Think I screwed up the spark plug change

[Ferret]

...which is why the car's now causing me trouble on ignition leads and is cranky in the mornings.

When I did the plug change, I swapped over to a bunch of denso plugs as they were cheap and came with a good reccomendation.

I've just discovered that denso plugs are gapped by default at .032 - since the change I've had developing problems with the ignition leads. I thought it was just because I'd destroyed one accidentally and bodged it back together.

I'm now experiencing rough running during startup and random misfires all over the place.

When I've checked the manual, it says the gap should be no larger than 0.031 with an optimal gap of 0.027 - would the 0.032 gap be causing all the trouble I'm having, as the breakdown voltage will be much higher causing the tired ignition leads to play up?

I've just lucked out and acquired a practically brand new set of magnecor 8mm blue silicone leads for free, I think I'm going to swap back to a set of bosch F8LCR plugs and check they're correctly gapped.

Shogun, have you had any experience with different plugs and gaps in the V12? Any good reccomendations?

Cheers y'all!

[shogun]

basically the M70 engine is not so sensitive on gaps (my opinion). I remember some people were not happy with the Bosch Platinum+4; 4 Electrode, my friend changed back from them to the standard F8LCR electrode on his 1992 750 M70 Highline.

BUT, which Denso did you use?
Denso tells us:
750iL E32 5.0L M70 1988 on K16R-U IK16 VK16 IK01- 0.7

so that means, Denso says the K16R-U should have a gap of 0.7

http://www.globaldenso.com/cgi-bin/g...&action=search

so adjust them to that. Or did you buy the wrong ones?

[Ferret]

basically the M70 engine is not so sensitive on gaps (my opinion). I remember some people were not happy with the Bosch Platinum+4; 4 Electrode, my friend changed back from them to the standard F8LCR electrode on his 1992 750 M70 Highline.

BUT, which Denso did you use?
Denso tells us:
750iL E32 5.0L M70 1988 on K16R-U IK16 VK16 IK01- 0.7

so that means, Denso says the K16R-U should have a gap of 0.7

http://www.globaldenso.com/cgi-bin/g...&action=search

so adjust them to that. Or did you buy the wrong ones?

I'm going to pull one this evening I think and have a look at it, see what it is etc - they were bought from a unipart, didnt pay much attention to them as the guy over the counter cross checked the parts number and pronounced them compatible.

Wont make that mistake again...

[shogun]

Install my performance chips only after the engine runs again perfect. Otherwise you might blaim it my chips you just received

You can also first install the EML chip only and run the car. The EML performance chip changes the throttle valve control to more sporty and wider openings, more crispy repsonse. Besides that it will eliminate the V-max 250 kmh limiter.
The 2 MOTRONIK Chips you can install later if you want, but when you install them, then both at the same time, otherwise the EML will go in limpmode.

Also you have to resync the system on the V12 then.

synchronisation of banks of M70 engine cylinders



The following information is important when replacing Motronic control or the EML unit or when the control modules were for some time without power.

Each control unit is programmed with certain basic values, which are only mean values.

A control unit receives various input values depending on engine load conditions and compares them with the stored values.
An daptive system compares the input values with stored curve family values, after which corresponding orders are put out to the concerned control elements.
If, for example the EML control unit were without current for a long period of time, its adaptive system would lose the stored values.
The adaptive system would have to read in and store the input values of a certain engine after restoring operation of an erased control unit or installing a new control unit.
This procedure could lead to erratic idling of the engine after starting and disturbances in overrun.
Consequently there must be conformance with the following procedures before an EML control unit is replaced or after restoring operation of a disconnected control unit or a disconnected battery.

-run engine to operating temperature.
Install (new) control unit and drive care. During test drive have the car coast three times from speeds above 5,000 RPM to the idling range in transmission range 1 (approx. 10 seconds).

-Have engine run at idle speed in transmission range P or N at least 5 minutes.

These measures serve immediate and precise synchronisation of both banks of cylinders in all operating conditions.

[Ferret]

Install my performance chips only after the engine runs again perfect. Otherwise you might blaim it my chips you just received

You can also first install the EML chip only and run the car. The EML performance chip changes the throttle valve control to more sporty and wider openings, more crispy repsonse. Besides that it will eliminate the V-max 250 kmh limiter.
The 2 MOTRONIK Chips you can install later if you want, but when you install them, then both at the same time, otherwise the EML will go in limpmode.

Also you have to resync the system on the V12 then.

synchronisation of banks of M70 engine cylinders



The following information is important when replacing Motronic control or the EML unit or when the control modules were for some time without power.

Each control unit is programmed with certain basic values, which are only mean values.

