Results of Coilpack Conductance Testing

[Doug_RS2]

Cylinder 1 ____ 138.7 nS ____ 7.20 Mohm
Cylinder 2 ____ 9.8 nS ____ 102.04 Mohm
Cylinder 3 ____ 9.5 nS ____ 105.26 Mohm
Cylinder 4 ____ 11.1 nS ____ 90.09 Mohm
Cylinder 5 ____ 134.7 nS ____ 7.42 Mohm

Coilpacks 1 and 5 have been replaced in the past. 2,3 and 4 look like they are originals.

If you read the SJM site :

http://www.sjmautotechnik.com/TROUBLE_SHOOTING/S4_Ignition.htm

whoever did this doesn't know how to use the DMM or converted the values wrong from Siemens to Impedance so I am a bit unsure on their actual values - I am more concerned with my different readings.

I think my middle 3 coilpacks might be on their way out and not performing at higher boost levels. I will measure the 4 newish ones Sal is lending me to see if they have the 130ish nS readings and if they do it looks like old coils are going bad.

I would like other peoples opinions on this.

[S2central.net]

Woah betty - quite a mad diffrence in readings there. What are you using to get such conductance readings ? I was thinking of buying a new DMM soon that had this functionality and range for the coil packs.


Paul

[Doug_RS2]

I am using an old Fluke 8010A (IIRC), maybe 8050A. They look old now and I never knew they had the conductance settings on it until I needed it this week.

There is a difference Paul but on the SJM site they had a hesitation that was casued by a coilpack and their readings were:

Cylinder 1 ____ 16.80 nS ____ 59.52 Mohm
Cylinder 2 ____ 0.02 nS ____ 50000.00 Mohm
Cylinder 3 ____ 23.85 nS ____ 41.93 Mohm
Cylinder 4 ____ 40.00 nS ____ 25.00 Mohm
Cylinder 5 16.50 nS ____ 60.61 Mohm

Known good Coilpack ____ 151.52 nS ____ 6.60 Mohm

This only showed itself when boost went upto 1.6Bar - now coilpack 2 on that is definitely different - That is why it concerns me that mine might be OK. It also looks as if they degrade with time, probably through heat cycling - they must get a lot of abuse being in a sealed box on top of the engine!

Maybe the x12 to x15 difference in output resistance is enough for mine to start misfiring above 1.85Bar - maybe it is something else - it needs more investigation and measurements.

I might try and find an adjustable spark plug tester so I can do some visual checks on how good the spark is from each coilpackat differeing spark distances - this should show up which coilpacks will not be performing - I can't find one in this country though - Any ideas??

[audiman]

Sounds like this may be your problem mate. Fingers crossed.

[Doug_RS2]

Cylinder 1 ____ 138.7 nS ____ 7.20 Mohm
Cylinder 2 ____ 9.8 nS ____ 102.04 Mohm
Cylinder 3 ____ 9.5 nS ____ 105.26 Mohm
Cylinder 4 ____ 11.1 nS ____ 90.09 Mohm
Cylinder 5 ____ 134.7 nS ____ 7.42 Mohm

Coilpacks 1 and 5 have been replaced in the past. 2,3 and 4 look like they are originals.

Here are the results of the 4 spare reasonably new coilpacks I borrowed from Sal:

Cylinder 1 ____ 20.9 nS ____ 47.84 Mohm
Cylinder 2 ____ 14.1 nS ____ 70.92 Mohm
Cylinder 3 ____ 14.8 nS ____ 67.56 Mohm
Cylinder 4 ____ 15.2 nS ____ 65.79 Mohm

These are closer values to my old ones rather than my new ones.
By the looks of this maybe it is the difference in resistance that is the problem rather than the actual values - or this has nothing to do with my high boost problems.

[audiman]

These are closer values to my old ones rather than my new ones

Dude, sals coils look loads better on paper. Have you fitted them up yet? Did it cure the car?

[Graham]

I am thinking of replacing the short leads from the coils to the plugs as mine look cracked and on there way south . Mine have BMW stamped on the side of them, is this right, i thought Audi and BMW were completely in competition with each other , so why would my car have BMW bits on??? Also does anyone know how much they cost???
Graham

[Doug_RS2]

I have already replaced the short HT Leads - I think they are made by BERU which Audi and BMW use so they might share parts. I don't think they are cheap!

I have 4 of Sals and I will just connect all of them up and use one of the newer ones of mine - I'll do that this afternoon if it stops raining.

[s2avant]

The spark plug connectors are £25.45 each!! I put 5 new ones in mine last year as they were a bit worse for wear.

Ben

[sal_s2]

I am thinking of replacing the short leads from the coils to the plugs as mine look cracked and on there way south . Mine have BMW stamped on the side of them, is this right, i thought Audi and BMW were completely in competition with each other , so why would my car have BMW bits on??? Also does anyone know how much they cost???
Graham

Theyre about 80 quid for the set from Martyn

[Doug_RS2]

I changed the coilpacks to the 4 from sal and kept my no.5 coilpack.

Took it for a drive and it seems to not hesitate in 5th at high rpm. It is hard to test - as it happened before with 4 bodies in the car. I'll see how it goes over the next couple of weeks.

[Markus]

I am using an old Fluke 8010A (IIRC), maybe 8050A. They look old now and I never knew they had the conductance settings on it until I needed it this week.

Doug,

at which connector did you measure the coilpacks? And do you really need conductance settings on the DMM? Can't I just measure the resistance and convert it to conductance (reciprocal of resistance, sigma = 1/R)?

There is a difference Paul but on the SJM site they had a hesitation that was casued by a coilpack and their readings were:

I can't seem to find the test readings on the SJM-site. Could you give me an URL?

[Doug_RS2]

SJM Testing:

http://www.sjmautotechnik.com/TROUBLE_SHOOTING/S4_Ignition.htm

The reason conductance setting was used was because the values are that large resistances, the resistance setting on the DMM does not go that high!

I measured the output of the coil - I removed the HT lead and connected the +ve/red lead to the HT connection and the -ve/ground/black to the metal of the coilpack.

[Markus]

SJM Testing:
http://www.sjmautotechnik.com/TROUBL...4_Ignition.htm

Am I blind or what, but I still can't find those SJM-coilpack values you posted previously on that page. Lots of stuff about POS-testing though.

I'll try to test my coilpacks tonight, but my DMM only goes up to 20 MOhms, so might be out of range. I did test my ht leads and they were all fine (resistance-wise that is) at about 4,8-5,0 kOhms.

[Doug_RS2]

They have removed the info on that page - strange