5 cylinder

[Ferrett 1962]

My toy has developed a problem, sounds like it only running on 5 not 6 cylinders when I start it but smooths out as the revs come up. I pulled the cover off the engine to find one of the coils is different from the others and an odd colour can anyone tell me if this looks right and how to test the coil packs

[Dave M]

Bremi coil, nothing odd about it, any one of those coils could be bad, BUT, start with basics.

If you really feel it spark related, pull the plugs, check their color for indications of poor ignition. Check the ceramics closely for cracks. When were they changed last? I had a subtle miss that took forever to diagnose because the crack in one ceramic was very slight. If they all check out, then check the rubber coil boots for cracks, exessive wear, deterioration. If all is good, test the coils ala Belntley instructions and a multimeter (if you don't have a Bentley, ask and I'll post the page).

Others will in what I've missed....

Good luck with it,

Dave

[shogun]

Bremi 11855 T is for BMW, Bremi says
BREMI - PREMIUM CAR SYSTEMS | Ignition Technology | Ignition cable sets | Ignition Coils | Glow plugs | Distributor Caps
1703360 BMW fits also on E34 besides many other BMW

BMW E34 E36 ignition coil 320i 325i 520i 525i M50 1703360
E34 - 520i, 525i - M50

E36 - 320i, 325i - M50
Testing, quote.....
How to test an ignition coil
A standard car’s distributor ignition coil can be tested by checking the ohms reading. Ohms can be read on a volt/ohms meter. Ohms is a unit of measure for the resistance that a wire or coil has. Ignition coils should be measured on the primary coil between batt and tach terminals. The batt is the coil ground. To check the secondary coil, check the ohms between the batt terminal and where the coil output wire plugs into. If the ohms read zero the coil connection is broken and the coil is no good. An open coil reading zero is the usual culprit of coils. Don’t test through the output wire though. The primary coil should read between .7 ohms and 1.7 ohms, if outside this range replace it. The secondary coil should generally read between 7.5K ohms and 10.5K ohms. If the ohms are not within the specified range for that paticular car, replace the coil. Coil resistance will also change and vary if the coil is hot or cold. This a generalized ohms range that fits most distributor coils. Another thing to remember is that sometimes a coil will only read bad after it gets hot. It may work intermittently after it gets hot also. Coil packs will generally read around .3 to 1.5 ohms on the primary side and 12.5K to 13.5K ohms on the secondary side. These figures will get you reasonably close to where the coil’s ohms need to be to work properly
How To Test Your Coil - Ignition Coil Testing - Test Your Coil For No Spark - Ignition Troubleshooting
How To Test Ignition Coils - Testing Igntion Coils - How To Articles

Coil Test - Testing Your Ignition Coil - Coil Resistance Test - How To Test Your Ignition Coil With an Ohmeter
probably the best is to do it with a oscilloscope

[Ferrett 1962]

Thanks I was unsure about the colour difference I havn't had the car long enough to have to poke around it much it has been perfect till now and it is getting around time to service it ( plugs, oil, filters and such ) anyway the problem has just shown up last week but I havn't been driving it so I will do the service anyway and see what happens. I don't know when it was last done I was told it was just before I got it and as I said it has been perfect till now although I think it may be down on power and using more fuel in the last month or so,I am not a young race driver I like it more for cruising which it still does well.

[Ferrett 1962]

Just started the car again (yet to do the plugs) the engine ran smoother but I could hear a strong sucking noise from the intake side. Wondering could the rough idle be a new leak in a hose under the manifold or is it normal noise. As I said I am not yet used to what is normal on this car.

[genphreak]

The culprit is likely to be a split TB hose/boot, the ICV hose or its manifold to host connector. These have a viton o-ring and a dodgy clip holding them in to the underside of the ITM, and can simply pop out leaving a massive airloeak.

The Bremic coil odd man out is probably a replacement as they are common when you order new ones. Pehaps one of the other 5 has now gone? Better test em all...

[Ferrett 1962]

Thanks everyone I am off the road at the moment so I am going to do a bit with the car. The vacuum noise was probebly always there but louder with the engine covers off I will mark and remove some to check, they are neglected till something goes wrong. Started the car again after a couple of days and it is smooth as a new engine again no misfire at all and this is the first hint at the age of the car so a little preventative work is in order. I havn't looked to see if there is oil in the plug wells as I have read but i might get the air hose out and blow some of the loose paint off in case it gets where it shouldn't when I change the plugs.Since the coils are all the same and it dosn't matter where the go I see they have been marked by someone and I wonder if there was a problem at some timeand they were marked to identify a similar problem.

[Paul in NZ]

5 cylinders on start up.......for me that indicated a head gasket

[Rustam]

Please do see if you can simply check and compare the resistances of the coils.

[Ferrett 1962]

Ok replaced the plugs and looked at the old ones and it looks to be oil fouled plugs by the post on plug condition
If anyone can read them better canyou give me an idea how bad it is and what needs to be done to fix the problem. The car has only been driven for short trips for a while 5k or so so could this be the problem and should I be doing some longer runs every now and then or htter plugs or what.