A control unit receives various input values depending on engine load conditions and compares them with the stored values.
An daptive system compares the input values with stored curve family values, after which corresponding orders are put out to the concerned control elements.
If, for example the EML control unit were without current for a long period of time, its adaptive system would lose the stored values.
The adaptive system would have to read in and store the input values of a certain engine after restoring operation of an erased control unit or installing a new control unit.
This procedure could lead to erratic idling of the engine after starting and disturbances in overrun.
Consequently there must be conformance with the following procedures before an EML control unit is replaced or after restoring operation of a disconnected control unit or a disconnected battery.

-run engine to operating temperature.
Install (new) control unit and drive care. During test drive have the car coast three times from speeds above 5,000 RPM to the idling range in transmission range 1 (approx. 10 seconds).

-Have engine run at idle speed in transmission range P or N at least 5 minutes.

These measures serve immediate and precise synchronisation of both banks of cylinders in all operating conditions.

Arrived yesterday, having evaded import tax completely... impressed!

Will be fitting these tomorrow, last thing after doing all the ignition kit and making sure the engine runs smoothly before doing the chips!

[Ferret]

Interesting, very interesting... just been to unipart and had a discussion with their parts manager about the plugs.

His parts system reccomends NGK ZFR5F-11's as the standard item for the M70 motor. When we double checked, the -11 means 1.1mm gap! That's 0.0433in when the manual states an absoloute max of 0.031!

Apparently the NGK system also reccomends it:
http://www.ngkpartfinder.co.uk/car_c...850&engine=5.0

If you follow through the link, apparently the 1.1mm gap is for the S70 engine o.O

However it's also reccomending the same gap for the 750i M70 engine:
http://www.ngkpartfinder.co.uk/car_c...750&engine=5.0


ZFR5F -> http://www.sparkplugs.com/more_info.asp?AAIA=&pid=32422
ZFR5F-11 -> http://www.sparkplugs.com/more_info.asp?AAIA=&pid=3692

The ZFR5F-11 cross references to the Bosch F8LCRX, not the Bosch F8LCR...

When we plugged the F8LCR into the bosch-NGK cross reference system the Bosch F8LCR came out as an NGK ZFR5F... surprise

I have a nasty suspicion that what's happened is the guy at Euro car parts has picked up the NGK ZFR5F-11 and gone "lets cross reference *this* to Denso" and voila I've got the wrong damn plugs...

I shall confirm tomorrow, but regardless... a 1.1mm gap would be insane for a non-coilpack distributor based ignition system.

Again, another moral to the story, check your part numbers and dont rely on the parts place to get it right for you!

[shogun]

http://cgi.ebay.co.uk/NGK-SPARK-PLUG...item2ea8752ef2
good price in the U.K.
Part No: ZFR5F-11

NGK SPARK PLUGS x12 BMW 750 E32



recommended by the chaps from the U.K.
http://the7seriesregister.co.uk/foru...howtopic=13332

that shop in the U.K. also has a lot of nice tools and other cheap items
http://stores.shop.ebay.co.uk/AUTOMO...D-TOOLS-DIRECT

check here
http://www.ngksparkplugs.com/
http://www.angelfire.com/extreme4/sk..._REFERENCE.htm
that is the easiest

http://www.clubplug.net/

http://www.clubplug.net/
for example my 750
Cars, Trucks & SUVs

1990 BMW 750iL 5.0 V12 M70 E32 MFI

Spark Plug Part No. Stock No. Plug Gap Photo
V-Power ZFR5F 7558 .032 n/a
G-Power ZFR5FGP 7098 .032
Laser Platinum PZFR5F * 3741 .032
Iridium IX ZFR5FIX-11 2477 .032

[Ferret]

http://cgi.ebay.co.uk/NGK-SPARK-PLUG...item2ea8752ef2
good price in the U.K.
Part No: ZFR5F-11

NGK SPARK PLUGS x12 BMW 750 E32

Yeah, my point here was though that the -11 version of this plug is not a good plug to use in the older lower HT voltage cars... you have to manually gap them. The non -11 version of the plug is set almost spot on!

[Ferret]

Hrr, as expected, the Denso's were the 1.1mm version and I'd not checked them :/

Lesson learned!

Now time to swap these to a nice shade of blue, the spare leads finally arrived!

[632 Regal]

Hrr, as expected, the Denso's were the 1.1mm version and I'd not checked them :/

Lesson learned!

Now time to swap these to a nice shade of blue, the spare leads finally arrived!

After I got my 850 I thought it ran pretty good (never driving one before) I hit the gas once and the engine went running on half the engine, went back and parked the thing. Ordered all the ign components, cap rotor wires plugs and installed. Popped in them 3 chips your looking at and after syncing the banks all I can say is WOW. One of the old caps had the electrode that contacts the rotor completely burned off. If you dont do your own work and shop parts prices this can get really expensive in short order... I'm sure this is why the previous owner sold it.

All I need now is step by step instructions for the new sunroof parts. I'm good mechanically but this stuff is like working on the Mars rover.