Bosch plugs

[EricinConejo]

Hi I just read comments on recent thread and I looked up the comments here regarding Bosch plugs,etc. I have a 96 850CI with 85k miles. The car had the original BMW marked Bosch super R1 187 F9LCR2 plugs. I was ordering various parts frm FCP Euro parts and they sent me Bosch Super FGR7DQP plugs. I am running complete stock set up and I am concerned about the issues mentioned in this thread. I hope I have seen enough in this thread but wanted to know if the plugs FCP sent me are just not going to work long term. They were not cheap! Thx for any comments

I would stick with the F9LCR2 plugs. BMW part #12-12-9-070-999. I've never had a hiccup with my 95 850CI M73 using these plugs. I believe the plug you have is a higher power plug for an updated M73 which was manufactured after September 1998 (M73TU, M73LEV, M73N).

To quote from http://forums.bimmerforums.com/forum....php?t=1818677

"In September 1998, the 750i was given a technically updated engine called the M73 TU (technical update). The cause for this update was to ensure that vehicles produced after this date fell within the emissions guidelines that the government set at that time. The update was not mechanical, but the ECU's and hardware were altered to give a lower emission value.

The M73 LEV engine is the American version of the M73 TU engine. LEV stands for Low Emission Vehicle, and the engine received further technical changes to fall in line with the American emissions legislations, which are more stringent than in the UK.

With the technical update, came the requirement to fit higher power spark plugs. This is mentioned in the Technical Bulletin you refer to, and states that any 750i manufactured after September 1998 should be fitted with the high power spark plugs.

Differences are-
*Electrically heated catalytic converters (E-cat) and E-cat control module
*Dual Batteries
*Long-life spark plugs
*Compact water-cooled alternator
*Transmission fluid/coolant heat exchanger
*Rapid-action coupling in the coolant and transmission fluid circuit
*Pulley diameters and accessory belts modified to compensate for new minimum idle speed (530 RPM)"

This apparently applies to other makes of vehicles that used this engine such as Bentley.

Also, this attached Service Information Bulletin DOES NOT list the E31 with M73 as an early model that can be retrofitted with the new plug.

Hope this helps.

[TwoEagle]

Hi I just read comments on recent thread and I looked up the comments here regarding Bosch plugs,etc. I have a 96 850CI with 85k miles. The car had the original BMW marked Bosch super R1 187 F9LCR2 plugs. I was ordering various parts frm FCP Euro parts and they sent me Bosch Super FGR7DQP plugs. I am running complete stock set up and I am concerned about the issues mentioned in this thread. I hope I have seen enough in this thread but wanted to know if the plugs FCP sent me are just not going to work long term. They were not cheap! Thx for any comments

Also have had 12 Bosch Super FGR7DQP on the shelf a couple of years. They ARE listed as a direct replacement for the original ones. Many opinions... have an impression that M70 people does not like it and with M73 it´s not so much a problem. I have an M73 engine...

[Pegjr]

Thank you all for ou thoughts on this. Many comments! I bought what I thought were some NOS F9LCR2 plugs from 4wheelautoparts website and what I received is the Bosch Platinum 4 FGR9DQP plugs. this is what Bosch shows as their current offering acceptableb to the early M73 engine

[moutine]

Bringing old topic up again...

An important factor missing in many of these discussions is the resistance of the WIRE.
IF the theory that high resistance and relatively weak coil is the cause of the M70 engine woes that many of us have experienced after changing to newer spark plugs, then we must consider the total resistance of plug + wire.
The OEM wires are resistors, so adding a higher resistance plug may tip the total resistance value over the top, especially if the OEM coil is weak.

Low ohm wires may allow the stock coils to work with the new high ohm plugs.

ByMW is right. Most of you totaly ignored the factor that there is resistance buil in wires. Actualy in connectors, wires itself are copper based tin coated zero resistance. But all the connectors has 1000ohms and sparkplug connectors is rated 5000ohms. And there is eaven 1000ohms in rotors. So... Over all resistance without sparkplug is 9000ohm in original system. MSD coil users usually need to change that coil connector into one that comes with coil kit and its zero ohms. It cuts away 1k.

However... It is possible to change sparkplug connectors to, lets say Beru ZLE-135 ones. They are high quality and rated 1000ohm only, but they are relatively quite expensive. 14-18 euros per pop.

One interesting plug I found is Champion OE003 aka C9YC. There is very litle info given of this plug, but seems to me it suitable. There is no resistor and plug connection is removable. That gives you the possibility to use way much chaeper E34 535 / E32 735 ignition wires made by Bremi.

[rosakirk12]

RAFFEAL , have a talk with Max Lumens about upgrading to 40k volt coils , and
maybe upgrading your ignition wires to Magnecore . Then you should be able to use platinum or iridium plugs .

I have had magnacore 8mm and would not recommend pulse generator is problematic.


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[JDP530]

I have had magnacore 8mm and would not recommend pulse generator is problematic.
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Did you have BMW sensors or aftermarket on the Magnacore wires? If you did have oem sensors I am wondering if wire insulation created a problem preventing sensors from working correctly. I have not had any luck with two or three different brands of aftermarket CIS sensors.

[ChrisFuture8]

After I got my car, I upgraded to a brand new set of 8mm Magnacore wires due to a complete noob mistake of pulling the connector lead off one of the spark plug wires.
Months later and I was on a trip down to southern California. The car ran like crap and I couldn't understand why. I first thought it was the fuel system cleaner additive that I poured into the tank before the trip. I used the gas pedal generously to burn enough fuel where I could add fresh fuel. That didn't help obviously. By the time I got to the destination, the sun had set. I opened the hood to check while the car was parked and engine running. I saw electricity arcing across the spark plug leads. Apparently, I didn't separate each lead far away enough and the electricity arc'ed over leads that were less than 1/2" apart. Who would have known if I didn't check under the hood when it was dark out!

[rosakirk12]

Did you have BMW sensors or aftermarket on the Magnacore wires? If you did have oem sensors I am wondering if wire insulation created a problem preventing sensors from working correctly. I have not had any luck with two or three different brands of aftermarket CIS sensors.

Sensor that came with the Magnacores. I suspect OE coupled with larger lead was getting weak signal.


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[JDP530]

After I got my car, I upgraded to a brand new set of 8mm Magnacore wires due to a complete noob mistake of pulling the connector lead off one of the spark plug wires.
Months later and I was on a trip down to southern California. The car ran like crap and I couldn't understand why. I first thought it was the fuel system cleaner additive that I poured into the tank before the trip. I used the gas pedal generously to burn enough fuel where I could add fresh fuel. That didn't help obviously. By the time I got to the destination, the sun had set. I opened the hood to check while the car was parked and engine running. I saw electricity arcing across the spark plug leads. Apparently, I didn't separate each lead far away enough and the electricity arc'ed over leads that were less than 1/2" apart. Who would have known if I didn't check under the hood when it was dark out!

Its been suggested for years to keep sparkplug leads separated but as you know, the harness on the V12 is run through a plastic housing so the wires are bunched up together. So I am surprised this doesn't cause issues with shorts between wires.

Sensor that came with the Magnacores. I suspect OE coupled with larger lead was getting weak signal.
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I am running an aftermarket set of wires advertised that set includes the OEM sensors and you can see the BMW logo stamped on them. You might look closely at the sensors on your wires and see if in fact they are OEM sensors.