100k ,new coils,bosch or eldor?
 

Hi Guys my 4.8is is coming up on 100k this week and I have done just about every maintance and repair except for the coils, I seen them on ECS tuning and BMW site .
My question is have anyone replaced the coils ?and which is better ? BMW has 2 coils listed . the price difference is minimal , bosch12138647689 ,or bosch 1213759437

Bosch is the OE for BMW - I would go with those

Check out the pricing at RockAuto on that coil choice. +1 on the Bosch coils $28

[QUOTE=Ricky Bobby;1074431]Bosch is the OE for BMW - I would go with those[/QUOE]

diffinently going with the Bosch, the correct one for my 4.8,the stock is more expensive.

Any fault codes or symptoms?

OP
Most coils will go 100+ WITH NO ISSUES. When they go bad from winding failures or over heating they will run HOT and burn through the insulation housings, or they just drop DEAD. If you are staying with the X5 for the long haul it is a good thing to replace all the coils at some point besides on the side of the hwy.

You can bench test them with a volt Ohm meter. Just read the resistance across the terminals. Any higher than the others? Toss them. Without a lab scope you can not do a full output test to determine the secondary output side. You need to understand that using just one of these tests you can have a coil that passes the resistance test but will fail under high loads (going up a hill for example).

See Below from another forum:
From the u shaped Ignition Coil Harness in the manual there are 3 connectors- 1, 4a, 15. It says that 15 is positive (+) and will be the one tested against ground. Coil primary 1(-) and 15 (+) resistance = approx. 0.8 ohms, Coil secondary= N.A., Spark Plug connector= Bosch- 1k ohm +/- 20%, Beru- 1k ohm +/- 20%. This is based on M52TU+ engines.

Bad ignition coils will give you a SES light. (Engine miss firing on Cyl #X)

Start with ensuring power to your ignition connector - pin 15 should have 12 volts...not fused so be careful while probing.

to test ignition coil primary resistance you can probe terminal 1 (-) and 15 (+)..and you should read approx 0.8 ohms.

to test spark plug connector resistance the Bosch should read 1K ohm +/-20%. (Note: these are the replaceable boots on the 3.0 engines.)

NOTE: I could not find any published source for the coil specs on the 4.8is motors, other than look for the miss firing code. Anyone?

Want to see real Coil on Plug (COP) readings?

Engine and Drivability Diagnostic Tools from Hickok | Waekon

Neat tools

A failing coil does not always cause an SES light. If there are no symptoms or trouble codes it is not necessary to replace the coils as PM. Once there is a trouble code I would then replace all of them. Since failure is never mass suicide, I would not do the replacement based on a concern of becoming stranded somewhere. If I was making a long trip, had a modded engine, towing or something along those lines it would be a different consideration.

Hi , a little shaking on cold start , I figure it's 100k o it time, my bmw of Greenwich only sell ELDOR coils, which I don't want.

So my shop doesn,t sell Bosch any more only Eldor which I really don,t want.