Technical Punto Mk2 1.2 16v Sporting Problem

[Jube]

Hi All,
I've just bought a Mark 2 Punto Sporting which is now unfortunately only running on cylinders 1 and 4. It idles and runs very poorly but does seem to pick up slightly at 3000 rpm and above.

The car is a 1.2 16v with Engine code - 188.A.5000 and Bosch ECU - ME7.3H4.

I've ran Fiat ECU Scan to the car and it showed Error codes P1555 (BATTERY MODULE TEMPERATURE SENSOR 2 SIGNAL CIRCUIT LOW INPUT) + P0235 (BOOST PRESSURE - Which seems a little strange on a non turbo engine?) which are probably unrelated.

I've already done the following:

1) Coil Pack unit replaced - Controls all four Spark Plugs.
2) Spark plugs and Leads changed.
3) MAP Sensor cleaned.
4) Injectors replaced.

Now as it's effecting Cylinders 2 & 3 I initially suspected the Coil Pack Unit (Single Unit on 16v) but as this has been replaced I'm now probably thinking I could have a broken head gasket between cylinders 2 and 3.

I'm going to do a compression test on the engine tomorrow to help diagnose the problem further.

Do the 16v's suffer with ECU problems like the 8v IAW59F ECUs do where they blow the coil drivers?

What are everybody's thoughts on the problem please?

Any assistance would be very much appreciated.

 

[Ziggy122]

By Fact its working on 2 coils and not the other 2 - i'd be compression testing AND Doing a sniffer test to see if there is a reason to it been lumpy!

Ziggy

 

[Skyperr]

Ideally you should get the feed to the coil serving 2 & 3 checked with a scope to see if the ECU is triggering the coils. The ECU normally takes a beating if the coil breaks down internally and arcs, or if ropey plugs or leads are used. Have you connected the feed for coil 2 &3 onto the other good coil, and check for a spark? If no spark the chances are the ECU is duff....

 

[Jube]

Thanks Ziggy/Skyperr for the speedy replies.

Ziggy - I initially ruled out the head gasket as the coolant level doesn't drop, there's no mayo on the dipstick/Oil filler cap, No bubbles in the expansion tank and no excessive white smoke from the exhaust.

But after swapping all of the obvious parts I'm starting to wonder about the HG now.

However, the compression test should hopefully shed a bit more light on the situation tomorrow.

I could also nip down to my friend's garage to get a sniffer test done by him as well.

Skyperr - My scope recently broke which is a shame. I've ran the engine with a plug in leads 2 and 3 grounded to the engine and both show a spark - I didn't check to see how bright the spark was compared to plugs 1 and 4 though.

The Coil Pack unit on my 16v (Unlike the two separate units on my 8v engine) only has one feed to control both integrated coil banks unfortunately.

Thanks again.