hey guys and gals

im having a problem with my engine again which i had about 10 months back.

as im driving along and particularly under acceleration the engine will loose power and car will buck, feels like a cylinder or two is dropping out. now last time this happened it turned out to be one of the coil packs so i replaced them but i cant see the coil packs failing already!

so i recon its down to either sparks or HT leads. i fitted champion eon spark plugs about 1000 - 2000 miles back and ive checked the HT leads and cant see any cracks or damage to them.

only recent job ive done to engine was change of fan belt 3 weeks ago which i also cleaned the bottom pulley and the sensor by it. but didnt move the possition at all. dont know if this will have anything to do with it.

any ideas?

No light coming on suggesting a management problem?

Cheers

D

You mean the alternator belt? not fan belt? The sensor is the crank/timing sensor that you cleaned, but it is sealed so if it is still screwed in place thats probably fine.

Look at the lead in the dark for any arcs (no not the forum member )

Kristian

rallycinq said:

No light coming on suggesting a management problem?

Cheers

D

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sorry forgot to mention the management light flicks up

kritip said:

You mean the alternator belt? not fan belt? The sensor is the crank/timing sensor that you cleaned, but it is sealed so if it is still screwed in place thats probably fine.

Look at the lead in the dark for any arcs (no not the forum member )

Kristian

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yer i meant alternator. got in the habbit of fan belt because everyone comes in work asking for fan belts! thats what i thought about the sensor, and i had no problems last time i changed it.

the thing with looking for arcs is the problem never happens when idling it only ever happens under acceleration.

you can rev it from the engine bay in neutral though...just turn the butterfly mechanism by hand. The part where the throttle cable ends up.

Kristian

Its easy to test the coil packs though so I wouldnt rule them out. Did you replace both of the coils or just one?

Otherwise just repalce the leads and sparks and go from there.

kritip said:

you can rev it from the engine bay in neutral though...just turn the butterfly mechanism by hand. The part where the throttle cable ends up.

Kristian

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ive tried that, its when accelerating under strain. i.e. when in gear and driving.

Bushboy said:

Its easy to test the coil packs though so I wouldnt rule them out. Did you replace both of the coils or just one?

Otherwise just repalce the leads and sparks and go from there.

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yer i replaced both coil packs. and the sparks are almost brand new. only thing i havent changed recently is leads, but they still look in good nick. possibly time for some magnecores

If its doing under load and acceleration, check all the wires carefully. The engine moves in the opposite direction to the wheels, remember school physics. Maybe have a very close look at the O2 wires in case they are shorting of something as the engine moves.

Cheers

D

If its the smaller type Marelli ECU :

Sounds to me like a simple ecu failiure. Quite common on the mpi Sei.

This is if its not the coils again, if they were good quality fiat ones then they shouldn't have gone.

Starts out as a simple hesitation now and again and if you leave it and leave it, it will drive as if its on two cylinders most of the time.

New one is around £200 from Fiat. But I would test the coils first.

Remove the ECU and check the hardware number (the numbers following the h/w on the ecu's label). If its below 100 chances are its a 'troublemaker ecu'.

Used an older processor which was normally Motorola which spiked the coil pack and ruined the 'power amplifier' to the coil.

The new ones (have a h/w number about 300 and something) use a siemens processor which will not do it again.

This was also very common on the mk 2 punto 8v ecu.

BUT do check the coils first as cheap ones are known to pack up prematurely!

James

i had the ECU replaced under warranty about a year into owning the car as something happened to it (my dad owned the car at the time so im not sure what.)

think ive found the problem. seems that the two connectors onto the packs are loose and wobble around and loose connection, hence loosing spark.

downside to buying aftermarket coil packs! just put a cable tie around the connectors to push them down onto the packs and not had a problem since!