New Bosch Ignition coil issues

[Kershaw]

I just ordered two brand new Bosch 00060 ignition coils. One after the other.

The first one read .7/7000 ohms (tested with my friend's expensive Fluke multimeter.) The second .7/6660 ohms.

What is going on here? Did they change the spec? Bentley clearly states the spec is .5/5000 ohms, anything higher and it should be replaced. The one I took out of the car read .7/5700

:hitler:

I'm pissed. Feels like nothing is going right with my e30 and this is just icing on the cake. Am I stupid and doing something wrong? And for the time being I'm out $130. Do I even have other options? I'm not exactly enthused to buy another fucking Bosch ignition coil.

edit: tell me what I'm doing wrong here. Besides my cheap multimeter.

[Kershaw]

Anyone?

[digger]

How does the car run with it?

[TobyB]

It's hard to get a meter accurate to .1 of an ohm. Especially that harbor freight one.
I have several of them. They are great for .99c, but not exactly precise.

And the dc resistance doesn't matter all that much. What does matter is the inductance
(hard to measure) and the turns ratio (also hard to measure, but the voltage (even harder
to measure) will give you that).

It comes back to what digger says- does it work?

A dead coil reads either 0.0 ohms
or infinite ohms- and it may only do so hot. But if it's close, it's working, and with 99.999% probability of working correctly.

Looking at the dc resistance is like standing 20 feet away from a running car and saying 'I don't hear anything wrong-' it's a valid test, but it doesn't really catch all faults.
Coils almost never, ever fail, anyway...

Not a good answer, but given that I'm standing 2500 miles away from you, it's what I got.

t

[Kershaw]

It's hard to get a meter accurate to .1 of an ohm. Especially that harbor freight one.
I have several of them. They are great for .99c, but not exactly precise.

Yeah, I keep them stashed in all sorts of spots. That's why I went to my friends house. He works in aeronautical avionics and his Fluke meters are very accurate. The HF meters couldn't read the primary resistance with any sort of accuracy, they would read anywhere between 2.1 and 1.6. The Fluke would consistently read .7 on the primary resistance. The secondary resistance was the same between the Fluke and the HF meters.

I don't know how it runs because I'd rather not put parts that don't meet spec straight out of the box in my car when I have an issue with the car not running properly already. And I've exhausted many many other options. IIRC, the coil in the car ran fine in another e30 as well, but so did every other part I tried. That's why I'm going for all new parts. I'm sick of this. But maybe it's worth a shot.

[digger]

what symptoms? why do you think its the coil?

[Kershaw]

what symptoms? why do you think its the coil?

http://www.r3vlimited.com/board/showthread.php?t=372569

My coil ran well in another car and coils rarely fail, but... I am just trying to be thorough here. No sense in putting stuff in the car that doesn't meet spec imo.

[digger]

i doubt the spec means much and it mighjt be specific to the genuine BMW ones which probably differs to aftermarket bosch as its a different unit?, when i tested mine it didnt meet spec but engine ran perfectly fine. At one point i put in a m30 coil and it also ran fine with different specs

[Kershaw]

That didn't make sense. Why even have specs then? Let's have con rods that are an inch different in length and a cylinder head with a twist in too...

[dnguyen1963]

That didn't make sense. Why even have specs then? Let's have con rods that are an inch different in length and a cylinder head with a twist in too...

Take electronic specs with a grain of salt. Hardware specs for rods and cylinder heads can be very defined.

[EyExR]

Same deal here. Brand new Bosch coil. I got the same exact readings as you... Such BS.

[Kershaw]

Yeah, they must have just changed the spec without telling anyone.

Anyway, it wasn't the coil that was giving me the 4k hiccup issues. Switching to megasquirt definitely fixed it. Not that this was a, "oh i'll just run over to autozone and pick this part up" type of a solution. Kind of a nuclear option. But it definitely worked. And for how little time it took install I'm kind of pissed I didn't switch to megasquirt a year ago.

I am running the new Bosch coil just because I paid for it and it's shiny.

[firemanory]

Same issue here.

Just bought a new Bosch coil for mine (with a currently working old as hell Bosch coil) and tried it out and .D....O...A. On way home to test it and will post up results. The new one is made in Brazil I believe.

If I remember correctly I had bought another one several years back with the same issue. I think I still have it..I'll post up results from multi-meter.

[jeffnhiscars]

I've been driving forever (almost) and have never had a coil go out. Clearly I have nothing useful to contribute :)