2003 golf mk4 1.6 no spark ,ecu problem or coils or?? (there is a confusing story to it) help please

Hi all i have a golf mk4 which has no spark. 2 weeks ago I went to do my first ever compression test on a car just for curiosity (which had cost me dearly) and got 150psi out of each cylinders which i was okay with. I then went to start the car after putting the coils and spark plugs in and the engine just cranks and does not start. When this happened i thought i would use jumpeer cables to start the car and i connected the red end and black end to each battery terminal on my car then when i went to connect the black and red end of the other side of the cable i left it on the floor as someone called me and the cable ends touched and one cable cut in half. The first thing i looked for was a fuse that had blown after just cranking and not starting and they all are fine i cannot see any blown fuse then i tested for sparks and there is none in each coil. I then asked garages if they will take my car if i tow it there but they said to get an autoelectrician (£80!)and so i did and he said everything is fine except no spark signal coming from ecu. So i sent the ecu away to a company called ecu express they said the main chip had gone and would have to get another ecu and code it so my key would work (£250 total!). i got the ecu back plugged it in and i have the same problem!! i phoned them up and they said it was tested before it was sent and that there is another problem else where and to get another autoelectrician to test it. i have spent £300 and the car still has the same problem which is annoying.

on another point i thought all that would be damaged if cables touch is the battery because the electricity would take the shortest route?? i think it was the compression test which damaged it som how because thats the reason i needed the cables in the first place but all i did was take the coils out..

is there anything else which anyone could think of as to whats going on? such as which pin is responsible for the spark signal and how to test it? i doubt all the coils would be faulty and give no spark.

any help would be helpful. Thank you!

You have been shafted by yet another ECU testing company, these people take advantage of the lack of understanding and the mistrust we have for “black boxes” when we think “it must be the computer”, we’ll in my experience it never is, except when it is. Almost every ECU testing company I come across is a scam, even Bosch themselves in Germany have shafted me twice! If I could take in 100 suspect ECU’s, hold them for 48 hours, charge £250 for the privilege and send them back as OK, I would get away with it 99% of the time, it’s easy money for preying on people’s fears. I feel a Watchdog article coming on which could start just down the road from me in Heanor...

You did did a compression test on a 16v 1.6 BCB code engine where you pulled the coil packs but left them connected to the wiring harness whilst you cranked the engine over, this instantly destroys the coil pack so you need four new coil packs. Even pulling a coil pack off of its plug can make it fail.

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Originally Posted by Crasher

You have been shafted by yet another ECU testing company, these people take advantage of the lack of understanding and the mistrust we have for “black boxes” when we think “it must be the computer”, we’ll in my experience it never is, except when it is. Almost every ECU testing company I come across is a scam, even Bosch themselves in Germany have shafted me twice! If I could take in 100 suspect ECU’s, hold them for 48 hours, charge £250 for the privilege and send them back as OK, I would get away with it 99% of the time, it’s easy money for preying on people’s fears. I feel a Watchdog article coming on which could start just down the road from me in Heanor...

You did did a compression test on a 16v 1.6 BCB code engine where you pulled the coil packs but left them connected to the wiring harness whilst you cranked the engine over, this instantly destroys the coil pack so you need four new coil packs. Even pulling a coil pack off of its plug can make it fail.

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Hi first thank you for the reply but the ecu guy said there was a blown main chip and the ecu could not be repaired so they sent me a second ecu which had been coded from the original ecu and I had the greenflag guy who came out initially and he tested it the same way though by putting the spark plug inside the coil and grounding the spark plug on metal and testing to see if there is a spark which would blow the coil? and so did the autoelectrician

Is there a way i can test my coils? they are 4 pin coils and would my ecu be damaged in anyway by doing the compression test or just the coils?

If the spark is tested with ALL the plugs grounded then there is no problem, the damage is done by cranking the engine over with the coil packs plugged in but with no plug inside and earthed, then the spark voltage has nowhere to go and yes in theory this can damage the ECU but ECU failure is extraordinarily rare, I get around one very 2 or 3 years BUT just recently I have had to do two on for one customers on his two different cars, serious bad luck as TTRS and A3 FSI quattro ECU's are not cheap!

i replaced coils today and it started up fine!! i got a spark then replaced them all! There is not much information on the topic of coilpacks going after a compression test obviously i know for the future but you gave invaluable information and it leads me to think, was the ecu even damaged? i am going to ask for original ecu back but still the electrician told me nothing about the coil packs....

I only found out about that sensitivity of coil packs the hard way. Back in around 2005 it beacame clear that the 3cylinder 12v was prone to jumping it’s timing chain after an oil change so we made the policy decision to always crank them over plugs out to build up oil pressure, thinking I would save a moment or two I left the coil packs plugged in and cranked it over, then I could not get it to start! You learn the hard way but it is a shame it has not become a well known bad thing to do. I really feel good if people learn from my hard learned mistakes and hate it when the same mistake is made right under my nose because I have failed to point it out.