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Matt
Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 21099
Experience:  BEng hons Mech engineering, in auto industry 22 years
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Fiat coupe 20v turbo, no spark on coilpack 4 from cambelt

Resolved Question:

Fiat coupe 20v turbo, no spark on coilpack 4 from cambelt end? Changed coil pack and spark plug but nothing? Lambda sensor changed last week. Fine when cold but after 30 minutes fault light comes on and starts misfiring.
Submitted: 5 months ago.
Category: Car
Expert:  Matt replied 5 months ago.

hello

if theres's no spark just on 1 cylinder and the coilpack is and plug is fine then that coild may not be getting any power?

I'd 1st check if you have 12V on the coil with the ignition on

and if you do then trace the coil wiring back to the ECU , checking for damaged insulation and corroded connections as you go

if all of this is OK its possible that the ECU is faulty and is not longer firing that coil

in which case I'd suggest to send it off for testing / repair

I can recommend these firms

http://www.the-ecu-doctor.co.uk/

http://www.bba-reman.com/uk/

Customer: replied 5 months ago.
Thought it might be looking like that! Runs fine for 30 minutes from cold then it stops firing. It has 12.37 volts on it when non running and 13.2 when engine fired up. I would assume as you say that there's no signal being sent to coilpack.
Expert:  Matt replied 5 months ago.

hello

thats correct and fiat ECU's of this era can often give issues as they age

I'd also locate the ECU earth terminals which run out of the engine bay wiring loom and are secured to the engine with ring terminals

as these are the ECU earth connections and must be bright and clean

Customer: replied 5 months ago.
Sorry for delay MattChecked some bits and now there's no Spark on number 3 from Cam belt end and ok on 4? Would you still be thinking ecu?CheersDan
Expert:  Matt replied 5 months ago.

Ok if the no spark situation has now moved from cyl4 to cyl 3 then I'd suspect that there's a problem with the distributor

so I'd pull the cap off and inspect it for cracks and check if the little carbon bush in the top that rubs on the rotor arm is intact and not missing

also check over the rotor arm for cracks

Customer: replied 5 months ago.
Bit random matt as we've talked about coil packs! Surely you realise coilpack = no distributor, cap etc ? Busy day? �� is it possible that It could be the phase sensor? Does that govern the spark signal from the ecu?Cheers
Expert:  Matt replied 5 months ago.

sorry

I saw the 1999 engine and did wonder if this was the distributor version as some people cail the distributor coil as the coilpack

and the 1999 year they did switch from distribtor to coilpacks

but that is only on the 4 cylinder not the 5

so getting back on point

as the lack of spark is moving from cylinder to cylinder then either there's a fault with the ECU or the wiring loom is shorting out and then crosstalking between the 2 cylinders

so it would be worth doing a continuity check / measurement

Customer: replied 5 months ago.
No worriesWill have a thorough look through loom and send ecu for test.Thanks for your help
Expert:  Matt replied 5 months ago.

glad to help

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Matt, Mechanical Engineer
Category: Car
Satisfied Customers: 21099
Experience: BEng hons Mech engineering, in auto industry 22 years
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