Measure up the coils?

[Kroegarn]

Is it possible to measure if a coils and the ignition modules (correct term??) are working properly... resistance or any other way to test them?

Had the car through the car wash thursday evening. Clean and shiny I got about 500 meters before huge misfires and dramatic loss of power. It was running harsh at idle and only managed about 1500 rpm at full throttle with a lot of soot on what sounded like only 2-3 cylinders igniting. Managed to drive the 2km home with full gas on 6th gear which gave me about 60km/h or the equivalent 37mph.

Its been standing (hopefully ashamed of itself ) in the garage until today and the problems had sadly not dried away

I have tried with some spare parts, coil pack and two ignition modules but with no greater success. The other coilpack I´m pretty sure has one broken coil and the car would not even start with that one mounted. Reverted back and it took some time on the starter before it barely started on the 2-3 cylinders Oh and some water had found its way to the fuse box, due to that the lid was not properly closed... a short circuit somewhere due to it?

[UrS4boy]

Coil and POS testing Info

Did you use the pressure washer on the engine? If so, you need to remove the OE 20VT coil plate and dry out all the components.

As for testing coils and POSs, I haven't ever seen a definitive way to put and multimeter on them and measure specific ohms resistance so you can declare a coil or POS channel good or bad.

However, there are some diagnostics that can help you pin-point the problem (at least when it is occuring at idle - misses at speed/under boost are almost always a coil issue).

POS/Coil Diagnostic: http://forums.quattroworld.com/s4s6/msgs/153152.phtml

POS info - check out the hyperlinks inside:http://forums.quattroworld.com/s4s6/msgs/15284.phtml

Coil info - check out the hyperlinks inside:http://forums.quattroworld.com/s4s6/msgs/4088.phtml

[rynaqui]

Most likely there is water in the coilpacks area after washing..need to get them off and dry out as above but more than likely the misfire will remain, spark plugs should be ok but coil packs won't be too happy.

[newsh]

He says he's already tried a different set of coils and POS.


Are you running a stock airbox? Did you get the air filter wet?

[newsh]

Also, if you drove home with 2 or 3 cylinders not firing, the plugs in those cylinders will be soaked with fuel, I'd take all the plugs out and clean/ dry them and take the coilpacks indoors and leave them on a radiator for a few hours.

[Kroegarn]

Tnx... I just removed the plugs and dried them with a cloth and put them back, perhaps not enough?

Though I got my hands on a complete "ignition-kit"(coils and POS) at a nice price so at the moment I´ll just wait for the delivery and muster up the energy to get at it later this week.

Although I realized today that I only tested one POS (with two spares)... so perhaps that other was the broken one....

/Mike

[UrS4boy]

Tnx... I just removed the plugs and dried them with a cloth and put them back, perhaps not enough? /Mike

Open up and dry off the four connectors to the two POSs and the coil power (the white plugs on the fire wall). Check the coil ground/earth at the corner of the cam cover (big thick brown wire).

[Kroegarn]

2b continued?

Had the "new" parts put on today (coils and both POS:es) and it started up somewhat rough but after 10-15 seconds on idle it started to ignite on 4 cylinders and soon after that all 5 were lightning up .

Moved back to the previous POS:es and the car ran fine... took it for a spin and got just about 2-300meters the same ugly fault showed its face and I stumbled back to the garage at 1500 rpm .

Reverted back to the "new" POS:es and car idled nice (missed sometimes) but when giving gas it choked and giving a little gas at the time it was possible to hit high rpms. The SB A/F also showed a too rich mixture.

Finally changed the older of the "newer" ones for an oldold POS I had in the garage. Then it ran as it should... at least for the 5-600meter I drove before hitting back to the garage. Did not dare to take for a longer spin

So will be "interesting" to see if the car will run fine now... perhaps at least to the next time I take to the car to the car wash. No engine wash earlier though... but perhaps, or probably, not related to the car wash at all....