasted spark (coilpack).. have you have a diagnosic check done on the car??

[thatnutter]

doesn't matter... yours has wasted spark (coilpack).. have you have a diagnosic check done on the car??

No not yet. That was going to be one of my next questions. The local Skoda garage want I think

[richardsfavorit]

They are having a laugh - seems nfair for just a quick check on diagnostic codes, my garage does it for nowt!

[poorly_felicia]

honestly its worth taking it into you local skoda place, unless you are absolutely sure that your normal garage have a VAG diagnostic system. If they dont they wont be able to access the engine management unit error codes and data reports. This is critical in sorting out a problem like this.

You local garage may just be offering a visual disassemble / reassemble check which may not be thorough enough to pick up an intermittent fault.